§ Mr. Patrick McNair-Wilson
asked the Secretary of State for Energy what progress has been made on the geothermal energy project at Marchwood, Southampton.
§ Mr. John Moore
The first results of the test which have proved the existence of a large deposit of water at a temperature of 70°C, are encouraging. Although it is too early to draw firm conclusions about the commercial usefulness of this new energy source, I am hopeful that the project team will be able to demonstrate that Britain now has a new and useful source of natural heat.
At Marchwood, the drilling was done to a depth of 8,600 ft, and the geothermal water was found at 5,600 ft. Allowing for heat loss in transit, the water will come to the surface at a temperature of 65° – 67°C. There is sufficient water in the Marchwood well to heat about a thousand houses over a period of several decades, and further wells of similar potential could be drilled into the same reservoir.
The use of geothermal heat is an entirely new technology for the United Kingdom. Although its uses are limited by the amount of geothermal water in Britain's rock structure, this new resource might eventually prove a useful alternative to conventional fuels in heating homes and offices.
A pump will be installed in late summer this year to bring the water to the surface, and project workers are looking at possible uses for the water in the local area. In the meantime, further tests will be done to assess the available volume and mineral content of the water.