The world's first sand battery has been built in Finland. This new system could be the key to clean renewable energy. It is a 7-metre high steel tank consisting of 100 tonnes of construction sand, two district heating pipes and a fan. The system will become a battery once the electricity generated by the wind turbines and solar panels heats the sand to 600 degrees Celsius. The tank is filled with 100 tonnes of low-grade construction sand. The system includes a fan to circulate the air and two district heating pipes.
The sand becomes a battery by heating it to 600 degrees Celsius using electricity generated by wind turbines and solar panels, which heats the air inside the sand. The hot air in the tank is then circulated by a fan through heat exchange tubes. The tank is surrounded by thick insulation so that the air temperature inside the battery can be kept at 600 degrees Celsius at all times.
When full, the sand battery can store up to 8 megawatt-hours of thermal energy. The system can deliver roughly 200 kilowatt hours of power through the heat exchanger tubes as energy demand increases. This is enough to provide heating and hot water for about 100 homes and a swimming pool. The battery is charged at night when electricity prices are lower. The system designers said the sand battery is easy to build and requires little maintenance. It is inexpensive to set up because it requires low-grade construction sand, which is not usually used in construction. They added that they could also use good quality sand, but this is unnecessary, and that there is a global shortage of the river sand in demand.
Pipes and sand are not used up in the battery. The only moving part that can fail is the fan, but this is easily replaceable
Sand has several properties that make it an excellent battery. The most important is that it can retain heat for a long time, even months. Also important is its inability to wear out. No matter how many times it heats up and cools down, it won't hurt you. The only thing that changes over time is that it becomes denser, which is not a problem, because it takes up less space and more sand can be added.
