ASSESSMENT OF WOOD ENERGY OPPORTUNITIES WITHIN THE GLASGOW & CLYDE VALLEY AREA
A REPORT FOR
FORESTRY COMMISSION SCOTLAND SCOTTISH ENTERPRISE GCV GREEN NETWORK PARTNERSHIP
PREPARED BY
JOHN CLEGG CONSULTING LTD THE CAMPBELL PALMER PARTNERSHIP LTD AND
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ASSESSMENT OF WOOD ENERGY OPPORTUNITIES WITHIN THE GLASGOW & CLYDE VALLEY AREA A Report for
FORESTRY COMMISSION SCOTLAND SCOTTISH ENTERPRISE GCV GREEN NETWORK PARTNERSHIP REPORT CONTENTS Executive Summary 1.
Introduction ........................................................................................... 8
PART 1: ASSESSMENT OF PRESENT SITUATION 2.
Woodlands in Network Partners’ Areas ................................................... 10
3.
Potential Availability of Roundwood & Fuelwood...................................... 20
4.
Present Markets For, & Disposal Methods of, Biomass ............................. 26
5.
Environmental Benefits of Wood Fuelled Boilers ...................................... 33
6.
Part 1 Conclusions ................................................................................ 37
PART 2: DEVELOPMENT OPPORTUNITIES 7.
Potential Wood Fuelled Boiler Sites ........................................................ 40
8.
Key Operational Fuelwood Supply Chain Issues....................................... 43
9.
Strategic Fuelwood Supply Chain Development Options ........................... 47
10.
Part 2 Conclusions & Actions ................................................................. 52
ANNEX 1 : Data Sources & Currency of the National Inventory of Woods & Trees ANNEX 2 : Summary of Scottish Air Quality Objectives ANNEX 3 : Details of Potential Wood Fuelled Boiler Installations Identified
© JOHN CLEGG CONSULTING LTD 1 Ravelston House Loan Edinburgh EH4 3LY Tel : 0131 343 6821 Fax : 0131 343 6823 Email : consult@johncleggconsulting.co.uk © THE CAMPBELL PALMER PARTNERSHIP LTD Lennoxtown Enterprise Centre 12 Railway Court Lennoxtown Glasgow G66 7LL Tel : 01360 312000 Fax: 01360 312750 Email : consultants@campbellpalmer.com
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CONVERSION FACTORS Hardwoods 1 green tonne = 50% MC on a wet weight basis 1 green tonne has a calorific value of 2,179 KWh / tonne 1 tonne at 30% MC has a calorific value of 3,332 KWh / tonne 1 green tonne has the same calorific value as 656 Kg at 30% MC Softwoods 1 green tonne = 65% MC on a wet weight basis 1 green tonne has a calorific value of 1,374 KWh / tonne 1 tonne at 30% MC has a calorific value of 3,421 KWh / tonne 1 green tonne has the same calorific value as 402 Kg at 30% MC
ABBREVIATIONS m3
Cubic metres
FOL
Free on Lorry
G & CV
Glasgow & Clyde Valley
GHG
Greenhouse gases
GIS
Geographic Information System
g tonnes
Green tonnes. Equivalent to 50% MC on a wet weight basis
ha
Hectares
kWh
Kilowatt hours
MC
Moisture content
NIWT
National Inventory of Woodlands & Trees
SRW
Small roundwood
TPO
Tree Preservation Order
Note that MCs are expressed on a wet weight basis throughout this report. Boiler Specifications and Fuel Moisture Content A fuel MC of 30% has been used throughout section 7 and annex 2 of this report to enable the direct comparison of woodfuel quantities at different sites. In reality, there is likely to be a range of values of MC for fuel supplied to different sites. It is important to note that although the bulk density of woodchip fuel increases non-linearly with increasing MC, the storage volume required increases by only a few percent over the entire range of MCs likely to be experienced. For example, for both softwoods and hardwoods, 650 tonnes of fuel at 30% MC becomes almost 1,000 tonnes at 50% MC for the same JOHN CLEGG CONSULTING LTD
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energy content. However, it should be noted that paying £50 per tonne for woodchip at 30% MC is equivalent to paying £33 per tonne for woodchip at 50% MC, i.e. to achieve the same energy cost per kWh. It is important to bear this in mind when negotiating fuel contracts, and to use a suitable fuel price calculator to carry out the necessary comparisons. All woodchip boilers can accept fuel with a range of MCs, this range being typically ± 10% on the nominal MC specification for the boiler. For all of the boilers detailed in this report, unless otherwise specified, it is recommended that the design MC for the boilers should be 40% enabling boilers to handle fuel between 30% and 50% MC.
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ASSESSMENT OF WOOD ENERGY OPPORTUNITIES WITHIN THE GLASGOW & CLYDE VALLEY AREA EXECUTIVE SUMMARY 1. The overall aim of the Glasgow & Clyde Valley Green Network Partners’ Programme is to develop a network of high quality Greenspace sites across the metropolitan area delivering a range of social, economic and environmental benefits; woodlands occupy about 13% of this area. The sustainable management of these woodlands involves costs and the Glasgow and Clyde Valley Green Network Partners, comprising 8 Councils, Forestry Commission Scotland and Scottish Enterprise, are looking amongst other things for ways to reduce them or generate additional income to meet those costs. One potential way of doing this is to sell woody biomass arising from woodland management operations to the rapidly emerging wood energy sector, as well as other markets which may have a high paying capacity. The Partnership appointed a team led by John Clegg Consulting to assess the opportunities and the results are presented in two parts in this report. PART 1 ASSESSMENT OF THE PRESENT SITUATION 2. There is no accurate information on the area and composition of the woods in the Green Network. Based on information prepared by the GeoInformation Group in 2005, and data taken from the Forestry Commission’s National Inventory of Woodland & Trees, it is estimated that there are approximately 4,746 hectares of established woods in the Green Network. The total area of established woods within the Green Network within each of the Council’s boundaries varies from 169 hectares for Inverclyde to 1,504 hectares for South Lanarkshire Council. There are an estimated further 1,614 hectares that comprise young trees, shrub or are felled areas or ground ready for planting. The average size of all the woods is very small and is approximately 1 hectare. The largest wood is estimated to be approximately 89 hectares. Based on a survey of the woods in Glasgow City undertaken in 2004, about 64% of the woods in the Green Network might be in Council ownership and the rest could be in a range of different ownerships. The total area of all woods within the Council Partner boundaries is estimated to be 53,274 hectares and of this total 25,333 ha comprise young trees, shrubs, felled areas and land being prepared for planting. 3. The objectives of owners are critical in determining how woodlands are managed. Council owned woods are primarily managed to deliver biodiversity and maintain the landscape as well as to provide recreational and educational opportunities for the public. None of the woods is managed on a purely commercial basis and this is likely to be the same for woods in other ownerships. The quality of most of the trees is generally poor as a result of a lack of past management. 4. Potential production of fuelwood will only occur intermittently, and from very small woods, as a result of other woodland management activities. Based on volume estimates from an assessment of Glasgow’s woodlands in 2004 it is estimated that the sustainable production of woody biomass from cleaning and thinning operations is approximately 4 m3 per ha per annum. Based on this assumption, it is estimated that the sustainable volume of wood fuel from the woods in the Green Network is 11,960 m3 per annum (7,846 tonnes @ 30% MC). Its availability will depend on other woodland management activities being undertaken. The estimated potential from the woods within the boundaries of all 8 Council’s is 70,411 m3 per annum (46,190 tonnes @30% MC). The latter total is sufficient to supply all the wood fuelled boilers likely to be installed in the foreseeable future. Other additional sources of potentially available woody biomass to supply wood fuelled boilers are from the maintenance of trees along streets, in school grounds and cemeteries, from recycled wood and from wood fuel supply companies located outside metropolitan Glasgow. 5. There are very important environmental benefits from installing wood fuelled boilers linked to climate change and the need to reduce carbon emissions in the most cost effective manner and to reduce the use of non – renewable fuel sources. The UK and Scottish Governments have ambitious policies for reducing carbon emissions and the fuel costs of wood fired boilers are almost half those of oil and gas fuelled boilers. Wood fuel also provides greater security of supplies as the UK becomes more dependent again on overseas fuel supplies. 6. The emissions from biomass boilers may bring certain particulates and gas emissions above the levels permitted under the Clean Air Act, particularly in central locations in urban areas. This is important and can usually be prevented by initially installing the correct type of boiler and emissions abatement equipment and operating it according to the manufacturer's instructions. In certain central locations where the emissions are already close to permitted limits, it may be necessary to JOHN CLEGG CONSULTING LTD
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model dispersions to check emissions before proceeding. Overall the particulates and gas emissions from correctly installed and operated biomass boilers incorporating emissions abatement equipment will in many cases be only slightly worse than those from gas boilers and much better than those for coal or oil boilers. 7. There are seven wood fuelled boilers already installed in metropolitan Glasgow and three further boilers have had grants recently approved to assist with the cost of installing them. Prices for wood chips generally range from £46 to £65 per tonne delivered at a MC of between 30% and 40%. Other markets that exist for logs and green woody biomass are: mulch / compost, firewood, sawlogs / wood turning, and animal bedding. There is also a rapidly developing market for wood chips outside metropolitan Glasgow because of the new wood fuelled electricity generating station at Lockerbie and the power plant at Caledonian Paper at Irvine in Ayrshire. Some material is chipped and left on site and some goes to recycling operators who can charge a gate fee of between £25 and £37 per tonne and also landfill tax where appropriate. 8. Only opportunities for using wood chips as a boiler fuel have been looked at in this study and a total of twelve potential wood boiler installations have been identified ranging in size from 50kW to 1.5kW. These opportunities have been looked at and assessed in detail along with another boiler that requires a supply of wood chips. The combined size of all the boilers would be 7,630kW and the indicative capital cost of installing them is estimated to be £3.2 to £3.6 million. The annual saving in fuel costs is estimated to be about £339,000 at present price levels. The estimated amount of carbon saved would be just over 3,500 tonnes. The installation of these boilers would increase the market for wood fuel in metropolitan Glasgow by about 9,000 tonnes per annum at 30% MC. Given present woodland management objectives, this is slightly more than is potentially available from woodlands, but there is more than sufficient green woody biomass potentially available from arboricultural and site clearance activities and from sources outside metropolitan Glasgow. 9. The key operational fuelwood supply issues are identified of which the most important is wood chip quality. Other issues covered are the storage options for woody biomass, the storage of chips in silos, fuelwood harvesting equipment, transport and aggregator sites, wood chipping and chipping equipment and wood supply contracts. 10. Three options for the strategic development of the fuelwood supply chain in metropolitan Glasgow are identified. Option 1 is to continue present support activities and wait for the private sector to develop the supply chain. The second option is accelerate the development of the fuelwood supply chain by continuing existing activities and by identifying a number of small local sites where woody biomass can be collected together before being taken to large sites where the material can be stored and dried before being chipped and transported to boilers. The sites could be operated by the Councils or by the private sector. Initially the use of the site would be free but as the market develops it may be possible to pay for the material. The third option could be adopted on its own or with one or both of the other two options. This would involve setting up a dedicated wood fuel supply chain/s linked to specific woods and one or more boilers using heat contracts. This would require accurate information on woody biomass quantities potentially available in each wood, investment in harvesting, transport, storage and chipping equipment and very clear organisational and managerial arrangements. It also involves risks for either Councils or the private sector operator/s. 11. The Green Network Partnership is in a strong position to assist in encouraging the development of wood fuel supply chains in metropolitan Glasgow and the installation of wood fuelled boilers over the next 3 years because : •
It will allow the scale of activities to be increased much more quickly than would otherwise be possible because it will have a strategic oversight of all activities in metropolitan Glasgow.
•
It will allow the development of the wood fuel market and the more sustainable management of woodlands to proceed more quickly than would otherwise be possible through supplying information and knowledge.
•
It is well positioned to encourage the development of the highest possible standards in the management of woodlands and the wood fuel supply chain, as well as in the installation of the most appropriate wood fuel boilers, at a time when knowledge is still relatively limited.
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Its assistance in the development of a new market has the potential to improve the financial income of woodland owners in metropolitan Glasgow and this in turn should allow the citizens of Glasgow to realise greater public benefits from woodlands through more sustainable woodland management. A further benefit though small in a global context will be the saving in the use of non-renewable fossil fuels and, in the longer term, the contribution to reducing global warming.
These are significant opportunities for the Green Network Partners to deliver small but locally significant environmental benefits.
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1. INTRODUCTION 1.1. The Glasgow and Clyde Valley Green Network arose from work done at the regional level by the Glasgow Metropolitan Community Planning Partnership. The Green Network Vision is:
“A partnership working to develop and sustain a high quality Green Network across the Glasgow and Clyde Valley metropolitan region, transforming the environment to improve the region’s competitiveness for investment, enhance quality of life, promote biodiversity and the sustainable use of natural resources, and encourage more healthy lifestyles”. This vision is supported by the Glasgow and Clyde Valley Joint Structure Plan which provides a co-ordinated approach to infrastructure development across the Glasgow metropolitan area. 1.2. The Green Network area is shown on map 1.1 on the next page. This area has the potential to deliver tangible, practical long term improvements to the quality of life for over 35% of Scotland’s total population and direct benefits to 1.8 million people living in west central Scotland. 1.3. The overall aim of the Glasgow & Clyde Valley Green Network Partners’ Programme is to develop a network of high quality Greenspace sites across the metropolitan area delivering a range of social, economic and environmental benefits. Woodlands occupy about 13% of this area and their sustainable management will, for example, help create jobs and make a contribution to climate change, but it will involve costs, and the Glasgow and Clyde Valley Green Network Partners are looking for ways to reduce costs or generate additional income to meet those costs. One potential way of doing this is to sell woody biomass arising from woodland management operations to the rapidly emerging wood energy sector, as well as other markets which may have a high paying capacity. ASSIGNMENT AIM 1.4. The Partnership, along with Scottish Enterprise and Forestry Commission Scotland, commissioned this study whose purpose was given in the Brief as being to:
Explore. assess and evaluate opportunities for developing the wood energy sector within the Glasgow and Clyde Valley area. The study was also required to consider both supply and demand issues to establish the nature and scale of public intervention that would be required in order to address issues of market failure and encourage the development of a stable and viable wood energy sector across the region. This report sets out the study’s findings. ACKNOWLEDGEMENTS 1.5. The assignment team would like to thank and acknowledge the numerous people we have consulted while undertaking the study, and for the very helpful information and advice they have all given us. We would especially like to thank the Steering Group comprising Penny Cousins of the Glasgow & Clyde Valley Green Network Partnership Programme, Trevor Blackburn of Forestry Commission Scotland and Euan Dobson of Scottish Enterprise for their support and helpful comments throughout the duration of the assignment.
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Map 1.1 The Location of the Glasgow & Clyde Valley Green Network
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2. WOODLANDS IN NETWORK PARTNERS’ AREAS 2.1. This section looks at: the sources of information on the woodlands in the Glasgow & Clyde Valley Green Network and the accuracy of that information; the best estimates of the area and numbers of woods in the Glasgow & Clyde Valley Green Network in total and within each Council area; and then the area of woodlands in all ownerships within each Council area. SOURCES OF INFORMATION ON WOODLANDS 2.2. There is no accurate information on the total area of woodlands in the Glasgow & Clyde Valley Green Network or on the individual woods within the Network. 2.3. In 2005 the GeoInformation Group Ltd mapped all the Greenspace with the Glasgow & Clyde Valley Green Network on behalf of the Glasgow & Clyde Valley Structure Plan Joint Committee with Scottish Natural Heritage and Forestry Commission Scotland as partners. The source of the information was aerial photos supplied by the Forestry Commission. The Company were not sure of the date when the aerial photos were taken but they believe it to be 1999 or 2000. The imagery was extracted from their national coverage by Getmapping Plc. The classification of all open space areas incorporated PAN 65 Open Space Typology. This meant open space was initially classified into one of the following 8 categories: • Public parks & gardens
• Sports areas
• Private gardens or grounds
• Green corridors
• Amenity greenspace
• Natural/semi-natural greenspace
• Playspace for children & teenagers
• Other functional greenspace
Where an area was classified as natural / semi- natural greenspace it was then further sub-classified as being woodland, open semi-natural or open water. AREA OF WOODLANDS IN THE G & CV GREEN NETWORK 2.4. The woodland area in the Glasgow & Clyde Valley Green Network, based on an analysis of the GeoInformation GIS, is given in table 2.1. Table 2.1 Estimated Area of Woodlands in the Glasgow & Clyde Valley Green Network by Council Area using GeoInformation Group GIS data Woodland Type
No of Woods
Coniferous Woodlands Coniferous - Other Coniferous / Non Coniferous Coniferous / Non Cofierous - Other Non coniferous Non - coniferous - other Total
204 29 383 275 709 1,016 2,616
Total Area of Woods Av Area of Woods ha¹ ha 211.8 1.0 25.3 0.9 382.9 1.0 350.7 1.3 605.3 0.9 982.5 1.0 2,558.5 1.0
2.5. The GeoInformation Group data indicates that there are 2,616 woods covering 2,558.5 hectares in the Glasgow & Clyde Valley Green Network area. We think that these figures are likely to be a significant underestimate because the classification methodology adopted means that all woods and small groups of trees in any one of the land use categories elsewhere in the Greenspace Network were not counted. As there are significant areas of trees that will been in categories identified as public parks and gardens, private gardens and grounds, sports areas, green corridors and other functional greenspaces, these areas will have been omitted from the totals in table 2.1.
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2.6. To improve the accuracy of the estimate for the area of woodland in the Green Network area, it was decided to combine the GeoInformation Group’s GIS data with the Forestry Commission’s GIS data from the National Inventory for Woodlands & Trees (NIWT) which was published in 2003. The NIWT recorded all woodland areas that were 2 hectares or more in size, as well as small woods, groups of trees, linear features and individual trees. The data sources and currency of the NIWT data are given in annex 1 to this report. The two combined datasets are considered to give the best available estimate of the woodland area in the Glasgow & Clyde Valley Green Network. 2.7. Combining the two datasets proved technically challenging as the GeoInformation dataset contained a significant number of polygons. Map 2.1 on the next page shows the location of all the woods identified by both datasets. The scale has to be very small to be shown in this report, but a large scale map has been supplied under separate cover to the Manager of the Green Network Partnership. 2.8. An analysis of the woodland area in the Green Network area, and within individual Council areas, using the combined datasets is given in table 2.2. The table shows that the combined datasets indicate a total area of well established trees in the Green Network area of 4,746 hectares. This is 85% greater than the estimate based on the GeoInformation data given in table 2.1. In addition there is an estimated further 1,614 hectares comprising young trees, shrubs, felled areas or land being prepared for planting. This significantly larger estimate of the woodland area in the Green Network area is likely to be more accurate because it should include most woodland, but it should not be taken to be a totally accurate figure as both datasets on which the estimate is based have some limitations. SIZE OF WOODLANDS IN THE G & CV AREA 2.9. An indication of the average size of woods in the G & CV can be obtained from the GeoInformation data provided in table 2.1. This shows that the size of individual woods is, on average, approximately 1 ha. This has important implications when considering the potential of the woodlands in the Glasgow & Clyde Valley Green Network area to provide a sustainable source of woodfuel and the reasoning for this is explained later in this report. 2.10. The combined datasets for the Glasgow & Clyde Valley Green Network area have also been analysed to identify the 5 largest woods in each Council area. Map 2.2 shows their locations in the Green Network area. More detailed information about the individual areas is given in table 2.3. In some cases the two datasets indicated different types of woodland cover for the same area and, where there were differences, the classification adopted was that used in the Forestry Commission’s NIWT.
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Map 2.1 Location of Woods in the Glasgow & Clyde Valley Green Network Area
Source: The GeoInformation Group (2005) and the Forestry Commission’s National Inventory of Woods & Trees (2003).
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Table 2.2. Estimated Area of Woodland in hectares in the Glasgow & Clyde Valley Green Network Area by Council Area
Woodland Species Composition Broadleaved Coniferous Mixed 155 40 383 City of Glasgow East Dunbartonshire 77 20 260 East Renfrewshire 37 8 127 Inverclyde 50 22 97 North Lanarkshire 291 125 839 Renfrewshire 124 59 311 South Lanarkshire 435 258 811 West Dunbartonshire 66 4 147 Total 1,235 536 2,975 Council
Total 578 357 172 169 1,255 494 1,504 217 4,746
Young trees 160 42 0 20 482 59 161 11 935
Other Woodland Shrub Felled Ground Prep 178 0 0 30 0 0 33 0 0 3 0 0 109 28 0 167 0 0 101 5 9 16 0 0 637 33 9
Total 338 72 33 23 619 226 276 27 1,614
Grand Total 916 429 205 192 1,874 720 1,780 244 6,360
Source: The GeoInformation Group, 2005 and the Forestry Commission’s National Inventory of Woodland and Trees, 2003.
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Map 2.2 Location of Five Largest Woods in each Council Area in the Glasgow & Clyde Valley Green Network Area
Source: The GeoInformation Group (2005) and the Forestry Commission’s National Inventory of Woods & Trees (2003).
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Table 2.3 Details of the Five Largest Areas Classified as Woodlands in the Glasgow & Clyde Valley Green Network Area Council Glasgow City
Total East Dunbartonshire
Total East Renfrewshire
Total Inverclyde
Total
Area (ha) Species 72.3 Shrub 29.5 Shrub 19.9 Shrub 17.1 Broadleaves 16.5 Mixed Species 155.3 37.7 Mixed Species 31.6 Mixed Species 14.6 Mixed Species 11.0 Mixed Species 9.8 Young trees 104.7 29.3 Shrub 19.4 Mixed Species 11.6 Mixed Species 9.2 Mixed Species 6.0 Mixed Species 75.5 13.4 Mixed Species 12.6 Mixed Species 5.7 Mixed Species 5.7 Mixed Species 5.0 Young trees 42.4
Council North Lanarkshire
Renfrewshire
South Lanarkshire
West Dunbartonshire
Area (ha) 37.6 33.3 30.4 29.7 26.0 157.0 57.4 23.4 21.4 20.7 20.5 143.4 89.3 43.7 40.2 32.2 30.1 235.5 14.0 12.0 8.4 7.7 7.0 49.1
Species Young trees Young trees Young trees Young trees Young trees Shrub Conifers Mixed Species Shrub Shrub Conifers Mixed Species Mixed Species Mixed Species Broadleaves Shrub Mixed Mixed Mixed Mixed
Species Species Species Species
2.11. The largest single area of woodland in the Glasgow & Clyde Valley Green Network area, based on the data available to us, is the 89.3 hectares of coniferous woodland in South Lanarkshire. The size of a wood is very important in influencing the economics of woodland management because of the economies of scale in operational activity costs that can be potentially achieved. However, an owners’ objectives for owning and managing a wood are of over-riding significance and this is considered further in Section 3. 2.12. An indication of the likely size distribution of the woodlands in the Green Network area can be gauged from the results of the survey of Glasgow City’s woodlands undertaken by John Clegg & Co et al 1 in 2004 the results of which are shown in diagram 2.1. This area is equivalent to approximately 12% of the Glasgow & Clyde Valley Green Network area.
1
John Clegg & Co, Bentleys, Cawdor Forestry, John Clegg Consulting Ltd & Yellow Brick Road, 2004. Glasgow City’s Woodlands: The Resource & Its Future Management.
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Diagram 2.1 Size Distribution of Glasgow City’s Woodlands which Provides an Indicative Sample of the Woodland Size Distribution in the Glasgow & Clyde Valley Green Network Area
500 450 400 350 300 Number/Area (ha) 250 200 150 100 50 0 Total Area (ha)
(0-1.0)ha
Number of Areas Total Area (ha)
(1.1-2.5)ha
(2.5-5.0)ha
(5.1-10.0)ha
Number of Areas (10.1-50.0)ha
(50+)ha
(0-1.0)ha
(1.1-2.5)ha
(2.5-5.0)ha
(5.1-10.0)ha
(10.1-50.0)ha
308
139
51
58
26
(50+)ha 2
142.7
237.5
186.6
427.7
455.0
147.1
2.13. The results in the diagram confirm that there are a large number of very small woods and a few slightly larger ones. OWNERSHIP OF WOODLANDS IN THE C & CV AREA 2.14. There is no source of information on the ownership of woods in the Glasgow & Clyde Valley Green Network area, but John Clegg & Co et al undertook a detailed survey of all Glasgow City woodlands in excess of 0.2 ha and 15% of all woods under 0.2 ha in 2004. During the survey every attempt was made to identify the ownership of the woodlands. The results are shown in Diagram 2.2. Diagram 2.2 Principal Owners or Types of Woodland Owners in the Public & Private Sectors in Glasgow City Providing an Indicative Sample of Woodland Ownership in the G & CV Water Establishment <0%
Unknown SEG
Wise Group 1%
10%
Conservation Group 1%
1% Rail <0%
Education Establishment Scottish Executive
<0%
8%
Residents <0% Private - farmer/estate 2% Private - devlpr/comm. 7%
GCC
Misc
64%
4% Health 1%
Greenbelt Co. 1%
Conservation Group
Education Establishment
GCC
Greenbelt Co.
Health
Misc
Private - devlpr/comm.
Private - farmer/estate
Rail
Residents
Scottish Executive
SEG
Unknown
Water Establishment
Wise Group
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2.15. The diagram shows that 64% of the woodlands are owned by the City Council and the rest are in a wide variety of different ownerships. We feel that this detailed analysis of the ownership of woodlands in Glasgow City, which is equivalent to approximately 12% of the Glasgow & Clyde Valley Green Network area, is likely to be representative of the range of woodland ownership categories in six of the Council areas in the Glasgow & Clyde Valley Green Network. The two Council areas that are exceptions are North and South Lanarkshire as they have much larger woodland areas within their boundaries, and ownership in these two Council areas includes Forestry Commission Scotland and private estates which have no significant holdings in Glasgow City. The ownership and average size of woodlands have important implications for the how the woods are managed, how actively this is done and the degree of support which they might be able to give in establishing a wood fuel market, or in becoming part of a dedicated wood fuel supply operation. AREA OF ALL WOODLANDS IN EACH COUNCIL AREA 2.16. The two combined datasets have been used to estimate the total area of all woodlands in each Council area, including the Glasgow & Clyde Valley Green Network area. Map 2.3 shows their distribution but the scale is of necessity very small in order to include the map in the report, but it shows that in the urban areas the woods are almost all very small, but further out, in the more rural areas, some Councils have much larger areas of woods within their boundaries. An analysis of the woodland area within each Councilâ&#x20AC;&#x2122;s boundaries is given in table 2.4 and shows that North and South Lanarkshire Councils have the largest woodland areas within their boundaries. 2.17. North Lanarkshire Council has 13 larger woodlands that it owns, covering approximately 660 hectares, and woodland management plans have been, or are being, drawn up for them all. Eleven of the woods comprise mixed broadleaves and two are coniferous. The broadleaved woodlands are predominantly policy woods and the others contain mostly mature and semi-mature trees and all are being managed mainly with the aims of delivering biodiversity, landscape and public recreational use. The coniferous woods are in need of thinning. 2.18. South Lanarkshire Council owns about 800 ha of woodland which comprises 4 main blocks and about 200 or more small woods. The Councilâ&#x20AC;&#x2122;s priorities for these woods are to provide biodiversity and maintain the landscape as well as giving public access for recreation. About 300 ha of the woods have reasonable access of which about 200 hectares are in Chatelherault Country Park, the remaining 100 ha being in the Clyde Valley. Of the 300 ha of woodland with reasonable access about 100 ha are conifers and the Council would like to fell these woods over a period of 20 to 30 years and replace them with broadleaves. There are a further 60 to 70 ha of woodland in a narrow band at East Kilbride. 2.19. The estimated 28,000 hectares of woodlands within the boundaries of Councils comprising metropolitan Glasgow is a substantial area and most of the woodlands are managed at present to meet objectives other than supplying wood fuel. Changes in woodland management objectives by a wide variety of owners, and higher prices, will be needed before substantial quantities of wood fuel could potentially become available to the market.
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Map 2.3 Location of Woods in Each Council Area including the Glasgow & Clyde Valley Green Network Area
Source: The GeoInformation Group (2005) and the Forestry Commission’s National Inventory of Woods & Trees (2003).
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Table 2.4 Estimated Area of Woodland in Each Council’s Area in hectares
Woodland Species Composition Broadleaved Coniferous Mixed 269 51 597 City of Glasgow East Dunbartonshire 233 387 717 East Renfrewshire 116 187 336 Inverclyde 220 774 465 North Lanarkshire 804 2,151 1,819 Renfrewshire 324 586 890 South Lanarkshire 1,074 11,966 2,285 West Dunbartonshire 472 285 933 Total 3,512 16,387 8,042 Council
Total 917 1,337 639 1,459 4,774 1,800 15,325 1,690 27,941
Young trees 264 680 578 91 3,038 474 9,291 1,436 15,852
Other Woodland Shrub Felled Ground Prep 202 9 0 56 23 0 40 0 763 33 15 203 236 234 127 282 37 8 434 527 6,145 18 89 0 1,301 934 7,246
Total 475 759 1,381 342 3,635 801 16,397 1,543 25,333
Grand Total 1,392 2,096 2,020 1,801 8,409 2,601 31,722 3,233 53,274
Source: The GeoInformation Group, 2005 and the Forestry Commission’s National Inventory of Woodland and Trees, 2003.
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3. POTENTIAL AVAILABILITY OF ROUNDWOOD & FUELWOOD 3.1. This section considers the influence of woodland ownersâ&#x20AC;&#x2122; objectives on the management of woodlands and the potential availability of logs and woody material (hereafter called roundwood); the potential quality of roundwood and its geographical distribution; a basis for estimating fuelwood availability from woods in the Glasgow & Clyde Valley Green Network area and then using this to indicate the potential availability of fuelwood. The section finishes by considering the alternative sources of fuelwood supply that are potentially available for wood fuelled boilers. WOODLAND MANAGEMENT OBJECTIVES 3.2. The objectives of the owner of a wood are critical in determining how it is managed. In many cases an owner may have more than one objective, and then the management of the wood depends on balancing the delivery of the various objectives. Most owners, particularly of larger woods, are seeking to meet the UK Woodland Assurance Scheme standards for delivering sustainable woodland management since roundwood from such woods tends to be much more acceptable ultimately to end use markets and therefore tends to fetch higher prices. 3.3. Our enquiries have indicated that where Councils own woodlands, their objectives are to deliver biodiversity and maintain the landscape as well as to provide recreation opportunities for the public. The particular priority will tend to vary with the individual woodland. In many cases the woodlands are covered by conservation and planning designations as well as TPOs. Financial returns from woodland management tend to be of much lesser concern to Councils than meeting other objectives and, to our knowledge, none of the Councils is seeking to manage their woods only on a strictly commercial basis to maximise their financial return. In our experience woodland owners, other than Councils, have a very diverse range of objectives in owning woods, such as screening, hope value in the land underlying the trees, biodiversity, cost minimisation, privacy, preventing development by others, but very few own woods in urban areas to produce returns from commercial roundwood production. It is of course possible for an ownerâ&#x20AC;&#x2122;s objectives to change and this will alter the way a wood is managed. 3.4. The management and maintenance of these woodlands, which is almost always undertaken by contractors for their owners, including Councils, costs the Councils and other woodland owners, money. Owners therefore normally tend to maximise the financial returns they get from the sale of any roundwood that arises from management and maintenance operations in order to help off-set costs, or in the case of Councils deliver value for money. Where harvesting and cleaning work is contracted out, the income from any sales made by contractors tends to be netted off against costs. When a new market for roundwood develops which provides greater income than previously, there may well be some scope to take out more roundwood than previously in order to help meet woodland ownership costs. The development of the fuelwood market in the last 3 years or so is one such opportunity. TREE GROWTH RATES, ROUNDWOOD QUALITY & GEOGRAPHICAL DISTRIBUTION 3.5. The majority of the woodlands in the Glasgow & Clyde Valley Green Network area mostly comprise a mixture of semi-mature and mature broadleaved species. We think that the average growth rate probably equates to a Yield Class of about 4 or possibly 6 on better sites. If the woods had been, and were being, managed solely on a commercial basis and conventional forestry practice spacing, and the aim was to maximise roundwood production for commercial timber production, this would suggest that they might yield theoretically a maximum of about 14 to 21 m3 of roundwood per hectare every 5 years on a sustainable basis. These woodlands have not, and are not being managed on that basis but the figures indicate a theoretical potential roundwood production if the woods were being managed solely to maximise income through growing sawlogs. If the woodlands were managed solely to maximise the production of fuelwood, then the species and stocking and management would be very different to what is happening at present and production of fuelwood could be considerably higher depending on what species was planted and what the initial spacing was. 3.6. The majority of urban woodlands have suffered from a lack of management over many years and mostly the objective of management was not to produce commercial timber directly. Consequently many of the trees are of poor quality and are unsuitable as sawlogs. Once the market for mining timber disappeared there was little use for most of the material other than for firewood, but even that was problematic as smokeless zones came in which discouraged the use of open fires. Some trees are of JOHN CLEGG CONSULTING LTD
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good quality and will, therefore, be suitable as sawlogs; as a result they can potentially provide an important source of income. 3.7. In practice many owners, such as the Councils, will only want to undertake light thinning operations from time to time in order to meet their other key woodland management objectives. More recently, Councils have undertaken, and are undertaking, management activities in a number of their larger woods after getting financial support through Forestry Commission Scotland’s “Woodland In & Around Towns” (WIAT) scheme after preparing detailed management plans. One exception, noted above, is South Lanarkshire Council which has plans to convert their coniferous woodlands back to broadleaves over a period of 20 to 30 years. 3.8. A further significant point is that the woodlands are predominantly small and cover a wide geographical area as the information in Section 2 has shown. Roundwood that comes from an individual wood usually only arises intermittently from a thinning. Hence, to provide continuity of roundwood to service a dedicated contractual supply to a specific wood fuelled boiler will require roundwood supplies to be collected together from a number of geographically distributed small woods. BASIS FOR ESTIMATING ROUNDWOOD AVAILABILITY 3.9. The enormous diversity of the woods in the Glasgow & Clyde Valley Green Network area, and in the rest of the woodland areas within Council boundaries in terms of species, quality, age, growth rates, ownership and amount of woodland management, means that it is very difficult to estimate the potential sustainable availability of roundwood, and especially fuelwood. 3.10. When John Clegg & Co et al undertook their survey of the woodlands within the Glasgow City boundary in 2004, they were asked to provide an estimate of the potential production of harvestable material when they visited each wood. They found that 35% of the woods were young, 35% needed no management, and vehicle access was a problem in 16% of them. Taking into account that the objectives of most owners were environmental or social and not commercial, their estimates of the amount of utilisable material from the woods visited within the City boundary over the next 10 years, predominantly from thinning and cleaning operations, but also from small areas of felling, are given in table 3.1. Table 3.1 Estimated Volume of Utilisable Wood from Glasgow City Woodlands over the Next 10 years. Operation 0 - 5 years Clean Thin Fell ² Total 5 – 10 years Clean Thin Fell ² Totals
Area ha
Cleaning Volume m3
297 154 14.5 465.5
7,425
447 128 3.5 578.5
11,175
Firewood SRW Volume Volume ¹ m3
m3
Conifer Logs Volume m3
1,640
280
480
Hardwood Logs Volume m3
915
Total m3 7,425 3,315 10,740
1,025
390
190
460
11,175 2,065 13,240
Source: John Clegg & Co et al, 2004. Footnote 1: SRW : Small roundwood suitable for use by the panel. pulp and paper industry. 2: Felling operations will take the form of group fellings and will be combined with thinning operations. The estimated volumes of utilisable material that could be realised are included with the thinning volumes in the table.
3.11. Table 3.2 provides an estimate of the average potential volume of roundwood that might be available annually per hectare as wood fuel, based on the information in table 3.1. For the purposes of estimating the potential quantities of fuelwood available, the quantities identified as firewood in table 3.1 JOHN CLEGG CONSULTING LTD
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have been combined with the estimated quantity of roundwood from cleaning operations. This material comprises small and misshapen trees that do not form the main trees that make up the canopy of the wood as well as trees that impede access or over hang the boundary; whether this material becomes available in practice will depend on the relative prices of the two products. Table 3.2 Estimated Sustainable Annual Volume of Predominantly Broadleaved Fuelwood from Woodlands within the Boundary of Glasgow City based on Data in Table 3.1 Years 0 to 5 Estimated Area of Woods Producing Potential Fuelwood
465.5 ha
Estimated volume suitable as wood fuel over 5 years
9,065 m3
Estimated annual volume suitable as wood fuel
1,813 m3
Estimated annual volume of wood fuel per hectare
3.9 m3
Years 5 to 10 Estimated Area of Woods Producing Potential Fuelwood
578.5 ha
Estimated volume suitable as wood fuel over 5 years
12,200 m3
Estimated annual volume suitable as wood fuel
2,440 m3
Estimated annual volume of wood fuel per hectare
4.2 m3
3.12. These figures in table 3.1 for fuelwood availability are less than the 7,448 green tonnes of fuelwood at a 60% MC (8,275 m3 or 6.2 m3 /ha/annum) that S Luker & Associates Ltd estimated could be harvested annually from 1,330 ha of woods within the boundary of Glasgow City in their May 2007 study. Their estimate appears to have been based on Forestry Commission growth data for a planted wood that that is managed to maximise hardwood sawlog production and is thinned every 5 years. Their fuelwood estimates are for all the thinning volumes that could theoretically be obtained according to Forestry Commission yield tables. Allowance was then made for site based constraints and “amenity management” by reducing volumes by 20%. 3.13. The John Clegg & Co et al volume estimates were based on individually visiting 584 woods within the Glasgow City boundary covering 1,596.6 hectares in 2004. Their estimates were made by a Chartered Forester with over 20 years of forestry experience, including working as a harvesting forester with the Forestry Commission, and who also had a good knowledge of the hardwood trade. 3.14. We feel therefore consider that the John Clegg & Co et al estimates of the likely total fuelwood availability are more realistic for the woods within the Glasgow City boundary given the Council’s woodland management objectives at the present time. 3.15. The figures in table 3.2 indicate that the sustainable volume of fuelwood that is potentially available from the predominantly broadleaved woodlands within the Glasgow City boundary is an average of approximately 4 m3 per annum over a 10 year period, based on the present objectives of owners and broadly similar prices for roundwood in all the markets. The majority of this material is expected to come from cleaning operations. A useful check on this figure can be obtained from information provided by Glasgow City’s Woodland Unit (P Cookson pers com, 2007) based on thinning operations that are about to start in two compartments in the 79 ha woods at the Pollok Country Park. It is estimated that one compartment should produce 28 m3 per ha and the other 17.6 m3 per ha. The Woodland Unit (P. Cookson pers com, 2007) thinks, at this stage, it is unlikely that the woods will be thinned again for at least another 10 years. This suggests an average annual production of timber of 2.8 and 1.8 m3 per annum. These figures show the variability that can be expected and they are also likely to be some of the highest figures for roundwood production that can be obtained from woods in the Green Network as the woods are one of the Council’s most extensive areas of woodlands. The proportion of roundwood that might be suitable as sawlog material in these estimated unit volume figures from the thinning JOHN CLEGG CONSULTING LTD
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operation is not known, but it should be higher than average for the woods in the Green Network because the woods are part of the Park and should have been well managed. The John Clegg & Co et al estimate for the average fuelwood availability volume for all woods in the Green Network area therefore appears to be of the right order of magnitude and most of the material is expected to come from cleaning and thinning volumes from woods that are not likely to have been so well managed. 3.16. The woodlands within the Glasgow City boundary are equivalent to approximately 12% of the Glasgow & Clyde Valley Green Network area and it is, therefore, considered that the estimated average annual volumes of available fuelwood within the Glasgow City boundary of 4 m3 per ha per annum on a sustainable basis should be a very good representative sample of all the woods in the Glasgow & Clyde Valley Green Network area and for the rest of the woods within the Council areas. As this is an average figure it will mean that some woods may produce double this figure, or possibly even more, and others may produce very little, or nothing. It can also be expected that the Green Network woodlands may also produce a small quantity of sawlogs and a very small quantity of coniferous small roundwood (SRW) for panelboard production; there are already well established markets for both types of material. The majority of roundwood will come from cleaning and thinning operations and is expected to be of poor quality. No significant market exists for this material at present, but it is potentially suitable as fuelwood for the rapidly emerging wood energy market. 3.17. Given the present estimated growth rate of the broadleaved trees we think that this available volume is one that is sustainable. Dramatic changes in product prices, such as a rapid escalation in fuelwood prices, could result in woodland owners changing their objectives, but there is no indication of this happening at present. 3.18. Branches very roughly account for about 50% of the volume of a broadleaved tree and therefore the available quantities of fuelwood could average more than 4 m3 per hectare depending on the size of the branchwood that it is economical and environmentally worthwhile recovering. In the John Clegg et al survey it was assumed that the smaller branch material would be chipped on site and left. ESTIMATED SUSTAINABLE VOLUME OF FUELWOOD POTENTIALLY AVAILABLE FROM WOODS IN THE GREEN NETWORK & WITHIN COUNCIL BOUNDARIES 3.19. The estimates of potential annual fuelwood availability in table 3.2 have made allowance for 35% of the woods being young and not producing any material; vehicle access being a problem in 16% of the area, 35% of the woods not needing any management and 36% being in a wide variety of different ownerships other than the Councils. In extrapolating the data to the woods in the Green Network, and within Council boundaries, we have assumed that fuelwood will be potentially available from 70% of the woodland areas. 3.20. In converting from a standing volume to a weight basis a conversion factor of 1 m3 to 0.9 green tonnes has been used which is based on a Forestry Commission standard conversion factor. This then gives an average estimated annual fuelwood availability of 3.6 g(reen) tonnes per ha. 3.21. The estimated average annual sustainable fuelwood availability figure of 3.6 tonnes per hectare has been applied to the area of woodlands in the Green Network area and to all the woods within each Councilâ&#x20AC;&#x2122;s boundaries and the results are given in table 3.3.
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Table 3.3 Estimated Potential Annual Availability of Fuelwood from the Woods in the Glasgow & Clyde Valley Green Network Area & within Council Boundaries Council City of Glasgow East Dunbartonshire East Renfrewshire Inverclyde North Lanarkshire Renfrewshire South Lanarkshire West Dunbartonshire Total
GNP Est. Est. Wood Fuel Potential Availability Est. Total Est Wood Fuel Potential Availability Woodland Area Woodland Area ยน ha g tonnes tonnes @ 30% mc ha g tonnes tonnes @ 30% mc 578 1,457 956 917 2,311 1,516 357 900 590 1,337 3,369 2,210 172 433 284 639 1,610 1,056 169 426 279 1,459 3,677 2,412 1,255 3,163 2,075 4,774 12,030 7,892 494 1,245 817 1,800 4,536 2,976 1,504 3,790 2,486 15,325 38,619 25,334 217 547 359 1,690 4,259 2,794 4,746 11,960 7,846 27,941 70,411 46,190
Footnote ยน: There are in addition an estimated 25,333 hectares of young trees, shrub, felled areas and land being prepared for planting which have potential to produce some wood fuel in due course. In total there are an estimated 53,274 hectares of woodland in all ownerships within metropolitan Glasgow. For further details see Table 2.4.
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3.22. The conclusions that can be drawn from the table are that: • The woods in the Green Network area have a significant quantity of fuelwood that is sustainably available from them. They could generate a gross income from fuelwood sales of up to about £200,000 once the fuelwood market has developed; • The estimated quantities available fully take into account the present objectives of most woodland owners; • Additional quantities of fuelwood could be potentially available on a sustainable basis if it was economic to remove very small diameter stem material and small branchwood, or the balance in owners’ objectives changed so that some priority is given to meeting economic objectives; • There are very large quantities of fuelwood potentially available from woodlands within the boundaries of Councils that could be used to supplement supplies from woods in the Green Network if additional fuelwood is required from local woodlands to supply wood fuelled boilers in metropolitan Glasgow. 3.23. Some of this potentially available fuelwood is already being used, either directly or indirectly, as wood chips for wood fired boilers by the following three organisations in Glasgow: Caledonian Tree Services. This is a commercial organisation offering wet and dried wood chips. It is thought that this material may be produced from woody biomass arising from tree surgery work; Bullwood Project. This is a small wood turning & wood working charity; The Coach House Trust. This is a charity that also has its own wood fired boiler (see table 4.1). 3.24. The amounts being used at present are not known, but are thought likely to be very small relative to the potential supplies that are available. OTHER SOURCES OF WOOD FUEL IN METROPOLITAN GLASGOW 3.25. There are three other potential sources of fuelwood within metropolitan Glasgow and these are: • Biomass Wood Fibre from Sources Other Than Woodlands: The main sources of this material are from Council operations involving the maintenance of trees along streets, in school grounds and in cemeteries. A significant amount of material also comes from parks and other green spaces, but it has been assumed that the clumps of trees in these places will have been identified as woodlands and will have been included in the figures given in Section 2. Woody biomass also becomes available from tree maintenance activities in private gardens and also from site clearance work prior to building work. The latter will produce considerably more than 4 m3 per hectare because whole sites are being cleared. No figures are maintained on the quantity of material produced from these sources, but one recycling contractor “guestimated” that it might amount to about 10% of the 100,000 g tonnes of biomass produced annually from metropolitan Glasgow. Glasgow City Council recorded that they sent 613 g tonnes of timber to landfill in 8 months in 2006 (S. Luker, 2007) which is equivalent to 919 g tonnes per annum. Considerably more material could have been produced than was actually recorded, but a proportion of this material may also have come from tree maintenance work in parks which would constitute a degree of double counting. Additional material may be produced by tree surgeons operating in the private sector. If the activities within each of the 8 council areas in metropolitan Glasgow produced about 1,000 g tonnes per year of woody biomass then there may be about 8,000 g tonnes of additional woody biomass from tree work in addition to work done in woodlands. Allowing for additional material from the private sector, the amount of additional material that could be converted into chips to supply the wood fuel market could be about 10,000 g tonnes per year or 6,560 tonnes at 30% MC. This would be in addition to the potential availability of fuelwood from woodland management and maintenance activities. • Recycled Wood: The companies, such as William Tracey Ltd, Scottish Water Waste Services, Viridor Enviroscot and WRG, that have contracts with metropolitan Glasgow Councils to handle their waste are collecting and recycling waste wood that is clean and free of chemical contamination and paints etc. This material is converted into wood chips using a hammer mill, JOHN CLEGG CONSULTING LTD
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with metal and other physical contaminants removed, and the majority of the material is sold to the panelboard industry. Some of the material is retailed to the public for mulching, horse and animal bedding, and as a covering for paths and play areas. We have not obtained an estimate of the amount of wood that is recycled annually in the Glasgow area, but it is very substantial, and will be far in excess of the total fuel required for wood fuelled boilers installed in metropolitan Glasgow in the foreseeable future. The recycling companies would willingly supply recycled wood as a boiler fuel if the operation produced more income for them than supplying their existing markets. Recycled wood chips are available for a chip size of 5 to 50mm and a MC of 20% to 30%, free on lorry (FOL), for about £45 per tonne. The main attraction of this material is the very low MC. The experience of using recycled wood as a fuel up to now has been that the quality of chip size has not been consistent enough and that some metals that are not magnetic can find their way into the chip supply. Both can lead to blockages in the supply feed to a wood fuelled boiler. If recycling companies paid more attention to chip quality, recycled wood would be a very competitive product as the MC tends to be in the range of 20% to 25%. • Short Rotation Coppice: The area of SRC established in Scotland up to March 2006 was approximately 150 ha (John Clegg Consulting with Cawdor Forestry, 2006 – Forecast Wood Fibre Availability & Demand in Scotland & Northern England to 2016 prepared for the Wood Fibre Processing Industry). Since then some further areas have been established. SRC has enormous potential as a fuel source but landowners have not yet perceived it to be sufficiently attractive financially compared with other land uses for them to commit land to SRC for periods of 5 or more years. As a result SRC should only be perceived as a potential source of future wood fuel for the long term as it takes approximately 5 years after planting to obtain full production. The scale of SRC planting in the next 5 years will depend on the grant support that it available under the new Scottish Rural Development Programme 2007 – 13. OTHER EXTERNAL SOURCES OF FUELWOOD 3.26. As Government policy has promoted and supported the installation of wood fuelled boilers for electricity production, such as EON’s plant at Lockerbie, and in a range of other small buildings, a number of organisations and companies have started to offer to supply wood chips. These companies and organisations are based outside metropolitan Glasgow and draw their supplies from elsewhere. Our enquiries have identified at least 5 large to very large organisations or companies that are presently interested in supplying wood chips to any wood fuelled boilers installed in Glasgow. These are Ayrshire Wood Supply, Buccleuch Energy, Bell Ingram, A W Jenkinsons Forest Products and Pentland Plants. At least one of the companies is supplying wood fuel to boilers that are already installed in the area. 3.27. Although fuelwood is readily available from these sources outside metropolitan Glasgow, there is a strong environmental case for supplying fuelwood from locally available sources to minimise transport costs, carbon emissions and the use of non-renewable fuel.
4. PRESENT MARKETS FOR, & DISPOSAL METHODS OF, BIOMASS 4.1. This section describes what markets are presently available for predominantly poor quality roundwood from broadleaved woodlands and what presently happens to that material. EXISTING MARKETS & PRICES 4.2. There are a few wood fuelled boilers already established in metropolitan Glasgow and there are some other sites where boilers can be expected to be installed very shortly following the award of government biomass boiler grants. The situation is summarised in table 4.1.
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Table 4.1 Sites Where Biomass Boilers Have Been Installed or are Expected to be Shortly Council
Site
Comment
Sites where Biomass Boilers are Installed North Lanarkshire
Glasgow City
Palacerigg Country Park (Cumbernauld)
Wood fuel requirement 19 tonnes pa @ 30% MC
Drumpelier Plant Nursery (Coatbridge)
Wood fuel requirement 71 tonnes pa @ 30% MC
Calderhead High School (Shotts)
Wood fuel requirement 256 tonnes pa @ 30% MC
Taylor High School (New Stevenson)
Wood fuel requirement 194 tonnes pa @ 30% MC
The Coach House Trust
Linked to 3 workshops
EMMAEUS Galgael Sites where Biomass Boiler Grants have been approved Glasgow City
John Wheatley College
Expected to use pellets
North Lanarkshire
Clyde Valley Stairs
Using waste from own workshop
Inverclyde
Ardgowan Estate
Two 230 KW boilers using wood chips
4.3. The wood fuel for North Lanarkshire biomass boilers is presently sourced and supplied by a company located outside metropolitan Glasgow. The 3 small biomass boilers located within Glasgow City source their fuel from within the City. 4.4. The market for wood chips is a new and developing one and therefore the prices for wood chips of different specifications are not firmly established yet. Also, prices for wood chips for small scale commercial and domestic heating schemes are commercially sensitive and are therefore not publicised. 4.5. The cost of producing wood chips from identified woods to meet different wood chip specifications for particular boilers in specific locations can be relatively easily calculated. These may be higher or lower than other organisations may be prepared to supply wood chips of similar specifications for i.e. market prices. Feasibility studies will identify what the situation is. Based on informal off-the-record guidance from two significant wood chip supply companies, prices for wood chips for small commercial and domestic boilers in the Glasgow area are presently between £50 and £65 per tonne delivered at a MC of between 30% and 45%, i.e. between 1.46p/kWh and 2.56p/kWh. Higher figures have been reported to us. It should be noted that all of business case evaluations in Annex 2 of the report were carried out at a fuel price of £50 per tone at 30% moisture content (1.46p/kWh). Should a higher fuel price arise per kWh the financial evaluation would need to be recalculated pro-rata on the ratio of fuel price increase. 4.6. If a shortage of wood chips develops in the future, prices could rise, but it seems possible market forces may cause wood chip prices to fall as more suppliers enter this new market; some of whom may be prepared to supply wood chips on a marginal cost basis while others may offer competitive supply contracts to become established in the market. Further downward pressure may also come from Balcas who will shortly start producing wood pellets from a new plant at Invergordon. Wood recycling companies are also considering entering the small commercial and domestic heating market. OTHER MARKETS IN METROPOLITAN GLASGOW
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4.7. To understand more clearly what is happening to woody biomass that is produced from site clearing operations and tree surgery work in the private sector, a very small telephone survey of 9 tree surgery businesses operating in Glasgow was undertaken to find out how they dispose of their material. They were selected because their phone numbers were given on a web site. 4.8. All contractors said that they wished to avoid any costs in disposing of woody biomass material that their operations generated. They did this by chipping the smaller material on site and returning the chips to the site, leaving larger logs on site to help biodiversity or through retailing the material in various markets which they themselves had developed. The markets the surveyed companies are supplying are given in table 4.2. The table shows that the majority of the material was converted into a mulch or firewood and the latter can be retailed dry at up to £100 per tonne. Hardwood sawlog prices vary widely in price depending on their quality; ease of access and the total quantity at any one site. Trees with sizes ranging between 0.6 to 1.0 m3 may fetch from £10 to £40 per m3; trees between 1.0 to 2.0 m3 may fetch from £15 to £80 per m3 and trees in excess of 2.0 m3 may fetch from £25 to £150 per m3. More than one survey participant commented that large scale wood chippers were extremely expensive to purchase and they would need a large amount of material to justify the cost if they were to enter the wood fuel market.
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Table 4.2 Markets Presently Supplied by a Random Sample of Tree Surgery Businesses Active in Metropolitan Glasgow
Name of Businesses
Type of Business
Arbor Master
Garden maintenance, landscaping, tree surgery
Central Tree Surgeons Caledon Arboricultural Glasgow Tree Surgeons
Tree surgery & site clearance. Offices in Glasgow & Biggar Tree surgery with log splitter agency
Glasgow Tree Services James McArthur John Meikle Contractors Ltd
Small company Small company Tree surgery & site clearance.
Orchard Street Tree Surgeons
Agents for wood fires Tree surgery & site clearance. Agents for wood fires
Redholme Timber Recycling
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Comments
All material mixed up / stones & soil. Handling & costs critical
All material mixed up / stones & soil.
Take material from tree surgeons
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Mulch / Firewood Sawlogs / Compost Wood Turning
√
√
√ √ √
√ √ √
√ √
√ √ √
√
√
√
√
√
√
Animal bedding
√ √ √
√
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4.9. All wished to avoid sending material to landfill as they would be required to pay a gate fee to the site operator of between £25 to £37 per tonne and in addition a landfill tax of £24 per tonne. The most unpredictable factor in the quantity of material produced is the amount of site clearance work for housing and commercial developments undertaken in any one year. EXTERNAL MARKETS FOR WOOD CHIPS 4.10. There is rapidly developing market for wood chips for large scale industrial boilers in Scotland. Two industrial boilers are located relatively close to Glasgow and both will come on stream fairly shortly. One is located at Lockerbie (EON) and requires up to 500,000 g tonnes of wood fibre per year and the other is located at Irvine in Ayrshire (Caledonian Paper). The fuel supply contractors are looking for wood fuel and have indicated that they are presently prepared to pay between £17 to £30 / tonne for wood chips with a MC of 40% to 50% MC delivered at their plants. Green wood chip prices are fetching up to £25 / g tonne and prices are rising. This means that any wood chips that are available in sufficient quantity will find a ready market at these prices, irrespective of whether there are one or more wood fuelled boiler installed in metropolitan Glasgow that require a wood chip fuel supply. DISPOSAL METHODS & COSTS
4.11. Green woody biomass that is removed from a site and not sold into a specific market will need to be disposed of, and the only legal route for doing this is to send it to a landfill site. These are operated by a number of contractors on behalf of Councils in metropolitan Glasgow. The present contractors used by each council, the sites where material is collected and the contractors’ operating sites are given in table 4.3. 4.12. Green garden waste for the whole of Glasgow is presently handled by 3 companies: G P Hire based at Blantyre; Scottish Water Waste Services based at Deerdykes near Cumbernauld; and William Tracey Ltd based at Linwood with a further site for green waste at Middleton. The locations of the 3 sites in relation to the Green Network area and metropolitan Glasgow are shown on map 4.1 which shows the sites are strategically located to the south, east and west of Glasgow. Material is brought to these sites by the councils in their kerb collection lorries. 4.13. Approximately 100,000 tonnes of green garden waste is composted each year at the three sites. The 3 companies need a regular supply of wood chips to provide the carbon necessary to allow rapid composting. These companies have, therefore, been prepared to accept woody biomass which they have converted into wood chips for their composting process. Any company or individual wishing to dispose of woody biomass has been charged a gate fee of £25 to £37 per tonne depending on the company. 4.14. During discussions with all 3 companies about the sources of woody biomass supplies and their handling of it, each indicated considerable interest in developing a wood fuel supply chain using green woody biomass as it would fit well with their existing activities. They all have sufficiently large sites to be able to store the material while it dried to the correct MC before chipping it. All indicated that they had little detailed knowledge of where boilers were being installed, or what the scale of fuel wood requirements are at present or might be in the future. One indicated that they would be very interested in entering the market if there was a guarantee on the quantities required at a price that made its supply financially viable, given that it might require a significant investment of up to £250,000 in a wood chipper as well as handling equipment and storage facilities. 4.15. Two companies indicated that if prices paid for wood fuel from green woody biomass were sufficiently attractive they might even drop charging any gate fees. None indicated that they might start paying for green woody biomass! 4.16. Even if the operators handling the Councils’ green biomass drop all gate fees it does not provide any incentive for woodland owners to supply to a wood fuel market; it simply removes a cost that they might or might not otherwise have incurred.
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Table 4.3 Existing Sites for Recycling Garden Rubbish & Green Woody in Metropolitan Glasgow & the Main Contractors Handling it Council East Dunbartonshire West Dunbartonshire
Glasgow City
Inverclyde North Lanarkshire
South Lanarkshire
Renfrewshire East Renfrewshire
Transfer Stations for Wood / Garden Biomass Mavis Valley, Bishopriggs Stanford Street, Clydebank Ferry Road, Old Kilpatrick Dalmoak, Renton Road Dawsholm Easter Queenslie Polmadie Shieldhall Pottery Street, Greenock Kirn Drive, Gourock Coatbridge WDR Centre, Coatbridge Dalmacoulter WDR Centre, Airdrie Deerdykes Recycling Centre Carluke East Kilbride Eastfield Hamilton Larkhall Strathaven Linwood Barrhead Greenhags
Site Type New site Not normal household waste
Civic amenity site - WTS Civic amenity site - WTS Civic amenity site - WTS Civic amenity site - WTS Civic amenty site + com waste Civic amenity site Civic Amenity Site Civic Amenity Site Council Use only Civic amenity site Civic amenity site Civic amenity site Civic amenity site Civic amenity site Civic amenity site
Agent / Contractor Scottish Water WS - Deerdykes / Johnstone W Tracey Ltd - Linwood W Tracey Ltd - Linwood W Tracey Ltd - Linwood Scottish Water WS - Deerdykes / Johnstone. Coach House Trust Scottish Water WS - Deerdykes / Johnstone Scottish Water WS - Deerdykes / Johnstone Scottish Water WS - Deerdykes / Johnstone W Tracey Ltd - Linwood W Tracey Ltd - Linwood G P Hire 60% + Scottish Water WS - Deerdykes G P Hire 60% + Scottish Water WS - Deerdykes G P Hire 60% + Scottish Water WS - Deerdykes Viridor Enviroscot + G P Hire - Blantyre Viridor Enviroscot + G P Hire - Blantyre Viridor Enviroscot + G P Hire - Blantyre Viridor Enviroscot + G P Hire - Blantyre Viridor Enviroscot + G P Hire - Blantyre Viridor Enviroscot + G P Hire - Blantyre WRG - Linwood G P Hire - Blantyre WRG - Linwood
NB Tree stems and larger branch material is not accepted at most civic amenity sites
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Map 4.1 Locations of the Three Companies Handling Glasgow’s Green Biomass
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5. ENVIRONMENTAL BENEFITS OF WOOD FUELLED BOILERS 5.1. “Climate change is widely recognised as the most serious environmental threat facing our planet. Emissions of greenhouse gases (GHGs), from the burning of fossil fuels (e.g. oil, coal, gas), are already making an impact on the world's climate. Perversely, those in the developing world - those who have contributed least to the problem historically and who are most vulnerable to its effects - will suffer the worst impacts. But rich nations are not immune and Scotland has recent first hand experience of the types of climate extremes that will become increasingly common as a result of climate change. By the end of this century Scotland will have warmer, wetter winters, less snowfall and an increased risk of flooding. 5.2. In response to the scientific consensus that human activities are having a noticeable effect on our climate, the Kyoto Protocol was agreed at the Third Conference of the Parties (CoP-3) to the UN Framework Convention on Climate Change (UNFCCC) in Japan in 1997. This international agreement aims to reduce developed countries' emissions of GHGs by, on average, 5.2% below 1990 levels by 20082012. The Protocol entered into force in February 2005, following ratification by Russia. The UK share of the collective Kyoto target assumed by the European Union under the Protocol is an emissions reduction of 12.5%. The UK Government has also set itself two more ambitious domestic goals: to reduce UK carbon dioxide (CO2) emissions by 20% by 2010; and to reduce CO2 emissions by some 60% by around 2050, with real progress by 2020.” (The Scottish Government web site, 2007). 5.3. In response to this situation the Scottish Executive published Changing Our Ways: Scotland's Climate Change Programme in March 2006. Through this programme, the Scottish Government is committed to tackling the issue and securing a safer, sustainable future for Scotland by, for example: •
encouraging more efficient use of energy by the public and Scottish businesses, while increasing "greener'' renewable sources of electricity and heat such as wind, wave, tidal, biomass (such as wood) and solar power;
•
supporting activities which promote new and cleaner vehicle technology and fuel, while urging the public to consider alternatives to driving cars (public transport, cycling, walking);
•
delivering significant carbon savings from Scotland's forests by increasing forest cover and through using more wood as fuel instead of fossil fuels;
•
promoting waste recycling initiatives - for both household and business waste under the National Waste Plan, to reduce waste to landfill sites and limit emissions of methane - a powerful greenhouse gas;
•
contributing to the development of a UK-wide policy framework on preparing for climate change to ensure Scotland is protected from the worst impacts.
5.4. In January 2007 all 32 councils signed the Scottish Climate Change Declaration which commits them to achieving significant reductions in greenhouse gas emissions from their own operations. The installation of wood fuelled boilers, where emission levels permit, is one of the practical ways of delivering on this Declaration. 5.5. In seeking to identify new sites where wood fuelled boilers might be installed we have gained the impression that there is not yet widespread understanding or acceptance of the environmental benefits that can be gained from installing wood fuelled boilers at both the policy and operational levels within a number of Councils. 5.6. The installation of more wood fuelled boilers in metropolitan Glasgow, particularly in Council buildings, could make an important contribution to alleviating climate change through saving carbon emissions and delivering a more sustainable future through using a renewable fuel. Although the capital costs of installing wood fuelled boilers are initially greater than oil or gas boilers, there are significant potential annual savings in fuel costs and they provide potentially greater security of fuel supplies at a time when the UK is becoming more dependent again on supplies of gas and oil from countries overseas JOHN CLEGG CONSULTING LTD
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that are less politically stable. EMISSIONS FROM BIOMASS BOILERS Air Quality 5.7. Currently there is a significant level of concern within local authorities in Scotland about the introduction of biomass boilers into areas covered by the Clean Air Act (CAA). Having eliminated the smogs of 40 years ago through the introduction of the CAA, and an almost complete switch to gas-fired boilers in cities, biomass boilers are now seen to threaten this situation. To understand why this is the case, an understanding of emissions is required. 5.8. The smoke from wood burning devices can cause serious health problems. Breathing air containing wood smoke contributes to: cardiovascular problems; lung diseases like asthma, emphysema, pneumonia and bronchitis; irritation of the lungs, throat, sinuses and eyes; headaches; and allergic reactions. There are hundreds of chemical compounds in wood smoke, including many that are irritating and potentially cancer-causing. Wood smoke pollutants include nitrogen oxides, carbon monoxide, organic gases and particulate matter. Particulate matter, the fine material that makes up smoke and soot, may be the most insidious component of wood smoke pollution. Most of these particles are so small that when inhaled they get past the hair-like cilia that protect the air passages of the lungs. They can lodge in the deepest part of the lungs, where the blood takes on oxygen. The particles can cause structural and biochemical changes, including scarring of the tissues. 5.9. Exposure to woodsmoke can have serious consequences for health. Several studies have shown that exposure to woodsmoke reduces lung function, especially in children, and increases coughs and other respiratory diseases. In Bogota, woodsmoke exposure may explain about half of all cases of obstructive airways disease. In Mexico City, famous for its traffic pollution, women exposed to woodsmoke had 3.9 times the risk of chronic bronchitis and 9.7 times the risk of chronic bronchitis plus chronic airway obstruction. If exposed for an average of 33 mins or more a day (200 or more hours/year), risks were 15 and 75 times higher than in women not exposed to woodsmoke. 5.10. Some particles are emitted directly into the air, and some form in the air from, in the case of biomass combustion, chemical reactions of nitrogen oxides and volatile organic compounds. Particles can cling to moisture droplets or simply drift in the air, and are referred to as “particulate matter,” abbreviated PM. Regulators generally divide particulate matter into two categories: PM10 and PM2.5: •
PM10 consists of particles, generally 10 micrometers or less in size. (The width of a human hair is about 30-200 micrometers.) The larger of these particles are deposited in the upper airways before they get to the lungs and most don’t get further into the body. PM10s comes from crushing and grinding operations, road dust, pollen, mould and biomass combustion;
•
PM2.5, or fine particles, are up to two-and-a-half micrometers in diameter. Fine particles come mainly from combustion sources, including vehicles that burn gasoline or diesel; power plants and factories that burn coal, oil, gas or biomass; forest or grass fires; organic molecules from vegetation and even fireplaces or woodstoves. This category concerns scientists the most, because these tiny particles can slip past our bodies’ defences and end up deep in our lungs;
•
Scientists are now beginning to study even smaller particles, called “ultrafines.” As yet, very little is known about these particles, which may be even more harmful to health than larger particles.
5.11. In addition gases, particularly nitrogen dioxide (NO2), are of particular concern because it is an irritant in the lungs where it forms nitrous acid. The overall air pollution index for a site or region is calculated from the highest concentration of five pollutants, Nitrogen Dioxide, Sulphur Dioxide, Ozone, Carbon Monoxide and Particles 10µm (PM10). 5.12. It is known that biomass boilers, when burning with complete combustion, produce more emissions than an equivalent gas boiler but fewer emissions than oil or other solid fuel boilers. The emissions of concern from biomass boilers are NO2 and PM10s, both of which are currently regulated under the CAA, and PM2.5s which are the subject of much concern as described above, are not currently regulated under the CAA, but for which voluntary target dates have been set commencing in 2010.
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Clean Air Act 5.13. In designated areas, the CAA stipulates the maximum concentrations of particulates and gases permitted in the air. The emission of dark smoke is not permitted in a CAA area, and grit/dust arrestment is required if the rate of biomass combustion is 45.4kg/hour or more. In the case of biomass boilers this represents a boiler with a power input of 115kW if the fuel has a moisture content of 45%, and only 75kW if the fuel has a moisture content of 60%. Appendix 3 details the target concentrations and dates by which the maximum concentrations have to be achieved for the CAA as applied in Scotland. 5.14. A particular problem in both Glasgow & Edinburgh is that concentrations of NOx and PM10s in some areas, notably near the M8 and on major roads in the city centres, already exceed the thresholds set by the CAA. This is because of PM10 and NOx emissions from vehicles, predominantly diesel vehicles. This problem is exacerbated in Glasgow, and in other areas near motorways and trunk roads which are the responsibility of the Scottish Government, because the local authority responsible for ensuring emissions are contained within the threshold values has no control over emissions on the major roads responsible for the pollution. In this situation local authorities have great difficulty in approving applications for the installation of biomass boilers because irrespective of how far emissions can be reduced from a biomass boiler using the systems described below, some emissions will still occur aggravating an already untenable situation. 5.15. The poor air quality associated with road traffic tends to be very localised, so even though the City of Glasgow is a designated CAA area this does not mean that air quality is poor across the city, just at certain ‘hot spots’. Consequently, a local authority with a designated CAA area should not make a blanket decision not to install biomass boilers in that CAA regulated area, but rather should examine proposed systems on a case-by-case basis. It will be possible to install biomass boilers in cities with CAA regulated areas, and for the emissions from those systems not to cause the total emissions in a given locality to rise above the threshold values. Biomass Boilers and Emissions 5.16. The complete combustion of wood produces emissions of fine particulates, NOx and CO2, whereas the incomplete combustion of wood results in the release of volatile organic gases, benzene and other undesirable substances some of which are carcinogenic. The emission of black smoke from a chimney is a visible sign of incomplete combustion. In order to ensure the complete combustion of wood fuel, biomass boilers require the following features: •
An adaptive fuel feed mechanism, which adjusts the amount of fuel fed into the boiler in real time depending on the instantaneous load on the boiler;
•
The monitoring of boiler flow and return temperatures, and their use via a control system, to regulate the fuel feed rate and combustion air fans;
•
Separately controllable primary and secondary combustion air fans (also tertiary air fans on boilers above about 5MW);
•
A flue gas oxygen sensor (Lambda sensor) to monitor the oxygen content of the flue and, via a control system, to ensure sufficient excess oxygen is supplied for complete combustion by regulating secondary and tertiary air fans.
5.17. All good wood boilers incorporate these features, all of which are essential for a boiler to operate in an area subject to the CAA. 5.18. In order to avoid the production of black smoke from a biomass boiler chimney the following conditions must be met: •
The boiler must operate within its turn down band, e.g. a 300kW boiler with a 3:1 turndown ratio must not operate if the load falls below 100kW. Either the boiler must switch off, or it must enter a slumber mode, or it must operate with a buffer vessel in parallel to accept the excess energy produced;
•
The moisture content of the fuel must be within the range the boiler can accept. In particular fuel with a moisture content greater than that which the boiler can accept will invariably produce black smoke. 5.19. However, fuel with a moisture content less than that which the boiler can accept will result in JOHN CLEGG CONSULTING LTD
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combustion at too high a temperature (in excess of 1,150 ยบC) producing a high concentration of NO2 because significant quantities of NO2 are formed by combining nitrogen and oxygen in the air at temperatures of 1,200 ยบC and above. Meeting the CAA Requirements 5.20. Currently, only one biomass boiler manufacture has received approval to operate boilers in CAA areas in the UK. Binder, an Austrian manufacturer, has had all of its boilers up to 2MW tested and approved. It is understood that at least one other manufacturer is also having its biomass boilers tested for approval. Unfortunately, this leaves the vast majority of boiler types uncertified and unusable in CAA areas. 5.21. As a result of this, and because of a number of biomass boilers already installed in CAA areas in Scotland, the Scottish government is currently funding tests on twelve biomass boilers in Scotland. These tests are to determine the level and nature of emissions from different types and sizes of boilers. However, once this information is available it does not translate directly to an emissions concentration at ground level. This can be done only by a process of dispersal modelling for the chimney height at a particular geographic location which is a service offered by environmental consultancies and the larger building services consultancies using bespoke software. 5.22. It is known that the majority of boilers, without any emissions abatement equipment fitted to the flue, produce levels of emissions which are too great to allow them to be operated in a CAA area. In order to reduce emissions to an acceptable level one or more of the following abatement technologies given in table 5.1 would need to be used in series with the flue. Table 5.1 Emissions Abatement Technologies Needed for Wood Fuelled Boilers in CAA Areas Technology Cyclone Grit Arrestor
Advantages
Disadvantages
Will take out most particulates down to about 20 micron
Will not take out a significant proportion of PM10s Will not take out any gas including NOx
Bag Filter
Will take out most particulates down to about 1 micron Will take out almost all PM10 & PM2.5 particulates
Electrostatic Filter
Wet Scrubber
Regular filter cleaning required A cyclone in series is advisable to reduce the load on the bag filter from larger particulates
Pressure losses through the filter are massive if fine particles are to be filtered out. This requires a large and energy hungry flue fan
Will not take out any gas including NOx
Will take out almost all particulates down to ultrafine particles i.e. smaller than PM2.5s
Must be used in series with a cyclone
Will take out almost all particulates down to ultrafine particles i.e. smaller than PM2.5s
Must be used in series with a cyclone
Will dissolve gases including NOx and CO2 Enables a high degree of heat recovery from the boiler flue gases
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Will not take out any gas including NOx
Weak acid produced as gases dissolve requiring neutralisation and the removal of salts from the scrubber water Significantly buoyancy
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reduces
flue
gas
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5.23. In order to ascertain the level of emissions from a boiler fitted with flue gas abatement systems, for each emission of concern the level of emission from the boiler must be multiplied by the abatement factor of the abatement technology. This figure would then need to be subject to dispersion modelling to obtain the actual emission level at a given location. Summary 5.24. Biomass boilers produce NO2, PM10 and PM2.5 emissions, and are not suitable for use in a CAA regulated area without suitable testing, authorisation and flue gas and particulate abatement. A number of technologies for flue gas and particulate abatement exist but only one, wet scrubbing, will remove NO2. Even with abatement systems fitted it is unlikely that the emissions from a biomass boiler can be eliminated altogether, although a very significant reduction in emissions is possible. In order to determine the likely emissions levels from a particular boiler at a particular location, dispersion modelling is required taking into account the proposed chimney height, local geographic and urban factors, and local weather. 5.25. The current concern about emissions from biomass boilers appears to be justified, especially as a biomass boiler will emit more particulates and NO2 than its equivalent gas boiler. Furthermore, in areas of cities regulated under the CAA, where emissions are already close to or exceed permitted levels, it may not be feasible to install a biomass boiler at all if it emits any particulates or NO2. With the current significant and worldwide interest in the effect of PM2.5 emissions from wood burning equipment, and with PM2.5s coming voluntarily under the CAA in two years time, the requirement for scrutiny of potential biomass boiler installations will only increase, as will the demands for ever greater flue gas and particulate abatement. Notwithstanding this, there appears to be no reason why biomass boilers should not be installed in CAA regulated areas providing a systematic and informed evaluation of a particular boiler in a particular location is first carried out. The particulates and gas emissions from correctly installed and operated biomass boilers, incorporating emissions abatement equipment, will in many cases be only slightly worse than those from gas boilers and much better than those for coal or oil boilers.
6. PART 1 CONCLUSIONS 6.1. The main conclusions that can be drawn on about the wood energy opportunities in relation to the woods in the Glasgow & Clyde Valley Green Network are: • The mainly broadleaved woods are estimated to cover approximately 6,360 hectares and of this total about 4,746 ha are well established and have potential to produce wood fuel. There are a further 46,914 ha approximately of woodland within the boundaries of the Councils that make up metropolitan Glasgow; • The primary objectives of most owners of woods in the Glasgow & Clyde Valley Green Network at present are to manage them for a variety of purposes, such as delivering biodiversity and landscape benefits, rather than to maximise financial returns from them; • It is estimated that woods in the Green Network area could still sustainably deliver about 7,846 tonnes of fuelwood per annum at a 30% MC while still delivering their present woodland management objectives. If all woods in metropolitan Glasgow are included then the quantity of fuelwood that all these woodlands might have available sustainably could amount to 46,190 tonnes per annum at 30% MC; • Significantly more wood fuel could be produced if the primary objective of owners was to change to one of supplying fuelwood, which is not the case at present; • The average size of the woods in the Glasgow & Clyde Valley Green Network is only about 1 ha in size, although there are some larger individual woods, and they are all geographically scattered throughout the Network area. Most of the woods will only require woodland management operations intermittently which will mean that potential fuelwood material will only become available from individual woods from time to time; • As the wood chip fuel market is a relatively new one, there are no significant supply chains linking JOHN CLEGG CONSULTING LTD
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the woody biomass arising from woodland management activities in the Green Network to any supply contracts for individual boilers, or to the wider fuelwood market at present; • As fuelwood will arise as a result of woodland management operations designed to deliver other objectives, it will be necessary to have continuity of woodland management activities and this will require the necessary funding to be available annually for woodland management work; • In addition to potential fuelwood supplies available from woodlands, there are estimated to be about a further 6,560 tonnes at 30% MC available in metropolitan Glasgow from tree surgery work on trees in the streets, cemeteries, school grounds and in private gardens; • In total, fuelwood that is potential available in the Green Network area could amount to approximately 15,000 tonnes per annum at 30% MC; • The existence of gate fees and landfill tax for any green woody biomass is a major disincentive to the material entering the wood fuel supply chain. Further investigation of alternative pricing policies with Council recycling contractors could encourage more material to enter the fuelwood supply chain if these contractors are more aware of the fuelwood market prospects and prices; • Investigations have revealed that there is an apparent lack of understanding about the availability of fuelwood in metropolitan Glasgow, and that this might be acting as a constraint on the installation of wood fuelled boilers. There are more than adequate fuelwood supplies available at the present time, mainly coming from companies from outside metropolitan Glasgow, to supply any new wood fuelled boilers that might be installed over the next 5 years or more. Therefore the lack of wood fuel is not a justification for not installing them; • Although fuelwood is readily available from outside metropolitan Glasgow for supplying any wood fuelwood boilers that are installed within Glasgow, there is a strong environmental case for supplying fuelwood from locally available sources to minimise transport costs, carbon emissions and the use of non renewable fuel. In addition, any woody biomass arising from managing woodlands in the Green Network area that can be sold into the wood fuel market will help to meet the costs of owning and managing the woods; • There is a very strong case for installing more wood fuelled boilers in metropolitan Glasgow, particularly in Council buildings, because of their contribution to reducing carbon emissions and delivering a sustainable future in line with UK and Scottish Government policies; • The emissions from biomass boilers may bring certain particulates and gas emissions above the levels permitted under the Clean Air Act, particularly in central locations in urban areas. This is important and can usually be prevented by initially installing the correct type of boiler and emissions abatement equipment and operating it according to the manufacturer's instructions. In certain central locations where the emissions are already close to permitted limits, it may be necessary to model dispersions to check emissions before proceeding. • The particulates and gas emissions from correctly installed and operated biomass boilers, incorporating emissions abatement equipment, will in many cases be only slightly worse than those from gas boilers and much better than those for coal or oil boilers. • Investigations suggest there may be a lack of knowledge and policy direction within some of the Councils about the positive contributions that wood fuelled boilers can make to these policies. This lack of clear direction may be constraining the installation of wood fuelled boilers; • It appears that there is very little detailed knowledge within the private sector, and amongst a number of Council staff, about how the wood fuel market is developing within metropolitan Glasgow and what quantities of wood fuel are required. This could be acting as a constraint on the development of the supply chain.
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PART 2: DEVELOPMENT OPPORTUNITIES
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7. POTENTIAL WOOD FUELLED BOILER SITES 7.1. The development and growth of the wood fuel market is dependent on the installation of wood fuelled boilers and this section looks at what potential opportunities there are within metropolitan Glasgow. It is only concerned with the opportunities for boilers requiring wood chips as the manufacture of wood pellets is economic only on a large scale, typically 100,000 dry tonnes (10% MC) per year or more and it would not be possible to supply such an operation from woodlands in the Green Network. Similarly, the markets for sawdust are well established but the amount of sawdust produced from the management of woodlands in the Green Network Area will be small. 7.2. The use of woodchips for heating requires boilers able to combust woodchips, and fuel storage systems able to accept woodfuel deliveries by one of a number of delivery mechanisms. The most economic method of fuel delivery, and the one with the minimum of health and safety implications, is by tipping into a silo. This requires either the silo to be located below ground or a lorry delivery ramp to the silo lip. All of the potential installations identified in this study are on the basis of fuel delivery by tipping into a silo. 7.3.
Potential sites for new wood fuelled boilers were identified by: •
Contacting the eight local authorities within the Green Network Area;
•
Discussions with the Scottish Community and Householder Renewables Initiative and The Lighthouse;
•
Contacting Glasgow based architects and building services engineers;
•
Using existing client contacts.
7.4. Wherever possible, potential installations were identified on the basis that an organisation had expressed an interest in a wood boiler or were intending to install a wood boiler. This approach was taken in order that the installations included in the study have a reasonable probability of proceeding. 7.5. In total twelve potential wood boiler installations have been identified ranging in size from 50kW to 1.5MW, plus one existing installation of 500kW, and these are in the following locations: ¾
Bridge of Weir Primary School, Renfrewshire Council
¾
Capelrig House, East Renfrewshire Council
¾
Queens Park Nursery, Glasgow City Council
¾
Ravenscraig Regional Sports Facility, North Lanarkshire Council
¾
Broadwood Stadium, North Lanarkshire Council
¾
The State Hospital, Carstairs
¾
National Semiconductor (UK) Ltd, Greenock
¾
IKEA, Glasgow
¾
Loaningdale Centre, Scottish Centres, Biggar
¾
Broomlea Centre, Scottish Centres, West Linton
¾
Wiston Lodge, Biggar
¾
Scotland Street Commercial Development, Glasgow
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7.6. In addition, Gartmore House, near Aberfoyle, has a 500kW boiler in operation and would welcome a good quality fuel supply at the right price. 7.7. A second site, heated by a coal boiler and which Glasgow City Council was keen to convert to a biomass boiler, was visited. While Lorne Street Primary School appeared to be a good candidate for conversion, an on-site inspection revealed this not to be the case. Access would not be possible for fuel deliveries without demolishing the Janitor’s garden wall, and the physical removal of the coal boiler and installation of the wood boiler would require extensive civil works including the use of a long reach crane. 7.8. A fuel MC of 30% has been used throughout this section of the report to enable the direct comparison of woodfuel quantities at different sites. Further very important information about the MC of fuelwood is given on page 2. 7.9.
A summary of the findings is given in table 7.1 on the next page.
Potential Boiler Installations 7.10 Appendix 3 contains details of the twelve sites for which survey and preliminary design work has been carried out. The following information is provided for each site: • • • • • • • • •
A brief description of the site; Information on the existing heating system; A heat load and fuel consumption analysis; The recommended biomass boiler size; The annual woodfuel requirement; Fuel storage options; Information on fuel deliveries; A summary table of savings and installation costs; An estimate of the annual maintenance costs.
This information has been relegated to an appendix because of the technical complexity and level of detail for each site. However, it should be noted that the information contained in the appendix represents almost 50% of the cost and time involved in the study. 7.11 Although the technical information is contained in an appendix, it does not imply that it is any less important than any other information in this report. Great care and attention to detail must be taken in selecting suitable sites for biomass boilers and in the design and integration of biomass boilers with existing heating systems. This, in turn, requires the involvement of a specialist biomass heating designer if a successful outcome is to be assured. Persons reading this report who are likely to be involved in setting up woodfuel supplies should make themselves aware of technical complexity of biomass installations, in particular the potential pitfalls, and the woodfuel specification required before agreeing to supply to any given installation. Biomass Boiler Maintenance 7.12 Biomass boilers must be maintained regularly and in accordance with manufacturers’ instructions if they are to operate reliably and achieve their typical design life of about 40 years. Weekly and monthly inspections and minor cleaning is required plus an annual overhaul; hence, the cost of maintaining a biomass boiler is much greater than that of gas or oil-fired boilers. However, it is not uncommon for oil boilers, in particular, to be operated for periods of several years without maintenance giving the impression that the maintenance costs for oil and gas boilers are virtually zero: this can make it difficult to compare the maintenance costs for fossil fuel boilers and biomass boilers directly. As a rule of thumb it is suggested that the maintenance costs for fossil fuel boilers are likely to be 10% - 20% of those for biomass boilers.
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Table 7.1 Summary of the Twelve Potential Wood Boiler Installations Identified During the Study Site
Location by Postcode
Boiler Size
Fuel Required at 30% MC (tonnes)
Indicative Installation Cost
Annual Fuel Cost
Annual Cost Saving
CO2 Saving
Payback
(tonnes)
Period (years)
Bridge of Weir Primary School
PA11 3QB
300kW
120
£130,000 - £180,000
£7,650
£10,850
103.2
12.0 – 16.6
Capelrig House
G77 6NH
50kW
30
£45,000 - £75,000
£2,050
£2,990
27.8
15.5 – 25.9
Queens Park Nursery
G42 9QL
400kW
360
£200,000 - £225,000
£22,970
£41,030
306
4.9 – 5.5
None
1,000kW
910
£240,000 - £300,000
£45,500
£45,630
577
5.3 – 6.6
Broadwood Stadium
G68 9NE
230kW
120
£100,000 - £150,000
£5,950
£9,500
102
10.5 – 15.8
The State Hospital Carstairs
ML11 8RP
800kW
1,220
£350,000 - £400,000
£61,000
£93,700
1,017
3.7 – 4.3
National Semiconductor (UK) Ltd
PA16 0EQ
1,200kW
3,500
Boiler installation currently planned for installation probably 2008
IKEA Glasgow
G51 4FB
1,000kW
>100
Boiler installed planned by IKEA 2008 for 2008
Gartmore House
FK8 3RS
400kW
650
Already installed and operating, but in urgent need of fuel supply
Loaningdale Centre
ML12 6LX
350kW
150
£180,000 £230,000
£11,380
£15,830
130
11.4 – 14.5
Broomlee Centre
EH46 7BU
300kW
140
£380,000 -£430,000*
£9,550
£16,580
>140
22.9 – 25.9
Wiston Lodge
ML12 6HT
100kW
80
£80,00 -£130,000
£5,500
£8,500
73
9.4 – 15.3
G5 8QB
1,500kW
1,600
£1,500,000**
£80,000
£85,000
1,050
17.6
7,630kW
8,980
£3,205,000
£251,550
£329,610
3,526
N/A
Ravenscraig Regional Sports Facility
Scotland Street Commercial Development Total
£3,620,000
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8. KEY OPERATIONAL FUELWOOD SUPPLY CHAIN ISSUES 8.1. If the environmental benefits of installing wood fuelled boilers in metropolitan Glasgow, and supplying wood fuel for them from the Green Network area woods are to be maximised, then the development of a reliable and efficient supply chain will be essential. This section reviews and assesses the main technical and operational components that would have to be considered in setting one up. WOOD CHIP SPECIFICATIONS & QUALITY 8.2. The designs of the installed wood fuelled boilers will determine the wood chip specifications that will need to be produced. The chip specifications that are likely to be required are: Chip Class
G50
Permissible Proportions & Respective Range for Particle Size Max 20%
60 100%
>16mm
Max 20%
Max 4%
16-2.8
2.8-1mm
<1mm
Water Content (W30 – 40)
30–40% on weight basis
Ash (A2)
1-5%
Content
Species Mix
–
a
Possible Extreme Values for Chips Max X section 5 cm
2
Max Length 12 cm
wet
Not an issue
8.3. Although the final specifications for wood chip fuel can only be determined when the boilers have been specified or installed, the specifications that any wood fuel supplies will need to meet are likely to be very similar. Experience in running wood fuelled boilers has found that woodchip supplies must consistently meet the quality standards for which the boiler was designed in order to stop outsized woodchips blocking the feed system, and woodchips which are too wet, from producing black smoke causing the boiler to flame-out and preventing them from operating at maximum efficiency. The wood chipping and screening process needs to be carefully controlled and monitored and this is not something that can be done very easily in woodland conditions as part of thinning and cleaning operations in very small urban woods. The single most important aspect of woodchip fuelled heating systems is woodchip quality, and the failure to achieve consistent and repeatable woodchip quality is to blame for the majority of problems experienced by woodchip boiler owners in the UK. WOODY BIOMASS DRYING / STORING AREAS 8.4. Woody biomass harvested during woodland management operations will need to be dried before the moisture content reaches the acceptable level which is likely to be between 30% MC and 40% MC on a wet weight basis. The woody biomass can either be left in the woods to dry or it can be moved to a site where it can be left to dry for a period of about 6 months depending on weather conditions. It is normally better to remove logs from woodlands to a specific site, particularly where the public has access to a wood as there may be potential Health & Safety issues if children started playing on piles of wood. 8.5. Woody biomass should always be stacked and stored to dry as roundwood and then chipped, rather than chipping the wood and then leaving it to dry in a pile. This is because wet woodchips in a pile decompose producing the heat resilient bacteria micropolyspora faeni and thermoactinomyces vulgaris, and Aspergillus moulds. All of these release dusts and are responsible for a disease known as Farmer’s Lung. On initial exposure the spores trigger an allergic reaction which produces antibodies; however, subsequent exposure to these mouldy dusts can generate a hypersensitive type of allergic JOHN CLEGG CONSULTING LTD
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reaction for which there is no cure. 8.6. It is, therefore, essential to have areas where logs can be stored for drying before being chipped and transported to a boiler. Storage areas do not have to be covered to dry woody biomass, but if they are, the material will dry faster. However, this saving in time has to be weighed up against the costs of constructing or leasing a covered storage area. STORAGE OF WOODCHIPS IN FUEL SILOS 8.7. Another Health and Safety consideration is that wet woodchips should not be stored in fuel silos for long periods as, again, mouldy spores can form. The woodchip should be turned over regularly in the silo by running the boiler sufficiently to ensure fuel does not reside in the silo for more than a few weeks at a time. If a boiler is to be switched off over the summer, the timing of woodchip deliveries should be such that the silo is left substantially empty by the time the boiler is switched off. If it is necessary to clean out a fuel silo because the chips have begun to decompose, a Health and Safety Risk Assessment must be undertaken to determine what level of personal protective equipment (PPE) is required for the person emptying the silo, and also to identify the correct disposal arrangements for the decomposing woodchips. FUELWOOD HARVESTING EQUIPMENT 8.8. As almost all woody biomass from woodlands in the Green Network, and elsewhere in metropolitan Glasgow, will be material that is harvested in the course of managing woods for other objectives, it means that no specialist felling equipment needs to be purchased. Where existing harvesting operations might benefit, if there is a larger quantity of potential fuelwood to collect from cleaning and thinning operations, would be in having some form of trailer and hydraulic grab available for extracting green woody biomass as there may be a large quantity of small material as well as large pieces that are unsuitable as sawlogs. As many of the individual woods will be small, the addition of a tractor may be all that is required to undertake cleaning operations in them. 8.9. A whole range of practical considerations need to be taken into account when deciding on what equipment to use, and contractors are usually more than capable in deciding the best equipment for the range of operational conditions that they face once a market has developed which generates income for them. TRANSPORT & AGGREGATOR SITES 8.10. Fuelwood is a relatively low value product at present and therefore transporting small quantities of it from a large number of very small woods on public roads is expensive. The key to developing a successful wood fuel supply operation is to minimise costs. As a rough guide every time a tonne of wood is handled it can cost up to ÂŁ10, so every time timber is handled unnecessarily it may add up to another ÂŁ10/tonne. Costs can be minimised by collecting woody biomass together at selected sites as close as possible to a number of woodlands so that material can be brought to the site, either to be stored until the moisture content has fallen and the material is ready to be chipped, or it can be picked up in, say, 20 tonne loads and taken to a larger storage site. Moving small quantities of material around in small vehicles on public roads to a distant storage site is costly and much more environmentally damaging. The key is, therefore, to find suitable aggregator sites which have the necessary planning approvals. Our initial enquiries about possible locations for fuelwood aggregator sites, which should not be regarded as comprehensive, have identified a number and these are shown in table 8.1. Some of these sites are on publicly owned land and others are owned and run by commercial companies. Further work is required to identify all possible sites; obtain permissions from planners, and possibly SEPA for some of them, and to decide on how they will be operated and by whom.
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Table 8.1 Initially Identified Potential Fuelwood Aggregator Sites Council East Dunbartonshire West Dunbartonshire Glasgow City Inverclyde North Lanarkshire
South Lanarkshire Renfrewshire
Potential Aggregator Sites
Area
Ownership
ha
217 Gartcraig Rd, Glasgow. G33 2SS
N/A
Glasgow City Council
Dunns Wood Road, Cumbernauld Limekilns Road, Cumbernauld Deerdykes Whitburn Chatelherault Country Park Newhouse Mill Rd, Blantyre Linwood & Middleton Linwood Johnstone Alexandria Helensburgh
2.0 1.3 9.6 10.6 1.0
NLC land NLC land Scottish Water WS Central Tree Surgeons SLC land G P Hire William Tracey Ltd Renfrewshire Council Scottish Water WS Redholme Timber Recycling Redholme Timber Recycling
N/A 3.2 0.5 0.5
East Renfrewshire
8.11. Map 8.1 shows the locations of these sites.
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Map 8.1 Locations of Initially Identified Wood Fuel Aggregator Sites in Metropolitan Glasgow.
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WOOD CHIPPING & CHIPPING EQUIPMENT 8.12. Wood chipping can be carried out either by disk or drum chippers. Disk chippers are the cheaper option and are usually found on the smaller scale. With disks, typically, up to 600mm diameter for the largest machines, their ability to chip is dependent not just on log diameter but also log moisture content and whether hardwood or softwood is involved. For example, a 300mm chipper would be able to chip 50% MC softwood of 220mm diameter but only 150mm diameter at 30% MC; the corresponding diameters which can be chipped are lower for hardwoods. However, woodchip quality and shape is usually better from disk chippers which produce consistent, almost square chips if operating within the limits quoted above. Drum chippers, on the other hand, are much larger and more expensive pieces of equipment able to handle whole trees and with a greater chipping rate because of their larger size. They produce woodchips which can be longer and narrower than disk chippers, and fuel quality in respect of chip size is achieved by screening the chips produced by the chipper.
Chips from a Disk Chipper
Chips from a Drum Chipper
An important consideration when chipping is that logs should be clean and free from earth, soil and sand and that chip should be produced on a paved surface, preferable concrete to prevent contamination of chips. If silica based material gets into the woodchip this can cause problems at the boiler through the formation of glassy clinker on the grate. This clinker can damage grate components, jam the grate mechanism and snap or jam the ash extract auger. WOOD SUPPLY & HEAT CONTRACTS 8.13. Unless a wood fuel boiler owner has their own woodlands and a very short fuelwood supply chain, the preferred arrangements are either to buy in chips from an outside supplier or to enter into a heat supply contract with them. As most boiler owners want the minimum of hassle and are only interested in the amount of heat generated, the increasingly common arrangement is for owners to enter into a heat supply contract whereby they pay only for the heat generated which is heat metered. This means that the owner does not need to be concerned about the calorific value, moisture content or other factors that might affect the heat generated from the wood chips.
9. STRATEGIC FUELWOOD SUPPLY CHAIN DEVELOPMENT OPTIONS 9.1. The Glasgow & Clyde Valley Green Network Partners have a number of options, both within their own Council boundaries, and strategically across metropolitan Glasgow as to how they wish the fuelwood supply chain to develop from Green Network woodlands and more widely for all woodlands. This section outlines those options. OPTION 1: SUPPORT THE EMERGING PRIVATE SECTOR SUPPLY CHAIN 9.2. This option is one that involves little additional action than is already being undertaken. A number of organisations are active in promoting the use of wood fuel and the installation of wood fuelled boilers, such as Forestry Commission Scotland. This report has described the rapidly emerging fuelwood market and the interest being shown by companies and organisations based in and outside metropolitan JOHN CLEGG CONSULTING LTD
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Glasgow in supplying it. All that is proposed with this option is to continue with the existing supporting activities, but for the Partners to become more involved in publicising information widely on the size of the wood fuel market within metropolitan Glasgow as more wood fuelled boilers are installed, and providing information of the potentially available wood supplies from the Green Network woodlands and from other woods in the area. This option is illustrated in diagram 9.1 and must be viewed in colour. 9.3. This option would also involve working with recycling and landfill operators to see if there are ways in which more of the green woody biomass from tree surgery work undertaken by the councils and private sector companies could be brought into the fuelwood supply chain rather than it going to landfill, or in some cases left on site. Overall this option involves almost no costs or risk for Partners. OPTION 2: ACCELERATE THE DEVELOPMENT OF THE FUELWOOD SUPPLY CHAIN 9.4. This option could be adopted at the same time as option 1 and involves the identification of a number of sites throughout metropolitan Glasgow where fuelwood can be either stored or collected prior to removal to other sites where it can be stored for the moisture content to fall. This would accelerate the development of a fuelwood supply chain based on all woods in metropolitan Glasgow, including woods in the Green Network and those in the private sector. A number of possible sites that have been identified while undertaking this study were listed in section 8, but a comprehensive survey was not carried out. These sites could then be opened to anyone that wishes to dispose of woody biomass including Councils, tree surgeons and householders etc. While those depositing woody biomass at the sites might not initially receive any money for the material while the fuelwood supply chain develops, a point might quickly arise where the site operator may pay for this material. This option is illustrated in diagram 9.2 and must be viewed in colour. 9.5. This option involves little costs to the Partners if the sites are already owned, and are not purchased, and it is also low risk. It is possible that it might be worth purchasing or leasing a site, and / or a covered area, in a particular area if it resulted in a significant reduction in transport distances for small quantities of woody biomass. They could be run as profit centres if chippers were on site. OPTION 3: SET UP DEDICATED FUELWOOD SUPPLY CHAIN CONTRACTS 9.6. This third option could be adopted on its own, or in combination with one of the other two options, and it would involve identifying specific woodlands within the Green Network area, and if necessary outside it, that would provide one or more dedicated fuelwood supply chains for one or more specified wood fuelled boilers. To do that would require the collection of detailed information on the amount of fuelwood each wood could provide on a sustainable basis while meeting their other management objectives; the purchase of harvesting and chipping equipment and vehicles to transport the material. It would also involve setting up a commercial contract with the organisation that was responsible for the operational activities which might also be required to meet the terms of a heat supply contract. By integrating the supply chain from the woods to the boiler the operator would capture the additional value added that comes from drying and converting woody biomass into wood fuel. This is illustrated in diagram 9.3 and must be viewed in colour. 9.7. The one area of woodland within the Green Network where this option might be potentially feasible is at Chatelherault Country Park where there are about 100 hectares of conifers and where South Lanarkshire Council’s plan is to convert them to broadleaves over the next 20 to 30 years. The conversion of these woods should provide a regular flow of potential fuelwood material as we understand that about two thirds of the trees are considered to be of poor quality. This option will no doubt be explored by the consultants that have recently been appointed by the Council to look at wood energy opportunities within the Council’s boundaries. 9.8. The organisation that took on a dedicated fuelwood supply contract could either be set up by one of the Councils, a social enterprise or the contract could be offered to the private sector. In all three cases there would be significant costs involved as well as risks for the operator, particularly in relation to ensuring there are adequate supplies of fuelwood that they can obtain from the woods while meeting many owners’ objectives of delivering biodiversity and an attractive landscape. The operator theoretically might have to compete for the supply tender initially with other wood fuel suppliers depending on what arrangements were made, which would be a further risk.
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Diagram 9.1: Option 1 - The Present Situation & How It Might Evolve
Wood Fibre So Existing & Potential Wood Fibre Sources
Recyled Wood
Outside Supplies
Single Trees
Woods
Woody biomass from Council operations is often chipped & returned to site or goes to landfill.
Felling
Extraction,
Private contractors seek alternative markets wherever possible to avoid gate fees.
Harvesting & Storage by private sector on a small scale for fire & fuelwood
Existing & Potential Markets
Green woody biomass also chipped & left on site.
External Markets
Wood Fuelled Boilers
Land Fill
Fire wood
Compost
Animal Bedding
Woody biomass not accepted at Civic Amenity Sites Quantities are small & almost all goes to alternative markets or landfill
Development of the wood fuel market will occur as more information on both the supply and demand for fuelwood becomes better known, and as prices rise, but it will be slow. It is possible that woody biomass from street trees and trees in parks, school grounds and cemeteries could find their way into wood fuelled boilers in metropolitan Glasgow, but it is more likely that the supplies and end uses will change very little. JOHN CLEGG CONSULTING LTD
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Diagram 9.2: Option 2 - Existing Activities & Supporting the Development of Aggregator Sites
Existing & Wood Fibre Wood So Potential Fibre Sources
Recycled Wood
Outside Supplies
Single Trees
Woods
Private sector or Council operations
Felling Extraction & Harvesting Develop Small, Local Aggregator Sites
Provided by Councils or private sector & operate as Profit Centres
Develop a few Large Aggregator Sites for Drying & Chipping
Use existing recycling operators, assist new businesses or operate by Councils
Transport/ Supply to Wood Fuel Markets Existing & Potential Markets
Green woody biomass also chipped & left on site.
Could be handled by recyclers or purchased by wood fuel suppliers External Markets
Wood Fuelled Boilers
Land Fill
Fire wood
Compost
Animal Bedding
Woods in Glasgow can increasingly supply local wood fuelled boilers
The existing wood promotion and support activities are continued. The establishment of small local aggregator sites, with no gate fees, will encourage tree surgeons, site clearers and households to deliver woody biomass to these sites with minimal travel costs. Large lorries can then take material to larger sites on the edge or outside urban areas where it can be stored as logs to dry before chipping and being supplied as a wood fuel. JOHN CLEGG CONSULTING LT D
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Diagram 9.3: Option 3 - Existing Activities, Development of Aggregator Sites & Dedicated Supplies
Green woody biomass supplied from specified woodlands
Re cycled Wood
Outside Supplies
Single Trees
Woods
Dedicated Wood Supply Chain
Develop small local aggregator sites &
Felling
Larger storage & chipping sites
Extraction Harvesting
In addition Councils could set up dedicated supply operations linking specific woods with one or more wood fuelled boilers.
Storage & Chipping Transport Supply to one or more specific wood fuel boilers
Existing & Potential Markets
Green woody biomass also chipped & left on site.
Alternatively this could be contracted to a private sector operator.
External Markets
Wood Fuelled Boilers
Land Fill
Fire wood
Compost
Animal Bedding
Woods in Glasgow can increasingly supply local wood fuelled boilers
The existing wood promotion and support activities are continued; small local aggregator sites and larger storage sites to dry woody biomass to required moisture content prior to chipping are established. In addition one or more dedicated supply chains are developed. This will require capital investment in harvesting, chipping & transport equipment & accurate information on potential wood biomass availability plus dedicated storage site/s. It provides potential to add value but there will be competition from other suppliers.
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PART 2 CONCLUSIONS & ACTIONS
10.1. The second part of this report has examined ways in which the development of the wood fuel market could provide opportunities for improving the management of the woods in the Green Network area, and elsewhere, and how this might be done. In this final section we set out our conclusions by linking our findings to those given in Part 1 and give the rationale for intervention by the Glasgow & Clyde Valley Green Network Partnership. CONCLUSIONS 10.2. The main conclusions reached are that:
•
• •
•
• • • •
There are some immediate opportunities for installing more wood fuelled boilers in metropolitan Glasgow. The combined size of all the boilers would be 7,630kW and the indicative capital cost of installing them is estimated to be £3.2 to £3.6 million. The saving in annual fuel costs is estimated to be about £330,000 at present price levels. The estimated amount of carbon saved annually would be just over 3,500 tonnes; The installation of these wood fuelled boilers would increase the market for wood fuel in metropolitan Glasgow by about 9,000 tonnes per annum at 30% MC; Most woods in the Glasgow & Clyde Valley Green Network area are being managed primarily to provide biodiversity and for landscape reasons but undertaking woodland management operations to achieve those objectives could result in the potential annual availability of 7,850 tonnes of wood fuel at 30% MC. This is slightly less than would be required to supply all the sites that have been identified where wood fuelled boilers could be installed. The shortfall in wood fuel for the boilers could be more than made up from the approximately 6,560 tonnes of woody biomass at 30% MC which it is estimated presently goes to landfill annually, or from the additional 25,155 tonnes of woody biomass material that is potentially available from other woods within the boundaries of Glasgow’s metropolitan councils; Whether fuelwood becomes available from the woods in the Green Network area will depend on woodland management operations being undertaken to assist in the delivery of biodiversity and landscape benefits, unless the objectives of owners change to one of primarily supplying wood fuel. Any fuelwood produced from the woods in the Green Network in excess of supplies needed for installed wood fuelled boilers at any point in time will find a ready market outside metropolitan Glasgow provided the chip specifications and quality consistently meet the required standards; Fuelwood is presently being supplied to wood fuelled boilers from outside metropolitan Glasgow, but it would be better environmentally if the wood fuel was sourced from woods within the area; There are no specific extant operational or technical issues to prevent the development of a fuelwood market and supply chain within metropolitan Glasgow. Based on a network of aggregator sites, chipping and storage facilities could each cost between £0.25 and £0.75 million per site depending on facilities available, and the equipment and covered storage required, and upwards of 3 operations might be viable in metropolitan Glasgow; The Glasgow & Clyde Valley Green Network Partners have 3 options for the degree of support that they could give to taking up the wood energy opportunities that exist for developing a wood supply chain within metropolitan Glasgow based on woods in the Green Network area:
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The first option would be to support the existing approach which involves leaving the existing interested government organisations to promote wood energy opportunities, such as Forestry Commission Scotland, and leaving the private sector to develop the market; The second option would be to accelerate the development of the wood supply chain in metropolitan Glasgow by identifying local sites throughout the area where woody biomass can be collected and left to dry, or moved to another site to dry in large lorries; The third option would be to set up dedicated fuelwood supply chains based on woods in the Green Network supplying specific local wood fuelled boilers. The latter could be set up by the councils or put out to tender but, in either case, this option will require significant investment to implement and will be more risky.
PROPOSED ACTIONS 10.3. Based on the conclusions reached, it is recommended that the Green Network (GN) Partnership:
• • • •
• • • • • •
Encourages the GN Partners to adopt policies involving climate change and sustainability to provide a policy setting for the installation of wood fuelled boilers; Encourages and supports individual Partner Councils to carry out detailed feasibility studies for the installation of wood fuelled boilers at the sites identified; Assists individual Partner Councils with finance, or arranging finance, for identified wood fuelled boiler installations where necessary; Raises awareness about the benefits of wood energy among the individual Partner Councils; the size of the market and the ready availability of wood fuel. This should be targeted specifically at the staff of Councils, the private sector operators who produce and handle woody biomass and the public. These activities should include the development of case studies and site visits where appropriate; Decides on which of the strategic fuelwood supply chain options they wish to adopt and proceed with one or more of them. Should the GN Partners decide on option 2, refine & agree strategic locations of woody biomass aggregator sites; Advises on the organisational arrangements for undertaking woodland management operations for individual Partner Councils; Advises the individual Partner Councils to prioritise woodlands in the Green Network area in relation to silvicultural & economic needs, and to proceed with undertaking the necessary operations that will result in fuelwood becoming available; Explores with Partner Councils the opportunities for removing gate fees on woody biomass / potential fuelwood; Explores the feasibility of developing a pilot woody biomass / fuelwood collection service for both public & private sectors; Discusses with tree surgeons and site clearance operators the possibility of working more closely with them on marketing and using woody biomass to minimise the possibility of woody biomass going to landfill.
10.4. There are some significant opportunities identified in this report in the rapidly developing wood JOHN CLEGG CONSULTING LTD
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energy market for the Glasgow & Clyde Valley Green Network Partnership to take forward. These opportunities should bring sustainable benefits to the woods in the area and helping in reducing the emission of carbon dioxide into the atmosphere. RATIONALE FOR GREEN NETWORK PARTNERSHIP INTERVENTION 10.5. The Green Network Partnership is in a strong position to assist in encouraging the development of wood fuel supply chains in metropolitan Glasgow and the installation of wood fuelled boilers over the next 3 years because: •
It will allow the scale of activities to be increased much more quickly than would otherwise be possible because it will have a strategic oversight of all activities in metropolitan Glasgow.
•
It will allow the development of the wood fuel market and the more sustainable management of woodlands to proceed more quickly than would otherwise be possible through supplying information and knowledge.
•
It is well positioned to encourage the development of the highest possible standards in the management of woodlands and the wood fuel supply chain, as well as in the installation of the most appropriate wood fuel boilers, at a time when knowledge is still relatively limited.
•
Its assistance in the development of a new market has the potential to improve the financial income of woodland owners in metropolitan Glasgow and this in turn should allow the citizens of metropolitan Glasgow to realise greater public benefits from woodlands through more sustainable woodland management. A further benefit though small in a global context will be the saving in the use of non-renewable fossil fuels and, in the longer term, the contribution to reducing global warming.
John Clegg Consulting Ltd The Campbell Palmer Partnership Ltd Cawdor Forestry Ltd December 2007
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ANNEX 1 DATA SOURCES AND CURRENCY OF THE NATIONAL INVENTORY OF WOODS AND TREES
Name: Digital Woodland Map for Scotland Scale: 1:25000 Data Source: The Land Cover of Scotland 1988 (LCS88) based on 1:25000 aerial photography (flown 1987-89) and OS mapping captured by MLURI for Scottish Office. Woodland Grant Schemes 1988-1995 – digitised from paper maps held by FC Scotland. 1995-2002 – WGS Digital data supplied by FC Scotland. FC New Planting 1988-1995 – digitised from FC paper maps. 1995-2002 – Digital data supplied by FC. Cloud & Urban Woodland – determined from NIWT survey of LCS88 data. Miscellaneous adjustments to original LCS88 as detected by Survey Foresters. Description Inventory
LCS88 Woodland Polygon >2ha Data updated by Woodland Surveys for the National of Woodland and Trees to include Forestry Commission (FC) new planting, New Woodland Grant Schemes, woodland in urban and woodland beneath cloud/shadow, at 31st March 2002. (Woodland areas are considered to have greater than 50% cover by tree crowns)
Feature Attributes Featcode: Interpreted forest type (IFT) Code IFT: Interpreted forest type (IFT)
e.g. 76
e.g. Broadleaved
Ref_date: Reference date Hectares: Area of Polygon in Hectares
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Feature Description Featcode IFT
Ref_date Description
70
Coniferous
310395
76
Broadleaved 310395
79
Mixed
310395
79
Mixed
310300 310301
82
Scrub
310395
83
Ground prepared planting
310395
84
Felled
310395
85
Young trees
310395
11
Young trees
310395
11
Young trees
310300 310301 310302
CONIFEROUS (plantation) - Conifers occur mainly as large plantations with well-defined edges and with trees of even age and height in regular rows. UNDIFFERENTIATED BROADLEAVED - comprises a wide range of woodland types from managed policy woodlands to dense b scrub. Tall scrub, comprising hazel, alder and willow or dominated birch, is also included within this category. UNDIFFERENTIATED MIXED WOODLAND - woods comprising a mixture of broadleaved and coniferous trees with at least 20% of e type. Areas of woodland generated by 2000 updating process. Merging data from various sources resulted in ‘gaps’ between polygons. Gaps of less than 50m and holes in woodland less than 1.0 Hectare, were assumed be woodland. UNDIFFERENTIATED LOW SCRUB - Occurring mainly on steep slopes in rugged terrain, gorse, broom, or occasionally juniper giving more tha 50% ground cover. RECENT PLOUGHING (unknown tree type) - Land recently ploughed preparation for tree planting. RECENT FELLING (unknown tree type) - areas where woodland has been felled and evidence of replanted trees cannot be seen. Areas of windblow will be included in this category. OPEN CANOPY (young plantation) - woodland, mainly coniferous plantation, between the stages of ground preparation by ploughing or ripping when no trees are evident and when the canopy of the develop wood closes. NEW GRANT SCHEMES - Areas of notified Woodland Grant Schemes not included in MLURI 1988 data capture. Polygons may represent the extent of approved/paid Grant Schemes and therefore do not necessarily indicate planted woodland throughout the whole polygon. Young trees should be present within the polygon. NEW GRANT SCHEMES - Areas of notified Woodland Grant Schemes 1995 – 2002. Polygons may represent the extent of approved/paid G Schemes and therefore do not necessarily indicate planted woodl throughout the whole polygon. Young trees should be present within polygon.
7
Young trees
310395
FC NEW PLANTING - additional areas of Forestry Commission new planting since MLURI data capture in 1988, up to 1995.
7
Young trees
310300
FC NEW PLANTING - additional areas of Forestry Commission new planting 1995 – 2002.
310301 310302 AREA IN CLOUD POLYGON - woodland areas obscured by cloud or
8
Coniferous
310395
9
Mixed
310395
AREA IN URBAN POLYGON - woodland within urban polygon.
68
Young trees
310395
FC LAND - Areas of Forestry Commission woodland missing from MLURI data identified during NIWT Area Analysis project.
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Extent: All Scotland Completion Reference date: 31st March 2002 Update: Based on FC new planting and grant schemes from 1st April 2002 to 31st March 2003 - will be available in 2004. Format: Arc Export (.E00) ArcView shapefile Other formats available on request Media: CD-ROM Spheroid: Airy Projection: Transverse Mercator Reference: OS National Grid Units: Metres Quality: Good Copyright: Forestry Commission Contact: Steve Smith - Head of Woodland Surveys, Forest Research, Forestry Commission HQ Tel: 0131-314-6357 Email: steve.smith@forestry.gsi.gov.uk or Graham Bull - Woodland Survey Officer (as above) Tel: 0131-314-6347 Email: graham.bull@forestry.gsi.gov.uk
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ANNEX 2 SUMMARY OF SCOTTISH NATIONAL AIR QUALITY OBJECTIVES Pollutant
To be achieved by
Air Quality Objective Concentration
Measured as
Benzene 16.25 µg m-3
All UK authorities
Running annual mean
31 December 2003
Authorities in Scotland and N. 3.25 µg m-3 Ireland
Running annual mean
31 December 2010
2.25 µg m-3
Running annual mean
31 December 2003
Authorities in Scotland Only
10.0 mg m-3
Running 8-hour mean
31 December 2003
Lead
0.5 mg m-3
Annual mean
31 December 2004
0.25 mg m-3
Annual mean
31 December 2008
200 µg m-3 not to be exceeded more than 1-hour mean 18 times a year
31 December 2005
40 µg m-3
31 December 2005
1,3-Butadiene Carbon Monoxide
Nitrogen Dioxide
Particles (gravimetric)
(PM10)
All authorities
Scotland Only
Particles (gravimetric) *
Annual mean
50 µg m-3, not to be exceeded more than 24-hour mean 35 times a year
31 December 2004
40 µg m-3
31 December 2004
Annual mean
50 µg m-3, not to be exceeded more than 24-hour mean 7 times a year
31 December 2010
18 µg m-3
Annual mean
31 December 2010
Annual mean
2020
(PM2.5) 25 µg m-3 (target)
All UK authorities
15% cut in urban background exposure
Annual mean
2010 - 2020
Authorities in Scotland Only
12 µg m-3 (limit)
Annual mean
2010
Sulphur dioxide
350 µg m-3, not to be exceeded more than 1-hour mean 24 times a year
31 December 2004
125 µg m-3, not to be exceeded more than 24-hour mean 3 times a year
31 December 2004
266 µg m-3, not to be exceeded more than 15-minute mean 35 times a year
31 December 2005
PAH *
0.25 ng m-3
31 December 2010
Ozone *
100 µg m-3 not to be exceeded more than Daily maximum of running 8- 31 December 2005 10 times a year hour mean
Annual mean
* not included in regulations at present
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ANNEX 3 DETAILS OF POTENTIAL WOOD FUELLED BOILER INSTALLATIONS IDENTIFIED
BRIDGE OF WEIR PRIMARY SCHOOL 1. Discussions with Mr John Douglas, Energy Manager for Renfrewshire Council, revealed that the Council has recently completed a programme of installing new gas-fired boilers in larger Council buildings. However, Mr Douglas was very keen to provide a site were the potential for biomass could be assessed and, hence, identified Bridge of Weir Primary School where oil-fired boilers are installed. 2. 1 Discussions with Mr John Douglas, Energy Manager for Renfrewshire Council, revealed that the Council has recently completed a programme of installing new gas-fired boilers in larger Council buildings. However, Mr Douglas was very keen to provide a site were the potential for biomass could be assessed and, hence, identified Bridge of Weir Primary School where oil-fired boilers are installed. 2 Bridge of Weir Primary School is located in Bridge of Weir, Renfrewshire and has over 400 pupils at the school. The building, erected in 1969 and maintained by Renfrewshire Council, is one storey and of single brick construction with minimal insulation and single glazing throughout. The building has a total floor area of approximately 3,200m2 and comprises classrooms, an assembly hall, kitchen, dining area and offices. Mr John Douglas, Energy Manager for Renfrewshire Council identified the school as being a possible candidate for the installation of a biomass boiler and requested that the feasibility of a biomass boiler be assessed as part of this study. Existing Heating System 3 The existing heating system comprises two oil-fired Hamworthy Broadstone boilers (estimated to be around 10 years old), each rated at 157kW input/130kW output, and one older Hamworthy boiler (estimated to be around 15 years old) rated at 355kW input/284kW output. The seasonal efficiency of the boilers is estimated to be 75%. The three boilers supply space heating, to a number of radiators and some fan convectors throughout the building, and hot water to a calorifier (estimated capacity of 4,000 litres), in the boilerhouse. A summary of the annual oil consumption and costs for the site is given in the table below. Utility
Energy Consumption
Cost
CO2 Emissions
Oil
500,000 kWh
ÂŁ18,500
125 tonnes
Heat Load and Fuel Consumption Analysis 4 The Janitor has records for oil consumption from November 2005 to November 2006 which were used to establish the patterns of oil consumption. Calculations were also carried out to estimate the peak and mean heating and hot water loads for the School as a check on the calculations carried out on the fuel data. The highest mean monthly power consumption is estimated to be 450kW whilst the annual mean power consumption is 290kW. Biomass Boiler Size 5 Analysis of the fuel usage data, before and after efficiencies of the existing boilers are taken into account, suggests that the highest mean load exceeds 300kW for only 10% of the time. Hence, a woodchip boiler, with a turndown ratio of 3:1 and rated at 300kW, with a 12,000litre buffer vessel, could supply the lowest mean load, outside summer months (around 100kW) efficiently and enable it to provide a substantial proportion of the heating and hot water load in the winter. The biomass boiler specified should be capable of handling woodchip fuel with a MC of up to 40%.
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6 A woodchip boiler with a rated output of 300kW fuelled by woodchips at MC of up to 40% is recommended. At lower MCs the boiler will require less fuel to provide the same output. The balance of the annual heating energy required would have to be provided by the existing oil boilers. 7 It should be physically possible to install a 300kW biomass boiler in the existing boiler house by removing the two smaller boilers and retaining the larger boiler oil-fired boiler for backup and peak demand. The buffer vessel would have to be installed external to the boiler house in a separate enclosure. Annual Woodfuel Requirement 8 For the purpose of calculating the woodchip fuel requirements it is assumed that woodchip would be delivered at a consistent MC of 30%. The calculation of the annual woodchip fuel requirement is based on the oil consumption calculated above and takes into account the seasonal efficiency of the existing oil boilers and the efficiency of a woodchip boiler. 9 Corrected for the oil and woodchip boiler efficiencies, and 90% of the energy supplied from woodchips, 397,060kWh of energy is required from woodchips. The minimum calorific value of woodchips at 30% MC is 3,421kWh per tonne, which means that 116 tonnes of woodchip would be required annually. The annual cost of woodchip fuel would be £5,800 priced at £50 per tonne. The annual cost of the residual 10% of oil is estimated to be £1,850 making a total annual energy cost for heating and hot water of £7,650. 10 The existing annual fuel cost for heating and hot water is estimated to be £18,500 for oil. The potential annual cost and CO2 savings on heating and hot water fuel would be around £10,850 and 103.2 tonnes respectively. Fuel Storage 11 A peak winter week, with the boiler operating continuously at full load, will require 4.4 tonnes of woodchips occupying 24m3. There are two options for the fuel storage at the school which are: Option 1 - Use the existing brick enclosure, contiguous to the boilerhouse, which currently houses the oil tank. This enclosure has a storage volume of around 26m3 which matches the fuel storage requirements for the school. However, a typical woodchip storage silo requires a square base (the enclosure currently has a rectangular floor, measuring 2.2m by 4.1m) to ensure the spring agitator (fuel sweeping mechanism located at the silo floor) can sweep all of the woodchip fuel onto the fuel feed auger to the boiler. Building works would be required to alter the shape of the existing enclosure whilst maintaining the required storage volume. There is space to the side of the boilerhouse and existing oil tank enclosure to install a new smaller oil tank. Option 2 – Construct a new storage silo in the field next to the boilerhouse. There is sufficient space in the field next to the boilerhouse to construct a woodchip storage silo with a storage volume of 24m3. The storage silo could either be installed above or below ground level. The advantage of installing a storage silo below ground level is that fuel can be tipped directly into the silo by a delivery lorry and this makes this the preferred option. Fuel Delivery 12 It is anticipated that the number of deliveries required, during a peak winter week’s heating conditions, could be up to 1 deliveries per week. The delivery mechanism would require careful thought and should, from a health and safety perspective, be carried out outside school hours. Delivery by tipper lorry would be the most efficient delivery method; however, a new storage silo would have to be constructed underground. If the existing oil enclosure could be modified to be used for fuel storage then woodchip fuel could be blown into the storage silo. To allow clear access to the boilerhouse, cars should not be permitted to park next to the boilerhouse. Summary of Savings and Installation Costs 13
The table on the next page summarises the savings and the estimated installation costs.
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Estimated Annual Savings
Recommendations
(£) Install a 300kW woodchip boiler and associated equipment OVERALL TOTALS
FINAL REPORT
kWh
CO2 (tonne)
: 61
Estimated Cost
Payback Period
(£)
(years)
£10,850
0
103.2
£130,000 £180,000
10.1
£10,850
0
103.2
£130,000 £180,000*
10.1
* The estimated installation cost excludes grants. 14
The annual maintenance costs are estimated to be £6,000.
CAPELRIG HOUSE _ EAST RENFREWSHIRE COUNCIL Introduction & Background 15 Discussions with Mr Hamish Campbell, Energy Manager for East Renfrewshire Council, revealed that the Council is currently considering installing a 10kW biomass demonstration project in a Council owned cottage. However, further discussion revealed that the Council may be interested in installing a biomass boiler in Capelrig House where the Council is considering replacing the existing oil-fired boiler with gas-fired boilers provided the cost to install a gas supply is not prohibitive. Hence, East Renfrewshire Council has identified the building as being a possible candidate for the installation of a biomass boiler, and requested that the feasibility of a biomass boiler be assessed as part of this study. 16 Capelrig House, located on the Grounds of Eastwood High School, Newton Mearns in East Renfrewshire, was erected in 1769 and is currently used as Council offices. The building has a total floor area estimated to be 800m2 over three storeys in the main building and 2 storeys in the extension. The building is A-listed and of solid stone construction with no insulation in the walls or the roof, and single glazed sash windows. Existing Heating System 17 The existing heating system comprises one Potterton Avon 241 oil-fired boiler (which has no rating plate and is estimated to be over 20 years old) which supplies low temperature hot water (LTHW) to a one-pipe heating system. The boiler is controlled by a timeswitch which is set to operate 24 hours per day otherwise comfortable room temperatures cannot be achieved in the building. Hot water in the building is provided by an electric immersion heater. The seasonal efficiency of the boiler is estimated to be no better than 70%. 18
A summary of the annual oil consumption and costs for the site is given in the table below. Utility
Energy Consumption
Cost
CO2 Emissions
Oil
144,000 kWh
£5,040
36 tonnes
Heat Load and Fuel Consumption Analysis 19 The mean monthly power consumption for heating is estimated to be 36kW based on the boiler firing, on average, 15 hours per day, 7 days per week, 38 weeks per year. Once the boiler’s seasonal efficiency, estimated to be 70% at best, has been taken into account this figure becomes 25kW. The
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peak heat loss, based on a peak heat loss density of 120 watts per square metre2, is estimated to be 90kW. This peak heat loss density is based on the building being heated, from cold, to 22C when the outside air temperature is -5C, however, the heating is permanently switched on and the building is, therefore, never heated from cold. With no boiler rating available from the existing boiler it is estimated that the boiler could be rated at 70kW output. Biomass Boiler Size 20 A biomass boiler, rated at 50kW and a 2,000 litre storage (buffer) vessel installed in parallel could provide at least 90% of the annual heating energy required. The balance of the annual heating energy required would have to be provided by either the existing, or a new, oil-fired boiler. The biomass boiler specified should be capable of handling woodchip fuel with a MC of up to 40%. 21 It would not be physically possible to install a 50kW biomass boiler and a 2,000 litre buffer vessel in the existing boilerhouse. The boilerhouse is located adjacent to a brick enclosure, which currently houses the oil tank, and a storage area (with refuse bins) which provides access to an emergency exit. If the existing boilerhouse could be extended into the storage area there would be sufficient space for the existing oil-fired boiler (for backup and peak heat loads), a 50kW biomass boiler and a 2,000 litre storage vessel. The existing fire exit may have to be altered if a biomass boiler were to be installed in this proposed area. Annual Woodfuel Requirement 22 For the purpose of calculating the woodchip fuel requirements it is assumed that woodchip would be delivered at a consistent MC of 30%. The calculation of the annual woodchip fuel requirement is based on the oil consumption above taking into account the seasonal efficiency of the existing oil boilers and the efficiency of a woodchip boiler. 23 Corrected for the oil and woodchip boiler efficiencies, and 90% of the energy supplied from woodchips, 106,730kWh of energy is required from woodchips. The minimum calorific value of woodchips at 30% MC is 3,421kWh per tonne, which means that 31 tonnes of woodchip would be required annually. The annual cost of woodchip fuel would be £5,800 priced at £50 per tonne. The annual cost of the residual 10% of oil is estimated to be £500 making a total annual energy cost for heating of £2,050. 24 The existing annual fuel cost for heating is estimated to be £5,040 for oil. The potential annual cost and CO2 saving on heating and hot water fuel could be £2,990 and 26.7 tonnes respectively. Fuel Storage 25 A peak winter week, with the boiler operating continuously at full load, will require 1.7 tonnes of woodchips occupying 6.5m3. The existing brick enclosure where the oil tank is stored has a total volume of 8.4m3 and could be modified, with minimal alterations required to the existing shape, to store woodchip fuel. There is sufficient space surrounding the building to install a new oil tank. Summary of Savings and Installation Costs 26
The table below summarises the savings and the estimated installation costs.
This peak heat loss density figure used is based on the results from detailed heat loss calculations carried out for buildings of a similar construction to Capelrig House.
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Recommendations
Estimated Annual Savings (£)
Install a 50kW woodchip boiler and associated equipment OVERALL TOTALS
FINAL REPORT
kWh
CO2 (tonne)
: 63
Estimated Cost
Payback Period
(£)
(years)
£2,990
0
27.8
£45,000 £75,000
£2,990
0
27.8
£45,000 £75,000*
15.0
15.0
* The estimated installation cost excludes grants. 27
The annual maintenance costs are estimated to be £2,000.
QUEENS PARK NURSERY – GLASGOW CITY COUNCIL Introduction 28 Discussions with Mr Warren McIntyre, Project Officer-Sustainable Development for Glasgow City Council (GCC), revealed that the Council is currently considering installing biomass boilers in four of the eight buildings identified in the ‘Wood Energy – City Produced Woodfuel for Renewable Heating’ report by produced by Steve Luker Associates in May 2007. The buildings being considered by GCC are Queens Park Nursery, East End Leisure Centre, Gorbals Leisure Centre and Shawlands Academy. In addition, the Council also has a number of buildings which currently have old coal boilers installed which are to undergo a programme of replacement and as part of the progressive replacement the Council is considering, where feasible, biomass boilers. As part of this study the Council identified Queens Park Nursery as being the primary candidate for the installation of a biomass boiler. 29 Queens Park Nursery, located within the grounds of Queens Park in the south side of Glasgow, was erected in the early 1900s. The grounds of the nursery comprise a listed building (used for offices), glasshouses (with a total floor area estimated to be around 2,200m2), workshops and storage sheds and car parking for land services staff. The glasshouses display a collection of sub-tropical plants, various types of flowers and foliage plants and ponds and tropical fish. Existing Heating System 30 Heating for glasshouses is provided by three, 37 year old, oil-fired Talisman Omega 1500 boilers with burners rated at 450kW each. In peak winter conditions two of the boilers will operate to supply heating to the glasshouses whilst one is used as a backup. The boilers are approaching the end of their working life (one of the boilers no longer operates) and are estimated to have a seasonal efficiency of no more than 65%. A summary of the annual oil consumption and costs for the site is given in the table below: Utility
Energy Consumption
Cost
CO2 Emissions
Oil
1,777,780kWh
£64,000
444 tonnes
Heat Load and Fuel Consumption Analysis 31 There are no records for oil consumption kept for the site and, hence, to establish heat loads the total oil consumption and basic heat loss calculations were carried out. The mean monthly power consumption is estimated to be 400kW based on the boilers firing for, on average, 16 hours per day, 7 days per week, 40 weeks per year. The peak heat load for the glasshouses, based on a peak heat loss density of 240W/m2 (and seasonal efficiency of boilers of 65%), is estimated to be 920kW. Once the seasonal efficiency of the boilers is taken into account, the peak and mean heat loads could be around JOHN CLEGG CONSULTING LTD
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600kW and 260kW respectively. Biomass Boiler Size 32 Without more detailed information on oil consumption or actual boiler efficiencies it is accessed that a boiler rated at around 400kW (ie between the calculated peak and mean heat loads) and a 8,000 litre storage (buffer) vessel installed in parallel could provide 85% to 90% of the annual heating energy required. The balance of the annual heating energy required would have to be provided by either the existing, or new, oil-fired boilers. It is recommended that, based on the age, condition and assumed seasonal efficiency of the existing oil-fired boilers, the Council installs a new oil-fired boiler which would provide backup (and peak lopping) to the proposed biomass boiler. The efficiency of a new oil-fired boiler could be up to 82% which would mean a boiler rated at 730kW (based on the calculations above) would be required to provide backup. 33 The extensive ground available in Queens Park Nursery means that there are a number of locations where the proposed biomass boiler could be installed. However, the optimum solution appears to be to convert part of the green storage sheds (located next to the site entrance and before the road access to the car park area) into a boilerhouse and install the woodchip boiler, backup oil boiler and buffer vessel. A short run of underground district heating pipe would have to be installed to connect to the heating system header in the existing boilerhouse. The storage silo could be installed to the north of the green storage shed, utilising the natural incline in the road for delivery lorries to tip woodchip into the silo. Some car spaces on the hill would have to be forfeited to allow delivery lorry access. Annual Woodfuel Requirement 34 For the purpose of calculating the woodchip fuel requirements it is assumed that woodchip would be delivered at a consistent MC of 30%. The calculation of the annual woodchip fuel requirement is based on the oil consumption above taking into account the seasonal efficiency of the existing oil boilers and the efficiency of a woodchip boiler. 35 Corrected for the oil and woodchip boiler efficiencies, and 90% of the energy supplied from woodchips, 1,223,530kWh of energy is required from woodchips. The minimum calorific value of woodchips at 30% MC is 3,421kWh per tonne, which means that 358 tonnes of woodchip would be required annually. The annual cost of woodchip fuel could be £17,900 priced at £50 per tonne. The annual cost of the residual 10% of oil is estimated to be £5,070 making a total annual energy cost for heating of £22,970. 36 The existing annual fuel cost for heating is estimated to be £64,000 for oil. The potential annual cost and CO2 saving on heating fuel would be around £41,030 and 306 tonnes respectively. Fuel Storage 37 A peak winter week, with the boiler operating continuously at full load, will require 16.6 tonnes of woodchips occupying 56m3. An example of the dimensions of storage silo required would be 5.3m by 5.3m by 2m high. If the method of fuel delivery is by tipping then the optimum shape of the base of the storage silo, in this case, would be square so that the spring agitator fuel reception mechanism can sweep all of the fuel into the auger feed to the biomass boiler. Summary of Savings and Installation Costs 38
The table on the next page summarises the savings and the estimated installation costs.
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39 Estimated Annual Savings
Recommendations
(£) Erect a Storage Silo Install a 430kW biomass boiler and associated equipment (including mechanical and civil works required) and connect to the existing heating system OVERALL TOTALS
kWh
CO2 (tonne)
Estimated Cost
Payback Period
(£)
(years)
-
-
-
-
£41,030
0
306
£200,000 £225,000
£41,030
0
306
£200,000 £225,000*
4.9
4.9
* The estimated installation cost excludes grants. 40
The annual maintenance costs are estimated to be £10,000.
RAVENSCRAIG REGIONAL SPORTS FACILITY – NORTH LANARKSHIRE COUNCIL Introduction and Background 41 The Ravenscraig Regional Sports Facility is being constructed on the site of the old Ravenscraig Steelworks by a consortium comprising North Lanarkshire Council, Sport Scotland and Ravenscraig Limited. Ravenscraig Limited is itself a consortium comprising Wilson Bowden Construction, Scottish Enterprise Lanarkshire and Corus. The steelworks site is being redeveloped into a new town to which Motherwell College is relocating, with a new town centre and a substantial housing development. The regional sports facility forms part of the strategy plan for the Commonwealth Games bid for 2014 where it would provide training facilities for athletes. The Regional Sports Facility will comprise: an unheated football hall measuring 112m x 80m, an athletics hall measuring 135m x 25.5m; a sports hall measuring 54m x 27m; and external sports pitches, all of which will be covered in Astroturf. 42 Discussions with representatives for North Lanarkshire Council revealed that the Council has applied for planning permission and funding for the installation of a biomass boiler to provide heating and hot water for Ravenscraig Regional Sports Facility. The proposed biomass boiler will be installed at the site subject to planning permission and funding being granted. Ravenscraig Regional Sports Facility is a new development and, hence, there is no consumption data available other than that calculated by this consultant in the ‘Heat Load Calculations’ section of the report below. Heat Load Calculations 43 Detailed calculations on heating and hot water loads have been carried out which showed that the total boiler energy output required could be 2,551,500kWh with an estimated mean heat load of 970kW. Biomass Boiler Size 44 A boiler sized on the mean heat and hot water load would be rated at an output of 1MW with a minimum efficient operating output of about 330kW. A woodchip boiler rated at 1MW with a 60,000 litre buffer vessel installed in parallel could provide up to 85% of the annual heating and hot water energy required. The balance of the annual heating and hot water energy required would need to be provided by gas-fired fuel boilers. Annual Woodfuel Requirement
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45 For the purpose of calculating the woodchip fuel requirements it is assumed that woodchip would be delivered at a consistent MC of 30%. The calculation of the annual woodchip fuel requirement is based on the estimated total annual energy output from the boiler of 2,551,500kWh for heating and hot water. Taking into account the estimated seasonal efficiency of the woodchip boiler of 82%, the energy required from woodchips is 3,111,590kWh per year. 46 The minimum calorific value of woodchips at 30% MC is 3,421kWh per tonne, which means that 910 tonnes of woodchip would be required annually. The annual cost of woodchip fuel could be £45,500 priced at £50 per tonne. If the same amount of output energy was to be provided by gas operating at a mean seasonal efficiency of 84%, 3,037,500kWh of input energy would be required. At the current mean price for gas of 3p/kWh this would cost £91,130. Hence, the potential savings from using a woodchip boiler are £45,630 and 577 tonnes of CO2. Fuel Storage 47 Ravenscraig Regional Sports Facility (RRSF) requires a minimum of 14 days fuel storage on site. This is calculated for the worst case winter conditions and represents the boiler operating continuously at 1MW for 14 days. At a woodchip MC of 30%, 50 tonnes of fuel would be required to provide 14 day’s fuel storage requiring 191m3 of storage space. The two fuel storage options currently being considered for the installation are an underground silo and on or more walking floors. Summary of Savings and Installation Costs 48
The table below summarises the savings and the estimated installation costs.
Recommendations
Estimated Annual Savings (£)
Install a 1MW biomass boiler and 60,000 litre buffer vessel associated equipment (including mechanical works) OVERALL TOTALS
kWh
CO2 (tonne)
Estimated Cost
Payback Period
(£)
(years)
£45,630
0
577
£240,000 £300,000
£45,630
0
577
£240,000£300,000*
5.3
5.3
* The estimated installation cost excludes grants. 49
The annual maintenance costs are estimated to be £12,000.
BROADWOOD STADIUM – NORTH LANARKSHIRE Background 50 North Lanarkshire Council (NLC) has applied for planning permission to install a 230kW biomass boiler at Broadwood Stadium and subject to approval will install the system. Broadwood Stadium, located in Cumbernauld, is a 10,000 all seated multi-use stadium complex comprising three stands, outdoor synthetic football pitches, a gymnastics centre and a leisure centre. Discussions with Council representatives revealed that detailed work has been carried out on the design and specification of the proposed biomass boiler and that further work would not be required as part of this study. However, the representatives stated that NLC would be interested in sourcing sustainable woodfuel at competitive costs. Hence, NLC is keen for the installation to be highlighted as a possible market for woodchip fuel in the greater Glasgow area. 51 As part of this study the potential annual woodfuel requirements for Broadwood Stadium have been calculated based on the following assumptions: JOHN CLEGG CONSULTING LT D
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•
Boiler operating at 70% of its rated output throughout the heating season;
•
Average heating season of 10 hours per day, 7 days per week, 36 weeks per year;
•
Woodchip fuel supplied at 30% MC.
: 67
52 The annual woodchip fuel requirement for the site could be around 119 tonnes. The annual cost of woodfuel could be £5,950 saving an estimated £9,500 (at the current mean price of 3.8p/kWh for oil). Summary of Savings and Installation Costs 53
The table below summarises the savings and the estimated installation costs. Recommendations
Estimated Annual Savings (£)
Install a 230kW biomass boiler and vessel associated equipment OVERALL TOTALS
kWh
CO2 (tonne)
Estimated Cost
Payback Period
(£)
(years)
£9,500
0
102
£100,000 £150,000
£9,500
0
102
£100,000£150,000*
10.5
10.5
* The estimated installation cost excludes grants. 54
The annual maintenance costs are estimated to be £5,000.
THE STATE HOSPITAL CARSTAIRS Introduction and Background 55 The State Hospital, Carstairs is Scotland’s secure psychiatric hospital operated by NHS Scotland. The Hospital is being totally redeveloped with the majority of buildings being demolished and replaced by new build. The redevelopment will comprise 22,000m2 of buildings, of which up to 20,000m2 will be new build. Of the 4 remaining buildings, two have been constructed within the last three years and the other two will be refurbished. 56 Fuel costs and environmental pressures are driving the design of the new buildings to be as energy efficient and environmentally sound as possible. The site is several km from the nearest gas main, and it has been established that extending the main to the hospital would be prohibitively expensive. While the hospital uses light fuel oil at present, its intention is to install a Biomass boiler to burn woodchips, with fuel oil as a back-up and to provide peak lopping in cold weather. The full design has been carried out and planning permission on the installation granted. Discussions with Steve Shon, Redevelopment Project Manager for the State Hospital, revealed that the Hospital would be very interested in sustainable woodfuel sourced at a competitive price. Heat Load Calculations 57 Detailed calculations on heating and hot water loads have been carried out which showed that the total boiler energy output required could be 3,419,600kWh with an estimated heat load of 800kW. Biomass Boiler Size 58 A boiler sized on the mean heat and hot water load would be rated at an output of 800kW with a minimum efficient operating output of about 270kW. A woodchip boiler rated at 800kW with a 38,000 litre buffer vessel installed in parallel could provide up to 85% of the annual heating and hot water energy required. The balance of the annual heating and hot water energy required would need to be provided by oil-fired fuel boilers. JOHN CLEGG CONSULTING LTD
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Annual Woodfuel Requirement 59 For the purpose of calculating the woodchip fuel requirements it is assumed that woodchip would be delivered at a consistent MC of 30%. The calculation of the annual woodchip fuel requirement is based on the estimated total annual energy output from the boiler of 3,419,600kWh for heating and hot water. Taking into account the estimated seasonal efficiency of the woodchip boiler of 82%, the energy required from woodchips is 4,170,240kWh per year. 60 The minimum calorific value of woodchips at 30% MC is 3,421kWh per tonne, which means that 1,220 tonnes of woodchip would be required annually. The annual cost of woodchip fuel could be £61,000 priced at £50 per tonne. If the same amount of output energy was to be provided by gasoil boilers operating at a mean seasonal efficiency of 84%, 4,070,950kWh of input energy would be required equivalent to 407,095 litres per annum. At the current mean price for gasoil of 38p/litre this would cost £154,700. Hence, the potential savings from using a woodchip boiler are £93,700 and 1,017 tonnes of CO2. Woodchip Fuel Silo 61 The preferred option at Carstairs Hospital is an underground fuel silo. At a woodchip MC of 30%, 68.5 tonnes of fuel would be required to provide 10 day’s fuel storage requiring 262m3 of storage space. This would require a silo measuring 9.3m x 9.3m with an average depth of 3m. To install such a large silo with an auger extract system would require a sloping floor such that the deepest part of the silo would be 4m deep or more. It is suggested that walking floor extraction system be installed. Summary of Savings and Installation Costs 62
The table below summarises the savings and the estimated installation costs. Recommendations
Estimated Annual Savings (£)
Install a 800kW biomass boiler and 38,000 litre buffer vessel associated equipment (including mechanical works) OVERALL TOTALS
kWh
CO2 (tonne)
Estimated Cost
Payback Period
(£)
(years)
£93,700
0
1,017
£350,000 £400,000
£93,700
0
1,017
£350,000 £400,000*
3.7
3.7
* The estimated installation cost excludes grants. 63
The annual maintenance costs are estimated to be £17,500.
NATIONAL SEMICONDUCTOR (UK) LTD 64 National Semiconductor, located in Greenock for over 30 years, specialises in manufacturing high performance analogue devices and subsystems for the electronics market including consumer goods and industrial and automotive applications. National Semiconductor owns and operates a factory on a 21 acre site, comprising Class 10,000 clean rooms, a warehouse, canteen, gym and offices. The plant operates 24 hours per day, 7 days per week throughout the year, without a shutdown. The plant is serviced by a Utilities Building containing three high temperature hot water (HTHW) dual fuel (gas/gasoil) boilers which operate at a temperature of 140C. National Semiconductor plans to install a biomass boiler to supply up to 90% of its annual hot water requirements. 65 An in-depth heat demand assessment was undertaken using weekly gas meter readings and heat meter data recorded every 30 seconds provided by the Client. This enabled the identification of the heating loads based on a 24 hour a day, 7 days a week operation. A biomass boiler rated at 1,200kW JOHN CLEGG CONSULTING LT D
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: 69
has been specified for installation at the site designed to take over 61% of the annual heat energy. A 1.2MW biomass boiler, operating continuously throughout the year, would require an estimated 3,500 tonnes of woodchip a year at 30% MC. A storage silo of approximate dimension 15m by 9m by 4m high would provide 11 days storage. This biomass boiler is planned for installation in 2008. IKEA, GLASGOW 66 The Glasgow IKEA retail outlet is located 5 miles west of Glasgow and was erected around 7 years ago. The site floor area is over 20,000m2 and operates 24 hours per day, 7 days a week. A Carbon Trust Initial Opportunities Assessment carried out by the Campbell Palmer Partnership over 2 years ago identified renewable energy technologies which could be considered for the Glasgow IKEA site. The report identified biomass as being a key opportunity for the company to reduce its CO2 emissions. Since the report fossil fuel energy costs have increased and the Company plans to install a biomass boiler rated between 800kW and 1,000kW to provide heating and hot water for the Glasgow IKEA store. 67 Discussions with the UK Maintenance and Energy Competence Manager revealed that the proposed biomass system is to be installed and commissioned by November next year and that consultants have been designing biomass systems for IKEA sites throughout the UK and Europe. The biomass systems are likely to be fuelled by wood pellet; however, the systems will be designed to take a proportion of woodchip also. Hence, IKEA would be very interested in the availability of a quality source of woodchip fuel at a competitive price which could be mixed with wood pellet fuel. The UK Maintenance and Energy Competence Manager granted permission for the IKEA Glasgow site to be identified in this report as a possible market for woodchip fuel in the greater Glasgow metropolitan area. 68 As part of this study the potential annual woodfuel requirements for IKEA Glasgow have been calculated based on the following assumptions: •
Boiler operating at 70% of its rated output throughout the heating season;
•
Average heating season of 15 hours per day, 7 days per week, 36 weeks per year;
•
Woodchip Fuel supplied at 30% MC;
•
15% of the total annual biomass fuel requirements supplied by woodchips.
69 Ten percent of the annual wood fuel requirement for the site supplied as woodchips would be about 100 tonnes. However, IKEA may, depending upon cost, be able to accept a greater proportion of woodchips increasing this tonnage. LOANINGDALE CENTRE (SCOTTISH CENTRES) Introduction and Background 70 Scottish Centres provide training and development programmes for schools, youth groups, social work services and special interest groups, at their five residential sites around Scotland. Discussions with the Chief Executive revealed that the organisation is interested in installing biomass boilers at their sites in Scotland. The Chief Executive requested that the feasibility of installing biomass boilers be assessed at two of their sites, the Loaningdale Centre and the Broomlee Centre (discussed below). 71 Loaningdale Centre, located in Biggar, South Lanarkshire comprises Loaningdale House, erected in 1858, and the residents building, erected in the 1960s with some annex blocks used as lodges and staff houses. The buildings are estimated to have a total floor area of 5,000m2 with minimal insulation and single glazed windows. Existing Heating System 72 Heating and hot water for the buildings are provided by a central boilerhouse and district heating system. The existing heating system comprises two kerosene oil-fired Clyde Combustion boilers each rated at 146kW input, and one new Potterton Eco Control NXR3 boiler rated at 227kW input. The seasonal efficiency of the boilers is estimated to be 75%. A summary of the annual kerosene oil consumption and costs for the site is given in the table on the next page: JOHN CLEGG CONSULTING LTD
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Utility
Energy Consumption
Cost
CO2 Emissions
Oil
667,690 kWh
£27,210
174 tonnes
Heat Load Analysis 73
Discussions with the Centre Manager revealed that: •
The peak daily kerosene oil consumption is around 500 litres or 4,785kWh. If heating demand is, on average, 14 hours per day during this time the mean peak heating load would be 350kW;
•
The lowest daily kerosene oil consumption is around 150 litres or 2,390kWh. If heating demand is, on average, 8 hours per day during this time the lowest mean heating load would be 180kW;
74 If the annual heating energy consumption is 667,690 kWh the mean annual heat load would be 200kW based on heating operating, on average, for 12 hours per day, 7 days per week, 40 weeks per year. Biomass Boiler Size 75 A biomass boiler, rated at 350kW and a 14,000 litre storage (buffer) vessel installed in parallel could provide an estimated 85% of the annual heating energy required. The balance of the annual heating energy would have to be provided by the existing oil-fired boilers. The biomass boiler specified should be capable of handling woodchip fuel with a MC of up to 40%. 76 It would not be physically possible to install a 350kW biomass boiler and a 14,000 litre buffer vessel in the existing boilerhouse, so that a new boilerhouse and fuel storage silo would have to be erected on the site for the proposed biomass boiler and buffer vessel. The extensive ground available in the Loaningdale Centre site means that there are a number of locations where the proposed biomass boiler could be installed. However, the optimum location for a new boilerhouse and storage silo would be behind the existing boilerhouse. This location would provide a natural incline for delivery lorries to tip woodchip into the silo. Annual Woodfuel Requirement 77 For the purpose of calculating the woodchip fuel requirements it is assumed that woodchip would be delivered at a consistent MC of 30%. The existing oil consumption is 667,690kWh. Corrected for the oil and woodchip boiler efficiencies and 90% of the energy supplied from woodchips, 500,770kWh of energy is required from woodchips. The minimum calorific value of woodchips at 30% MC is 3,421kWh per tonne, which means that 146 tonnes of woodchip would be required annually. The annual cost of woodchip fuel would be £7,300 priced at £50 per tonne. The annual cost of the residual 15% of kerosene oil is estimated to be £4,080 making a total energy cost for heating of £11,380. 78
The existing annual fuel cost for heating is estimated to be £27,210 for kerosene oil.
79 The potential annual cost and CO2 saving on heating fuel could be £15,830 and 130 tonnes respectively. Fuel Storage 80 Discussions with the Centre Manager revealed that he would like 2 weeks woodchip fuel storage volume available. Hence, if the woodchip boiler was to operate for, say, 14 hours per day at full load 24 tonnes of woodchip would be required occupying 95m3. An example of the dimensions of storage silo required would be 5.6m by 5.6m by 3m high. 81
The table on the next page summarises the savings and the estimated installation costs.
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Estimated Annual Savings
Recommendations
(£) Install a storage silo Install a 350kW woodchip boiler and associated equipment (including mechanical and civil works required) OVERALL TOTALS
kWh
CO2 (tonne)
: 71
Estimated Cost
Payback Period
(£)
(years)
-
-
-
-
£15,830
0
130
£180,000 £230,000
£15,830
0
130
£200,000 £230,000*
12.6
12.6
* The estimated installation cost excludes grants. 82
The annual maintenance costs are estimated to be £10,000.
BROOMLEE CENTRE Introduction and Background 83 Broomlee Centre, erected in 1939, is located in West Linton in Peeblesshire and is used by youth and adult groups. The centre comprises 12 single storey lodges of wood construction with single glazing. There are six accommodation buildings used by clients, two smaller accommodation blocks for staff and teachers, an assembly hall, dining hall, toilet and shower blocks and also the Centre Manager’s house on site. Three of the accommodation huts have been retrofitted with roof, wall and floor insulation, and a further three buildings at the centre have been retrofitted with loft insulation only. Also on site is a separately leased Meditation Hall which is due to come back under the centre’s full ownership next year. Existing Heating System 84 The lodges were originally heated by district heating with a central boilerhouse supplying low temperature hot water to a wet heating system in each lodge. There have since been standalone heating systems installed in each of the lodges with a complex combination of different fuel types and heating methods. Direct-fired LPG air space heaters supply heat to the Assembly and Dining lodges; electric heaters provide heating to three client accommodation blocks, the staff and teacher accommodation blocks and the Manager’s house; three client accommodation blocks and the separately leased Meditation Hall are each heated independently by their own kerosene oil boilers. 85 Two of the client accommodation buildings and Centre Manager’s house use electric immersion heaters to provide domestic hot water (DHW), whilst DHW for the remaining blocks is provided by a central oil boiler which uses the existing district heating pipework. 86 A summary of the annual fuel consumptions and costs for Broomlee Centre is shown in the table below. The costs and consumptions reflect the future potential heating of the toilet/shower blocks by electricity, which at present are not heated, and the inclusion of the Meditation Hall which is currently under lease, but is due to be under full ownership of the Centre again next year.
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Annual Energy Consumption (kWh)
Utility
Annual Cost (£)
Annual CO2 Emissions (tonnes)
Diesel
143,852
£5,164
36.0
Electricity
147,954
£16,275
63.6
Kerosene
148,770
£5,969
37.2
LPG
102,043
£3,885
21.8
542,619
£31,294
158.6
Total
*Note: Values for energy consumption are estimated from heat loss calculations of the buildings, due to a lack of detailed information at the site. Heat Load Analysis 87 With limited fuel consumption information available, heat loss calculations were carried out to identify the peak and mean heat loads for the site. The results of the calculations are given below: •
The peak heat load for all of the buildings on the site is estimated to be 430kW;
•
The mean heat load is estimated to be 215kW;
•
The annual hot water energy use is estimated to be 143,850kWh;
•
The annual heating energy requirements are estimated to be 398,770kWh.
Biomass Boiler Size 88 A biomass boiler, with a rating of around 300kW and a 12,000 litre storage (buffer) vessel installed in parallel could provide an estimated 85% of the annual heating energy requirements. It is estimated that a 300kW oil-fired boiler would be required to provide backup to those buildings which are currently heated by electric LPG heaters respectively. The existing oil-fired boilers for domestic hot water provision and space heating could be retained for backup and peak lopping. The balance of the annual heating energy would have to be provided by the existing oil-fired boilers. The biomass boiler specified should be capable of handling woodchip fuel with a MC of up to 40%. 89 There is insufficient space available in the existing boilerhouse to provide woodchip fuel storage and install a new 300kW biomass boiler and a 12,000 litre buffer vessel, but there is adequate space available next to the existing boilerhouse to install a new central biomass boilerhouse and fuel storage silo for the proposed biomass system. However, it is likely that the existing staff car spaces may have to be sacrificed in order to provide space. Existing underground ducts, which were once used for a district heating system, could be brought back into use for the proposed central biomass district heating system. Annual Woodfuel Requirement 90 For the purpose of the calculating the woodchip fuel requirements it is assumed that woodchip would be delivered at a consistent MC of 30%. The existing heating and hot water energy consumption is 542,620kWh. With a complex mixture of electric and oil heating systems on the site it is outwith the scope of this work to take the mixture of the efficiency of the systems into account. It is estimated that 461,230kWh of energy could be required if 85% of the energy could be supplied from woodchips. The minimum calorific value of woodchips at 30% MC is 3,421kWh per tonne, which means that 135 tonnes of woodchip would be required annually. The annual cost of woodchip fuel would be £6,750 priced at £50 per tonne. The annual cost of the residual 15%, supplied from oil boilers once all of the buildings are heated by wet heating systems, is estimated to be £2,800 making a total energy cost for heating of £9,550. JOHN CLEGG CONSULTING LT D
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91
The existing annual fuel cost for heating is estimated to be £26,130.
92
The potential annual cost saving on heating fuel could be £16,580.
: 73
Fuel Storage 93 Discussions with the Centre Manager revealed that she would like 2 weeks woodchip fuel storage volume available. Hence, if the woodchip boiler was to operate for, say, 14 hours per day at full load 20.2 tonnes of woodchip would be required occupying 80m3. An example of the dimensions of storage silo required would be 5.2m by 5.2m by 3m high. 94
The table below summarises the savings and the estimated installation costs. Recommendations
Estimated Annual Savings (£)
kWh
CO2 (tonne)
Estimated Cost
Payback Period
(£)
(years)
Install Wet Heating Systems
£50,000
Connect each building to the district heating system
£80,000
Install District Heating Pipework Erect a Biomass Boilerhouse and Storage Silo and Install a 300kW woodchip boiler, 300kW oil-fired boiler and associated equipment (including mechanical and civil works required) OVERALL TOTALS
-
-
£100,000
£16,580
0
Unknown
£150,000 £200,000
£16,580
0
Unknow n
£380,000 £430,000*
10.3
24
* The estimated installation cost excludes grants. 95
The annual maintenance costs are estimated to be £8,500.
WISTON LODGE Introduction and Background 96 Wiston Lodge, erected in the 1850s, is a B-listed building located on a 55 acre estate in Wiston, South Lanarkshire. Wiston Lodge was owned by the YMCA from 1947 before a staff management buyout in 2007. The Lodge is used to provide training days and courses in team building and experiential education for children, young people and adults. The building comprises bedrooms, public rooms, a games hall and offices and has an estimated total floor area of 1,600m2. In addition to the main Lodge there is the ‘Little Lodge’, located to the rear of Wiston Lodge and erected in the 1970s, housing classrooms. Discussions with the site Manager revealed that there are long-term plans to demolish the ‘Little Lodge’ and replace it with a new building. Existing Heating System 97 Heating for Wiston Lodge is provided by 2 kerosene oil-fired Trianco boilers each rated 87.5kW input/70kW output whilst hot water is provided by direct oil-fired Hamworthy DRSE 18P/P rated at 20kW input/16kW output (with a storage capacity of 300 litres) which has a backup 300 litre water storage tank. The boilers supply low temperature hot water (LTHW) to a one-pipe heating system and are JOHN CLEGG CONSULTING LTD
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estimated to have a seasonal efficiency of no better than 75%. The boilers are controlled to operate 24 hours per day otherwise comfortable room temperatures cannot be achieved in the building. A summary of the annual kerosene oil consumption and costs for the site is given in the table below: Utility
Energy Consumption
Cost*
CO2 Emissions
Kerosene Oil
379,400 kWh
£14,000
174 tonnes
* Estimated by site representative Heat Load Analysis 98 The mean monthly power consumption for heating is estimated to be 90kW based on the boilers firing, on average, 15 hours per day, 7 days per week, 38 weeks per year. Once the boilers’ seasonal efficiency, estimated to be around 70%, has been taken into account this figure becomes 63kW. The peak heat loss, based on a peak heat loss density of 120 watts per square metre3, is estimated to be 190kW. This peak heat loss density is based on the building being heated, from cold, to 22C when the outside air temperature is -5C, however, the heating is permanently switched on and the building is, therefore, never heated from cold. Biomass Boiler Size 99 A biomass boiler rated at 100kW and a 4,000 litre storage buffer vessel installed in parallel could provide about 90% of the annual heating energy required based on the current operation of operating the heating system continuously. The balance of the annual heating energy required would have to be provided by the existing oil-fired boilers. The biomass boiler specified should be capable of handling woodchip fuel with a MC of up to 40%. 100 There is insufficient space in the existing boilerhouse or adjacent rooms (the old coal bunker and water heater room) to install a 100kW biomass boiler, 4,000 litre buffer vessel whilst retaining the existing oil boilers. As the buildings are also listed it would be better to utilise the space behind the existing boilerhouse to erect a new boilerhouse and new storage silo. The ‘Little Lodge’ is located at least 2.5m above the level of the proposed site of the new boilerhouse and fuel storage silo. Hence, if the ‘Little Lodge’ is to be demolished then access could be provided for delivery lorries so that they can tip into the fuel storage silo. This is the most efficient method of fuel delivery; however, other delivery options for the site could be bagged delivery or by pneumatic conveying but these are not recommended. Annual Woodfuel Requirement 101 For the purpose of calculating the woodchip fuel requirements it is assumed that woodchip would be delivered at a consistent MC of 30%. The existing oil consumption is 379,400kWh. Corrected for the oil and woodchip boiler efficiencies and 90% of the energy supplied from woodchips, 281,200kWh of energy is required from woodchips. The minimum calorific value of woodchips at 30% MC is 3,421kWh per tonne, which means that 82 tonnes of woodchip would be required annually. The annual cost of woodchip fuel would be £4,100 priced at £50 per tonne. The annual cost of the residual 10% of kerosene oil is estimated to be £1,400 making a total energy cost for heating of £5,500. 102
The existing annual fuel cost for heating is estimated to be £14,000 for kerosene oil.
103 The potential annual cost and CO2 saving on heating fuel could be around £8,500 and 73 tonnes respectively. Fuel Storage 104 Discussions with the Centre Manager revealed that he would like 2 weeks woodchip fuel storage volume available. Hence, if the woodchip boiler was to operate for, on average, 15 hours per day at full
3
This peak heat loss density figure used is based on the results from detailed heat loss calculations carried out for buildings of a similar construction to Wiston Lodge.
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load 7.9 tonnes of woodchip would be required occupying 29m3. storage silo required would be 3.1m by 3.1m by 3m high. 105
: 75
An example of the dimensions of
The table below summarises the savings and the estimated installation costs. Recommendations
Estimated Annual Savings (£)
Erect a new Storage Silo and Biomass Boilerhouse Install a 100kW woodchip boiler and associated equipment (including mechanical and civil works required) OVERALL TOTALS
kWh
CO2 (tonne)
Estimated Cost
Payback Period
(£)
(years)
-
-
-
-
£8,500
0
73
£80,000 £130,000
73
£80,000 £130,000*
£8,500
11.7
12.6
* The estimated installation cost excludes grants. 106
The annual maintenance costs are estimated to be £5,000.
SCOTLAND STREET COMMERCIAL DEVELOPMENT Introduction and Background 107 A Masterplan is in preparation for a large commercial development on Scotland Street, Glasgow with a total developed area of about 50,000m2. This is likely to comprise offices with an area of 42,000m2, a hotel of 5,600m2 plus small retail, leisure and crèche developments. The site extends along the south side of Scotland Street from the Murgatroyd building to the corner of Shields Road and back to the railway sidings. The site will surround the historic Scotland Street School Museum. 108 A meeting was held with members of the Design Team to discuss the possibility of installing a district heating system, powered by biomass, for the site. There has already been some discussion between the client, Tiger Developments, and members of the design team about making this development an exemplar for best practice development, and the client was pleased to give permission for a preliminary evaluation of the potential for district heating and biomass to be carried out as part of this study. This involved: estimating peak and mean heating and hot water loads for the proposed buildings, and hence annual energy consumption; estimating the extent of the district heating network required; and initial cost estimates for the additional costs required for biomass and district heating. Heat Load Calculations 109
Detailed calculations on heating and hot water loads have been carried out which showed that: •
The peak heat input to the district heating network on a cold winter day 3.25MW;
•
The mean heat input to the district heating network on an average day during the heating season would be 1.25MW;
•
The peak heat input to the district heating network in summer would be about 900kW;
•
The mean heat input to the district heating network in summer would be about 300KW.
(-5C) would be
Biomass Boiler Size JOHN CLEGG CONSULTING LTD
THE CAMPBELL PALMER PARTNERSHIP LTD
CAWDOR FORESTRY LTD
: : 76
FINAL REPORT
ASSESSMENT OF G & CV WOOD ENERGY OPPORTUNITIES
110 A biomass boiler sized on the above loads would be rated at an output of 1.5MW with a minimum efficient operating output of about 400kW. A 60,000 litre buffer vessel installed in parallel could provide 80%-85% of the annual heating and hot water energy required for the site. The balance of the annual heating and hot water energy required would need to be provided by gas-fired fuel boilers. Annual Woodfuel Requirement 111 For the purpose of calculating the woodchip fuel requirements it is assumed that woodchip would be delivered at a consistent MC of 30%. The calculation of the annual woodchip fuel requirement is based on the estimated total annual energy output from the boiler of 4,693,000kWh for heating and hot water. Taking into account the estimated seasonal efficiency of the woodchip boiler of 85%, the energy required from woodchips is 5,521,000kWh per year. 112 The minimum calorific value of woodchips at 30% MC is 3,421kWh per tonne, which means that 1,600 tonnes of woodchip would be required annually. The annual cost of woodchip fuel could be £81,000 at £50 per tonne. If the same amount of output energy was to be provided by gas boilers also operating at a mean seasonal efficiency of 85%, at the current mean price for gas of 3p/kWh this would cost £166,000. Hence, the potential savings from using a woodchip boiler are £85,000 and 1,050 tonnes of CO2. Fuel Storage 113 One week’s fuel consumption on a peak winter week would be 42 tonnes of woodchip at 30% MC. To store one week’s supply of fuel would require a silo measuring 8m by 8m by a mean depth of 3m. The ideal location for this silo would be the southwest corner of the site where the adjacent Shields Road rises to the railway bridge outside the site. A slip road would be required to provide access to the site for articulated bulk carrier vehicles which could deliver up to 16 tonnes of fuel at a time. Hence, 3 deliveries per week would be required on cold winter weeks. Environmental Issues 114 The location of the site in an industrial area immediately adjacent to the M8 means that the usual issues surrounding large vehicle movements in cities should not be a concern at this site. The most significant environmental issue is the need to comply with the Clean Air Act, in particular to prevent the release of particulates and to avoid increasing local NOx emissions. The costing below includes for a wet scrubbing system on the boiler flue which would remove residual particulates and dissolve the NOx. Costs Included 115 The cost below includes for a boilerhouse, boiler, wet scrubber, flue, fuel silo, fuel fed system, district heating network, heat metering to all buildings, additional controls and a slip road. Summary of Savings and Installation Costs 116
The table below summarises the savings and the estimated installation costs. Recommendations
Estimated Annual Savings (£)
Install a 1.5MW biomass boiler
£85,000
kWh
CO2 (tonne) 0
1,050
Estimated Cost
Payback Period
(£)
(years)
£750,000
17.5
District heating system £750,000 OVERALL TOTALS 117
£85,000
0
1,050
£1,500,000
17.5
The annual maintenance cost for the biomass system is estimated to be £15,000.
JOHN CLEGG CONSULTING LT D
THE CAMPBELL PALMER PARTNERSHIP LTD
CAWDOR FORESTRY LTD
ASSESSMENT OF G & CV WOOD ENERGY OPPORTUNITIES
FINAL REPORT
: 77
EXISTING BOILER INSTALLATIONS Gartmore House, Stirlingshire 118 Gartmore House, an 18th Century Country Mansion located within the Loch Lomond and The Trossachs National Park, is owned and operated by The Gartmore House Trust, a Christian charity. The Trust has recently installed a 550kW Froeling Boiler and a district heating system to serve Gartmore House and other buildings on the site. The boiler can accept woodchip with a MC of up to 50%, and at present Gartmore House is purchasing felled timber with a MC of 50% or more, and is hiring a chipping contractor from Perthshire to chip on site. Peter Sunderland, the Chief Executive, is concerned that he is currently unable to source a reliable supply of woodchips locally, and is very interested in the possibility of a wood fuel supplier located to the north of Glasgow. 119 Gartmore House is located on the A81, 4 miles south of Aberfoyle and 15 miles north of the East Dunbartonshire boundary. Although Gartmore House itself is outwith the Green Network area, there is a clear business opportunity here for a wood fuel supplier located to the north of Glasgow and within the Green Network area being able to supply fuel, especially if fuel at a lower MC than 50% could be made available. Peter Sunderland estimates that up to 1,000 tonnes of woodfuel per year could be required at a MC of 50%, which translates to 650 tonnes per year at 30% MC. The original study and specification for this system was carried out by the Campbell Palmer Partnership who estimated that a minimum of 400 tonnes of fuel a year would be required based on the use of the buildings at the time of the study in November 2004. Since then, and encouraged by more reliable and cost effective heating systems, more extensive use is now being made of the buildings on site which will have increased the fuel demand. In summary, a minimum of 400 tonnes and a maximum of 1,000 tonnes of fuel per annum will be required depending on use of the buildings and MC. 120 Overall, between Gartmore House and the installations above, in excess of 1,300 tonnes of woodchip per year at 30% MC are required for these installations, and some of this could be supplied from the Green Network.
JOHN CLEGG CONSULTING LTD
THE CAMPBELL PALMER PARTNERSHIP LTD
CAWDOR FORESTRY LTD