The transition to green energy requires finding a way to efficiently store energy in large quantities. Because solar and wind sources supply energy when it is available, not when it is needed, the world is testing batteries that can compensate for this.

Another type is offered in Finland. Polar Night Energy announced the opening of the world’s first commercial sand battery on the company’s territory Vatajankoski in a few hours drive from Helsinki. This is reported by New Atlas.

It is a thermal energy storage system built around a large insulated steel tank – about 4 meters wide and 7 meters high. The tank is filled with ordinary sand, dry and cleaned.

The world's first sand battery went into operation in Finland: it will help heat houses with central heating
Sand battery for heat storage. Source: Polar Night Energy

When the sand is heated using a simple heat exchanger embedded inside, the entire “battery” is capable of storing an impressive 8 megawatt-hours of energy at a rated output of 100 kW. At the same time, the sand is heated to almost 500-600°C. If necessary, energy is extracted in the same way.

Vatajankowski uses the accumulated heat together with excess heat from the data storage servers to power the local heating system. Heated tap water can be used to heat buildings, be used in industry, or in any other situation that requires heat.

“Converting electricity into heat is really simple. However, turning heat into electricity requires turbines and more complex things. As long as we use heat as heat, it remains simple,” says technical director of Polar Night.

The company claims its system has an efficiency of up to 99%, retains heat with minimal loss for months, and can last for decades. Polar Night sees the system as a simple and cheap way to store energy. It plans to create more batteries with hundreds of megawatts of nominal power, where the sand will be heated to 1000 °C.

It should be noted that the system will find application in regions with central heating. However, it is used in many countries in the world. Almost half of all Scandinavian homes have it in one form or another. Central heating can also be found in Northern China and the USA.