From Verge Grass to Bio-Fuel – a possibility to make conservation pay? Dr Nick Cheffins, Peakhill Associates Ltd
Low Input High Diversity (LIHD)Biomass: Key questions • The biological potential of LIHD Biomass as a feedstock for bio-fuel (and other industries)? • What technologies should we consider? • Can a supply chain be built that will allow LIHD Biomass to be processed into a renewable asset? • What are the economic, regulatory and social, implications for developing LIHD Biomass supply and processing chains?
Low Input High Diversity (LIHD)Biomass Segregated LIHD biomass from rural road verges and other linear landscapes can yield
Woody biomass
Coarse seed headed grasses and other herbaceous material
Fine grass cuttings
European Verge harvesting technologies tested between 2016 - 2019 Belgian Herder Kontannier self propelled verge harvester with integral trailer
Mulag harvester system mounted onto a Mercedes Unimog tool carrier with demountable trailer
Cut and Collect verge Harvesting 2018 - 2019 Lincolnshire Verge Harvesting Ltd designed and built verge harvester. Support funded by Lincolnshire LEP Innovation grant 2017. First highways test 2018.
1.2m cut and collect flail with suction arm with eight tonne (26m3) interchangeable trailer Harvester aims to harvest up to 80 tonnes per day at minimum forward speed of 5kph
Anaerobic digestion: first target technology as a conversion route for LIHD Biomass to biofuels • Slightly different populations of microbes are dominant at each stage of the process • Stages 1 to 3 happen fast – due to a range of acidogens that like pH 5.5 – 6.0 • Stage 4 happens more slowly – the methanogens evolve the pH to between 7.0 – 8.5 • The AD design compromise is often to have one tank for stages 1-3 & a second for 4
Methanogenesis tank (second stage)
Digestate storage tank (Final stage)
Feedstock mixer
Hydrolysis tanks X 2 ( First stage)
‘Wet’ continuous flow Anaerobic Digester that is capable of utilising LIHD Biomass for up to 30% of its feedstock intake
Dry Anaerobic Digestion • Uses a wider ranger of higher dry matter material • Holds material for a longer period up to four months • Produced biogas and a solid residue
LIHD Biomass tissue changes during a season’s growth: Rodriguez et al. (2017).
Seasonal changes in LIHD tissues can alter economic performance Dry matter yield t / km
Digestiblity = bio-methane yield / unit dry matter
March
April
May
June
July
Aug
Sept
Oct
Nov
Monetary value / t feedstock to AD plant operator function of dry matter digestibility and content
LIHD Biomass and AD operations Possible cooperative / CIC led harvesting venture H1
Centralised silage store
H2
AD or other use
H3
Bids for verge management subcontracts within Local Highways Partnership covering 10km average radii areas
Silage is denser and stable compared to as fresh LIHD biomass. Can be supplied to contract and moved longer distances (up to 15km)
LIHD Biomass v Field grown Energy Crops Benchmark variable costs for AD energy crop production (2018 Agricultural Budgeting and Costing 86th ed. Agro Business Consultants Ltd www.abcbooks.co.uk ) Contractor charges / ha
ÂŁ/ha
Cultivation
Ploughing Harrow precision drill rolling spraying Fertilizer Total Input (Seed, fertilizers & crop protection)Costs / ha Maize inputs / ha Grass inputs / ha Hybrid rye inputs / ha Complete silage harvesting costs /ha at specified tonnage maize grass hybrid rye LIHD Biomass Cost / t fwt at benchmark tonnages
Permanent pasture
Maize
Hybrid rye LIHD Biomass
55 45 42
28 24 194
55 45 42 12 14 24 50
28 24 194
0 0 0 0 0 0 0 0
436 154
346 t Fwt/ ha 38 26 36 13
165 135 143.00 20.92
13.04
18.97
135 10.80
LIHD Biomass producer cooperative and AD propositions • If an cooperative can sell 2,500 LIHD at £18 / t FWt and entails harvesting and ensiling costs of £10.80 the transaction would produce a gross margin of £18,000 minus costs of transport to the AD plant. • If the AD plant substitutes the biomass for its farm grown maize it could save around £7,300 on its feedstock production costs. • However if the LIHD is purchased it could release land for other crops. • Using a winter wheat bench mark gross margin of £728/ha this could realise an increase of £47,894 • Taken together the receiving farm / AD operation might see a variable cost improvement of £55,195.
New and emerging technologies • Developing LIHD as waste stream for anaerobic digestion or equivalent bio fuel producing technology • Some key technology is already available to utilise this class of waste stream • Comminution technologies & thermophilic AD hydrolysis to improve existing digester performance • ‘Dry’ Anaerobic Digestion • Bio refining for fuels and organic materials
• Essential to establish partnerships to achieve an economic scale in both the supply chain and conversion technologies
Challenge of the status of road verge biomass within the regulatory framework and waste classification • Under the EU’s Waste Framework Directive Cut & Collected LIHD Biomass from road verges is considered to be a waste as it is a “substance… …which the holder discards…” because it is “an unwanted by product of a process” •
https://www.gov.uk/government/publications/legal-definition-of-waste-guidance/decide-if-a-material-is-waste-or-not
• Many AD plants are not registered under Standard Rules (SR) p rmits to accept waste • Safety levels of any the major chemical contaminants are not breached by LIHD verge biomass • Further work needed to accurately assess levels of plastic contamination on rural road verges • Separating AD digestate fibre before spreading liquid fertilizer to land may be a good option.
Policy and Strategic options on status of LIHD Biomass from road verges • Seek to have verge biomass admitted to Standard Rules (SR) permit 2012-10 AD sites under a List of Waste code variant of 02-01-03 that included ‘Plant tissue waste from non-farmed landscapes’. This could include road verges, common land, public green spaces and nature reserves where there was no holding number, or... • Seek to have verge biomass classified under List of Waste code 20-0201 citing current EA operational practice and add that to the SR 201210 permits. • Continue research into LIHD Biomass as a class of lignocellulosic biomass as a bio refinery feedstock.
Verge conservation organisations as LIHD entrepreneurs • May have to work at a different scale – several 1,000’s km of road verge • Form a new structures; e.g. an arms length trading company, a cooperative, a CIC etc. • With new partners – Local highways Partnerships, other holders of ‘non farmed landscapes’ – sea defence owners, National Trust, RSPB etc. • Offering new services – semi commercial harvesting , storage & transport • Serving new customers – Local Highways Partnerships, AD operators, Biorefineries • Aiming to recover some / all of the costs of managing verges for biodiversity – possibly making a profit!!
Recyclates: glass, metals, plastics, paper timber etc RDF: plastics, timber, card & paper OFMSW: residual food & other organic wastes including contaminated paper and card sent to either / or LIHD Biomass: enters with comingled food and green waste stream from local council
Biofuels and/or platform chemicals for local bio based industry with negligible residues
Biomethane to road fuel or heat/electricity + residual biomass to land, composting or combustion
Thank you for your attention and patience! Dr Nick Cheffins Nick.Cheffins@Peakhill-associates.co.uk +44 7812096682