PyPSA-DE: Open-source German energy system model reveals savings from integrated planning

TL;DR

This work addresses the challenge of achieving Germany's net-zero target by 2045 through cost-aware, integrated planning across electricity, heating, transport, and hydrogen. It introduces PyPSA-DE, an open-source, high-resolution energy-system model built atop PyPSA-Eur that minimizes total system costs via a linear optimization over 2020–2045 in 5-year steps with 3-hourly temporal resolution and regionally detailed networks. Key findings show that integrated planning with regional price zones can reduce transmission expansion by up to one third and cut grid tariffs, while enabling substantial renewables deployment and efficient offshore wind integration, aided by hydrogen and cross-border interactions. The results underscore the practical value of cross-sectoral optimization for policy design and demonstrate the model's adaptability as a transparent, open-source tool for Germany and potentially other European contexts.

Abstract

Germany has set an ambitious target of reaching net zero greenhouse gas emissions by 2045. We explore how integrated cross-sectoral planning can reduce costs compared to existing national plans. Our new linear optimization model PyPSA-DE simulates the electricity and hydrogen transmission networks, as well as supply, demand, and storage in all sectors of the energy system in Germany and its neighboring countries with high spatial and temporal resolution. While our new model shows strong electricity transmission grid development, total expansion is one third lower than in the national grid development plan, lowering costs by 92 billion EUR$_{2020}$ to 191 billion EUR$_{2020}$ and average grid tariffs by 7.5 EUR$_{2020}$ / MWh. These savings are mainly due to integrated planning and operation, a market design with regional prices, and a system-optimal usage of offshore wind. PyPSA-DE is open-source and can readily be adapted to study related issues around the energy transition.

Figures (6)

• Figure 1: Installed capacities of renewable energy sources (RES) and batteries, and transmission grid expansion for the year 2045 using historical weather data from 2019. Offshore wind is shown at its grid connection point. The installed capacities follow the renewable potential, with onshore wind found predominantly in the North and solar power found predominantly in the South.
• Figure 2: Electricity balance for the month of January for the year 2045. During the event of low renewable energy generation (19th to 26th), hydrogen and gas backup power plants step in, supplemented by electricity imports.
• Figure 3: Expansion of the hydrogen grid until 2045, shown together with locations of H2 production (left) and H2 demand (right). The electrolysis is placed primarily near the coastline to help with the integration of offshore wind resources and thus save on expensive DC projects.
• Figure 4: Comparison of the average wholesale electricity price plus average grid tariffs in 2045. Left: scenario with a single bidding zone and grid expansion according to the national grid development plan (NEP), Right: scenario with regional price zones and reduced grid development according to PyPSA-DE. In the PyPSA scenario all end users benefit from a lower average electricity price, despite price differences between the regional zones.
• Figure 5: Investment needs for the electricitry transmission grid until 2045 according to the NEP, and potential savings according to the PyPSA-DE methodology, differentiated by enabling assumption and affected grid components.