Polar Night Energy's Sand Battery

Energy Cities & Regions

Sand battery stores renewable energy and produces clean heat

Project Facts


Applied Financing Solutions
Grants, Private Equity, Other

Project Dates
Start: 2022
In operation since/from: 2024

The Story

Polar Night Energy’s sand battery is a large-scale high temperature thermal energy storage that uses sand or sand-like materials as its storage medium. It stores energy in sand as heat. It has three main purposes: 1. To store excess wind and solar energy, 2. to participate in all existing grid balancing markets, and 3. to produce heat and power without burning. The sand battery helps the growth of wind and solar energy production and the decarbonization of the heating sector. The sand battery has a lot of potential to save emissions. According to an assessment by Mission Innovation, Polar Night Energy’s sand batteries may save over 100 Mt of CO2e per year in 2030. The amount is approximately 3% of the current EU emissions or double the emissions of the today’s New York City. Polar Night Energy’s vision is to decarbonize energy production and to be the global market leader in large-scale thermal energy storages for renewable energy. The company was founded in 2018 by Tommi Eronen and Markku Ylönen.

Success Factor | Hero Moment

Polar Night Energy constructed and operates the world’s first commercial sand-based thermal energy storage for Vatajankoski Oy, an energy utility in Western Finland. The sand battery, which has a hundred tons of sand inside, provides low emission heat for district heating network of Kankaanpää, with 200 kW heating power and 8 MWh capacity. The sand battery’s commissioning began in May 2022, and it was put into actual operation in July.

Polar Night Energy, Finland

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Energy Efficiency, Innovation, Energy Storage