Geothermal district heating and power generation in Altheim
Overview
A geothermal district heating network has been operating in the Austrian town of Altheim for more than 30 years, heating the homes of some 2000 people. Commissioned in 1991, the hydrothermal system has served as a model for further geothermal developments in the region and beyond. Today, a total of seven geothermal district heating networks are in operation in the Innviertel region of northern Austria.
The Altheim plant is operated by the municipality and produces 27.1 GWh of thermal energy per year. The geothermal brine, which has a temperature of 105°C, is extracted through a production well and, after passing through a heat exchanger, is reinjected into the aquifer at a depth of about 3 kilometres.
Electricity
In 2002, Altheim became the first geothermal plant north of the Alps to produce electricity. In a pilot project, it was demonstrated that power production from geothermal sources is also possible in central Europe and with temperatures just slightly above 100°C. The unprecedented project was realised in an international research network with participants from Austria, Germany, Italy and France and with financial support from the European Union, the Austrian government, and the regional energy supplier.
The power plant has an installed capacity of 1 MW and uses an organic Rankine cycle. After powering a turbine and generating electricity, the geothermally heated water is still hot enough to achieve the necessary temperature for the district heating. Because the power station operates so quietly and produces no emissions, it was possible to build it in the centre of Altheim, right behind the town hall.
Summary
Year of commissioning: 1991
Installed thermal capacity: 11.4 MW
Heat production per year: 27.1 GWh
Power production: 2002
Installed electrical capacity: 1 MW
Operator: the Municipality of Altheim
Well depth: two wells, 2300 m and 3000 m
Temperature: 105°C