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: www.open.ac.uk/t206

Chris Dunham Director, Sustainable Energy Action

Presentation to Renewable Energy Sources in an Energy-Efficient London conference

City Hall, London, October 11th 2002

Aims

Brief overview of renewable energy technologies

Potential contribution of solar, wind & other renewables to London’s Electricity needs

Solar Energy - an Enormous resource

Most renewable energy sources are derived from solar power

Solar power input to Earth is 10,000 times world’s current rate of fossil & nuclear fuel use

Solar power can be used directly - for heating and electricity generation

Indirect forms of solar energy - biofuels, hydro, wind & wave power

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?

On-Shore turbines: 1.5 MW (e.g. Swaffham) Output in London c. 1500 - 3000 MWh/yr Number of on-land turbines to provide 1% of London’s

Electricity (0.31 TWh) = c.100 – 200 Where? Parks? Brownfield sites? Riverside? Off-shore turbines in Thames Estuary: 3 MW capacity each Output c. 8,000 MWh/yr per turbine No. of Offshore Turbines to provide 10% of London’s

electricity (3.1 TWh): c 400 (1200MW) Say, 5 wind farms each with 80 turbines? 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

How Fast? c.f. Germany: 10,000 MW installed in <10yrs

Biofuels for London: How Much Could they Contribute? Biofuels are storable: useful as backup to intermittent

renewables But biomass conversion efficiency low: c.0.5%. So output

from energy crops only c. 5 kWh/ sq m/yr Also require efficient combustion to avoid greenhouse gas

(e.g. methane) emissions If used for CHP, Elec. O/P / sq m, c.2kWh; Heat c. 2kWh Area to provide 10% of London Electricity (3.1TWh) = 1550

sq km = All land area! For 1%, need c.10% of land PLUS contributions from waste: Tree waste Landfill gas Anaerobic digestion Municipal Waste incineration – controversial

What about Hydro, Wave Tidal & Geothermal?

Hydro: potential v. low: no mountains, low rainfall

Wave: climate in Thames estuary not very energetic. But technology developing fast

Tidal: large barrages impractical & low tidal range

But tidal current turbine technology developing fast.

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