The world’s first Geothermal power station was built in 1911 in Larderello, in Southern Tuscany, Italy. Since Roman times steam and hot water springs emerging from this geologically active ground has been used for hot water and for bathing.
In 1904 emerging steam was used to turn a small turbine which in turn powered five light bulbs – the first ever demonstration of geothermal electricity generation. In 1911 the Valle del Diavolo (Devil’s Valley) was chosen as the site of what would remain the world’s only geothermal power station for almost half a century. By 1913 a 250kW power station had been built which provided power for the Italian electric railway system.
Cold water is pumped down to super hot granite rocks located close to the surface. High pressure 200+ degree celcius steam is returned which turns turbines and generates electricity. Currently around one million homes are powered by geothermal electricity from Landerello – almost 5,000 GWh per year, or 10% of the world’s total geothermal electricity production.
Although geothermal is a renewable energy source, eventually the hot rocks below the surface will cool. Since the 1950’s the steam pressure from the Valle del Diavolo site has falled by 30%.