In the report “Solar heat in Sweden” the Swedish Energy Agency recently surprised everyone by showing that, in Sweden, it is profitable to replace half of the burning of wood chips and pellets with solar heat and seasonal storage facilities when conditions are favourable. This means that 11 TWh or 10 million cubic meters of forest fuel does not need to be burned to provide heat for Swedish households, rather the heat can instead come mainly from the sun and waste heat.
Now the Swedish Energy Agency has granted SEK 2.8 million, approx. €263 000, to a project where the University of Dalarna, the University of Halmstad and Absolicon Solar Collector AB in Härnösand will show how to build energy storage facilities for Swedish district heating networks that can store heat from summer to winter.
– This is the first step towards a large-scale rollout of solar heating in the Swedish district heating networks, and it is great that it is coming to fruition so quickly after the Swedish Energy Agency showed the huge potential of solar heating in Sweden, says Joakim Byström, CEO of Absolicon.
The purpose of the project is to show how solar heating and storage of heat in pit storage facilities like those built in Denmark can change the energy supply in Swedish district heating networks, from burning biofuels to using solar heat and residual value.
The pit storages facilities built in Denmark have managed to reach a cost below SEK 5 per kWh for heat storage. This can be compared to batteries used to store electricity which cost SEK 2,000/kWh of stored energy.
If this project can verify the Swedish Energy Agency’s findings that it is profitable to allow pit storage facilities in combination with solar heating and efficiency, to replace 11 TWh of biofuel, the industry will face a revolutionary change. To find out quickly, the project will evaluate the cost-effectiveness of solar heating and pit storage facilities through case studies for three district heating networks, and then draw general conclusions for the whole of Sweden.
The project will also produce a list of which of the district heating networks in Sweden where the geological conditions for large pit deposits are suitable and how many solar collectors of different types are needed.
The project’s long-term goal is to introduce large-scale heat storage for Swedish district heating networks and to increase knowledge about how large-scale solar heating technology together with thermal seasonal storage facilities can contribute to reducing dependence on burning fuels.
