New renewable source ‘to generate 1GW by 2015’
A green energy source that could provide 1GW of power by harnessing the pressure of the earth's interior has officially been added to the UK's renewables mix after receiving renewable accreditation from Ofgem.
Geo-pressure is a technology new to the UK, but already used across Europe and North America, that harnesses the high pressures of fluids extracted from the earth to drive turbines that produce green electricity.
In the UK the technology will mostly be used with natural gas, but geo-pressure turbines can be driven by a number of “carriers,” said Tony Taylor, chief operating officer at 2OC, the company behind the project.
“My analogy would be that it’s the same as a water mill, the water passes through the turbine and it comes in and goes out of the system completely unchanged, all you’re doing is extracting the pressure,” he explained.
“There are several other units using water vapour as a carrier, others use a mixture. Often when you drill into the ground you get a variety of gases including nitrogen that you can use to drive the facility,” he told edie. The technology can also be used in conjunction with geothermal energy facilities, he added.
Having secured RO subsidies, the Bath-based company is ready to install its first geo-pressure turbines in the UK at a hydrogen production plant in Teesside.
Two turbines will be fitted into the pipeline supplying natural gas to the BOC hydrogen plant in North Tees starting in April, expected to be up and running later next year.
With a capacity of 500 to 700kW, the turbines will produce enough power to make the Teesside plant – the UK’s biggest hydrogen production facility – self-sufficient in energy.
But 2OC’s plans for the UK are much more ambitious – the company expects to be generating 300MW of geo-pressure power by 2010 and 1GW by 2015.
The company will fit most of its UK geo-pressure turbines to gas de-pressurising stations, and has already identified two thousand sites across the country.
Natural gas emerges from well heads in the North Sea at pressures of around 300bar, down to 80 bar by the time it reaches the coast. The natural geo-pressure helps the gas travel along pipelines but pressures are still far too high for use once it reaches consumers, and have to be reduced at pressure reduction stations using valves.
Geo-pressure turbines harness the kinetic energy that would otherwise be wasted: “Our technology, which is already demonstrated, achieves the same pressure reduction as the valves but achieves it by making the high pressure gas drive a small turbine which generates electricity,” 2OC said.
The company is determined to emphasise its support for all forms of clean energy, and sees its technology as complementing sources like wind, solar and biomass.
“Our view is that geo-pressure adds to the renewable energy mix – it’s decentralised, mechanically very efficient, and produces the energy at the right time when you need” as the turbines give a continuous energy output that peaks in winter, said Tony Taylor.
“It’s also capable of being built in or around the edges of towns, it’s unobtrusive, and has small, compact units,” he added – a factor that should make planning permission relatively easy to obtain.
“We know that through a variety of factors the renewables industry is struggling to achieve Government targets, and we hope that by becoming part of the mix we can help get us closer to those targets,” he said.
Overall, geo-pressure “could become an important renewable resource worldwide,” he added.
For more information on geo-pressure technology see www.2oc.co.uk.
More details can also be found on the website of Cryostar, the French company which developed the technology used by 2OC.
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