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Landmark Sewage Project at Didcot Sends First Ever Renewable Gas to Grid

Centrica logo British households are today cooking and heating their homes with renewable gas - produced from human waste - for the first time.

Biomethane gas from Didcot sewage works in Oxfordshire will produce enough renewable gas to supply up to 200 homes.

The landmark project at Didcot - a joint venture between Thames Water, British Gas and Scotia Gas Networks - marks an important milestone in the UK's efforts to decarbonise the gas grid and move towards a low carbon economy. It is hoped this will be the first of many similar projects.

Biomethane from all sources will make a contribution to decarbonising the gas grid by delivering renewable heat to households through the existing gas network and central heating boilers. According to a study by National Grid, it could account for at least 15 per cent of the domestic gas market by 2020.

Energy and Climate Change Secretary Chris Huhne said:

"It's not every day that a Secretary of State can announce that, for the first time ever in the UK, people can cook and heat their homes with gas generated from sewage.

"This is an historic day for the companies involved, for energy from waste technologies, and for progress to increase the amount of renewable energy in the UK.

"I know there are other similar projects across the country that are close to completion, so this is just the start of a new era of renewable energy."

Sewage arrives at the Didcot works from some of Thames Water's 14m customers to be treated and recycled back to the environment.

Sludge, the solid part of sewage, is then treated further in warmed-up vats in a process called anaerobic digestion, where bacteria break down biodegradable material, yielding biogas.

Impurities are removed from the biomethane before it is fed into the gas grid. The whole process - from flushing a toilet to gas being piped to people's homes - takes around 20 days.

Martin Baggs, Chief Executive of Thames Water, said:

"We already produce £15m a year of electricity by burning biogas from the 2.8bn litres a day of sewage produced by our 14m customers. Feeding this renewable gas directly into the gas grid is the logical next step in our 'energy from waste' business.

"What we have jointly achieved at Didcot is a sign of what is to come, which can be replicated across our network and indeed the whole country. Every sewage works in Britain is a potential source of local renewable gas waiting to be put to use."

Mr Baggs was speaking at a breakfast barbecue at Didcot sewage works to celebrate today's historic achievement. Bacon butties were served to invited guests after being cooked on a grill powered by the biomethane that is now being fed into the gas grid.

Gearóid Lane, Managing Director of Communities and New Energy, British Gas, said:

"At British Gas, we're already leading the way with low carbon and renewable technologies for Britain's homes, and now we're helping local communities use local resources to generate their own energy. This renewable gas project is a real milestone in Britain's energy history, and will help customers and the environment alike.

"Renewable gas has the potential to make a significant contribution to meeting the UK's energy needs. Gas from sewage is just one part of a bigger project, which will see us using brewery and food waste and farm slurry to generate gas to heat our British Gas homes."

John Morea, Chief Executive of Scotia Gas Networks, also at the barbecue, said:

"Just as Thames Water has to clean sewage waste, we have to clean the gas to ensure it's fit for purpose to pump into our network. The gas that we are transporting from Didcot doesn't arrive from the North Sea or abroad, but instead comes from the very homes we are delivering the gas to. That's got to be recycling at its very best.

"We've been delivering gas to our customers in its traditional form for many years, however this project enables us to see how biomethane can offer a unique, green solution to heating our homes for decades to come."

The project took six months to complete and cost £2.5m.

Biomethane Facts

The average person produces 30kg (dried-out sewage sludge) of sewage per year that could be used for producing gas. That means that the UK's 62.5m people could in theory (see note below) generate enough renewable gas to meet the annual demand of 200,000 homes, up to 1% of the UK's population.

If all 9,600 sewage treatment facilities in the UK were fitted with this technology, they could provide enough renewable gas for up to 200,000 homes. (Note: in reality it would be unrealistic to fit every works in the UK with this technology as some only treat a very small number of people's sewage. But it does show huge potential for growth in this area.)

Published 05/10/2010

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