Temps de lecture :2 minutes
It is not necessary to live in Iceland to enjoy the benefits of hydrotherapy, produce electricity or heat agricultural greenhouses with geothermal energy. In the centre of Paris, buildings (the Maison de la radio) are heated this way and there isn’t a volcano in sight! This is also the case in the United States, New Zealand and the Philippines for example. Indeed, all over the world, the soil beneath our feet is hot… The closer one gets to the central core (4000°C), the hotter it is : the temperature goes up by an average of 3°C every 100 m.
This source of heat is exploited in different ways. High temperature geothermal systems produce electricity in geothermal power plants. By drilling down to 500m, one reaches the water vapour (between 150° et 350°C) held under pressure in the subsoil like a pressure cooker. This powers a turbine which in turn produces electricity. There are plenty of geothermal resources favourable to electricity production around the Pacific (28% of geothermal electricity in the Philippines), Russia and Central and Eastern Europe but on a world scale, geothermal energy accounts for less than 1% of electricity needs.
Low temperature geothermal systems are used to produce heat. Hot water (between 20°C and 150°C) that circulates in the subsoil’s permeable rock is sucked up and used to heat houses, buildings, agricultural greenhouses and piscicultural basins. Lastly, there are very low temperature geothermal systems that use heat stored in soil that isn’t very deep to provide air conditioning and supply hot water to individual houses.
Technology is now ready and competitive enough to develop this energy that is not yet being used to its full potential. The Earth is offering us geothermal energy, clean renewable energy that is available day and night and does not take part in destabilising the climate.