National Grid outlines plans to harness zero carbon gas power

The Blue-NG venture will utilise the pressure in gas pipes for two power plants

The National Grid has said that work has already begun at two sites to install an innovative new technology capable of harnessing the latent energy stored inside the UK's gas pipeline network.

The first unit is planned to start generating power in mid-2010 and will be in Beckton, East London. The second plant will be based in Southall, West London, and is planned for late 2010. Both plants will have an output of about 20MW.

"Work has started at these two sites, and there are six other potential sites around the country that we are looking at," said a spokesman for the National Grid.

Gas drilled from underground is held at enormous pressure in the pipes, and this pressure needs to be released at eight pressure reduction sites around the UK before being fed into homes. This process produces a tremendous amount of energy without any associated carbon emissions, that to date has been wasted.

The National Grid partnered with engineering firm 2OC to form a joint venture called Blue-Ng that has developed a new turbine technology, known as turbo-expanders, capable of harnessing this power.

Early tests of the technology revealed that the gas has to be pre-heated as its temperature drops hugely during the reduction process, beyond the level where its energy can be harnessed by the turbo-expanders.

The National Grid said that it planned to overcome this barrier by installing a combined heat and power plant next to the site which will pre-heat the gas. The plant will burn liquid biomass and as well as heating the gas will produce its own electricity which will be fed into the grid separately.

The CHP engine will run on vegetable oil squeezed from local rapeseed, though Blue-Ng is also experimenting with other fuels, such as synthetic oil made from wood.

Blue-NG calls the whole design a combined heat and intelligent power unit and claims it is up to 70 per cent more efficient at producing energy than a standard combined heat and power unit.