Sand Energy Storage

Robin Low
2 min readDec 5, 2022

Finnish startup Polar Night Energy and local Finnish utility Vatajankoski have together built the world’s first commercial sand-based, high-temperature heat storage system that can be powered by solar and wind.

This is such a great idea as storing renewable energy is usually a challenge as batteries degrade over time and could cause more waste. Water does create challenges, and storing water using gradient usually requires specific types of landscape like waterfalls or cliffs to pump the water up, and it does not work in winter when temperature freezes the water over.

In Finland, this 23-foot-tall steel container is filled with 100 tons of sand (Lowest grade sand that cannot be used in construction) Hot air blown through pipes heats the sand to 500–600 degree celcius and the sand can hold the temperature for months, so power generated in the summer can be used to heat homes in the winter. Polar Night Energy says it has 100 kW of heating power and 8 MWh of energy capacity

The sand battery is connected to the grid and runs when the electricity is cheapest — that’s usually when renewables are powering it. It is also next to a data center, which pumps waste heat into the sand battery. The plan is to use the energy-storage silo to store energy from wind or solar sources.

When energy prices are high in winter, the sand storage system discharges heat that warms water for the heating system that pumps water in the town.

I feel that such innovation is the beginning of a whole other series of innovation that we can expect as the world pivots to renewable energy and efficient and cheap storage will be definitely in demand.

Robin Low

Author, Traveler, Innovator. Focuses on Social Impact and Innovation.