The future of energy supply: The dream of self-sufficient life

Dhe Germans are preparing for the winter. Electric fan heaters are sold out in hardware stores, and firewood and charcoal briquettes are also hard to come by. Some people go into the forest with a chainsaw to get supplies for the wood stove at home. Solar systems are also in demand like never before, the waiting times for systems and craftsmen extend well into next year.

People’s eyes have long ceased to focus solely on how to get through this winter as warmly and inexpensively as possible. Many suspect that energy prices will remain high for a long time to come. There is a growing demand for concepts that rely on a high proportion of the energy generated by the company itself. An overview of what is feasible – in the individual house, in the individual town and in the whole country.

The house

Until recently, the prefabricated building on Kopernikusstraße in Aschersleben was one of many that were once built in the GDR. Five floors, four entrances, 60 apartments – practical, but no longer innovative. That should change.

The housing association of the 27,000-inhabitant city in Saxony-Anhalt is currently having the 1972 prefabricated building converted into an efficient house that is supposed to cover its own energy needs over large parts of the year: with well-insulated outer walls, solar modules on the roof and the facade, electricity storage and with infrared heaters in the then only 22, but larger apartments. The concept for this came from the engineer Timo Leukefeld, who teaches at the Technical University of Freiberg.

The house is currently a big construction site. Two storeys were demolished, from the rest the precast concrete parts of the outer wall and the load-bearing walls inside are still standing. The previous flat roof is replaced by a south-facing sloping roof packed with solar panels. Modules are also to be attached to the outer facade and the balcony fronts. The whole house is packed up.

The heat pump preferred by Federal Economics Minister Robert Habeck (Greens) is not used for heating, but another electricity-based system: infrared heating. This has the advantage that it is significantly cheaper to buy, explains Leukefeld. “Instead of pipes, we only have to lay power cables.” Infrared heaters use more electricity than heat pumps to run, but maintenance and repairs are cheaper. “We’re stuffing too much technology into the houses,” criticizes Leukefeld. He advises systems to be as simple as possible and to consider the costs over the entire life cycle of a heating system.

The Aschersleben ex-panel building should be 62 percent self-sufficient when it is occupied in the coming year. In the cold winter months, green electricity is to be purchased. Why not 100 percent self-sufficiency? “That would be far too expensive,” says Leukefeld. Even so, the calculation was not easy. The refurbished apartments are said to cost between ten and eleven euros in rent per square meter, but not cold, but warm. In addition to electricity and heat, the planned all-inclusive rent should also include two car-sharing electric cars.

For the next project of this kind, Leukefeld plans to reduce the level of self-sufficiency somewhat, to 55 percent. Then the rent could also be lower. As proud as the engineer is of this project, he also sees the limits of what is feasible. In large cities, as much self-sufficiency as in Aschersleben is hardly possible. Too little roof space in relation to the living space, too many shadows from neighboring houses, which reduce the solar yield. “We can perhaps bring 25 percent of the building stock to this level,” estimates Leukefeld. There is hardly more.

The village

gas price shock? Sold out charcoal briquettes? Rush for fan heaters? The 130 residents of Feldheim can safely ignore the current news situation. The village in Brandenburg has been completely self-sufficient in its energy supply for twelve years. Electricity and heat are generated right on the doorstep, in a wind farm, a biogas plant and a wood chip power plant. Since the end of the EEG surcharge, Feldheim residents have only paid 12 cents for a kilowatt hour of electricity and 7.5 cents for a kilowatt hour of gas. On the market today, gas costs about three times as much.