Researchers want to use heat from urban soil for heating

Most people will already be familiar with the basic situation: it is usually noticeably warmer in large cities than in the countryside. Urbanization, industrialization and climate change are responsible for different effects. As a result, the soil in the cities also warms up faster and only cools down later. An international research team has now analyzed this fact in more detail. Their idea: cannot this ground heat be used to heat houses using geothermal energy? To do this, they looked at thousands of locations on different continents. The result: heat has already accumulated in the ground at about fifty percent of the locations studied. The situation is likely to get even better in the future. The researchers estimate that by 2099, between 73 and 97 percent of the locations studied could be used for geothermal energy at ground level.

There are fewer unwanted side effects than with traditional geothermal heat

With classical geothermal energy, water is pumped to great depths to use the geothermal energy there. So the heat comes from within the earth. However, with the approach currently being explored, simply passing groundwater through a heat exchanger would be sufficient. The cooled water would then flow back down. If groundwater is not available, an external heating medium can also circulate in a closed circuit. The big advantage of this approach is that you don’t have to drill holes that deep. On the one hand, this saves costs, but on the other it also reduces unwanted side effects such as unwanted earthquakes. In addition, in theory, action is needed anyway. Because if the groundwater continues to heat up, sooner or later this can lead to problems with drinking water quality. Ground-based geothermal systems could offer a solution here.

Until now, too much oil and gas has been used for heating in Germany

There is an urgent need for new ways of generating heat to heat apartments and houses. Because about seventy percent of the energy consumption of private individuals can be traced back to this. Until now, fossil fuels have mainly been used for this. This not only harms the climate, but has also become extremely expensive since the Russian war of aggression in Ukraine. Creative approaches such as the idea now presented by the international research team are therefore currently most likely to be implemented in the near future. In the summer, such a system could also be used in reverse: the groundwater would then help to cool the cities. So far, however, the researchers have only shown that such a process could actually be implemented in some places. It must now be implemented by politics and industry. The first pilot projects could also provide further important insights.

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