Opportunities for hydrogeothermal uses in NE Germany: from site evaluation to project realization

Low enthalpy geothermal systems are well established in north-eastern Germany. The first German hydrothermal doublet started heat production in Waren/Müritz in 1984. Since then other sites in Mecklenburg-Western Pomerania and Brandenburg were explored and realized. Very recently the geothermal heating plant of Schwerin-Lankow has officially started operations and will substitute about 20 percent of fossil energy use in this town.

In most of these projects deep saline aquifers of Mesozoic age were used, which formed in the eastern part of the North German Basin. The well suited reservoir sandstones were often deposited in fluvial and deltaic systems within up to 15 km wide distributary channel belts. The porosity and permeability of channel facies sandstones reach very high values up to 30 % and >6 Darcy, respectively.

On basis of integrated sedimentological-palaeontological investigation and facies analyses using cores and wire logs of numerous deep wells, 15 different stratigraphic channel systems could be detected and mapped (www.sandsteinfazies.de). The results can be used together with temperature distribution data for a first site evaluation. Estimations of productivity and temperature have to be combined with numbers of potential users and existing or planned heat distribution infrastructure in larger communities.

The Geological Survey and ministries of Mecklenburg-Western Pomerania will encourage politicians and decision makers to think about geothermal energy use in their field of responsibility but also support investors to claim for financial support to realize renewable energy projects. This includes open access to available geological and geophysical data according to the Geological Data Act (GeolDG).