
United Utilities has partnered with the National Grid to convert a by-product of the wastewater treatment process into gas for injection into the local gas pipeline network and fuel for a fleet of sludge tankers.
The UK first is being hailed as a ground-breaking initiative and is centred on one of the country's largest wastewater treatment plants at Davyhulme in Manchester.
The scheme has been given the green light by winning Defra funding.
Caroline Ashton, United Utilities biofuels manager, said: "The team is thrilled to have won this funding which will give the project a huge boost.
“It has been in development for some time, but now we can put our plans into action and the people of Manchester will soon be using 'poo power' to heat their homes."
Biogas is produced when wastewater sludge is broken down by the action of microbes in a process known as "anaerobic digestion".
The biogas then needs to be upgraded to biomethane which is a renewable fuel with similar properties to natural gas. The biomethane can then be safely compressed for use in vehicles or injected into the gas grid.
Caroline explained: "Sewage treatment is a 24-hour process so there is an endless supply of biogas. It is a very valuable resource and it's completely renewable. By harnessing this free energy we can reduce our fuel bills and reduce our carbon footprint."
Janine Freeman, head of National Grid's Sustainable Gas Group said: "Biomethane is a fuel for the future. Renewable electricity from sources such as wind power is already available, but this is the first time we will be able to supply renewable gas to consumers. This pilot is an important step in helping deliver a low carbon energy future.
"Not only are we reusing a waste product, but biomethane is a renewable fuel, so we helping to meet the country's target of 15% of all our energy coming from renewable sources by 2020.
"This pilot project should supply gas to about 500 homes and the overall potential of biomethane from a plant like Davyhulme would be to supply a small town of about 5,000 homes. "
The plans involve installing the upgrade equipment, a gas compression and fuelling station, plus a pipeline to link into the local gas distribution network. The GBP4.3 million project should be operational by early 2011.
One of United Utilities' sludge tankers has already been converted to run on diesel and compressed natural gas, and this has confirmed that a dual fuel system does not affect the engine performance of such heavy vehicles.
Caroline explained: "When we have the kit in place to utilise the gas produced on site, we should be able to save hundreds of thousands of pounds a year in fuel costs with the 24 tankers we aim to convert initially."
National Grid say there are no fundamental technical difficulties to injecting biomethane into the gas distribution network. Several plants in Europe have demonstrated this is a safe way to deliver renewable gas generated from domestic sources.
To meet the conditions of the grant, the new installation at Davyhulme will be used as a demonstration plant for engineers and politicians to visit from around the world.
Caroline Ashton added: "This is just the latest exciting chapter in the story of Davyhulme. The plant was leading the world nearly 100 years ago when modern treatment processes were developed there, and it's wonderful that this kind of innovation continues today."
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