Despite all the media attention on wind, solar and even wave power as key sources of renewable energy, the UK's largest green energy provider is biomass – using wood, annual crops or waste materials as fuel for heat and electricity. It now generates over 2% of our total electricity, enough to power more than 2m homes. In addition, it produces about 1% of heat for our homes and industry.
And it has the potential to deliver even more in the future, helping the UK to meet its target of 15% of energy from renewable sources by 2020 and reduce dramatically greenhouse gas emissions from heat and power generation, which contribute to climate change.
Heat and power can be generated from a large range of biomass fuels, such as wood, grasses and organic wastes. It is considered renewable because it is either based on wastes which would otherwise go to landfill or on energy crops and forestry that, after being harvested, can be grown again.
But like all "green" products, it's important that we assess its entire environmental impact before giving it the green light.
A new report launched by the Environment Agency this week shows that biomass energy has the potential to be a clean, sustainable energy source – but only if we do it properly.
The best forms of biomass energy have the potential to produce up to 98% less emissions than coal power. The worst would have higher greenhouse gas emissions overall than gas power.
Our report sets out how we can achieve our goal of clean, sustainable biomass. And it makes clear that we should avoid the same problems that have afflicted biofuels – which saw a headlong rush, followed by an abrupt slow down after the total environmental impact of growing crops for fuel had been recognised.
So what should we be doing to ensure that the emerging biomass sector blossoms into a green and low-carbon industry for the future?
The Environment Agency's report: Biomass: carbon sink or carbon sinner analysed the carbon footprint of a range of methods of biomass energy production and comes out with some clear recommendations. The carbon footprint is the overall greenhouse gas emissions from producing, processing, transporting and using the biomass to generate heat and power.
First, the biomass needs to come from sustainable sources, using wastes and local sources as much as possible, while avoiding major land use changes and minimising use of nitrogen fertilisers where crops are used. Second, the processing of the biomass into fuel needs to be efficient, consuming as little energy as possible. Finally, the generators used to turn biomass into useful energy need to be as efficient as possible. This means where possible using the heat generated to heat homes or in local industries.
Bearing in mind the difference between "good" biomass and "poor" biomass, it's important that we have a consistent approach to this emerging industry. Worryingly, there are currently no plans to ensure that best practice is followed, and there is little to suggest that the emerging biomass industry will adopt these standards without encouragement from the government.
We are therefore calling for immediate action to ensure that the biomass industry is encouraged to meet the recommendations outlined above and delivers the lowest carbon energy possible.
This means providing greater incentives for the most efficient plants that produce heat and power rather than electricity only. It also means requiring all plants that receive any public support to accurately report on their greenhouse gas emissions. Eventually, it is likely that we will need minimum standards for all generators.
Government needs to take the lead to develop an industry that meets strict standards and delivers clean heat and power. The prize of a major contribution to the UK's renewable energy and greenhouse gas targets is great. The alternative – an industry using inefficient generators to burn anonymous fuels – could ultimately do more harm than good.
Tony Grayling is head of climate change and sustainable development at the Environment Agency.