Microrenewables Kevin Lindegaard Renewable Energy Development Officer Dorset County Council 24 April 2007
Microrenewables Heating • Solar water heating • Heat pumps • Pellet and log boilers Electricity • Photovoltaics (PV) • Small scale wind turbines • Micro hydro
Energy basics • Unit of power is the Watt (W) • 1 k. W = 1000 W • To convert power to energy multiply by number of hours • Using a 100 watt bulb for 10 hours = 1000 Watt hours = 1 k. Wh
Domestic energy use • Electricity = 2, 500 5, 000 k. Wh • Gas = 8, 00025, 000 k. Wh • Oil = 4, 000 litres 1 k. Wh of electricity costs 10 p 1 k. Wh of gas = 2. 5 p 1 k. Wh of oil = 4 p
Solar Water Heating Unglazed Flat plate Increasing efficiency/cost Evacuated tube
Domestic systems • • 50% of hot water needs overall 80 -100% of needs in summer 3 -4 m 2 array Roof should face between SE and SW and avoid shading 35 -45° pitched roof or mounted on Aframes Need to have new hot water tank 1500 -2000 k. Wh/year 20 -30 years useful life
What does it cost? Technology Evacuated tube 4 m 2 6 m 2 Installer / £ 3, 150 £ 4, 200 £ 5, 000 / / £ 1, 500 £ 2, 500 Installer / £ 3, 400 / / DIY / £ 2, 500 £ 4, 200 £ 5, 500 DIY Open (direct) 3 m 2 Installer Flat plate 2 m 2 DIY Closed Installation £ 2, 115 / DIY = VAT @ 17. 5% and no grant Installer = VAT @ 5% and £ 400 grant / /
What is the pay back? • Savings are best in off -gas areas DIY • Long paybacks but Flat plate fossil fuel prices increasing Evacuated tube Pay back* 9 years 17 years 31 years * Based on replacing on peak electricity saving £ 162 per annum
Opportunities • Domestic hot water (not heating) • New build eco homes • B&B, hotels • Swimming pools • Campsites
Heat Pumps • Ground source • Air source • Water source • Harness solar energy stored • in ground, air or water sources • Uses electricity to drive compressor to raise heat to useful temperature • 1 k. Wh of electricity in provides • about 3 -4 k. Wh of useful heating
Options • Provides space &/or DHW, (potential also for summer cooling) • Best niche is new build, because: - Well insulated - Combine with other works - Best with under floor heating • Limited visual impact
What does it cost? Cost including Grant distribution system 8 k. W Ground source HP £ 10, 000 -13, 000 7 k. W Air source £ 6, 000 HP 8 k. W Water £ 6, 500 Source HP Pay back ~15 -20 years £ 1200 £ 0
Biomass heating Room heater Herz Ökofen Extraflame Boilers Stove with back boiler Rika Kalorina KWB Thermia
Heating with wood pellets • • • Room heaters or back boilers 3 times greater density than wood chip Flowable Cheaper to transport than other biomass Compact and clean handling (dust free) for domestic market Automatic ignition and feed Cope with variable load demands and can be operated on a timer Integral hopper Very efficient with low emissions
Showstoppers? • Need space for fuel storage • Good access for deliveries • Bulk buying is best - bagged pellets are 2 x the price of bulk deliveries • More hands on • Ash removal
Log boilers Froling Pyromat Vigas
Log boilers Vigas 25 boiler • Very efficient and as sensitive and controllable as an oil boiler • 120 -litre log magazine - stores enough logs for about 14 hours burning • 4 kg/hour and will use about 12 tonnes or 25 m 3 of cut logs per year • Hands on – manual filling • £ 4, 500 (£ 5, 300 with 1000 litre accumulator tank)
25 year fuel costs Fuel type Unit cost 25 year cost* Heating oil 40 p litre £ 40, 714 Gas 2. 5 p/k. Wh £ 18, 750 Wood pellet Grain £ 160 tonne £ 85 tonne £ 24, 000 £ 15, 300 Logs £ 80 tonne £ 14, 100 * Based on annual fuel usage of 30, 000 k. Wh
How much do they cost ? Fuel type Boiler make and model Wood pellet Okofen 25 k. W Grain Kalorina 25 k. W Approx cost inc installation £ 15, 000 £ 7, 000 Logs £ 4, 500 Vigas 25 k. W £ 1500 grant available Pay back 5 -15 years versus oil
Photovoltaics (PV) Thin Film Polycrystalline Si Increasing efficiency/cost Monocrystalline Si
Photovoltaics (PV) • Use semi-conductor cells to convert light into electricity • Inverter turns direct current (DC) into alternating current (AC) which can be used or sold to the grid • Low maintenance, with 25 year lifespan • Can be roof mounted (bolt-on) or roof integrated • Work best in direct sunlight - need to avoid shading • Remote applications
PV Domestic system • • 1. 5 -2 k. Wp 12 -24 modules area of 12 -40 m 2 1500 k. Wh/year £ 12 -14, 000 30% grant available Lifestyle changes 800 k. Wh per annum would save about £ 96 per annum against buying electricity from the grid – no pay back
Roof mounted wind • Need to be on high buildings • Designed to work in turbulent conditions • Limited planning issues in non listed buildings • Wind speeds avg 3. 5 m/s • 1. 5 k. W – supposedly produces 1000 k. Wh p/a Swift 1. 5 k. W Windsave 1 k. W
What does it cost? Rotor (M) Rated power Power output p. a. at 5. 0 m/s 5. 5 m/s Total cost inc. installation LCBP Grant Windsave 1. 75 1000 W 883 k. Wh 1, 000 k. Wh £ 1, 600 £ 480 Swift 2. 1 1500 W 1, 031 k. Wh 1, 307 k. Wh £ 4, 500£ 6500 £ 1, 350 Pay back ?
Stand alone wind turbines Iskra 5 k. W Proven 2. 5 -15 k. W
Costs, outputs and sizes Proven 2. 5 k. W Proven 6 k. W Iskra 5 k. W Price inc installation £ 14, 000 £ 21, 000 £ 18, 000 Grant £ 2, 500 £ 5, 000 6. 5 or 11 9 or 15 12 or 15 3. 5 5. 7 Tower height (m) Blade diameter (m) Output (k. Wh/yr) Pay back ~11 years 3, 500 at 5 ms 10, 000 at 5, 000 at 4 5 ms ms
Micro Hydro • Run of river schemes e. g. historic water mills or hilly areas with spring fed streams • Generally < 100 k. W • Can be used in rivers with as little as 1 m heads • Most cost effective of all renewable resources where suitable sites exist
How it works
Micro Hydro – pros & cons þ þ þ ý ý Weirs and leats are in many cases still usable Zero annual fuel costs & low running costs Long lifetime - generator (15 yrs), turbine (25 yrs) High reliability and availability High load factor (50 -70%) Reasonable pay back period (<10 years) River flow rates vary so low output in summer Grid connections can be expensive Low electricity prices paid to small producers Planning
How much does it cost? • • Installation costs ≈ £ 2000/k. W A 10 k. W system would cost £ 20, 000 LCBP grant - max of £ 5000 Payback = 9. 5 years
More information • Low Carbon Buildings Programme www. lowcarbonbuildings. org. uk • Energy Saving Trust case studies www. est. org. uk/myhome • Dorset Energy Group www. dorsetforyou. com/climatechange • Renewable Energy Association www. r-e-a. net
More information • Solar Trade Association www. greenenergy. org. uk/sta • Ground Source Heat Pump Association www. nef. org. uk/gshp • British Wind Energy Association www. bwea. com/small • British Hydropower Association www. british-hydro. org • Biomass Energy Centre www. biomassenergycentre. org. uk 01420 526197 • Woodfuel South West Advice Service 08450 740674 • Woodfuel suppliers www. logpile. co. uk 01908 665555
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