The sand battery is the idea of two Finnish engineers, Markku Ylönen and Tommi Eronen. It is simplicity itself. Make a really big pile of sand. Heat it with excess renewable electricity to around 500º C , then use that heat later to heat homes, factories, even swimming pools. They say the sand can stay hot for 3 months or more.
The first installation has 100 kW of heating power and 8 MWh of energy capacity. “This innovation is a part of the smart and green energy transition. Heat storage can significantly help to increase intermittent renewables in the electrical grid. At the same time we can prime the waste heat to usable level to heat a city. This is a logical step towards combustion-free heat production,” he adds.
Each system is fully automated and has a nominal power rating of up to 100 MW and a storage capacity of up to 20 GWH. The projected cost of a system is less than 10 euros per kWh of storage capacity. The company says, “Production of renewable energy sources such as wind and solar power is highly volatile and only partly overlapping with the consumption in time. As these volatile electricity sources increase rapidly in societies, more and more energy storage technologies will be needed.