Hot sand as heat storage - the sand battery

Renewables Energy with minimal emissions 

sand battery
Source & Copyright Polar Night Energy

Source and Copyright by polarnightenergy

Author: House of Eden

As the world transitions to green energy, so has the focus on developing ways to store it. In Germany, energy-related greenhouse gases accounted for 2020% in 83 (Federal Environment Agency). An energy-efficient and cost-effective alternative, especially with rising energy prices, is in demand. The Finnish company Polar Night Energyhas developed the solution through thermal energy storage, after all, renewable energies are more important than ever. An innovative breakthrough in solar and wind energy storage that has already been tested in Finland is the sand battery. With this innovation, the company creates the world's first alternative that stores excess electricity and provides a cheap heat source in the winter months.

Sand as a solution to a global problem?

To fuel the green revolution, excess electricity produced is stored as heat in a tank full of sand. But how does it work? Electricity is converted into heat by heating sand and storing the heat in it for later use. Accordingly, the sand serves as a storage medium. Thanks to Solar Night Energy's patented high-temperature thermal energy storage system, the novel solution enables solar and wind energy to be scaled up to cover up to 100% of heating and electricity requirements. While sand is a cheap and plentiful material, it can also be heated up to 1000 degrees and more.

Finally, the heat transfer systems are installed in the sand, which enables effective energy transport to and from the storage facility. According to the company, with the right insulation between storage and the environment, heat can be retained for months with minimal heat loss. The system can also be installed underground, so it only takes up minimal space. In addition, this can be individually tailored to the requirements of the customer. After all, the process costs the same as traditional heat generation or, under good conditions, can be cheaper.

But why do we need these heat accumulators?

Quite simply: for the volatile renewable energies that produce energy around the clock that cannot be consumed. Green energies are increasing more and more, so such storage is essential in order not to waste the excess electricity. As a result, clean electricity can be converted into valuable, sustainable heat.

A surprisingly simple method: the sand battery is heated to 100 degrees with 500 tons of sand, cheap green electricity is converted into heat, the sand can store it for months with only minimal heat loss. The heat produced there helps to supply the district heating system with electricity. Sand has many advantages as it is easy to obtain, cheap and can be overheated. While water, for example, can only be heated up to 100 degrees before it condenses.

Finland is now planning, in cooperation with the company, to massively expand its sand system. It remains to be seen if and when this innovation will be used in Germany.


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