The drilling machine Astrid

For the actual tunnel drilling, we used the 128m long 500 tonne drilling machine, Astrid. The section from Amager Power Station to Adelgade in Central Copenhagen and then on to Fredensgade near Rigshospitalet (the University Hospital) took 10 months at a speed of 10–25m per day. In addition to the drilling, Astrid also lined the tunnel with concrete rings.

40m deep shafts

The tunnel was not the only part of the construction that required drilling and excavation works. MT Højgaard also established three large tunnel shafts 25-40m deep and up to 25m wide. The district heating tunnel itself was drilled between the three shafts.

MT Højgaard handed over the tunnel to the next contractor in 2008. They installed the permanent district heating pipework, while we completed the shafts’ internal walls, floors, stairs and elevator shafts.

Economic and environmental benefits

Calculations show that the tunnel saves the city 200,000 tonnes of CO2 emissions per year, equivalent to the emissions from 53,000 cars. The economic and environmental benefits arise from the fact that the heat is produced at Amager Power Station’s new efficient plant, which uses CO2-neutral biomass to produce district heating.