World’s 1st Sand Battery developed in Finland - Down to earth

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Last Updated22/03/2023

Finland has successfully installed the world’s first sand battery that can store heat from various energy sources for months.

The battery is a massive steel silo, 7 m tall and 4 m wide with 100 tonnes of sand, and was installed in Finland’s Kankaanpaa town in June 2022.
It is connected to the town’s centralised heating network that keeps buildings and public water systems warm.

For charging the sand silo, air is heated to 600°C in the electrical air heater.
The hot air is then circulated inside the silo using a heat-exchange pipe and blowers to raise the temperature of the sand at the silo’s core to 600°C.
When the storage enters the discharging stage, the blowers are used to pump air into the pipe inside the sand silo.
Once the air reaches 200°C, it is transferred to the air-to-water heat exchanger, where it is used to boil water.
It is then sent to the heating network.

The storage system requires electricity at all times to charge the battery, monitor the temperature during standby, and run the blowers when the battery is used.
The installed battery can store 8 megawatt-hours (MWh) of energy and release heat at 0.1 MW, which is enough to provide heating and hot water for about 100 homes and a public swimming pool.

The Finnish researchers replaced water with sand in the battery system because of its advantages.
Sand can be heated up to 600 degrees Celsius (°C), whereas water starts to boil at 100°C.
It also has low heat conductivity, which reduces energy loss.

Heat accounts for half of the world’s energy use, followed by transport (30%) and electricity (20%), as per the International Energy Agency (IEA).
Currently, 80% of the world’s energy comes from dirty fossil fuels.