The Heatstore project recently kicked off, allocating 16 million euros of EU funds to research market-ready technologies for seasonal underground storage of sustainable thermal energy. 23 European companies from nine countries are participating.
Six demonstration projects in the Netherlands, Belgium, Germany, France and Switzerland are testing underground storage technology for storing sustainable heat from the summer to use in the winter. The emphasis is on storage of geothermal heat and other sustainable heat sources such as waste heat from industry.
Heatstore not only demonstrates and studies heat storage, but also strives for the rapid transfer of technology to the business segment. In addition to the project coordinator ECN (now part of TNO), Dutch participants include IF Technology, power company ECW, water research institute KWR and the Netherlands Institute for Ecology (NIOO-KNAW).
High heat demand during the winter and lower heat demand in the summer. Underground storage makes it possible to make optimal use of the surplus of heat and supply from variable sources (i.e. from solar heat) in the summer.
Storing higher temperatures on a larger scale
By efficiently combining heat sources and storage technologies, it should be possible in the future to bridge an entire season with stored thermal energy. In the Netherlands, heat is stored underground to supply heat networks in the winter. Saving thermal energy for later use is already done, but not yet on a large-enough scale that would be needed for the sustainable heating of an area, district, city or region. This large-scale thermal storage in the subsoil enables an optimum use of sustainable sources such as geothermal heat, industrial waste heat and power-2 heat from variable solar and wind energy, at lower costs and with lower impact on above-ground space.
Part of the project is a thermal storage site of at least 20,000 megawatt hours in the north of Germany. This storage will take place under Energy Combination Wieringermeer in Middenmeer. Greenhouse horticulture in this area has a great need for thermal energy.
Preventing negative impact of thermal storage
In order to realize the potential, it is essential that underground heat storage does not negatively affect other uses of the subsoil, such as for drinking water production. This is also part of Heatstore. For example, KWR is investigating not only how much of the stored thermal energy can be recovered, but also what determines the impact of the heat that does escape. To this end, ongoing monitoring at the current underground thermal storage pilot Koppert-Cress will be further expanded.
Smarter heat networks with storage
The participating parties want to increase the storage temperature between 25 and 90 degrees. This also offers advantages when linking storage in a heating network. By using underground aquifers, wells or empty mines, thermal energy can be stored. In the project, storage technologies are demonstrated in combination with various heat sources: geothermal heat, solar heat and waste heat from, for example, waste processing. By smartly matching sources, users and storage in a heating network, the costs of the entire system can decrease sharply. The goal is at least a 20% reduction in cost.
The combination of expertise from research institutes and the participation of the business community is necessary to enable large-scale underground storage of thermal energy. Heatstore wants a quick transfer of the technology quickly to the business world so that results can be analyzed. The project also investigates social integration, useful business models and relevant legislation.