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In the 1980s, scientists announced a series of breakthroughs that did not turn out to be as successful as they first thought they were. In December 2022, US researchers extracted more energy from nuclear fusion than they put into it for the first time. We all know that coal and oil will become obsolete in the future. The world needs to become climate neutral. It is the only way the Earth can remain habitable in the long term – climate researchers all agree on this. Wind, hydropower, biomass and sunlight are ready to drive this major transformation. But power plants with nuclear fusion reactors could also still play a vital role in light of the recent successes that have been made in this areas. How seriously should we be considering nuclear fusion with regard to the energy and climate problems?

What is nuclear fusion?

The process of nuclear fusion is the physical process which generates the energy that the sun emits. Nuclear fusion has been researched for decades, as it offers an almost unlimited source of clean and carbon-neutral energy. Since the fusion process can be interrupted at any time, unlike nuclear fission, it is also considered particularly safe.

In conventional nuclear power plants, the fission of heavy atoms such as uranium mainly generates radiation energy and thermal energy in the form of heat. In nuclear fusion, on the other hand, the two hydrogens deuterium and tritium are fused together with the help of a plasma jet. The fusion of these two substances produces a helium nucleus and a large amount of usable thermal energy in the form of heat. The idea is to then use this thermal energy in power plants to drive steam turbines and electricity generators.

What potential does nuclear fusion offer?

One of the key advantages of nuclear fusion is that it can be a virtually unlimited source of energy. Unlike fossil fuels, which are finite, nuclear fusion can be powered by the hydrogen isotopes deuterium and tritium.

Deuterium occurs abundantly in nature (in seawater, for example). Tritium must be ‘incubated’ from the metal lithium using neutron irradiation. Lithium reserves are limited, but there are still enough to be used in large-scale nuclear fusion. Just one gram of the deuterium-tritium mixture can generate 90,000 kilowatt hours of energy in a power plant, which corresponds to the combustion heat of 11 tonnes of coal. For comparison, the energy released during the fission of one gram of uranium corresponds to the combustion of 2.5 tonnes of coal.

Tritium could be produced in the nuclear fusion reactors themselves in the future. This means that nuclear fusion could provide energy for centuries or even millennia. In theory, a fusion power plant of the future could generate one to two gigawatts of electricity. In comparison, the most powerful nuclear reactor in the world currently generates about 1.6 gigawatts of electricity.

The disadvantages of nuclear fusion

Despite its promising possibilities, nuclear fusion also has a number of disadvantages compared to renewable energy sources and nuclear energy.

Low technological maturity: nuclear fusion is still in the research and development phase and is not yet a viable energy source. Scientists have made considerable progress in understanding the physics of nuclear fusion, but the technology to harness this energy on a large scale has yet to be developed. A number of experimental reactors are currently being commissioned or are still being built, such as the International Thermonuclear Experimental Reactor (ITER) in southern France. This is still in the testing and demonstration phase. The technologies for using renewable energy, meanwhile, are becoming more and more efficient and sophisticated.

High initial input energy: nuclear fusion reactors require a considerable amount of energy to start and maintain the fusion reaction. This energy must come from an external source – such as a conventional power plant. This means that nuclear fusion power plants still need fossil fuels or other energy sources to get started. Whereas renewable energy technologies, on the other hand, rely only on nature’s energy as an input.

High costs: the development, testing and construction of nuclear fusion power plants require investment costs adding up to several billion euros. These costly power plants are difficult to finance for countries with limited resources. This is a significant disadvantage compared to renewable energy sources, the costs of which have fallen significantly in recent years and which can increasingly compete with conventional energy sources. For comparison, the total cost of the ITER project was initially estimated at €5 billion. At over €15 billion, the international nuclear fusion research project has already cost three times as much. To illustrate the comparison between the two energy types further, the Borkum Riffgrund West offshore wind farm, which has a capacity of 400 megawatts, costs approximately €1 billion. In addition, many wind and solar systems can be installed on a small scale, making them affordable and accessible to individuals and communities.

Radioactive waste: as with nuclear fission, nuclear fusion also produces radioactive radiation. Unlike nuclear fission, however, nuclear fusion produces waste with a much shorter half-life. The radioactivity of the waste decreases rapidly, with it dropping to one ten-thousandth of the initial value after about a century. After one to five hundred years of decay, the radiotoxic content of the waste is comparable to the hazard potential of all the coal ash from a coal-fired power plant, which always contains natural radioactive substances. Radioactive waste from nuclear power plants, on the other hand, has a half-life of 24,000 years.

What politicians and researchers have to say

Some politicians, especially those among the ranks of Germany’s Free Democratic Party (Freie Demokratische Partei, FDP), want the country to become a pioneer in the use of nuclear fusion. The FDP’s parliamentary group leader Christian Dürr is adamant that the first nuclear fusion reactor that produces electricity for businesses and households needs to be built in Germany. For this reason, he sees it as the government’s duty to lay the legislative groundwork for the development of nuclear fusion. The opposition are also calling for further investments. The leader of the opposition, Friedrich Merz, is pleading that more attention be paid to nuclear fusion, as he sees it as an opportunity to reduce energy dependence on Russia.

For the Head of Fusion Research at the Fraunhofer Society (Frauenhofer-Gesellschaft), one thing is clear: Germany already has knowledge in key technologies that are relevant to the development of nuclear fusion. For example, researchers at the Max Planck Society (Max-Planck-Gesellschaft) are world leaders in the field of magnetic confinement, which is needed to stabilise the plasma. Germany also occupies a leading international position in laser technology and the optical industry, which is necessary for laser-driven fusion. Given the recent successes, he considers it vital that he continue to focus and expand research and development in these areas of technology so that Germany and Europe can also become a central provider in the field of nuclear fusion in the long term.

However, researchers at Lawrence Livermore National Laboratory, who achieved the milestone in December 2022, are urging caution and believe there is still a very long way to go before nuclear fusion can be used profitably for industrial purposes. Nevertheless, the international ITER project, in which Germany is involved, aims to achieve what has not been possible so far – extracting more energy from nuclear fusion than is put in. It plans to create the first plasma needed for nuclear fusion in 2025.


Germany and a number of other countries have set themselves the goal of becoming climate neutral by 2050. At the same time, climate researchers emphasise that the scope for action to avert massive global warming is becoming ever smaller. The solution here could be nuclear fusion, a process in which hydrogen atoms fuse in fusion reactors under extreme conditions, releasing enormous amounts of energy that can be used to generate electricity. Nuclear fusion is seen as an unlimited source of clean and carbon-neutral energy. Initial successes in scientific testing are further fuelling the political discussion. The demand to increase investment in the research and development of nuclear fusion is growing. However, the advantages and the hype are offset by a considerable range of disadvantages. From a technological point of view, nuclear fusion as a sustainable energy source is still in its infancy. It is currently still very unclear how ‘science and technology’ will progress in the coming decades, or how long governments will continue to be prepared to bear the enormous investment costs for research and development until it is ready for the market.

The takeaway here is that nuclear fusion will certainly not make a significant contribution to tackling the energy and climate problem in the next 20 to 30 years. But research and development should still be further pursued with new international research alliances to strengthen collaborations, promote the exchange of knowledge and jointly bear the immense costs. We are eagerly awaiting any new developments and will give you another update when we have more to report on – which should be in 20 to 30 years at the latest.

You can find more exciting topics from the adesso world in our blog posts published so far.

Picture Maximilian Hammes

Author Maximilian Hammes

Maximilian Hammes is a consultant in the utilities sector with a focus on digitalisation projects in the energy industry. He is an experienced IT service manager who sees himself as an interdisciplinary all-rounder with a focus on project management and requirements engineering.

Picture Jonas Schnorrenberg

Author Jonas Schnorrenberg

Jonas Schnorrenberg is a mechanical engineer and works at adesso as an consultant in the Utilities division with a focus on consulting companies in the energy industry. His focus in recent years has been on managing projects in the field of energy and power plant technology. After completing his master's degree in mechanical engineering, he is now continuing his education part-time as part of a master's degree in business administration.

Picture Stephen Lorenzen

Author Stephen Lorenzen

Stephen Lorenzen is a managing consultant and has been working in the energy industry for almost 3 years. He sees himself as a pragmatic and interdisciplinary all-round consultant with several years of professional experience in innovation management, requirements engineering and classic as well as agile project management.





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