Subway construction in Germany has had a flaw since the collapse of the city archives in Cologne: too expensive and too lengthy, it has hardly been carried out on a large scale for decades. In Hamburg, too, the critics of the construction of the fifth subway line are not few and they never tire of emphasizing the disadvantages of the complex subway construction compared to the much faster tram construction.
The Greens in Hamburg are also among the advocates of the idea of above-ground rails integrated into the existing street space mentioned in the Hanseatic City of Stadtbahn. And so the Green transport senator Anjes Tjarks begins almost every speech he makes on the subject of the U5 by justifying why building this subway is the right thing for the city after all. In a nutshell: one had planned and rescheduled for too long and as a result no new rails were built for forty years. For the parts of the city that were left behind as a result, a high-performance means of transport was needed, the subway. In addition, the preparatory work has progressed so far that stopping the project is the wrong way to go.
The left recently called for such a stop. Like the BUND environmental protection association, they are among the fiercest opponents, partly because the construction of the subway produces so much CO2 that it will only take decades to improve the environmental balance.
The Senate, which is led by the Red-Green Party in Hamburg, and Hamburger Hochbahn, the operator of the subway network, are now countering this argument. Tjarks and the CEO of Hochbahn, Henrik Falk, announced on Tuesday that the U5 will be built in the most climate-friendly way possible. Tjarks made it clear that the answer to the problem of high emissions from the construction of the subway cannot be not to build it. The answer must be to do everything possible to build as climate-friendly as possible, if not climate-neutral.
According to calculations by Hochbahn and the transport authority, around 2.5 million tons would be needed if the U5 were to be built like the four subway lines that already exist in the Hanseatic city. Above all, the building materials steel and cement and their production are considered to be major CO2 emitters. A lot of CO2 is also emitted during the excavation, removal, storage and disposal of soil and when operating the tunnel boring machines.
That’s why Hochbahn boss Falk has had to make a lot of phone calls since the decision to set new standards for climate-friendly construction with the construction of the U5. As he reported on Tuesday, he called numerous CEOs of large German industrial companies to find out to what extent the companies are able to supply steel, cement and other building materials that have a good climate balance. In addition, the Hochbahn planners began to redesign the stops, making them slimmer and shorter, for example by relocating the stairs and elevators and moving technical rooms from the tunnels to the ticket halls.
70 percent of CO2 emissions are to be saved as a result, as well as through the use of green electricity throughout the building. That was a “very successful reduction,” said the technical director of U5 GmbH. Tjarks and Falk affirmed that this is a figure that can be assumed to be calculated conservatively and is therefore achievable in any case. At the end of the construction period, which is scheduled to last until the end of the 2030s, it may even be in a much better position.
From Hochbahn’s point of view, the new railway line is a “project of the century”. Trial operation on the first, almost six-kilometer-long section of the U5 East is planned for the end of 2027. The entire U5 project covers a distance of around 24 kilometers. It should lead from Bramfeld via Steilshoop and City Nord to the main station and from there through the city center via the university and university clinic to the arenas in the Volkspark. The city expects 270,000 passengers a day.
A cost calculation for the project has not yet been made. However, Falk announced that this would be available by the end of the year. Because Hamburg wants support from the federal government for the U5 project and a corresponding application for funding will be submitted this year. He will then also receive information about the costs. Incidentally, Falk does not expect these to increase as a result of the climate-friendly construction. “In the beginning we will have a few issues where we think that conventional construction would have been cheaper.” However, this will not have a major impact “on the route” of the construction time.
The proven critics of the project could not convince Tjarks and Falk with their presentation. The BUND, for example, announced on Tuesday that the plans presented “cannot be seen as an adequate solution to the problem of the enormous CO2 emissions in the construction of the U5 subway”. All measures to avoid CO2 through the use of less material and efficient construction are to be welcomed, “since they improve the climate balance of the U5,” said BUND state manager Lucas Schäfer. However, many of the improvements promised by the industry in the production of steel and concrete are still subject to great uncertainty as to when they will actually be implemented.
