Seasonal storage of solar heat
Seasonal storage of solar heat can make the energy available throughout the year. When the solar heat is deposited in the ground, it can be harvested when needed, even through the coldest and darkest winter months.
Inaventa Solar is developing an innovative concept for seasonal in-ground storage of heat, which also can also facilitate efficient storage where there is a lot of water in the ground - storage of heat in water-rich masses. At our solar collector factory at Jevnaker, Norway, we have drilled deep energy storage wells, which we are now starting to “charge” with energy from the roof-integrated solar heating system at the factory building, combined with surplus heat from the production plant. The stored energy will be used to heat the factory hall in winter and to extend the growing season in a nearby greenhouse.
Enova has contributed to the funding of the development and piloting of this concept.
Contributor to the green shift
A significant part of the energy use in buildings, is utilized for heating. When this heat energy can be produced without climate emissions, and without burdening the grid in the event of large power needs, it means that the concept can be an important contributor to the green shift.
Storing heat in bedrock can improve the utilization of several variable heat sources but is particularly interesting in combination with solar heat. This is because the significant heat production takes place in the summer, while the heat demand is continuous and peaks in the winter.
More than 50% of deposited heat can be recovered
A prerequisite for a successful traditional heat energy storage well, is that the ground does not contain permeable water-bearing layers, ie that the water moves through the bedrock. This is advantageous in projects where boreholes are used in combination with heat pumps, but is unsuitable for heat storage. In Norway, water permeable bedrock is very widespread.
However, our concept involves establishing barriers to water penetration around the rock volume used for storage. This means that there no longer has to be a limiting requirement for the rock to be dry. The solution contributes to an increase in the heat capacity of the rock. Calculations show that it is possible to recover more than 50% of the heat that is fed into the wells.
Inaventa Solar will be able to offer seasonal storage solutions for future solar energy projects.