Worldwide, the demand for energy in the relevant end-user sectors is rising continuously despite increased energy efficiency. This particularly affects electricity use and natural gas use in the industrial and mobility sectors. At the same time, the declared goal of international climate policy is to limit global warming to less than 2° C by 2100. Germany aims to have achieved extensive greenhouse neutrality by 2045. To achieve this, the use of renewable energies is to be expanded from the current 40 percent to 80 percent and fossil energy sources are to be completely eliminated.
Defossilization - replacing fossil fuels with renewables
Alongside wind and solar energy, hydrogen technology plays a central role in German energy policy. In addition, experts are exploring alternatives for long-term energy sovereignty, free of fossil fuels and extensive import constraints.
The search for a quasi-inexhaustible, weather-independent and, above all, emission-free energy source is keeping international research groups busy. The USA and Europe in particular are focusing on progress in the development of controlled nuclear fusion. The goal is to reproduce the generation of solar energy on a laboratory scale on Earth. Unlike nuclear fission, energy in nuclear fusion is created by the controlled fusion of atoms.
Recent breakthroughs in the field of fusion research give reason to hope that practical fusion devices can be developed in the long term. If further developed, nuclear fusion could become a mainstay for meeting the world's energy needs. After all, as much energy can be obtained from one gram of fuel in nuclear fusion as from the combustion of eleven tons of hard coal.
Magnetic fusion and inertial fusion - different approaches to energy generation
In nuclear fusion, light atomic nuclei are fused together, releasing binding energy that is subsequently converted into usable forms of energy.
The implementation of nuclear fusion on Earth is technically highly demanding. In order to fuse the initially strongly repulsive atomic nuclei, extremely high pressures and temperatures (of about 200 million ° C) must be generated and maintained over certain periods of time. The resulting plasmas can no longer be confined in material vessels.
Therefore, magnetic fields are used for confinement in the so-called magnetic confinement fusion (MCF "Magnetic confinement Fusion Energy"). Strong energy losses due to the emission of light quanta in the X-ray range and the loss of hot particles must be compensated for by constant reheating. In international large-scale projects, research reactors based on different magnetic field geometries are operated, in which the necessary plasma pressure could be maintained for seconds to minutes so far. A positive energy balance could be achieved for the first time in 2035 with the currently largest research instrument ITER (International Thermonuclear Experimental Reactor), which has been operated since 2007 in the Cadarache research center in southern France by the member states of EURATOM, China, India, Japan, Russia, South Korea and the USA.
In contrast, an important breakthrough has recently been achieved in inertial fusion (IFE "Inertial Fusion Energy"). Using a large number of high-dimension short-pulse lasers, the fusion mixture enclosed in small capsules is briefly compressed to the density and temperature necessary for fusion. At Lawrence Livermore National Lab LLNL (California, USA), this technique was used to ignite a burning fusion plasma for the first time in the world in 2021. In this case, the energy recovery was 70 percent of the energy introduced for compression and ignition. In December 2022, a net energy gain of more than 150 percent was demonstrated for the first time at LLNL. Thus, more energy was recovered than was put into the experiment. A decisive milestone in fusion research.
Despite the successful physical experiment, there is currently no experimental facility in the world for inertial fusion in civil energy research. To achieve this goal, significant engineering achievements will be necessary in the coming decade. The first private-sector companies, supported by large investment funds or international corporations, are therefore becoming involved in this field. In particular, laser-driven nuclear fusion is meeting with great interest.
Technologies made in Germany provide relevant contributions to fusion research
Germany already has extensive know-how in key technologies that are relevant to the development of fusion research. In the field of magnetic confinement, for example, researchers of the Max Planck Society have a worldwide reputation. In laser technology, which is necessary for the ignition of plasmas in inertial fusion, Germany occupies a leading international position. For example, experts at the Fraunhofer-Gesellschaft are working on the development of high-performance ultrashort-pulse lasers. Material sciences are also among the competencies of the German research landscape in this field.