Renewing London’s Energy Godfrey Boyle Co-Director, Energy & Environment Research Unit, Open University +Course Team Chair T206 Energy For a Sustainable Future. Try ourTaster Website: Chris Dunham Director, Sustainable Energy Action Presentation to Renewable Energy Sources in an Energy-Efficient London conference City Hall, London, October 11 th 2002

Aims n Brief overview of renewable energy technologies n Potential contribution of solar, wind & other renewables to London’s Electricity needs

Solar Energy - an Enormous resource n Most renewable energy sources are derived from solar power n Solar power input to Earth is 10,000 times world’s current rate of fossil & nuclear fuel use n Solar power can be used directly - for heating and electricity generation n Indirect forms of solar energy - biofuels, hydro, wind & wave power n Solar is sustainable - won’t run out; few/no greenhouse gases or pollution; equitable global distribution

Renewable Electricity for London: How Much Could PV Contribute?  Land area of Greater London: c.1500sq km  London Electricity Demand: 31 TWh/yr  Annual solar radiation: c.1000 kWh/sq m  Average PV module efficiency: c.10%  So PV Module output: c.100 kWh/sq m/yr  Area to provide 10% of electricity (3.1TWh) from PV = 31 sq km = c.2% of London land  Where? Roofs of houses & flats; roofs & facades of commercial & public buildings; alongside roads & railways; petrol stations, car parks &c..

Renewable Electricity for London: Wind Power Contribution? n On-Shore turbines: 1.5 MW (e.g. Swaffham) n Output in London c MWh/yr n Number of on-land turbines to provide 1% of London’s Electricity (0.31 TWh) = c.100 – 200 n Where? Parks? Brownfield sites? Riverside? n Off-shore turbines in Thames Estuary: 3 MW capacity each n Output c. 8,000 MWh/yr per turbine n No. of Offshore Turbines to provide 10% of London’s electricity (3.1 TWh): c 400 (1200MW) n Say, 5 wind farms each with 80 turbines? n c.f. new Danish Horns Rev offshore wind farm: 80 x 2 MW turbines. First 2 UK offshore wind farms at Scroby Sands and North Hoyle: 30 x 3 MW turbines n How Fast? c.f. Germany: 10,000 MW installed in <10yrs

Biofuels for London: How Much Could they Contribute? n Biofuels are storable: useful as backup to intermittent renewables n But biomass conversion efficiency low: c.0.5%. So output from energy crops only c. 5 kWh/ sq m/yr n Also require efficient combustion to avoid greenhouse gas (e.g. methane) emissions n If used for CHP, Elec. O/P / sq m, c.2kWh; Heat c. 2kWh n Area to provide 10% of London Electricity (3.1TWh) = 1550 sq km = All land area! For 1%, need c.10% of land n PLUS contributions from waste: n Tree waste n Landfill gas n Anaerobic digestion n Municipal Waste incineration – controversial

What about Hydro, Wave Tidal & Geothermal? n Hydro: potential v. low: no mountains, low rainfall n Wave: climate in Thames estuary not very energetic. But technology developing fast n Tidal: large barrages impractical & low tidal range n But tidal current turbine technology developing fast. n Geothermal: absence of aquifers. Some potential from ground source heat pumps?

Renewable Electricity for London: Summary & Conclusions Off-shore wind in Thames Estuary probably fastest and cheapest way to achieve a high renewables contribution Solar PV also could make a substantial contribution, but requires large areas is currently expensive: mass production could cut costs dramatically Biofuels require very large land areas & efficient combustion essential to avoid greenhouse gas emissions Little potential for hydro Wave & tidal currents might make a significant contribution in longer term