WIND & SOLAR ENERGY RESOURCE STUDY
Mike Glanfield EPSILON CONSULTANTS (IOM) LIMITED
INTRODUCTION: Epsilon Consultants (IOM) limited were commissioned by Nationwide International to carry out a 12 months investigation into exploiting the wind & solar energy resource on the roof of the Isle of Man headquarters building at the following site address: Nationwide International Samuel Harris House 5 – 11 St Georges Street Douglas Isle of Man IM1 1AJ The site location is shown on the following map reprinted from Google Earth:
Figure 1.0 St. Georges Street, Douglas.
The scope of this study does not extend to making a recommendation for a particular model of wind turbine generator (WTG) or solar PV array. Example power outputs and cost estimates for a selection of devices shown on the Power Predictor website are included elsewhere in this report for informational purposes only.
Nationwide International
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COMMENTARY: The device selected for wind & solar monitoring was the Power Predictor 2.0 supplied by Better Generation Limited and recorded the following data onto a standalone data logger fitted to the base of a 3.6 metre high mast:1) Wind speed (m/s) 2) Wind direction 3) Solar irradiation (w/m2) 1. Wind speed The wind speed data for the 12 month period of measurement is reprinted below from the Power predictor webpage and the results are described as “fairly low wind�. The average and modelled wind speeds for the site and are also shown overlaid on the chart.
Figure 1.1 measured wind speed data (m/s)
Average monthly measured wind speeds ranged from 2.5 m/s in July 2012 to 6.0 m/s in December 2013 with an average wind speed for the entire measurement period calculated to be 4.0 m/s. The measured average wind speed data for each month of site monitoring is shown in the table below and displayed on the bar chart that follows:
Nationwide International
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Month June 2013 July 2013 August 2013 September 2013 October 2013 November 2013 December 2013 January 2014 February 2014 March 2014 April 2014 May 2014 Annual average
WIND SPEED RESULTS Average wind speed (m/s) 2.7 2.5 3.1 3.6 4.4 3.2 6.0 4.9 6.2 4.3 3.3 3.3 4.0 m/s
Average wind speed (mph) 6.0 5.6 6.9 8.0 9.8 7.1 13.4 10.9 13.9 9.6 7.4 7.4 8.8 mph
Table 1.1 average wind speeds
Figure 1.2 average wind speeds (m/s)
The minimum average wind speed value by which a wind turbine generator becomes economically viable is generally given as 4.0 m/s so this site only just qualifies under this criterion.
Nationwide International
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The fairly low wind speed results are reflected in the low capacity factors and annual power yields for wind turbine generators shown in the power report. This is turn translates into lengthy payback periods for a wind turbine installation that are reflected in the two financial illustrations. The software used by the suppliers includes modelled wind speed data based upon the topography for this site gives a modelled mean wind speed of 4.9 m/s. The measured overall average wind speed of 4.0 m/s is slightly lower than the modelled data. 2. Wind direction The following results show that for the measurement period the dominant wind direction for the site is from the Northwest (21.4%) to the Southwest (18.7%) quadrant with the wind blowing consistently from the West for the greatest percentage of the time (30.5%).
Figure 2.1 wind direction
Wind directional information is important in helping to determine the optimum location of a wind turbine generator if an installation is to be considered in due course.
Nationwide International
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3. Solar irradiation The solar irradiation data for the 12 month period of measurement is reprinted below from the Power predictor webpage and the results are described as “weak solar�. The average and modelled solar irradiation levels for the site and are also shown overlaid on the chart.
Figure 3.1 measured solar irradiation data (w/m2)
Average monthly measured solar data ranges from 17.7 w/m2 in December 2013 to 170.3 w/m2 in July 2013 with an overall average solar irradiance for the 12 month period calculated to be 82.5 w/m2. The measured solar irradiation data for each month of site monitoring is shown in the table below and displayed on the bar chart that follows:
Nationwide International
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SOLAR IRRADIATION RESULTS Solar irradiation (w/m2)
Month June 2013 July 2013 August 2013 September 2013 October 2013 November 2013 December 2013 January 2014 February 2014 March 2014
151.2 170.3 119.8 78.8 46.3 39.6 17.7 20.5 41.8 82.5
April 2014 May 2014 Annual average
116.6 69.8 82.5 w/m2 Table 3.1 solar irradiation (w/m2)
Figure 3.2 solar irradiation (w/m2)
Nationwide International
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The weak solar irradiation results are reflected in the low capacity factors and annual power yields for solar PV arrays shown in the power report. This is turn translates into lengthy payback periods for a solar PV installation as indicated in the two financial illustrations. The software used by the suppliers utilises modelled solar irradiance data based upon the topography for this site gives a modelled mean solar irradiance of 107.1 w/m2. The measured overall average solar irradiation of 82.5 w/m2 is lower than the modelled data. 4. Power report The power report reprinted below from the Power Predictor website enables comparisons to be made between the estimated capital costs, capacity factors, power outputs, carbon savings and payback periods for a selection of wind turbine and solar PV devices.
Nationwide International
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5. Example financial reports Example financial illustrations for wind turbine generators and solar PV arrays are included below and are based upon the unit cost of electricity currently payable on the Isle of Man (commercial tariff): 5.1
AMPAIR 6.0 kW wind turbine generator
Make & model: Ampair 6kW Blade diameter Rated output Estimated cost Capacity factor Predicted energy generation Percentage used on site Carbon saving Cost of electricity Gross savings per annum Annual maintenance cost Net savings per annum Simple payback Annual ROI
5.2
5.5 metres 6.0 kW £15,000 8.4 % 4,235 units 100% (assumed) 2,287 kg £0.1353 per unit £573 £300 £273 55 years 1.8 %
WESTWIND 10 kW wind turbine generator
Make & model: Westwind 10kW Blade diameter Rated output Estimated cost Capacity factor Predicted energy generation Percentage used on site Carbon saving Cost of electricity Gross savings per annum Annual maintenance cost Net savings per annum Simple payback Annual ROI
Nationwide International
6.2 metres 10.0 kW £40,300 6.5 % 5,475 units 100% (assumed) 2,956 kg £0.1353 per unit £740 £300 £440 92 years 1.1 %
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5.3
WESTWIND 20 kW wind turbine generator
Make & model: Westwind 20kW Blade diameter Rated output Estimated cost Capacity factor Predicted energy generation Percentage used on site Carbon saving Cost of electricity Gross savings per annum Annual maintenance cost Net savings per annum Simple payback Annual ROI
5.4
9.8 metres 20.0 kW £69,000 7.8 % 13,106 units 100% (assumed) 7,077 kg £0.1353 per unit £1,773 £300 £1,473 47 years 2.1 %
KYOCERA 2.7 KWp PV array
Make & model: Kyocera KD Type Estimated cost Capacity factor Predicted energy generation Percentage used on site Carbon saving Cost of electricity Gross savings per annum Annual maintenance cost Net savings per annum Simple payback Annual ROI
5.5
Polycrystalline £14,559 8.4 % 1,913 units 100% (assumed) 1,033 kg £0.1353 per unit £259 nil £259 56 years 1.8 %
SUNTECH 2.8 KWp PV array
Make & model: Suntech VD Type Estimated cost Capacity factor Predicted energy generation Percentage used on site Carbon saving Cost of electricity Gross savings per annum Annual maintenance cost Net savings per annum Simple payback Annual ROI
Nationwide International
Polycrystalline £15,700 7.1 % 1,674 units 100% (assumed) 904 kg £0.1353 per unit £226 nil £226 69 years 1.4 %
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5.6
SHARP 2.5 KWp PV array
Make & model: Sharp ND Type Rated output Estimated cost Capacity factor Predicted energy generation Percentage used on site Carbon saving Cost of electricity Gross savings per annum Annual maintenance cost Net savings per annum Simple payback Annual ROI
Nationwide International
Polycrystalline 2.5 kWp £14.763 7.5 % 1,554 units 100% (assumed) 839 kg £0.1353per unit £210 nil £210 70 years 1.4 %
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