Optimizing Battery Storage for Germany’s 2030 Energy Transition: Scope, Costs, and Carbon Impacts

As Germany advances toward its 2030 energy transition targets, large‑scale battery systems are widely promoted as a key instrument to manage the volatility of wind and solar power. This paper develops a data‑driven simulation framework to quantify how much grid‑scale batteries can realistically contribute to Germany’s power system in 2024 and in a 2030 expansion scenario, in terms of backup energy reduction, system costs, and carbon footprint. The analysis uses 15‑minute data for generation and load from 2022–2025 and constructs future scenarios by upscaling photovoltaics, onshore wind, offshore wind, and demand in line with the Study "Climate‑neutral Germany 2045". Volatility is decomposed into a slowly varying component, covered by backup plants, and a normalized residual load that feeds the batteries; for each battery capacity, an optimal moving‑average window is determined to maximize annual battery output and minimize backup energy. Model validation against 2024 pumped‑storage operation shows that the framework reproduces observed annual storage output well. Across both 2024 and 2030, battery benefits scale approximately with the logarithm of installed capacity, while costs and battery‑related emissions increase linearly. Under optimistic assumptions, about 300 GWh of batteries can supply only 4–6% of annual demand and cannot replace firm backup capacity, implying that batteries are valuable for short‑term balancing but have limited potential for seasonal adequacy.