Geothermal energy

Natural hot water has been used since at least the nineteenth century for industrial purposes. The first geothermal power station was built in Italy in 1913 and produced 250 kW. Now 22 countries generate electricity using geothermal energy. However, its conversion efficiency is low, ranging from 5 to 20 per cent. Much greater efficiency is realised with the direct use of this energy for space or district heating. Then it rises to between 50 and 70 per cent.

Alternatively, hot dry rocks can supply energy by means of boreholes through which water is pumped and returned to the surface to provide space heating. This is known as the borehole heat exchanger system (BHE). In Switzerland, for example, it is a major source of energy with one borehole for every 300 persons.

If much more heat is required from the BHE in winter than can flow back in summer, a means must be found to regenerate the ground by artificial means. This opens the way for the dual use of BHEs - heat collection in winter and heat rejection in summer. With buildings they can therefore be used for both heating and cooling.

The UK was one of the leaders in the field of hot dry rocks geothermal research. However, efforts to achieve a commercial return on this energy route have proved unsuccessful and further work has been abandoned.

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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