The First Commercial Sand-based Heat Storage in the World Will Be Built in Finland – Big Step for Carbon Neutral District Heating

Vatajankoski and Polar Night Energy have signed an agreement to construct a sand-based heat storage with 100 kW heating power and 8 MWh capacity. It will provide heat for Vatajankoski’s district heating network in Kankaanpää, Finland.

Vatajankoski, an energy utility based in Western Finland, and Polar Night Energy have agreed to start constructing and operating a sand-based high temperature heat storage based on Polar Night Energy’s patented technology.

The storage will be placed on Vatajankoski’s power plant area and it will provide heat for Vatajankoski’s district heating network. It is the world’s first commercial solution to store electricity in the sand as heat for use in a district heating network.

Today, big part of the heating energy in the world is produced by burning fossil fuels and wood. Electrification of the heating sector is one of the key factors on the way to reach the climate targets. Heat storages provide an essential part connecting the heating and electricity sectors.

– Polar Night Energy’s goal is to provide heat efficiently and with a minimal carbon footprint to the end-users. This is a big step towards carbon neutral district heating. Our sand-based heat storages can be used anywhere along an electrical grid. As a material, sand is durable and inexpensive and can store a lot of heat in a small volume at a temperature of about 500–600 degrees Celsius, says Polar Night Energy’s CTO Markku Ylönen.

Vatajankoski is happy to co-operate with Polar Night Energy in testing and validating the first-of-a-kind high temperature heat storage unit as a part of their energy network.

Vatajankoski uses the heat provided by the storage to prime the waste heat recovered from their data servers which are intended for renting high-performance computing capacity. Depending on the season, the temperature of the 60-degree waste heat from the servers must be raised to 75–100 degrees before it is fed into the district heating network.

– We are actively developing our energy production portfolio towards a 100% sustainable and emission-free future. Polar Night Energy provides a perfect solution for our needs. Our negotiations have been smooth, and we look forward to testing the technology in commercial environment. With this solution, we can further reduce the share of district heating produced by combustion, says Vatajankoski’s Managing Director Pekka Passi.

Construction starts immediately

The actual heat storage is about 4 meters wide and 7 meters high steel container with Polar Night Energy’s patented and automated heat storage system inside.

Vatajankoski will prepare the site to be ready for the heat storage installation during the summer. The complete steel container will be delivered to the site and put in place during early autumn 2021. Then it will be filled with sand, finished up and connected to the electric grid and district heating network.

According to the plans, the heat storage will be ready to provide heat to Vatajankoski’s customers already at the end of this year. The full-scale utilization of the storage will begin during the year 2022.