(Frankfurt a. M., 30.06.2025) What share of electricity generation does which energy source have, and what role will they play in Germany's electricity supply today and in the future? These and other questions are crucial in order to make a well-founded assessment and classification. The Power Engineering Society within VDE (VDE ETG) would like to contribute to an objective public debate and provide decision-makers with relevant information with background papers on the four central renewable energy sources. "As an independent institution with a deep technical understanding, we can classify developments scientifically and make realistic assessments," says Petri.
Underestimated hydropower: potential even during blackouts
In 2024, electricity generation from hydropower accounted for just under 8 percent of the total amount of renewable electricity. In the previous year, it reduced national CO2emissions by 6.4 percent. Hydropower has significantly lower fluctuations than wind and solar power and therefore also achieves the highest availability compared to other forms of energy. "In the event of a blackout, hydropower plants have the advantage that they are generally capable of black starts, i.e. they can restart on their own after the power outage," says Petri.
Wind energy is the strongest pillar: 27 percent of gross electricity consumption covered
With 27 percent of gross electricity consumption in Germany, wind energy accounted for just over 50 percent of renewable electricity generation in 2024. At favorable locations, the turbines achieve up to 3,500 full-load hours/year on land and up to 4,500 full-load hours/year offshore. During expansion, high-wind turbines with high output are installed at locations with high wind conditions, while so-called low-wind turbines with lower generator output and the same rotor diameter are suitable for locations with low wind conditions. The onshore expansion targets are up to 570 TWh by 2045, which is supported by the Wind onshore Act. Since 2023, it has obliged the federal states to make 1.8 to 2.2 percent of their land available for wind energy. "Wind energy can cover over 50 percent of the total electricity demand in the long term," says Dr.-Ing Martin Kleimaier, Head of ETG Department V1 Generation, Consumption and Storage in the Electrical Energy Supply System. "Grid expansion and innovative storage solutions are crucial for a stable supply."
Strong growth in photovoltaics: output has more than doubled since 2016
In 2024, photovoltaics covered around 14% of Germany's gross electricity consumption and, at 72.2 TWh, ranked second after wind power in the renewable energy sector. The full load hours are around 920 to 990 per year. PV output has more than doubled since 2016. High or even increasing expansion rates are expected to continue in the coming years. By 2040, the aim is to quadruple total output compared to 2024, with the expansion requiring greater flexibility in consumption and the expansion of storage capacities in the medium term. "We are on the right track with the rollout of smart metering systems, which enables grid-oriented control," says Prof. Hendrik Lens, Deputy Head of ETG Department V1. "In terms of long-term storage, surpluses from photovoltaics can also be used to produce hydrogen using electrolysis if this is economically feasible."
Flexible use of biogas: electricity generation on demand as a goal
The largest energy contribution to electricity generation from biomass comes from the fermentation of cultivated biomass and residues. A total of 28.7 TWh of electricity was generated from biogas and around 3 TWh from biomethane in Germany in 2023, giving them a share of 6.1 percent of gross electricity generation. At present, it is still common practice to operate biogas cogeneration plants (CHP) with almost constant output, i.e. independently of the energy fed in from wind and sun. In order to enable system-oriented, flexible operation in the future, biogas storage facilities must be available. With the same biogas volume, the output of CHP plants at one location can be multiplied, allowing them to make a significant contribution to the urgently needed flexible power plant output. Petri explains: "The idle and operating range must be taken into account when considering the capacity of these storage facilities. The idle range indicates how long biogas can be produced and fed into the storage facility without operating the CHP - for example when there is a surplus of electricity from the sun and wind. In contrast, the operating range shows how long the CHP can be operated at full power with biogas from the storage facility in order to provide peak load in an electricity shortage situation." In addition to these biogas storage facilities, the stored biomass reserves and controllable biogas production provide further flexibility potential.
With the published papers, the VDE ETG aims to provide well-founded impetus for the further expansion of renewable energies and a fact-based discussion.
The four background papers on wind energy, hydropower, photovoltaics and biomass/biogas are available to download here free of charge (German version).
