It was developed in Finland. It could resolve one of the big problems of renewable energy. It can ensure continuous supply all year round. The revolutionary sand battery is already in operation in that country.
The device uses low-grade sand heated with inexpensive electricity produced by solar or wind power. The sand stores heat at about 500°C. It can then be used to heat homes in winter when energy is more expensive.
There is already a small generating plant using this new system. The key is sand stacked in a silo, a total of 100 tons. The biggest problem they present is intermittency. That is, how to keep the lights on when the sun is not shining or there is not enough wind.
It is operating in the village of Kankaanpää, western Finland. Young engineers installed the first commercial system with a sand battery. The company is Polar Night Energy.
Electricity produced at low cost heats the sand to a temperature of up to 500°C. A stream of hot air is recirculated into the sand. This loses heat very slowly and is a very effective means of storing it. It is estimated that sand can be kept at about 500°C for months.
When energy prices rise, the battery can release air at high temperatures. It would heat water in the district heating system, which in turn heats homes, offices and even the local swimming pool.
Green energy for everything
One of the biggest challenges now will be to be able to use this for electricity as well as heat. The efficiency of the system drops dramatically when it is used to supply electricity to the grid.
Storing green energy in the form of heat also has other applications. For example, for the industrial sector. The heat used in the production of food, beverages, textiles or medicines comes from burning fossil fuels.
“It’s really simple. We liked the idea of trying something new, of being the first in the world to do it,” said Pekka Passi. He is director of the Vatajankoski generating plant
The revolutionary sand battery is an original proposal – will it succeed in the future?