Polar Night Energy (PNE), a Finnish company, is recognized as a pioneer in large-scale energy storage solutions that do not require lithium. Instead, the company has turned to a readily available resource: sand. In 2022, they unveiled the world’s first sand battery.
Sand batteries are an immediately available technology.
PNE’s solution involves using resistive heating to leverage surplus electricity during peak hours. The energy is used to heat air, which is then transferred to a sand tower via a heat exchanger. The melting point of sand is several hundred degrees Celsius, enabling the sand tower to store high amounts of energy.
Importantly, the battery is designed to store energy for months at a time, providing a long-term storage option. To demonstrate their technology, PNE established a small sand battery in western Finland using 100 tons of sand sourced from construction.
The stored thermal energy can be used to heat water and pump it to offices and homes during winter. While the conversion rate of thermal energy to electricity is relatively low, it can still be beneficial as an industrial heating source, which is a major contributor to emissions.
Unlike innovations that take years to mature and reach the market, sand batteries are an immediately available technology. Since showcasing their technology, PNE has been offering sand-based energy storage solutions through two introduced products.
One has a heating capacity of 2MW and an energy capacity of 300 MWh, while the other boasts a heating capacity of 10MW and an energy capacity of 1000 MWh (1 GWh). The latter serves as a technology demonstration tool expanded by 100 times, which the company has constructed and revealed in an interview.