Archive: https://archive.today/KMSq0 From the post: >>Technology provider Polar Night Energy and utility Lahti Energia have partnered for a large-scale project using Polar’s ‘Sand Battery’ technology for the latter’s district heating network in Vääksy, Finland. The project will have a heating power of 2MW and a thermal energy storage (TES) capacity of 250MW, making it a 125-hour system and the largest sand-based TES project once complete. It will supply heat to Lahti Energia’s Vääksy district heating network but is also large enough to participate in Fingrid’s reserve and grid balancing markets. Polar Night Energy’s technology works by heating a sand or a similar solid material using electricity, retaining that heat and then discharging that for industrial or heating use.