Polar Night Energy embraces renewable energy by providing stable and affordable heat storages for district heating and industrial applications. Polar Night Energy heat storages provide a way to be prepared for Smart and Green Energy Transitions and highly altering energy prices. A “sand battery” is high-temperature thermal energy storage that uses sand or sand-like materials as its storage medium. It stores energy in sand as heat. Its main purpose is to work as a high-power and high-capacity reservoir for excess wind and solar energy. The energy is stored as heat, which can be used to heat homes, or to provide hot steam and high-temperature process heat to industries that are often fossil-fuel dependent.

As the world shifts towards higher and higher renewables fraction in electricity production, the intermittent nature of these energy sources cause challenges to energy networks. The sand battery helps to ambitiously upscale renewables production by ensuring there’s always a way to benefit from clean energy, even if the surplus is massive.

The first commercial sand battery in the world is in a town called Kankaanpää, Western Finland. It is connected to a district heating network and heating residential and commercial buildings such as family homes and the municipal swimming pool. The district heating network is operated by an energy utility called Vatajankoski.