Repairing the heart of Copenhagen’s district heating system

Ramboll has assisted The Metropolitan Copenhagen Heating Transmission Company (CTR) in replacing the main valves of Copenhagen’s district heating transmission system.

Due to an unstable operation, the valves of ‘chamber 130.12’ needed to be replaced, which is the heart of the Copenhagen district heating system delivering heat to approximately 250.000 households. This is the first replacement since it was installed in the 1980s. Ramboll acted as the Owner’s Engineer and supported the client with planning and detailed design, as well as construction management and supervision.

The transmission capacity of the chamber is more than 700 MW, making it the main connection from the cluster of power plants located on the island of Amager to the city of Copenhagen.

The six sets of main valves (DN700) with bypass valves (DN200), are among the largest in the Copenhagen transmission system, and play a crucial role in the control of the transmission system, enabling sectioning and emergency shutdowns for part of the network.

Since the replacement of the valves requires that all heat transmission through CTR’s tunnel from Amager to Copenhagen is stopped, the project required nearly all production of both heat and electricity on Amager to be shut down, making the time schedule the primary concern for the project.

“We have used our many years of experience within district heating and comprehensive knowledge of CTR’s system to complete the detailed planning of the project. Along with a highly talented and efficient team that has been in close cooperation with the contractor, this led to completion 13 days ahead of the very tight scheduled deadline. For the client, this meant significant reductions in the operating costs”, says Søren Ørsted from Ramboll’s District Energy division.

Overcoming practical challenges

Due to its underground placement close to the railway, accessibility to the chamber proved to be challenging with respect to safety measures, especially when using cranes. To ensure safe conditions, the safety organisation of the railway company was included early in the project, thereby enabling the inclusion of their input in the planning.

To optimise the timeline and keep the shutdown period as short as possible, the contractor’s input was included early in the planning, which proved to be valuable, both with respect to time estimation, creative solutions, and instilling a sense of ownership.

With rigorous planning, both the removal of the old valves weighing more than five tonnes, as well as the installation of the new prefabricated pipe sections and valves of more than three tonnes went smoothly.

Source: Ramboll