Geothermal Plant with Absorption Heat Pump in Thisted. Integration with Heat and Power Plant and Use for Heat Storage and Removal

Abstract

A geothermal plant in Thisted has produced and reinjected millions of cubic meters of a 15% saline geothermal water in a sandstone reservoir without corrosion or injection problems since 1984. The plant uses an absorption heat pump driven by heat from a combined heat and power incineration plant and the driving heat is fully recovered on the district heating network. Denmark has no volcanic activities and no hot springs, but many reservoirs with warm geothermal water which can be used for district heating. The geothermal resources exceed the energy needed for heating in Denmark for hundreds of years and a sound geothermal concept with low heat production costs has been developed. The ongoing establishment of large combined heat and power plants in Danish towns does however delay the further geothermal development. Heat production costs, plant concepts, absorption heat pump concept, operation experiences from Thisted and future applications such as use for heat storage and injection of are discussed. A computer program calculating energy balances and costs for geothermal plants is also introduced.