Economic Sweet Spot in the Mix of Renewable Energy Generation and Battery Storage in Power Grid of Germany

Abstract

This simulation study is based on hourly generation and consumption data for electrical energy in Germany for the years 2022–2025. The simulation uses multiplication factors for real renewable energy generation and the inclusion of variable electricity storage capacities to model future 100% renewable electricity generation in Germany. Based on this model, the investment volume that would be necessary for such 100% renewable electricity generation is also modeled using real investment costs. These costs can then be used to derive calculations for electricity generation prices. The data for the individual years 2022/2023, 2023/2024, and 2024/2025 are entered into the simulation to identify changes in consumption/generation and compare them with the known consumption and installation data, thus verifying the simulation and obtaining additional development information from the year-on-year comparison. The most important results of the simulation calculations are: If you want to establish 100% renewable energy generation in Germany with 100% security of supply, then... ...there are hundreds of different possible combinations, ranging from less renewable generation with huge storage facilities to high generation capacity with small storage capacities. ...the optimal combination of energy generation and energy storage in terms of investment costs is 3.9 times the renewable generation capacity and 2700 GWh of storage capacity (based on data from 2022/23). This translates to ~32kWh of storage capacity per capita in Germany. Less than expected. Conversely, this storage size can cover the average consumption in Germany for about two days. Here, too, some similar studies have calculated a higher required storage size. The calculated electricity costs average is €0.09/kWh (between €0.07 and €0.17/kWh). Despite high storage capacities, this is still the cheapest form of energy available today. The evaluation of the calculated hourly storage usage shows that the storage capacity is only needed on a few days of the year (~5%). On ~95% of the days of the year, only a maximum of 20% of the storage capacity is needed. This is indicative that multiple uses for the storage facilities (e.g., grid-connected car batteries) are possible. The few calculated complete storage charging cycles per year indicate an extremely long service life for the storage facilities. Overall, these results show the potential that lies in controlling consumption. Incentives to shift electricity consumption from the few hours/days of the year with low generation (~5%) to other hours/days have a huge impact on the required storage size and on security of supply. Even simple price control, which has long been in place in many regions of the world, would have a major impact on consumption. Price incentives should be created for ideas such as free shifts for large consumers or flexible control of other large consumers during the few energy-critical hours/days. After all, industry is looking for ways to reduce energy prices. The annual development of the data shows that although there is a positive trend in installed generation capacity, this is not yet reflected in the amount of energy actually consumed. There are probably still systemic obstacles that favor other types of energy generation. One possible explanation could be that other generators are more difficult to regulate and therefore wind generators are being curtailed? However, the most surprising result of the simulation calculations is the huge amount of surplus energy that could be generated but (as of today) is not needed at all. With the above-mentioned optimal composition of generation/storage, 90% more energy could be generated per year than is needed. And that without additional costs! This is where the discussion about the use of this free surplus energy should begin (international energy trading, synthetic/PtL fuels for air transport/ships, water treatment, hydrogen, etc.). This surplus energy, which can be generated free of charge, would be available for new marketing strategies and would reduce energy costs for everyone through additional marketing. This work will hopefully contribute to a more objective discussion about future energy production, as the calculated results for the necessary storage capacities are surprisingly low, the calculated energy costs are unrivalled, and the amount of free surplus energy is extremely high. With the great potential for renewable energy production even in Germany (solar roof areas, offshore wind areas, etc.), achieving a power grid powered 100% by renewable energies seems within reach. A targeted social, industrial, and political approach is essential to ensure that finite resources are not wasted on unrealistic and/or distant future desired scenarios. The simulation calculations can be performed using data from any region of the world. The study will be further developed using data from other regions of the world in order to calculate individual results for these regions on this basis. The focus is particularly on simulating changes in consumption behavior and its influence on the simulation results. This is the English translation of the published original German text.