Finland’s radical answer to renewable energy’s biggest headache: The world’s largest sand battery

The industrial-scale sand battery in Finland's Pornainen can cover almost one month of the town's heating demands in the summer and as much as one week in the winter.Polar Night EnergyA small town in southern Finland has turned to the world's largest commercial sand battery to fix what many see as the most critical problem facing renewable energy: intermittency.Standing at 13 meters tall and 15 meters wide, the eye-catching facility uses 2,000 metric tons of crushed soapstone to store clean energy in the form of heat to provide 100 megawatt-hours of thermal energy.That's enough to provide the 5,000 residents of Pornainen with nearly one month of heat demand through the summer — and roughly one week of demand in the winter.Commissioned by Finnish district heating company Loviisan Lämpö and developed by Polar Night Energy, the giant sand battery launched last year as part of a push to introduce a flexible heat production technology and reduce carbon emissions generated by the local district heating network. Polar Night Energy said the project is estimated to have slashed greenhouse gas emissions from the heating network by almost 70% and reduced the use of wood chips by about 60%. An...