Case Vatajankoski

Polar Night Energy has developed and operates the world’s first commercial sand-based thermal energy storage system for Vatajankoski. This 200 kW Sand Battery, with an 8 MWh capacity, provides heat for the district heating network in Kankaanpää, Finland.

Vatajankoski uses the heat provided by the storage to prime the waste heat recovered from their data servers before feeding the waste heat into the district heating network. 

The system has achieved an overall efficiency of approximately 60–70%, which is in line with expectations. Efficiency improves with larger Sand Batteries, as their scale significantly enhances performance.

The Sand Battery, standing about 7 meters high with a diameter of approximately 4 meters, has been well-received by the client. It has met all the performance criteria agreed upon prior to installation.

Environmental impact:

• 91,000 kg CO2e: Emissions saved compared to traditional wood chip combustion (403 kg CO2/MWh) from August 2022 to July 2023.
• 61 kg CO2/MWh: Emission coefficient for heat produced at the Kankaanpää site during this period, based on measured electricity consumption, real-time emissions data from Fingrid, and heat production data.

Client feedback:

“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.” – Pekka Passi, Managing Director, Vatajankoski

Vatajankoski is a New Energy Company, that operates in three business areas: energy efficiency and circulation, district heating and cooling , and electricity distribution. The company utilises and pilots global technologies locally with focus is on sustainable, intelligent, and emission-free energy solutions.