Jens Borchsenius, Research Technician at DTU Energy, within the Department of Energy Conversion and storage, agreed to give us the tour and answer questions about the findings so far and future plans. The current prototype contains “only” about five tons of rocks contained inside a round vault going into the ground, where it is surrounded by insolating material.
Once the testing on the prototype is over, a real larger-scale version will be made to demonstrate the idea. It was a very interesting hour spent away from the desk, which opened my eyes to low-cost and simple, yet innovative and promising ways of storing excess power. Read more about the project here.
In California, a large fraction of electricity consumption goes into airconditioning during the summer. In Denmark there’s a similar demand for heating during the winter. Contrary to other Nordic countries however, Denmark relies on district heating instead of electric heating for over half of the residential houses in the country. 64% of all households are heated with radiators that contain hot water heated at a local district heating facility, which typically produces electricity as a bi-product . With this rock storage, air heated by passing it through the hot rocks, can be used create steam which can run a conventional steam turbine and create electricity OR the hot air can be used to directly heat water for district heating.