19.08.2024
International
Is the German energy transition at an end in its current form? This is the conclusion of a study by Prof. Dr.-Ing. Markus J. Löffler of the Westphalian Energy Institute (WEI) at the Westphalian University of Applied Sciences. In it, he takes an in-depth look at the fluctuation problem of renewable energy sources and the associated challenges for security of supply. The conclusion: if there is no change in energy policy, the existing and currently planned power plant capacities will no longer be sufficient in just a few years.
As part of the energy transition, Germany plans to cover its entire electricity demand exclusively with renewable energies such as wind and solar power by 2045 (source: EEG 2023, among others). Biomass and run-of-river power plants are also to be used to a much lesser extent. In his study "Energiewende und Versorgungssicherheit – Dunkelflauten erfordern Handeln!" (Energy transition and security of supply – dark lulls require action!), Prof. Markus Löffler addresses the associated risks for security of supply. "If we continue on the current course with the existing gaps in power plant capacity, we will be sitting in the dark again and again in just a few years," says the expert in high-voltage technology. "As already stated in the position paper of the Westphalian Energy Institute, Germany is endangering its economic competitiveness and social peace with this strategy. Renewable energies are not necessarily the panacea for a secure energy supply." According to Löffler, the potential lies in optimising periods of over- and under-supply through the use of controllable power plants.
Energy production from wind and solar power is not constant, as it is subject to fluctuations due to the weather and the time of day. These fluctuations do not match the actual electricity demand of consumers. This results in periods of over- and under-supply, which can lead to long-term blackouts. "In the event of over-supply, solutions could include storing the excess electricity, shutting down PV or wind power plants in good time, even if this is uneconomical, or exporting it abroad, if possible," explains Prof. Löffler.
A greater challenge is ensuring the electricity supply during periods of darkness and calm, i.e. when darkness and calm winds occur at the same time. According to the study data, numerous periods of darkness and calm could occur within a six-year period, lasting between one and 265 hours (approx. eleven days). In these cases, the loss of wind and solar power would often result in power deficits of over 150 gigawatts (GW). Short-term deficits of up to six hours could be easily compensated for by existing battery and pumped storage power plants. Medium-term deficits of up to 18 hours could also be compensated for under favourable conditions, according to the study results. "To compensate for longer-lasting deficit phases of up to eleven days, we would need controllable gas or hydrogen power plants in Germany with at least 150 GW of callable power. By 2035, only 10 GW of hydrogen power plants are currently planned, compared to the 35 GW of gas power plants that are currently available. Or, if necessary, we would have to resort to electricity imports, as the existing battery storage and similar technologies would not be sufficient," the Gelsenkirchen-based energy expert continues. We would be dependent on additional, reliable energy sources that could quickly step in when renewable energies are no longer sufficient.
Controllable power plants would have to be operated at an average of just under 500 full-load hours per year, with a large number of short to medium-length operating times. The problem: due to the infrequent use when energy is insufficiently produced by renewable sources, controllable power plants are not economical. The production costs for a megawatt hour of electrical energy could amount to up to 730 euros. Investments in such plants would hardly be profitable, as the operating times are too short and the electricity production would be disproportionately expensive. This would also apply in particular if the power plants were to be supplied with hydrogen of an unknown origin, with unreliable delivery and at hydrogen trading prices. Such backup power plants would therefore not be built, regardless of their operating resources (natural gas, hydrogen and, if necessary, nuclear power), until the conditions for their operation change. Runtime comparable to today's, beyond the use in situations of shortage, would lead to an improvement in economic efficiency. One solution would therefore be to combine controllable power plants for continuous operation with other controllable power plants to compensate for load and supply fluctuations.
"Even if it sounds counterintuitive in the current energy and climate change debate, the expansion of renewable energies would also have to be significantly reduced," Löffler explains, adding: "This would lead to lower surpluses and thus enable greater use of more reliable – controllable – energy sources." However, a significant reduction in renewable power plants would also reduce overproduction capacity, which would make the in-house production of hydrogen almost impossible. The missing hydrogen would then have to be obtained from European or other foreign sources. This could prove to be problematic if other countries are faced with similar energy supply situations.
According to Prof. Löffler, the current planning and implementation of the energy transition still has significant weaknesses. The study concludes that without the use of reliable, controllable power plants, security of supply cannot be guaranteed and the energy transition in its current form must be considered a failure. "The present study therefore calls for a reorientation of the energy transition strategy in order to ensure a sustainable and secure electricity supply until 2045," summarises the specialist.
The data basis for the study "Energiewende and security of supply – dark lulls require action!" by Prof. Dr.-Ing. Markus J. Löffler is the second position paper of the Westphalian Energy Institute from 2023, which is based on data from the Federal Network Agency and the European Network of Transmission System Operators for Electricity (ENTSO-E). Löffler is a member of the Westphalian Energy Institute (WEI) at the Westphalian University of Applied Sciences, which has been working on energy technology issues for more than a decade, focusing on renewable energies, energy conversion and distribution, energy economics and policy, and energy use.