Information on the Ariadne Scenario Explorer

About the Copernicus-Project Ariadne

Climate targets alone are no guarantee of success. Concrete measures are needed to achieve them. This is where the Ariadne project comes in and shows ways through the complex issues of the German energy transition. The project examines energy transition strategies and their systemic effects as well as sectoral interactions. Ariadne analyzes political instruments to achieve climate targets in an efficient and socially balanced way. And Ariadne researches which governance and institutions are necessary to shape effective climate protection. In a consortium of more than 25 research institutions, Ariadne conducts a joint learning process with politics, business and society, explores options for shaping the energy transition and develops important orientation knowledge for political decision-makers.
More information on the Ariadne project

The Ariadne Scenario Explorer contains an ensemble of quantitative, model-based scenarios that describe transformation paths to German climate neutrality in 2045. This scenario data is the latest update and addition to the scenario ensemble that forms the basis for the Ariadne Scenario Report 2025:

Recommended Citation

When using the Ariadne scenarios, please include a link to this scenario explorer, as well as a reference to the underlying scenario report:

Gunnar Luderer (Hrsg.), Frederike Bartels (Hrsg.), Tom Brown (Hrsg.), Clara Aulich, Falk Benke, Tobias Fleiter, Fabio Frank, Helen Ganal, Julian Geis, Norman Gerhardt, Till Gnann, Alyssa Gunnemann, Robin Hasse, Andrea Herbst, Sebastian Herkel, Johanna Hoppe, Christoph Kost, Michael Krail, Michael Lindner, Marius Neuwirth, Hannah Nolte, Robert Pietzcker, Patrick Plötz, Matthias Rehfeldt, Felix Schreyer, Toni Seibold, Charlotte Senkpiel, Dominika Sörgel, Daniel Speth, Bjarne Steffen, Philipp C. Verpoort (2025):
Die Energiewende kosteneffizient gestalten – Szenarien zur Klimaneutralität 2045. Kopernikus-Projekt Ariadne, Potsdam.
https://doi.org/10.48485/pik.2025.003

Scenario Data

The scenario data will soon be published on Zenodo and linked here.

Scenario Description

Technology mix (KN2045_Mix)

This scenario describes a path to achieving climate neutrality with a mix of technologies and energy sources that is largely geared towards cost efficiency. The expansion of renewable electricity generation largely achieves the politically set targets. The mixed energy source portfolio includes imports at a medium level. In terms of the use of direct electrification and indirect electrification, it falls between the Focus on Electrification and Focus on Hydrogen scenarios described below. A mix of instruments is used to achieve the climate targets.

Focus on Electrification (KN2045_Elek)

The focus here is on the ramp-up of technologies for the direct electrification of the sectors, meaning that the market penetration of electric vehicles and heat pumps, for example, is highest in this scenario. Electricity is the preferred energy source for final energy and the expansion of renewable electricity generation achieves the politically set targets. Successful electrification limits the demand for hydrogen in Germany, which is primarily produced by electrolysis in Germany and supplemented by low imports of hydrogen or e-fuels. As in the Technology Mix scenario, the climate targets are reached through a mix of instruments. Electricity imports from neighboring European countries are at an adequate level (2030: +/- 0 TWh, 2045: 50-150 TWh).

Focus on Hydrogen (KN2045_H2)

In this scenario, the focus is increasingly on the use of hydrogen and e-fuels and therefore more on the ramp-up of technologies for the indirect electrification of energy consumption compared to the Technology Mix scenario. Direct electrification remains dominant in those areas where it has clear cost advantages over indirect electrification. The expansion of renewable electricity generation largely achieves the politically set targets and the climate targets are achieved through a mix of policy instruments. Electricity imports are at a rather moderate level; imports of hydrogen and e-fuels are adequate (up to 800 TWh/a possible by 2045 driven by demand). This is based on the assumption of a well-developed hydrogen infrastructure that is coordinated with European partners and that renewable energy potential can be better utilized through cheaper storage and electrolysis.

Low demand (KN2045_NFniedrig)

This scenario is characterized by a lower final energy demand resulting from a faster penetration of climate-friendly, efficient technologies, accelerated infrastructure expansion, energy-saving behaviour of the population (e.g. switching to local public transport, resulting in fewer car journeys), broader public acceptance and, if necessary, stronger regulation and adjusted monetary incentives. In the long term, the same climate policy ambition for achieving climate targets is assumed as in the Technology Mix scenario (largely identical CO2 price path as in the Technology Mix scenario, slight overfulfillment of the Climate Protection Act (KSG) 2030 targets possible, achievement of climate neutrality in 2045). In terms of energy supply, the scenario also corresponds to the Technology Mix scenario with a mixed portfolio of technologies and energy sources.

High demand (KN2045_NFhoch)

In this scenario, the transformation of final energy demand is persistent, i.e. energy demand is higher than in the Technology Mix scenario. This is due to the fact that the ramp-up of climate-friendly, efficient technologies and the expansion of infrastructure is slower in this scenario, while lower public acceptance and possibly less regulation or fewer incentives prevent a rapid transformation. Despite comparable long-term political ambition as in the technology mix scenario, it is possible that the 2030 KSG targets will not be met. Climate neutrality in 2045 is ultimately achieved. As in the Low Demand scenario, the expansion of renewables up to 2030 is demand-driven. In terms of energy supply, the scenario corresponds to the Technology Mix scenario with a mixed portfolio of technologies and energy sources.

Existing policies (ExPol)

In this scenario, all climate policy measures implemented on the cut-off date of December 31, 2023 are continued. The achievement of the GHG reduction targets is not part of the scenario formulation and is therefore not guaranteed. The target of climate neutrality in 2045 is not achieved in this scenario.

Model Documentation

Ariadne enables a particularly detailed perspective on the energy transition through the use of different, mutually complementary models. The models REMIND (PIK), REMod (Fhg-ISE) and PyPSA-DE (TUB) provide a view of the overall system in Ariadne. These results are in turn closely linked to the sectoral view of the industry model FORECAST (Fhg-ISI), the transport models ALADIN and ASTRA-M (both Fhg-ISI) and the buildings model REMod (Fhg-ISE).
More information on the models used

Scenario Data Ariadne 1 (1st Funding Phase 2020-2023)

The scenario data that forms the basis of the first Ariadne scenario report from 2021 as well as further information can be found at:
https://data.ece.iiasa.ac.at/ariadne/

Funding Acknowledgement

This scenario data was compiled as part of the Kopernikus project Ariadne funded by the German Ministry of Research, Technology and Space.

Contact

If you have any questions about the scenario data, please contact Frederike Bartels ([email protected]), Dominika Sörgel ([email protected]) or Gunnar Luderer ([email protected]).