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Cost-efficient and Climate-friendly Transformation Strategies for the German Energy System up to 2050

At the United Nations Climate Summit in New York on September 23, 2019, the Federal Republic of Germany committed to achieving greenhouse gas neutrality by 2050. Specifically, Germany set the target of reducing the greenhouse gas emissions to 80 to 95% that of 1990 by 2050. Furthermore, the greenhouse gas reduction paths proposed for this purpose are enhanced by a large number of detailed sub-targets (e.g. the share of renewable energies in electricity generation) which the Federal Government considers necessary in order to achieve the overall reduction target. Although this canon of targets has been successively developed and expanded over the past decades, the question of whether the proposed transformation paths are cost-optimal strategies remains unanswered.

The aim of this study is to identify the most cost-effective CO2 reduction strategies which achieve Germany's climate protection goals by 2050. For this purpose, two CO2 reduction scenarios are analyzed. The first scenario is subject to a reduction target of 80% by 2050 (scenario 80), while the second scenario is subject to a reduction target of 95% (scenario 95). With the exceptions of the agreed nuclear phase-out and the forthcoming coal phase-out by 2038, no further targets of the Federal Government are adopted.

A novel model family developed by the Institute for Techno-economic Systems Analysis (IEK-3) is used to conduct this analysis, which captures the high degree of the German energy system’s complexity. Special features are the high temporal and spatial resolution of energy demand and generation profiles, the detailed mapping of PtX pathways and the simulation of future global energy markets (e.g. hydrogen, synthetic fuels). Additionally, a special methodological feature is the ability to include data uncertainties in the analysis, which enables the identification of robust solution strategies.

Selected results

The analysis shows that a reduction of greenhouse gas emissions by 80% is feasible from both a technical and an economic perspective. Increasing the reduction target to 95% is much more demanding and correlates with considerable additional costs. The analysis also shows that the reduction strategies, and thus also the resulting technology portfolio, differ considerably from either scenario. Notably, measures that prove to be necessary and cost-efficient for achieving an 80% target are not necessarily part of a reduction strategy that leads to a reduction of 95%. In selected cases, they can even be counterproductive. Furthermore, the results show that by achieving the desired emission reduction target in either scenario, there is a significant reduction in energy imports compared to today. Nevertheless, some energy imports are still necessary for achieving a reduction target of 95%, albeit to a much less extent than with an 80% target.

The replacement of fossil energy carriers increases electrification in all sectors and thus a subsequent increase in electricity consumption and the use of bioenergy. A CO2-free electricity supply is therefore a necessary prerequisite to achieve the overall emission reduction targets. In all scenarios, wind power and photovoltaics are the backbone of the future electricity supply. For example, in scenario 95 the installed wind power capacity increased by a factor of 4 and the photovoltaic capacity by 3.7 compared to today. The implementation of energy efficiency measures in all sectors is also an important adjustment factor for achieving the greenhouse gas reduction targets, and is shown to have a pivotal role in either scenario. Finally, the use of hydrogen plays an important role due to its diverse application possibilities (storage, end use applications). This is especially true for scenario 95, where the demand for hydrogen amounts to about 12 million tons in 2050. More than 50% of this is covered by domestic production, while the remaining share is covered by liquid hydrogen imports.

Scenario presentation in Berlin on 31.10.2019

Handover of the studyPresentation of the study in the Haus der Bundespressekonferenz (from left to right: Prof. Dr. Detlef Stolten, Parliamentary State Secretary Thomas Rachel, MdB, Dr. Martin Robinius, Dr. Peter Markewitz)

Answering the questionsAnswering questions about the study by the scientists of IEK-3 (from left to right: Dr. Peter Markewitz, Prof. Dr. Detlef Stolten, Dr. Martin Robinius)

Additional Information

Prof. Dr.-Ing. Detlef Stolten

Director IEK-3

Prof. Dr. Detlef Stolten
Phone: +49 2461 61-3076
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Contact Person

Dr. Peter Markewitz
Phone: +49 2461 61-6119