Wind Power Is Intermittent And Solar Is Seasonal And Only Available During The Day
Wind energy is intermittent. It is impractical to store wind-generated energy in batteries for long periods of time. That is problematic because particularly in mid-winter it can be brutally cold and calm at the same time causing both demand for electricity to spike and for the supply of wind-generated electricity to be close to zero for weeks on end.
Sand-Based Thermal-Energy Storage Technology Suitable For Long-Term Storage Of Heat
Polar Night Energy Ltd has created a sand-based thermal energy storage system to address the market.
We convert electricity to heat, and store it for later use. We use sand as the storage medium, which leads to safe operation and a natural balance in the storage cycle. Additionally, sand is a cheap and abundant material, which can be heated up to 1000 °C and even higher.Inside the sand we build our heat transfer system that enables effective energy transportation to and from the storage. Proper insulation between the storage and environment ensures long storing period, up to months, with minimal heat losses.
The size of our storages varies from tens to thousands of cubic meters. It is possible to locate the storage underground, reserving minimal space from the often highly valued square meters in construction sites.
The first system was commissioned in July 2022 in the small town of Kankaanpää, Finland. The system acts as a heat storage for the town's district heating network.
The 4m x 7m x 10 m storage has a thermal output capacity of 100 kW and a storage capacity of 8MW.
1000 C is a pretty high temperature. I wonder if this plant could store process heat generated with wind-powered electricity when it costs next to nothing heat for industrial plants as well.
Conclusion
This technology seems very promising. It is generates no waste, sand is very cheap and abundant, the plant has very low operating costs, no hazardous materials are needed and the system is suitable long-term storage of heat.