It's not all about fuel

The UK currently gleans 9.4% of its energy from renewable sources, but that is not enough. In the next eight years that figure must rise to 15% to conform with European environmental directives. At first sight that might not sound like too big a challenge; the proportion of UK energy generated from renewable sources grew by 2.6% last year, and if it were to continue in that fashion until 2020, 30% of our energy would be renewable.

Unfortunately it's not that simple, according to Adrian Higson, a biobased chemical consultant at NNFCC in York, UK. Most of the recent gains have been due to developments in extracting methane gas from landfill waste, he says. But technologies that extract energy from waste products like sewage, rubbish and waste cooking oil are reaching maturity; they are unlikely to continue providing additional improvements. 'I think meeting that target is going to be potentially quite difficult,' says Higson.