Drax power station to burn wood and biomass
12 November 2012 Last updated at 01:24 GMT
The government is being criticised for subsidising companies to generate electricity by burning wood instead of coal in power stations.
The policy - which will help Britain achieve mandatory EU targets for renewable power - is supposed to benefit the environment, because burning wood creates fewer greenhouse gases than burning gas or coal.
But green groups say it could actually have the opposite effect, because the wood is being shipped from countries around the world to be burned in Britain.
The BBC's Environment analyst Roger Harrabin visited Drax power station in North Yorkshire, which will start to burn increasing amounts of wood and other biomass instead of coal in the coming years.