Previously known as Fortum Värme, the company adopted its current name a short while ago. “The company was renamed because the City of Stockholm bought half of it from Fortum about a year ago. In this respect, the city wants to be an active owner of its large stake in the energy company. It also meant much more cooperation with the city than before, both on practical and environmental matters. For example, we are working together to decommission our coal-fired heating plant in Värtan by 2020,” says Hans Jakobsson of Stockholm Exergi. Stockholm Exergi’s goal is to use 100% renewable fuels by 2022. This is of major im-portance for Stockholm’s climate strategy, since the city aims to be fossil-fuel-free by 2040. Stockholm is already considered one of the world’s cleanest capitals, having been rated the third most sustainable city in a comparison of 100 cities in the world.

A new culvert with better insulation
Stockholm Exergi manages 2,900 kilometres of district heating network in Stockholm area. The company invests some 300–350 Million Swedish kronor per year in the renewal of its network.  “A future challenge lies in the need to largely replace old culverts. We have replaced several special square culverts, and that is what we still have to prioritise,” Hans Jakobsson says.  Major ongoing renewal projects include the replacement of an old main pipeline between the Hässelby and Akalla districts in western Stockholm. “This will need to be replaced due to aging. In addition, we need to increase the size of  the pipe, from DN600 to DN800, so that it can transfer more heat energy between production facilities,” says Jakobsson, responsible for the project in Stockholm Exergi.

Uponor Infra will supply 7,000m of pre-insulated Wehotherm district heating pipes for the project. Wehotherm district heating elements are designed for the underground installation of district heating pipeline systems. Their polyurethane rigid foam preinsulation and rigid connection structure provide the system with excellent insulation properties, mechanical strength and a long life. “We have worked on several projects with Uponor, which was clearly the best choice of supplier for this project.” “With Uponor Infra´s district heating system, we will obtain a new culvert with better insulation,” says Hans Jakobsson.

Challenging work in the middle of a city
Construction of the new pipeline began in December 2017 and the work will be completed in September 2019.  The installation work has been fairly challenging, due to the pipeline´s location in a busy city environment with heavy traffic. “Laying large pipes in the middle of a city always involves challenges. The route crosses Mälarbanan, one of the busiest railway lines in Stockholm, and the management shaft is next to a major road in the city. Traffic works are also ongoing in the same area,” says Project Manager Rikard Söderström of Fjärrvärmeprojekt Sverige AB.  “The route also extends through an in-dustrial area with heavy traffic. There is little space for storing the pipes, which sets high demands on transport,” he adds. 

Rikard Söderström praises Uponor Infra’s deliveries, service and flexibility during the project. “Everything works just fine. Based on close dialogue with Uponor, we are able to plan the work as efficiently as possible. Their service has been excellent – we have no cause for dis-satisfaction! It’s very easy to work with Uponor,” Söderström sums up.