Bern to turn old oil tanks into heat stores

Bern’s local energy company plans to convert two disused oil tanks into heat stores for the city’s district heating network, SRF reports. The tanks, in western Bern, have been empty for 15 years.

The steel tanks will store hot water produced for the network and release heat when demand rises, such as in the morning when households turn on their heating and use hot water. They will be recharged at night and on weekends, when demand is lower, using heat from a waste incineration plant.

Energie Wasser Bern (EWB) expects the project to save about 1,000 tonnes of CO2 a year. The conversion is due to take three years and cost about 15 million francs. The tanks will be reinforced and insulated to hold water heated to 90 degrees Celsius.

EWB’s head of energy production, Thomas Bücherer, said inspections found the tanks to be in good condition and suitable for reuse for about another 50 years. The project is the first conversion of its scale in Switzerland, according to SRF.

Jörg Worlitschek, an energy technology professor at Lucerne University of Applied Sciences and Arts, said heat storage would be important to the energy transition, noting that nearly half of energy consumption goes to producing heat for industry and households.

EWB is also planning a seasonal borehole heat store on agricultural land at the edge of Bern. It would store excess heat underground in summer for use in winter. The oil-tank project is designed for shorter-term storage, with the first households expected to receive heat from the converted tanks in about three years.