Dispatches investigates a subsidised renewable energy industry that turns trees into fuel to keep the lights on in Britain, and in your home. But is burning wood instead of coal really an environmentally friendly answer to climate change? Reporter Antony Barnett travels to the forestlands of the south-eastern United States to find one source of this controversial 'carbon-neutral' fuel. Britain's households spend at least £500 million a year on biomass, which by 2020 will provide up to 30% of our renewable energy. But is there a wider cost to the environment? Barnett visits the biodiverse wetlands of Virginia and North Carolina where millions of tonnes of wood are harvested and processed into pellets, which are burnt in one of Britain's largest power stations.