Fraunhofer Institute for Solar Energy Systems ISE
Fraunhofer Institute for Solar Energy Systems ISE

Paths to a Climate-Neutral Energy System

Study

Federal States in the Transformation Process

Authors of the Study: Connor Thelen, Lina Ganter Næss, Hannah Nolte, Markus Kaiser, Patrick Jürgens, Paul Müller, Charlotte Senkpiel, Christoph Kost
Fraunhofer ISE | November 2024 (English translation May 2025)

Study: Paths to Climate-Neutral Energy System – The German Energy Transformation in its Social Context

Objective of the Study

The study “Paths to Climate-Neutral Energy System in Germany – Federal States in the Transformation Process“ examines various paths to achieving climate neutrality in Germany by the year 2045. It depicts societal and geopolitical developments in four scenarios and considers the transformation of the energy system at the federal state level.

System studies like this one enable a comprehensive analysis of the energy system. This study includes developments in the sectors of the energy industry, industry, buildings, and transport, as well as the consideration of technical carbon dioxide (CO2) sinks, referred to hereafter as Negative Emission  Technologies (NET). By using the energy system model REMod, which represents Germany at the federal state level, various structural factors of the federal states can be considered. Additionally, it is possible to analyse energy exchange within Germany for electricity and hydrogen from a total system perspective.

Besides technical factors, societal and geopolitical developments are central factors that determine the success of the energy transition and influence possible paths to climate neutrality.

Study: Paths to Climate-Neutral Energy System – The German Energy Transformation in its Social Context
© Fraunhofer ISE

Scenario Approach

This study models four possible future worlds. The "Technology-neutral" scenario describes a cost-optimal transformation of the energy system. In the "Efficiency" scenario, an accelerated expansion of renewable energy technologies is assumed, which could be realised, among other things, through accelerated approval procedures. Additionally, energy is better utilised through efficiency and sufficiency measures. A lower CO2 budget was assumed for this scenario. The "Persistence" scenario is characterised by investments in combustion technologies and a delayed transformation, while in the "Robust" scenario, the energy system is exposed to various geopolitical crises and shocks.

The energy system model REMod (Regenerative Energy Model) developed at Fraunhofer ISE was used for the simulation and optimization of the scenarios.

The results of the study are visualized on the data platform energy-charts.info.

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