| Abstract |
Denmark has widespread geothermal aquifers, which can be used for district heating. However, combined heat and power (CHP) plants cover the heat demand on the Danish districtheating networks. The Danish geothermal development has thus been concentrated on a single geothermal plant in Thisted, development of the geothermal concept - and assistance to projects abroad. More power from windmills etc. and the increasing efficiency of CHP plants may reduce the heat production from CHP plants and create a need for new geothermal plants. The possibility of establishing a geothermal plant in the Copenhagen area is being investigated. The Danish Government has granted financial support for the initial phases. The geothermal plant in Thisted with an absorption heat pump driven by an incineration CHP plant operates with low costs and low energy consumption. The plant has operated without injection problems for the 15% saline geothermal water in a sandstone aquifer since 1984. Design concept, investment costs and operating strategy for the plant were reported in papers from the World Geothermal Congress 1995. The performance of the plant has been improved further and the plant is now expanded to a higher flow (170-200 m3/h) and with another absorption heat pump, which together with the old can cool the geothermal water to around 10?C. Widespread geothermal aquifers can be used to produce heat with a high efficiency from geothermal plants with both absorption heat pumps and electric heat pumps integrated with heat and power plants. Such plants can become an important part of an efficient system designed to cover the total need for heat and power. Geothermal plants may also be used for the storage of heat and injection of CO2. DONG (Dansk Olie & Naturgas A/S) has developed geothermal concepts and computer models for design, financial evaluation and optimisation of operating strategies. It has been involved in geothermal projects in Sweden, Germany, Russia, Poland, Latvia, Check Republic, Slovakia and Lithuania as project manager or partner / subcontractor to other Danish companies. DONG provides project management for assistance to the design and construction of a geothermal plant in Klaipeda, Lithuanian in co-operation with Houe & Olsen on a project initiated by PGI. Absorption heat pumps shall extract 17-20 MW heat from 600-700 m3/h 38?C water re-injected at 11 ?C through 2 wells in Devonian sandstone. The Danish Environmental Protection Agency has granted 3 million USD for the assistance to the planning, design and construction. |