Among other things, clear expansion goals, large-scale geological exploration and the development of skilled workers are required.
"Achieving the climate neutrality of the heating market is a huge challenge and requires a whole bundle of measures," explained Professor Rolf Bracke, head of Fraunhofer IEG and co-publisher of the current geothermal roadmap for Germany. "Market players such as energy suppliers, industrial companies, the housing industry, the financial sector, politics, administration, trainers and municipalities need new instruments for this complex implementation task."
The strategy paper is intended to provide all stakeholders with the necessary information on the geothermal heat supply, the versatility of the heat market, and the technological realisation of the heat transition. The aim is to provide recommendations for action in order to implement the potential of geothermal energy in terms of climate-neutral heat supply.
The roadmap now presented discusses the contribution of geothermal energy to the heat transition. The focus is on the hydrothermal reservoirs, i.e. thermal water-bearing rocks at depths between 400m and 5,000m. Geothermal water can be pumped from deep wells at temperatures between 15 and 180 degrees Celsius. They are available independent of the season and time of day and can be used in particular for municipal heat supply, district heating, housing and the provision of industrial process temperatures. The technology is mature and has been used in many European cities, such as Paris and Munich, for decades.
The heating sector accounts for 56 per cent of the national energy demand. Only 15 per cent of the heat is regenerative. While hydrogen and biomass will primarily have to cover the high-temperature requirements of the energy-intensive basic industry in the future, solar thermal and geothermal options in particular are available for low-temperature uses below 200 degrees Celsius. The advantages of geothermal energy lie in the baseload capacity and the small space requirement, even in cramped inner-city conditions.
According to estimates in the roadmap, hydrothermal geothermal energy (possibly combined with large heat pumps) as a heat source for district heating networks could cover around a quarter of Germany's total heat requirements, i.e. around 300 terawatt hours of annual work with 70GW of installed capacity. In 2020, 42 plants nationwide delivered 359MW of installed heat output and 45MW of electrical output (2020). Public households and private companies will have to invest €2 to €2.5 billion per gigawatt of installed capacity over the next 10 years to build up this geothermal generation infrastructure and to connect it to municipal distribution infrastructure for heat. This enables competitive heat production costs of less than €30 per megawatt-hour to be achieved.
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