Finland pours 100m gallons of water into giant pit to store heat for homes

Hyvinkaa is embarking on an ambitious project to fill an old gravel pit with 100 million gallons of water, designed for thermal energy storage. This facility is set to provide approximately 25% of the city's heating requirements during the colder months. While construction is scheduled to continue until late April 2027, the facility is expected to start charging by late summer 2027.