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Giant Gravel Pit Becomes World's Largest Heat Battery
9 Nov
Summary
- A former gravel pit is being transformed into a massive thermal energy storage facility.
- The storage will hold 100 million gallons of water, charged with cheap summer energy.
- This innovative system aims to cover a quarter of local heat demand and stabilize prices.
The city of Hyvinkaa is constructing what it claims to be the world's largest pit thermal energy storage facility within a former gravel pit. Approximately 100 million gallons of tap water are being used to fill a 66-foot-deep basin, which will store heat charged during periods of low energy cost.
The municipal heating company expects this innovative reservoir to meet close to a quarter of the local heat demand. Water, heated to between 104°F and 194°F (40°C and 90°C), will be circulated using diffusers. This system allows the utility to capture cheap summer electricity and industrial waste heat for later use during peak winter demand.
Once fully operational in late April 2027, the facility is projected to provide 18,000 megawatt-hours of heat per charge. This could warm approximately 1,000 detached homes annually. The project, costing €33 million, aims for stable heating prices and a reduction of about 4,850 U.S. tons of CO2 emissions each year.