Energy and Resources

Energy Systems of the Future

A secure, affordable and sustainable energy supply is critically important for Germany and the rest of Europe. But how do we go about transitioning to such a system? This question is addressed by Energy Systems of the Future (ESYS), a joint initiative of acatech (lead institution), Leopoldina and the Union of the German Academies of Sciences and Humanities. Over 160 energy experts from academia and industrial research collaborate in interdisciplinary working groups that draft publications presenting the latest energy research on topical policy and social questions and proposing policy options. The initiative focused on three themes in 2024: carbon management, base-load power plants and nuclear fusion.

Carbon dioxide: a greenhouse gas, but also a resource

Even in a net-zero economy, it won’t be possible to completely prevent all greenhouse gas emissions – there will always be some residual emissions from sectors like agriculture or cement production. Meanwhile, carbon will remain an indispensable resource for the energy system and the economy as a whole in years to come. This means that new technologies that prevent greenhouse gas emissions will not be enough on their own – “carbon management” will also have a key role. Carbon management involves preventing any greenhouse gases generated from entering the atmosphere or removing them from it so they do not contribute to global warming. Recycling the captured carbon reduces demand for fossil carbon.

The German government’s “Carbon Management Strategy” and “Long-term Strategy on Negative Emissions” form the cornerstone of its carbon management policy. ESYS responded to these strategies in its Discussion Paper An Integrated Approach to Carbon Management: Requirements of an Overall Strategy Combining CCS, CCU and CDR. The publication highlights the overlap in terms of the technologies and infrastructure required by the three pillars of carbon management – carbon capture and storage, carbon capture and utilisation and carbon dioxide removal. While this overlap can create synergies, it can also lead to conflicts of use. All three pillars must therefore be addressed in an integrated manner from the outset, and this includes coordinating their regulation.

The ESYS Discussion Paper CO₂ as a Raw Material: A building block of a climate-neutral carbon economy explains exactly how carbon dioxide can be utilised. It concludes that the chemical industry can use CO₂ as an alternative source of carbon for various products, and its utilisation will thus probably be necessary in this sector. However, since it consumes a lot of energy and doesn’t always reduce greenhouse gas emissions, its use should be subject to detailed analysis.

Does the German energy system need base-load power plants?

Because base-load power plants can deliver a continuous supply of energy, they have been a key pillar of Germany’s energy system in years gone by. However, their high investment costs mean that, in order to be profitable, they must operate almost continuously. What role do they have in a net-zero greenhouse gas energy system? This question is addressed in the ESYS Discussion Paper Nuclear Fission, Natural Gas, Geothermal Energy, Nuclear Fusion. The Future Role of Baseload Power Plants, which draws on detailed modelling carried out by the Fraunhofer Institute for Systems and Innovation Research ISI. The Discussion Paper shows that a reliable energy supply can be achieved without base-load power plants, but would require storage systems for solar and wind power in conjunction with residual-load power plants that only run when needed. Greater flexibility with regard to electricity consumption would also be necessary. Since the supply of renewable energy needs to be expanded anyway, base-load power plants don’t significantly alter the total cost of the energy transition. Nevertheless, low greenhouse gas emitting base-load technologies like nuclear power plants, natural gas-fired power plants with carbon capture and nuclear fusion power plants could form part of a predominantly renewables-based energy system. While this would help to reduce hydrogen imports, for example, it would only make sense if it was more cost-effective than the alternatives. However, their long construction and usage times mean that new base-load power plants are only a long-term option. 

Scaling nuclear fusion up from the lab to industrial production

Will nuclear fusion one day provide a climate-friendly, continuously available energy source that doesn’t require a lot of space and is powered by fuels that can be produced locally? Research breakthroughs in recent years have boosted hopes that this could happen. But what is the current state of fusion research? What challenges still stand in the way of an operational fusion power plant and what opportunities might the technology offer in years to come?

The ESYS Discussion Paper Can Nuclear Fusion Contribute to a Net-Zero Energy Supply? Opportunities, Challenges and Timeframes explains that although the physical processesunderlying nuclear fusion are largely understood, the first power plants are unlikely to be operational before 2045. This means that they cannot be a substitute for the expansion of renewable energy before this date. However, fusion power plants could contribute to a climate-friendly energy supply in the longer term. The ESYS In a Nutshell! publication Is Nuclear Fusion an Energy Source of the Future? provides an overview for people who are interested in this topic but do not yet know much about it. The acatech IMPULSE Nuclear Fusion Made in Germany. Options for Building an Innovation Ecosystem for Nuclear Fusion explores policy options for supporting the development of nuclear fusion research and its transfer into application in Germany. While technology-neutral public funding should be made available for basic research, private and international partners should also be brought on board. As far as the technology’s regulation is concerned, it must be coordinated internationally and should remove barriers to innovation. Furthermore, the paper recommends that a fusion roadmap should be drawn up with the following two goals: the construction of a prototype power plant that is connected to the grid in a realistic operating environment, followed by the construction of a power plant capable of sustaining itself without subsidies.

Geothermal technologies in urban settings: the key role of towns and cities in the heating transition

More than half of the energy consumed in Germany is used to provide heating – and just one sixth of this energy is renewable. The expansion of zero-carbon heating thus has huge potential for the heating and energy transitions. Combining climate protection and greater heating supply autonomy, geothermal technologies hold particular promise in urban settings. The acatech STUDY Geothermal Technologies in Urban Settings. A Contribution to the Heating Transition and Climate Protection analyses realistic ways of exploiting the potential of geothermal energy and explains how it could supply 20 percent of the entire German heating market.

Geothermal heating is particularly suited to urban settings

With their high energy demand and consumer density – i.e. the density of houses and apartments requiring heating – it is almost as if Germany’s 81 cities and metropolitan regions were made for geothermal technology. Moreover, they have the infrastructure needed to supply large amounts of energy, while geothermal rigs take up very little space in densely populated areas and generate few emissions.

Urban areas are an ideal location, especially for medium-depth to deep hydrothermal energy, which can supply sufficient heat without taking up too much space. Geothermal’s storage capacity also makes it suitable for powering climate-neutral cooling systems, something that will become increasingly important in urban settings as climate change progresses.

Rolf Emmermann, study leader and acatech Member

New technological advances in recent years have significantly improved the efficiency and commercial viability of geothermal technology, to the extent that it is now also relevant to sectors such as the food and chemical industries. There has also been a step change in the quality and availability of soil structure data. This information provides a clearer picture for new geothermal plants, enabling more reliable planning and enhancing their profitability.

The expansion of geothermal energy can benefit Germany’s technology and business sectors in numerous ways. It strengthens security of supply with net-zero heat derived from domestic resources and increases the heating market’s resilience.

Jan Wörner, acatech President

Greater Munich area forges ahead with geothermal heating

Munich is already showing how geothermal technology can be used to provide heating and cooling for different-storey buildings. The Bavarian capital plans to supply its district heating system with fully carbon-neutral, deep hydrothermal energy by 2040.

Towards a national geothermal strategy

The acatech STUDY also sets out the requirements that urban areas must meet in order to expand geothermal energy, and the options available to them. As well as engaging in strategic heating supply planning, it is important to consider carbon pricing and public programmes for exploring local potential. Government can create incentives for private and municipal investors by covering the risks, while transparent involvement of the general public can strengthen acceptance of new geothermal technologies.

Building and living: making housing affordable again

Providing affordable housing is one of the most pressing challenges facing our society. A study by the Pestel Institute* identifies a shortage of approximately 550,000 homes in Germany (as of February 2025), while over eleven percent of people in Germany lived in overcrowded dwellings in 2024, according to the Federal Statistical Office. Furthermore, the United Nations Environment Programme (UNEP) has established that the buildings sector is responsible for around 40 percent of energy and process-related CO₂ emissions and over a third of energy demand globally. Resource conservation and efforts to combat climate change thus call for a fundamental realignment of the buildings sector. It is also necessary to make our cities climate-resilient and adapt them to changing housing arrangements and lifestyles.

These are the issues addressed by Building & Living: Platform for Networking, Synthesis and Transfer, a project coordinated by acatech and funded by the Federal Ministry of Education and Research (BMBF). Some 60 experts from science and industry are working together to formulate proposals for transforming the buildings sector. What are the barriers to building affordable housing? And how can existing buildings in urban areas be sustainably developed through adding storeys, conversion and redensification? Three interdisciplinary working groups have been established to identify and prioritise the relevant themes and develop concrete solutions for them as the project progresses:

• The “Building materials, construction and energy” working group focuses on the “generally accepted technical standards” (German: allgemeine Regeln der Technik) and on modular and serial building. It also covers incentives for adding storeys, building extensions and conversion, and the promotion of public acceptance.
• The working group on “Urban and neighbourhood development” addresses building for the common good in the redensification process, as well as resource activation and intelligent rebuilding solutions.
• The “Transformation and implementation strategies” working group analyses the solutions developed by the other two groups, assessing their scalability, feasibility and economic potential.

In 2025, the solutions developed by the working groups are being presented and refined in group Delphis. The recommendations are being discussed in citizens’ councils, with a particular focus on potentially conflicting goals and public acceptance. The platform’s website, which went live in early 2025, will feature a digital map of current living labs in Germany that fall within the project’s scope. The results and practical recommendations for government, industry and the general public will be published in a variety of different formats.

Affordable housing is a key challenge for our society. The focus of our platform is on existing buildings, as there is enormous potential in terms of conversion, adding storeys and redensification. This allows us to provide more housing while at the same time saving resources. The aim is to enable affordable, liveable and attractive housing, and to make our cities fit for the future.

Jan Wörner, Project Manager Building & Living: Platform for Networking, Synthesis and Transfer, and acatech President

* Content only available in German