Thermal grids must be fully decarbonized by 2050 at the latest. In the City of Zurich, the use of natural gas is set to fade out by 2040. Today, thermal grids still require fossil fuels to cover peak loads and the increased heat demand in winter. Alternatively, thermal energy storage can offer a cost-effective solution to avoid fossil fuels by storing excess renewable heat and making it available when needed. To overcome the space limitations in the city, new possibilities are being explored to realize large-scale seasonal thermal energy storage systems in the underground. In addition to technological advancement, business models and policy recommendations will be developed to increase public acceptance and accelerate implementation.
Link to article on thermal storage
