Drilling for power source
Published 24/09/2010 | 05:00
PRODUCING heat and electricity from geothermal power is not new technology -- plants that were built in 1892 in Idaho, US, and in 1904 in Italy, continue to generate electricity and produce power.
There are still numerous power-producing plants in Iceland and 34 in Paris. Another 16 are in Munich, with plans in place to build a further 150 across Germany.
The technology works by drilling two wells up to five kilometres into the Earth's core. At this level, rock has a sponge-like consistency, and contains water at temperatures of up to 130C.
Hot water from the aquifer or geothermal reservoir is pumped to the surface using a production well. The heat from the liquid is then extracted through a heat-exchange system on the surface.
This takes the heat from the geothermal water, and transfers it to another liquid which is used to drive turbines and produce electricity. The electricity generated is fed to the national electricity grid through a substation. The remaining colder fluid is pumped back down into the reservoir through the second well so it can be reused at a later date.