Brief
The small Danish town of Vojens, home to 7,480 people and known for its less sunny climate, hosts the world’s largest seasonal solar heat storage project in operation since 2016. It supplies 2,000 households every year with renewable heat generated thanks to the sun’s free energy, reaching a solar thermal capacity of 49 MWth.
Technology
The sun’s energy is captured by flat plate collectors distributed across a 70,000m² area. The resulting solar thermal energy is then stored in a 200,000m³ tank.
This extensive storage functions as a seasonal heat storage, enabling the solar thermal plant to contribute over 50% of the annual heat production to the district heating network. Thanks to this big share of renewables in heat production, Vojes reduced its carbon emissions by approximately 6,000 tonnes per year.
The remaining heat is generated by three gas engines, a 10 MW electric boiler, an absorption heat pump, and gas boilers.
