Interest in Geothermal Energy is Growing

The German government is also looking at further developing deep geothermal energy to create a nationwide climate-neutral heat supply by 2045.  According to studies, deep geothermal energy could generate around 300 terawatt hours of heat annually from an installed capacity of 70 GW — more than half the future heat demand of all buildings.

Using Heat Pumps to Extract Heat from the Earth’s Surface
Increasingly, however, geothermal energy is also being harnessed from sources close to the earth’s surface using heat pumps. In boreholes just 50 to 400 meters deep, a closed pipe system carries water from the surface to underground and then back, heating it 10 to 20 degrees C. A heat pump then uses this energy to output water at 30 to 70 degrees C, which is then used to heat buildings.

Researchers believe using this shallow geothermal energy in Germany offers heating potential similar to deep geothermal energy. In Germany, these two technologies alone could satisfy the entire future heating demand for buildings.

How Much Does Heat from Deep Geothermal Energy Cost?
According to analysis by six German research institutes, generating heat with deep geothermal energy costs less than three euro cents per kilowatt hour (kWh).

Before Russia’s attack on Ukraine, natural gas could generate heat even cheaper than this for many municipal utilities in Europe. That made it unattractive to invest in the construction of deep geothermal energy plants. Since Russia’s invasion, however, sharply rises in gas prices have pushed that cost to more than 12 cents per kWh, changing the calculation. Municipal utilities are now showing great interest in deep geothermal energy for heat supplies.

Can Geothermal Energy Completely Satisfy the Demand for Heat?
No. The heating demands of the world’s buildings can be met by the near-unlimited potential of deep geothermal energy and near-surface geothermal energy.

But industrial applications sometimes require temperatures of over 200 degrees, which, with present technologies, are generally unattainable with geothermal energy. For such high temperatures, heating with electricity, biogas, biomass and green hydrogen are the climate-friendly alternatives.

How Quickly Can Deep Geothermal Energy Start Supplying Heat?
Over the past century, the oil and gas industries in particular have amassed considerable knowledge of the earth’s subsurface, on drill techniques, how to train personnel, and have developed sophisticated technology. Professor Rolf Bracke, head of the Fraunhofer Institute for Energy Infrastructure and Geothermal Energy (IEG), told DW he is confident that geothermal energy can be expanded rapidly “if the oil and gas industries turn their attention to geothermal energy.”

But he says if those companies continue to focus on oil and gas production because it generates more money, there would be insufficient personnel and drilling technology to rapidly expand geothermal energy. According to Bracke, it takes two to three years to develop geothermal heat sources if approval is granted quickly, and about three times longer than that in Germany due to bureaucratic delays. The German government now wants to speed up this process and increase heat energy production tenfold from the current production of 1 terawatt by 2030.

Can Deep Geothermal Energy Cause Earthquakes?
Yes. In regions with seismic activity, geothermal energy can trigger small earthquakes when water is injected into the subsurface at too high a pressure, triggering existing stresses. In some cases, the tremors have resulted in cracks in buildings and public opposition to this technology.

According to Bracke, there have been no reports of earthquakes in regions without underlying stresses. Meanwhile, geothermal techniques have also been improved: surface tremors can now be avoided with lower underground water pressures and more sophisticated monitoring methods,

But compared to oil, gas and coal extraction, geothermal is far less risky, Bracke emphasized, and “by far the safest source of energy from our earth.”

Gero Rueter is a radio and online editor at Deutsche Welle.This article is published courtesy of Deutsche Welle (DW).