A group of homes in Silkeborg, Denmark get their renewable heat through a thermal network or ‘thermonet’.
Six shallow boreholes, 120 metres deep, supply geothermal energy to the 15 houses. This energy is at an average of 8°C. They then supply individual geothermal Thermia heat pumps, which deliver the heat to the houses.
The homeowners pay the same heating tariff as conventional district heating customers.
The geothermal boreholes, thermonet, and heat pumps are owned by district heating company Silkeborg Forsyning.
The aim of the project was to provide residents with affordable collective heat supply comparable to conventional district heating, which is typically not economically viable in small towns.
The solution reduces the need for relatively expensive vertical boreholes – rather than one borehole per house, with a total depth of 1,345 metres, fewer boreholes are needed with a total depth of 720 metres – by enabling them to be shared between houses via the thermal network.
