Interim report on the Dena grid study: More wind energy, more economical homes – savings

They shine on the meadows, cross the squares, cross the streets: masts and lines carry electricity from large power plants via substations to homes and businesses. But the energy transition is changing the system: atomic and carbon cells are gradually disconnecting from the grid, and more and more solar cells and wind turbines are supplying electricity on a small scale. The probable future federal government made up of the SPD, the Greens and the FDP has declared that it wants to push the change forward.

But what should electricity and gas infrastructure look like in a climate neutral future? The German Energy Agency (Dena) addresses this in its network study, which is funded by the Federal Ministry of Economics. The interim report Dena plans to present on Monday contains urgent advice for the next government coalition. “We discussed our proposals very widely,” explains Dena boss Andreas Kuhlmann: “with network operators and the energy industry, but also with the federal government, states and non-governmental organizations.”

Planning: It starts with planning. So far, Germany has drawn up separate grid development plans for electricity and gas every two years. “There are a lot of fundamental questions from the population,” says Hannes Seidl, energy systems manager at Dena, “that go beyond individual grid development plans”. And this is also true: the more electric heat pumps replace gas heating systems, for example, the more inept it seems to plan separately for the future of these infrastructures.

Dena advocates that in the future the federal government should first establish a model for all energy networks, in a process with a lot of participation. It “should ideally start next spring,” says Kuhlmann. “Then the individual network development plans could be based on the new upstream system development plan from 2024.” In the interim report, the federal agency develops such a model, based on various studies and scenarios.

Buildings: Insulated facades, thicker windows: Dena expects the energy needs of all buildings in Germany to drop dramatically over the next few years and decades if homes become more efficient. “The state should tighten energy standards for new buildings in the future”, demands Kuhlmann. Existing buildings would also need a greater depth of renovation if they were to be converted to make them more energy efficient. “We need to make significant progress with the renovation rate,” warns Dena’s boss. In fact, buildings were the only sector that failed to meet the federal government’s CO₂ savings targets in 2020.

The study predicts that renovated and newly built homes in particular are likely to use heat pumps for heating in the future. Of course, there is still some uncertainty as to how renovable buildings should be heated in the future without natural gas or oil. Hopes rest here, for example, on large, more efficient heat pumps that could supply local heating networks. “You can use peaks in electricity production, for example at lunchtime, to smooth out peaks in heat load, for example in the evening,” explains expert Dena Alexander Müller. Alternatively, homes could be heated with climate neutral gases such as “green” hydrogen; but it is still a scarce commodity.

Traffic: A similar picture emerges for mobility: “Electric drives will dominate in passenger cars and light trucks”, predicts the interim report. International shipping and air traffic, on the other hand, will likely need bio or synthetic fuels, produced with a lot of green electricity.

Either way, it could become a challenge for the grid if many cars want to recharge their batteries at the same time. Here, if necessary, access rights are required, demands Kuhlmann: “Network operators should be able to postpone the consumption of private facilities such as charging stations if there is also a threat of overloading. The auto industry recently warned against corresponding legislative plans: The prescribed shutdown would be a bad signal for electric car owners and builders, the argument goes.

Industry: Whether it is a steel mill or a chemical plant: Many industrial companies will have to make major modifications to their plants in order to make them run on electricity, biomass or “green” gases. instead of coal and natural gas. Dena predicts that the demand for electricity and hydrogen will increase dramatically. “Therefore, the electricity grid must be strengthened or extended in part. “

Until now, complains Kuhlmann, the rules on network charges have encouraged companies to consume electricity as evenly as possible; so-called peak loads, on the other hand, can be expensive. This does not fit well in a future where different amounts of wind and solar power are still available. “There is a need for a corresponding adjustment here,” says Kuhlmann: Rather, network operators would need incentives to offer flexibility – and incentives for buyers to use flexibility.

Electricity production: But where does all the electricity that a climate neutral Germany needs come from? Dena predicts that the republic will continue to meet demand “largely through domestic production.” Of course, without nuclear and climate-damaging reactors, this would require nearly three times the capacity of onshore wind turbines by 2050, thanks to additional, more powerful systems. The installed capacity of all offshore wind farms and photovoltaic systems is expected to increase fivefold. Nevertheless, Germany as a whole is likely to shift from being an exporter to being an importer of electricity.

Indeed, according to the exploratory document, the SPD, the Greens and the FDP wish to simplify the planning and approval procedures for renewable energies. Solar systems should be mandatory on new commercial buildings, “the rule” on new private buildings. In addition, the traffic lights want to see two percent of the land area dedicated to wind turbines, and offshore capacities are also expected to increase significantly.

Networks: Although the energy system is increasingly decentralized, it needs lines which in the future will mainly transport the large amount of “green” energy from northern Germany to industrial centers further south. The study even specifies that the transmission capacity provided for in the development plan for the electricity network by 2035 is “not sufficient”.

On the other hand, the amount of gas is likely to decrease if, for example, fewer houses are heated with the energy source in the future. According to Dena, some of the existing lines could carry these “green” gases in the future. However, the closure of some gas lines could not be “ruled out” in the medium term.

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