One in four Austrian households is connected to a district heating network, and half of the energy is currently generated using fossil fuels. The use of solar and wind energy or waste heat from industrial plants would be more climate-friendly. However, the heat must be stored in order to be available when needed. One solution is earth basin heat storage, which is reminiscent of an underground reservoir the size of a football field. It is formed from dykes built all around.
Such a new type of storage facility exists in the municipality of Høje-Taastrup in Denmark, half an hour’s drive from Copenhagen. The basin has a capacity of 70,000 cubic metres of water. The thermal energy from heating plants and waste incineration plants is stored there for the district heating system all year round.
Image: Ioannis Sifnaios DTU
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Image: Ioannis Sifnaios DTU
To achieve this, special covers and seals are necessary. These are made of a special plastic that can withstand temperatures of up to 90 degrees Celsius. The material, which is unique on the market, was developed in a joint project by the Johannes Kepler University and the plastics technology company Agru from Bad Hall.
Gernot Wallner played a key role in this. Born in Burgenland, he studied plastics engineering in Leoben and has been teaching at the Johannes Kepler University in Linz since 2010, where he heads the “Christian Doppler Laboratory AgePol”. There, research is carried out into how the durability of plastics changes under various environmental influences, such as high temperatures.