Wedoany.com Report-Aug. 29, Finland has introduced the world’s largest sand battery, a 1 MW/100 MWh thermal storage system developed by Polar Night Energy, in Pornainen. Commissioned by Loviisan Lämpö, the industrial-scale unit began operations in June and now serves as the primary facility for the company’s district heating network.

The sand battery has performed effectively, surpassing efficiency targets and replacing the region’s previous woodchip plant throughout the summer. The system stores clean electricity as heat in approximately 2,000 tons of crushed soapstone, housed in a structure nearly 13 meters tall and 15 meters wide. It delivers 1 MW of thermal power with a storage capacity of 100 MWh, enabling optimized energy use over days or weeks.

Polar Night Energy noted that the battery participates in electricity reserve markets, charging based on electricity prices and signals from Finland’s grid operator, Fingrid. This capability supports grid stability and enhances energy system flexibility.

Sari Multala, Finland’s Minister of the Environment, stated: “Energy storage plays an important role in the energy transition, where combustion-based production is phased out and society moves toward carbon neutrality. The Pornainen sand battery is a great example of how the clean transition can be advanced through the electrification of district heating networks.”

The technology offers a sustainable solution for storing and utilizing renewable energy, particularly for applications requiring high temperatures. Liisa Naskali, Polar Night Energy’s Chief Operating Officer, highlighted the potential for industrial uses, stating that sand batteries can deliver heat above 100°C, surpassing the capabilities of electric boilers and heat pumps. The company is in discussions for additional large-scale thermal storage projects to support district heating, hot air, and process steam production.

Polar Night Energy is also preparing to launch a pilot project in the coming weeks to test its power-to-heat-to-power sand battery technology, further advancing its innovative approach to energy storage. The Pornainen facility demonstrates Finland’s commitment to sustainable energy solutions, contributing to reduced industrial emissions and supporting the transition to a carbon-neutral future.