UK green power boost will raise costs sharply - report
If Britain raises its target for green energy output to 20 percent by 2020 then the system costs could grow by as much as 400 pounds ($622.2) million a year, the consultants said in a study for the Department of Trade and Industry (DTI).
The UK currently has a goal of meeting 10 percent of its power needs from renewable sources by 2010.
The main factor pushing up the costs is the unreliability of renewable energy, especially wind power, which means more investment will be needed in short-term balancing and in gas-fired power stations to ensure security of supply.
"Wind can make (only a limited contribution) to system security because of...the risk of low wind speeds across the whole country for prolonged periods," said the report.
Other costs include extending the grid if wind farms are built in remote locations off north-west Scotland and Wales.
The report was commissioned as the government prepares its white paper on energy policy which is expected to be published early next year.
A report to the government last year recommended Britain raise its renewables target to 20 percent by 2020 as part of its strategy to cut emissions of greenhouse gases which many scientists blame for causing climate change.
ILEX said boosting renewables use even further to 30 percent of the UK's power needs will increase costs to as much as 500 million pounds a year.
The cheapest scenario, increasing renewables' contribution to 20 percent, will cost about 150 million pounds but depend on using more predictable energy sources, such as biomass, and building less reliable wind farms closer to consumers, which would cut transmission costs.
Britain currently generates only three percent of its power from green sources.