British Gas unveils 'energy from sewage' schemeDidcot sewage works pioneers gas from human waste
06 October 2010
A scheme that uses sewage to produce renewable gas for UK homes has been unveiled by British Gas.
Didcot sewage works - together with Thames Water, British Gas and Scotia Gas Networks - is providing gas for 200 households produced from biomethane gas, originally from human waste.
In a satisfyingly circular process, the homes that produce the waste in the first place will benefit from the end product: gas that they can use for cooking and heating.
The process of turning waste into useable domestic gas involves heating sewage sludge in large 'digester' tanks to activate a natural biological process called 'anaerobic digestion'.
This harnesses the power of bacteria in breaking down the biodegradable material, which emits a biogas. The gas is then cleaned, treated to smell like normal gas, and fed into the national gas grid. The whole process, from flushing a toilet to gas being piped into people's homes, takes around 20 days.
With the average person producing 30kg of dried out sewage sludge each year, the UK population could theoretically generate enough renewable gas to meet the annual demand of 200,000 homes or 1% of the population.
More gas schemes to follow
The Didcot project, which took six months and £2.5m to complete, is predicted to be the first of many projects of its type, with other similar schemes currently close to completion around the UK.
According to a study by National Grid, renewable heat from biomethane from all sources could account for at least 15% of the domestic gas market by 2020.
Energy and climate secretary Chris Huhne called this 'just the start of a new era of renewable energy.'
For advice on greener energy, check out our guides to green energy and saving energy at home.
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