25.04.22 “There is huge interest at the moment” Interview with Dr. Frank Kabus • Reading time: 4 min.


Dr. Frank Kabus has been working in the field of geothermal energy for 35 years and during this time he has experienced many highs and lows. In this interview, the CEO of Geothermie Neubrandenburg GmbH takes a look back over the varied history of geothermal energy in Germany and explains why he is currently sending out more quotations in a day than he used to in a month.

Frank Kabus, you have been working in the geothermal industry for decades. How did it all begin?

The company Geothermie Neubrandenburg GmbH has been in existence for exactly 30 years. But its origins go back even further than that to a nationally owned business founded in 1986 in East Germany (GDR), which I joined in 1987. At the time, the government had decided to take deep geothermal energy to new heights in the GDR and to supply the northern part of the country with geothermal heating. The aim was to replace the old brown coal power plants. When the Berlin wall fell, the company had almost 800 employees and had already sunk 30 boreholes. We did things properly back then. By the time Germany was reunified, there were three geothermal energy plants operating or ready for operation. 

What happened then?

In 1992 there was a management buy-out and the current company was formed. But after reunification, deep geothermal energy was not nearly as important, because there was a large amount of cheap gas on the market. We went through a lot of highs and lows and drew up a huge number of concepts, most of which remained on paper. But we did build some plants, mainly in Bavaria and also outside Germany. In around 2005, there was a new upturn, because combined heat and power (CHP) plants began storing heat in underground aquifers. Ten years later, this market had disappeared again with the development of wind and solar energy, because the CHP plants have operated in a totally different way since then. They focus on the electricity exchange and are often shut down. With this operating model, geothermal storage for excess heat is no longer needed. 

Has the current political situation led to new interest in deep geothermal energy?

There is huge interest at the moment. We are receiving a lot of enquiries and I am sending out two or three quotations every day. In the past it was only one or two a month! In the last two months in particular there has been a significant increase in interest because many municipal utility companies are concerned about problems with the gas supply. Alongside the political situation, technical progress has also made deep geothermal energy more attractive again. Here in the North German Basis, the thermal water has a temperature of between 50 and 80 degrees Celsius, while the district heating networks need temperatures of 75 to 85 degrees. Around five years ago, electric high-temperature heat pumps with a huge output in the megawatt range were developed and these can efficiently increase the temperature of the water. This has also revived the interest in deep geothermal energy. 

How much potential is there for deep geothermal energy in Germany?

That is difficult to say. On the one hand, the geological conditions have to be right and, on the other, geothermal plants are only a worthwhile prospect in towns with more than 10,000 inhabitants and a correspondingly large demand for district heating. I estimate that it would be possible to supply around half of the district heating networks in the North German Basin with geothermal energy. 

How long does it take to build a new geothermal energy plant?

The construction of a new plant takes around three years, or two if you are lucky. But you need to remember that the approval process is very complex because it is based on mining law. However, the authorities responsible have learned a lot over recent years. 

Are there enough companies to allow for a rapid expansion of deep geothermal energy in Germany?

At the moment it is really difficult to find plant construction companies, because all of them have full order books. It is not easy to get hold of the necessary materials either. Many things depend on the actual local circumstances and have to be adapted accordingly. There are no standard solutions in this area. 

How expensive is the supply of heat from deep geothermal systems?

That is also difficult to say. A new geothermal plant costs between 15 and 20 million euros and out of this a total of 10 million can be spent on the borehole alone. As the operating costs are relatively low, it is mainly the investment costs that determine the price of the energy. In other words, the cost per kilowatt hour depends primarily on the volume. I am currently working on a study for a municipal utility company which involves estimating the price for a specific case. Without any state subsidies, the price is likely to be around five percent higher than gas. Including the subsidy, it will be about 20 percent lower. 

Geothermie Neubrandenburg GmbH (GTN) employs 24 people and is the only engineering company in Germany that covers the entire spectrum of services in this field, from the initial geological concepts, the exploration, and the plant planning through to monitoring plant operation. GTN has already planned eight deep geothermal energy facilities and supervised the implementation. It is also responsible, for example, for the concepts for the geothermal heat storage system in the Reichstag and the other parliament buildings in Berlin. 


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