Finland's Giant Sand Battery: A Revolution in Energy Storage?

Published at : 23 Dec 2025

Finland is heating an entire town with a giant box of... sand? The world's largest sand battery, a 100 MWh thermal energy storage system, is now online. It promises to store renewable energy for weeks or even months, providing clean heat during the darkest days of winter. But how does it really work, and could this be the solution for the energy transition in Germany and beyond?

In this video, I dive deep into the science behind this incredible innovation from Polar Night Energy. We'll explore how simple sand (or in this case, crushed soapstone) can be heated to 600°C to store massive amounts of energy. We'll also look at the AI-powered software that makes it economically viable and the huge advantages it has over traditional batteries.

This video was created by my editorial team.
Editorial: Nina Bürger, Tabea Desch, Jacob Beautemps
Editing: Aron Kamenz, Sören Rensch, Neo Sanjuan Thiele

Sources:
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