Sweco does geothermal energy assignment in Stockholm’s Old Town

Sweco has been commissioned by property company Hufvudstaden to establish an aquifer thermal energy storage and recovery facility to provide two properties in Old Town (Gamla Stan) with eco-efficient geothermal heating and cooling.

In the first phase of the project all of Hufvudstaden’s properties in central Stockholm were ranked in order to find the best places for conversion to a geothermal energy system. This was achieved by investigating the geological and hydrogeological conditions at each location. It turned out that the two properties with the highest ranking were situated next to each other at Slussplan in Stockholm’s medieval city district.

During the second phase the properties’ cooling and heating demands were identified as well as the changes needed for adaptation of the buildings’ HVAC system for a conversion to geothermal heating and cooling. Aquifer thermal energy storage and recovery facilities can manage both these things with one single production system.

The rest of the project consists, among other things, of drilling down to the ground water in the Stockholm ridge, which lies directly beneath the buildings in Old Town. Furthermore, tests and groundwater sampling need to be carried out for the permit application that requires the approval of the Environmental Court before the facility can ultimately be completed. By the time the aquifer thermal energy storage and recovery facility is up and running the need for purchased energy will be reduced by around 80%.

Facts

Geothermal energy is a generic term for various methods to extract and store heat or cold in the ground. Sweco has approximately 40 years of experience of geothermal energy facilities and has designed most of the major plants in Sweden. In recent years, a special section for geothermal energy has been created. The section is based in Malmö and is today a national and international center of excellence for geothermal energy.