NIt’s a game of thought, but in a few years time the many data centers in Frankfurt could make a noticeable contribution to the city’s heat supply. Constantin Alsheimer, CEO of Mainova AG, announced on Thursday that the district heating network of the energy supplier would be expanded in the next few years so that data centers can feed the waste heat from their cooling devices into it. In the next few years, for example, a new line will be laid along Hanauer Landstrasse, where there are a large number of data centers that have so far been releasing their warm exhaust air into the environment.
Whether the operators will feed them into the city’s supply network in the future will depend very much on the success of the first project of this kind in Frankfurt’s Gallus. A new residential area called Westville is currently being built there. The heat cycle there should be closed in a good two years: the project developer Instone Real Estate is building 1,300 apartments on the former Telenorma site, and the neighboring data center operator Telehouse is supplying the energy-rich raw material to supply them with hot water and heating. Mainova takes care of the technical implementation. That sounds easy, but it is technically uncharted territory – and the largest project of its kind in Germany to date.
60 percent target
Its greatest difficulty lies in the fact that the telehouse data center has a lot of waste heat to offer in the form of heated cooling water, but this is just warm, not hot. Around 30 degrees Celsius is supplied via the 500 meter long cable from the data center to the technical center in the residential area, 70 degrees are required. This difference, as project manager Kolja Franssen explains, is balanced out in two heat pumps, i.e. the water is heated in them, although electricity is also used. The first brings it to 60 degrees, the second then to 70. Compared to a cycle that works with cold water, however, around 80 percent less energy is used, says Franssen.
So far, those involved have assumed that 60 percent of the heat supply comes from the telehouse energy. The rest comes from Mainova’s district heating network, which is also used on particularly cold days or in emergencies when Telehouse is temporarily unable to deliver. In this way, 400 tons of carbon dioxide a year should be saved in the settlement with around 3000 residents, three kindergartens, restaurants and a supermarket.
Future residents can also save directly. Since Telehouse is giving away its energy, district heating can be offered more cheaply than elsewhere in the city, announced Ralf Werner, who is responsible for the Rhine-Main area at Instone. The contract with the data center operator runs for 15 years. During this period, the participants hope that their example should have set a precedent. For the energy transition, technology openness is needed, said Mainova boss Alsheimer. In the case of Frankfurt, district heating is basically a very promising technology – if it is fed from more sources than just the power plants. To do this, the network is being converted so that heat can also be fed in at lower temperatures, so that less energy would have to be used in the power plants.
The data centers offer themselves as suppliers. There are already more than 60 in Frankfurt, and more are being built. Only three months ago, the initiative called DC-Heat, which consists of scientists, companies and municipalities, calculated that, at least on paper, by 2030 all office and residential buildings in the city could be heated exclusively with the waste heat from the data centers. Even with the first project at Gallus, “Frankfurt, the world’s largest internet hub and data center hotspot, will set the pace on the way to a climate-neutral data center,” praised Mayor Peter Feldmann (SPD).
The idea for this goes back to Béla Waldhauser, the managing director of Telehouse Deutschland GmbH, which belongs to a Japanese group. Originally, he and Instone boss Werner met to talk about the difficulties that could arise from the neighborhood between the data center and the residential area. In the end, the plan for this cooperation came out, which the city and Mainova were also quickly convinced of. “I ran into open doors with my idea,” said Waldhauser.