Energy recovered from sewage water in Sandvika, Norway

This case study is part of a project catalogue produced by ReUseHeat to inspire how to utilize excess heat from urban sources for heating and cooling purposes. The catalogue contains 25 existing or planned projects, 12 of which are Danish and 13 from other European countries.

Description

In 1989, the local district heating company in Sandvika, a suburb of Oslo, started operating two heat pumps that utilized sewage water for both heating and cooling purposes. The heat pump facility, Sandvika Energisentral, has since produced cheap and environmentally friendly energy for local consumers.

With the urban expansion in Sandvika throughout the 1980s came an increased need for district heating. It was decided that a new central heating system would utilize excess heat from sewage water in two 6.5 MW heat pumps. The system further enabled district cooling, and the project was one of the first to combine district heating and district cooling in northern Scandinavia. Since construction, delivery of both heating and cooling has increased. As modern office buildings install more and more data units, the district cooling demand increases. The project further includes defrosting pavements in winter, a popular need in urban northern communities.

The heat pumps are supplied with sewage water from a major wastewater change,l leading sewage water away from the areas of Olso, Bærum and Asker to a wastewater treatment plant. To be near the wastewater channel, the heat pumps are placed in a subterranean cavern, excavated from bedrock. Oil-burning vessels and a conventional refrigeration unit were integrated into the system to supplement the heat pumps. In 2008, a third heat pump of 10 MW was installed. In 2013, approximately 95% of the production needed came from heat pumps and the remaining 5% was produced by the peak load units.

The project will lower energy prices and provide environmental benefits, as fossil fuels will not be used to produce district heating and cooling. As the system is optimized, the total amount of refrigerant R134a used in the heat pumps will also be lowered.

Sandvika, Norway

ReUseHeat

The operation began in 1989

IVL Swedish Environmental Research Institute

Related Celsius content:

Don’t waste the wastewater: Clean energy from sewage

Waste heat recovery from sewage water in Cologne, Germany

Excess heat from sewage in Hamburg and Singen, Germany

External links:

Sandvika Energisentral, Oslofjord Varme, Handbook – 25 cases of urban waste heat recovery