Berlin too wants to move away from gas and oil towards sustainable energy: and yet no one fancies taking a cold shower or freezing at home. More and more people are therefore using geothermal energy. In 2004, there were 132 geothermal energy facilities in the city, in 2018, it was a whopping 3,500 facilities.
This involves pipes being installed vertically in the ground often at a depth of up to 100 metres. A mixture of water and brine circulates through the pipe system, drawing the heat from the surrounding rock and groundwater. In Berlin, it is quite cold at such depths below ground with temperatures ranging between approx. 10 and 12 °C. A heat exchanger raises these to a pleasant room temperature. This process, however, cools down the ground and also the groundwater. When planning such systems, this needs to be factored in.
How much energy can geothermics generate for my run-off-the-mill single-family home? And how quickly can the ground balance out the heat that has been extracted? Berlin has calculated maps of geothermal potential drawn from the results of almost 15,000 boreholes, data on the thermal conductivity and heat capacity of the different types of rock and the groundwater level. The maps indicate the suitability for the use of geothermics of each location and form the base for planning such facilities.
