Let's rethink heating

District heating is the most common form of heating in Denmark, covering approximately 64% of all Danish households. With geothermal energy, thousands of district heating customers can have a sustainable source of heated water running through their radiators. This transition to geothermal energy would not require households to make any changes or adjustments.

A geothermal plant consists of at least two underground wells and an above-ground installation. The geothermal water is circulated in a closed loop: The water is pumped up through a production well, and the energy is transferred to the district heating system through a heat exchanger and heat pumps. A heat pump ensures that the water has the right temperature and draws any excess heat out of the geothermal water. Then, the cooled geothermal water is pumped directly back into the underground through an injection well.

Two wells are drilled: a production well, from which the hot water is pumped up, and an injection well, into which the cooled water is pumped down again. The wells are placed approximately 1.500 meters apart. The exact distance depends on a number of subsurface factors, and the wells are always placed so as to ensure optimal pressure and temperature conditions in the subsurface.

The warm water is pumped up from geothermal underground sandstone reservoirs, i.e., soil layers that lie 1.000-3.000 meters below the Earth's surface. In (or rather under) Denmark, the water temperature in these soil layers ranges from 40-80 degrees Celsius.