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 kW = 1000 W • To convert power to energy multiply by number of hours • Using a 100 watt bulb for 10 hours = 1000 Watt hours = 1kWh

Domestic energy use

• Electricity = 2,500 - 5,000 kWh • Gas = 8,000 25,000 kWh • Oil = 4,000 litres

Lights and appliances 13% Energy Use in the Home Cooking 5% Hot water 24% Heating 58%

1 kWh of electricity costs 10p 1 kWh of gas = 2.5p

1 kWh of oil = 4p

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 • 3-4m 2 array • Roof should face between SE and SW and avoid shading • 35-45° pitched roof or mounted on A frames • Need to have new hot water tank • 1500-2000 kWh/year • 20-30 years useful life

What does it cost?

Technology Installation Closed Flat plate Open (direct) Installer DIY Installer DIY Evacuated tube Installer DIY 2 m2 / / / / £4,200 £2,115 3 m2 £3,150 / £3,400 £2,500 £5,500 / 4 m2 £4,200 £1,500 / / 6 m2 £5,000 £2,500 / / / /

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 • Long paybacks but fossil fuel prices increasing DIY Flat plate 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 kWh of electricity in provides •about 3-4kWh 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?

8 kW Ground source HP 7 kW Air source HP 8 kW Water Source HP

Cost including distribution system Grant

£10,000 -13,000 £6,000 £6,500 £1200 £0 £0 Pay back ~15-20 years

Biomass heating

Room heater Boilers

Herz Extraflame

Stove with back boiler

Rika Kalorina Ökofen 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 2x the price of bulk deliveries • More hands on • Ash removal

Log boilers

Vigas Froling Pyromat

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 Heating oil Gas Wood pellet Grain Logs Unit cost 40p litre 2.5p/kWh £160 tonne £85 tonne £80 tonne 25 year cost* £40,714 £18,750 £24,000 £15,300 £14,100

* Based on annual fuel usage of 30,000 kWh

How much do they cost ?

Fuel type Boiler make and model Wood pellet Okofen 25 kW Grain Kalorina 25 kW Logs Vigas 25 kW Approx cost inc installation £15,000 £7,000 £4,500 £1500 grant available Pay back 5-15 years versus oil

Photovoltaics (PV)

Thin Film Polycrystalline Si Monocrystalline Si Increasing efficiency/cost

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

• 1.5-2kWp • 12-24 modules area of 12-40m 2 • 1500 kWh/year • £12-14,000 • 30% grant available • Lifestyle changes • 800 kWh 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 kW – supposedly produces 1000 kWh p/a

Swift 1.5 kW Windsave 1 kW

What does it cost?

Windsave Swift Rotor (M)

1.75

2.1

Power output Rated p.a. at power 5.0 m/s 5.5 m/s

1000W 1500W 883 kWh 1,031 kWh 1,000 kWh 1,307 kWh

Total cost inc. installation

£1,600 £4,500 £6500

LCBP Grant

£480 £1,350 Pay back ?

Stand alone wind turbines

Proven 2.5 -15 kW Iskra 5 kW

Costs, outputs and sizes

Price inc installation Grant Tower height (m) Blade diameter (m) Output (kWh/yr)

Proven 2.5 kW

£14,000 £2,500 6.5 or 11

Proven 6 kW

£21,000 £5,000 9 or 15

Iskra 5 kW

£18,000 £5,000 12 or 15 3.5

5.5

5.7

3,500 at 5 ms 10,000 at 5 ms 5,000 at 4 ms Pay back ~11 years

Micro Hydro

• Run of river schemes e.g. historic water mills or hilly areas with spring fed streams • Generally < 100 kW • Can be used in rivers with as little as 1m heads • Most cost effective of all renewable resources where suitable sites exist

How it works

Micro Hydro – pros & cons

          Weirs and leats are in many cases still usable Zero annual fuel costs & low running costs Long lifetime - generator (15 yrs), turbine (25yrs) 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/kW • A 10 kW 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

• Woodfuel South West Advice Service 01420 526197 08450 740674 • Woodfuel suppliers www.logpile.co.uk

01908 665555