Nuclear fusion: experts expect first power plant in 20 years at the earliest
Experts from the Leopoldina and other institutes have looked at the current status of nuclear fusion research. There is still a long way to go.
(Image: UK Atomic Energy Authority)
The physical principles of nuclear fusion are understood. However, it will take at least another 20 years before it can be used for commercial energy generation. Energy experts from the German National Academy of Sciences Leopoldina, the German Academy of Science and Engineering and the Union of the German Academies of Sciences and Humanities believe this is the case. The majority of experts believe that realizing a power plant in 10 to 15 years, as some start-ups promise, is unrealistic.
The momentum in nuclear fusion research has accelerated in recent years, as can be seen from the increasing number of companies and start-ups involved in this field. In the long term, nuclear fusion could provide electricity in a climate-neutral energy system, reduce import dependencies and be used to produce hydrogen, for example, the researchers write (PDF).
So far, there is no prototype for any of the magnetic and inertial fusion concepts; many practical challenges still need to be overcome before a power plant can be operated. These include increasing the energy yield, obtaining the fuel tritium, researching the plasma and producing particularly resistant materials and high-performance lasers. The experts see financing as a challenge that should not be neglected. It may be 25 years before the first fusion power plant is up and running. That would be too late to make a significant contribution to the German and European climate targets for 2045 and 2050 respectively.
Delayed ITER project
Magnetic fusion technology is at a slightly higher level, for example in terms of the laboratory-scale test setup. Inertial fusion processes were developed somewhat later and were subject to military secrecy for a long time because some experiments also have military applications and, among other things, improved the understanding of processes in hydrogen bombs.
The first prerequisite for a nuclear fusion power plant, self-sustaining nuclear fusion, has been systematically approached by research in recent decades. The experts mention laser fusion experiments at the National Ignition Facility (NIF) in the USA. In 2021, the Lawson criterion was exceeded for the first time in a controlled fusion reaction in the laboratory. The criterion is the ratio of the amount of energy released from the fusion reaction to the amount of energy introduced into the plasma. This has not yet been achieved with magnetic fusion.
The experts also do not expect the positive energy balance with the ITER research reactor, in which the first plasma ignition is to take place in 2034. The facility is too small and not designed for this. This step is to be achieved by the subsequent demonstrator DEMO, which may feed electricity into the grid in 2050 and generate the required tritium itself on site. The ITER management presented a new schedule in July of this year. According to this, the project will be delayed by several years.
Power generation costs
For a fusion power plant to operate economically, the nuclear fusion conditions would have to be reliably fulfilled over a longer period of time or at a high repetition rate. In the case of magnetic fusion, the plasma would have to be kept stable over a period of hours to days. Previous records are in the range of minutes.
With inertial confinement fusion, it is crucial to increase the bombardment rate in addition to increasing the power of the energy pulse introduced into the target. Today, due to the long cooling times of the laser, only a few firings per day are possible, at the highest energy level one shot every two days. For power plant operation, however, the frequency would have to be 10 to 20 plasma ignitions per second.
How expensive electricity from fusion power plants will be cannot be reliably determined at present. However, despite all the uncertainty, there are already estimates of the electricity generation costs of future fusion power plants. In an overview study of various reactor designs of fusion power plants, the range is between 38 and 157 dollars per MWh. In view of the uncertainties associated with new large-scale technology, the experts assume that the upper end of the cost range will be reached.
(anw)