On 13th of December 2022, the head of the U.S. Department of Energy (DOE) and other federal scientific leaders announced that an experiment of nuclear fusion reaction they ran at the Lawrence Livermore National Laboratory in California achieved “net energy”. The meaning of this result was “the reaction generated more energy than was put in to initiate the reaction”. It is the first time humankind has achieved this landmark, after more than 60 years of global research, development, engineering and experimentation with billions in investment for many decades.

Nuclear Fusion is the way that the Sun makes power, but recreating a useful nuclear fusion reaction here on Earth has eluded scientists for decades. Achieving net positive energy paves the way for fusion to move from a laboratory science to a usable limitless energy source, although large scale commercialization of nuclear fusion could still be decades away. The U.S. government has put huge amounts of federal money into nuclear fusion research since the 1950s and in the last decade invested about $700 million per year. The European Union contributes 45% to the most ambitious ITER project. It is the world’s largest nuclear fusion experiment with 35 nations collaborating. For the period 2021 to 2027, the EU decided to allocate €5.61 billion to the project. Also, the EU invested €300 million in nuclear energy research in 2021 as part of Euratom, the EU’s five-year €1.38 billion programme. In recent years, private investors have put almost $5 billion into nuclear fusion startups as the increased urgency in addressing climate change has made clean energy solutions particularly attractive. About 33 international companies are involved in nuclear fusion research, according to Forbes. Also, in the last years some other nuclear fusion experiments had limited success. The Eurofusion consortium were able to produce 59 megajoules of heat energy from nuclear fusion across a period of five seconds (in 2021). This result surpasses a previous record from 1997, when 22 megajoules of heat energy was generated. The results were achieved at the Joint European Torus, or JET, facility in Oxfordshire, U.K, co-funded by the European Commission. This review introduces the main concepts of nuclear fission (nuclear power plants) and nuclear fusion experiments in the last 60 years and the fundamental challenges that scientists encountered until now to achieve a rate of heat emitted by a fusion plasma that exceeds the rate of energy injected into the plasma centred on Tokamak reactors and stellarators which confine a deuterium-tritium plasma magnetically.