When I heard this news I was surprised and I liked it for its simplicity. Some Finnish kids have come up with the wonderful idea of storing energy using sand as a storage material.
Sand, apart from being cheap and very abundant in nature, can be heated up to almost 1,000 degrees without degrading. And that is what his idea consists of, in having a sand silo, which is heated with surplus renewable energy, and that heat can then be used to heat buildings, flats, swimming pool water, etc….
A simple and original idea at the same time that they have already put into practice. They have formed a company called Polar Night Energy , , and have built a first installation of 4 x 7 meters where they have placed 100 tons of sand, which is working in tests in Finland.
The electrical energy passes through a heat exchanger placed in the sand, which heats up to more than 500 ºC, and since the whole is well insulated, the heat can be preserved for months. When heat is needed, it can be extracted to heat buildings, homes, etc...
The system is very inert, and without any contamination. It is 99% energy efficient and can work for dozens of years. The simpler things are, the longer they last in operation.
And the sand does not have to be very special either, almost any type of sand works as long as it is clean. And all this means that the cost of the installation is estimated at 10 euros/Kwh. which is more than competitive.
An explanatory video from the BBC can be seen at: https://youtu.be/Azaf9tKJNoA
The pilot test installed in Finland will demonstrate the feasibility of the idea, and I hope and wish that it will be positive. And in the future, installations can be made to store up to 20 GWh to provide heat to a multitude of more or less nearby installations.
As the system is so simple, it can be carried out anywhere, and with such elementary means, it can be replicated anywhere.
Obtaining heat for heating is one of the important energy consumptions, and this simple system can change the way we do it in the future.
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