Fusing two hydrogen nuclei releases a huge burst of energy – in nature, this is the type of physical reaction that powers the sun and the other stars. The great advantage of the technology is that it does not emit greenhouse gases; nor does it emit heavily polluting or highly radioactive substances, making it a highly attractive energy source. It is also virtually inexhaustible as it uses a blend of easily obtainable elements as fuel: deuterium and tritium, two hydrogen isotopes. Deuterium comes from seawater, while tritium can be produced by a physical reaction with lithium. On the downside, as you have to heat the hydrogen isotopes to temperatures of more than 100 million degrees, it's very difficult to replicate the process artificially on earth. At those temperatures the isotopes lose their electrons and turn into plasma; the nuclei can then fuse to release their atomic energy. Magnetic confinement technology is being investigated as a potential means of achieving fusion continuity control in power plants. As its name suggests, the technology uses extremely powerful magnetic fields to control the plasma in which the fusion takes place.

The journey towards this technological revolution will be a long one, but will lead to a more sustainable future. The proof? All it takes to get the same amount of energy produced by 8,500 tonnes of gasoline is 1 kilogram of “fusion fuel”, which has the added benefit of not releasing any greenhouse gases or hazardous waste. This is why we're focusing on magnetic confinement fusion and why we’re collaborating with leading public and private research bodies to develop it. We see it as a turning point in the decarbonization process.  

Fusion takes place when two nuclei from hydrogen isotopes join together and form a new, heaver element, such as helium. Hydrogen is used in the form of two isotopes: deuterium and tritium. The nuclei of the two isotopes, in addition to a proton, have one and two neutrons respectively. The sun, on the other hand, uses the single-proton hydrogen isotope, protium, by far the most abundant in the Universe (99.98%).

Whatever kind of isotope the process begins with, two hydrogen atoms have the same charge, meaning they tend to repel each other electrostatically. That means temperatures of hundreds of millions of degrees are needed to fuse them together. Thermal agitation enables fusion to take place inside a gas ionised at a very high temperature called plasma. The main technical difficulty to solve involves managing the plasma, which must be confined in a high vacuum, within a limited space and, given its very high temperature, without coming into contact with the machine’s surfaces. This is accomplished by using a tokamak, a russian acronym for toroidal chamber with magnetic coils: a doughnut-shaped (toroid) device which, through an extremely powerful magnetic field generated by super magnets placed around the chamber, it creates plasma at extremely high temperatures and swirls it around its doughnut shape without allowing it to come into contact with the walls. This is where the name magnetic confinement fusion comes from. “Turning on” a fusion reactor involves inserting a blend of deuterium and tritium into the tokamak, carefully heating it to a plasma state and then, by increasing the temperature further, bringing it to the point where fusion can take place. The fusion process releases highly energetic neutrons, which are soaked up in a “blanket”: this is a thick coating that contains the fusion chamber. MIT and CFS’ innovative idea is to use a molten salt in the blanket containing a lithium-6 enriched isotope; when it is hit by a neutron, the lithium breaks up into a tritium and a helium atom. The tritium is then separated from the salt and fed back into the tokamak, where it mixes with the deuterium. This means that the tokamak becomes virtually "self-sufficient". Throughout these stages – from capturing the neurons to cooling the reaction chamber – the molten salt reaches very high temperatures (more than 600 °C); it is placed through a heat exchanger, which extracts the heat to feed a power plant or heat storage plant, before returning back into the blanket. This allows a huge amount of energy to be extracted from the reactor.

The largest programme in this field is the International Thermonuclear Experimental Reactor (ITER), an international project involving the European Union, the Russian Federation, the United States, Japan, China, South Korea and India. In all, 35 countries are participating. Launched in 2005, the ITER project involves building a large pilot tokamak fusion reactor in Cadarache, in the South of France, which should be ready by 2025. This initial plant will provide the understanding required to build DEMO in 2050. According to its designers, this colossal reactor should be the first demonstration reactor capable of outputting energy to the grid.

Eni is particularly excited about  the Commonwealth Fusion Systems (CFS) project, a spin-out from the Massachusetts Institute of Technology (MIT) which we have been collaborating on since 2018. Founded as a start-up by a group of researchers and scientists from MIT who were working on plasma physics and fusion, the company has created significant synergies between scientific knowledge and a dynamic business sector by establishing a partnership with MIT’s Plasma Science and Fusion Center and leading global private investment groups. 2025 is also the date when CFS expects to unveil its first pilot reactor. Known as SPARC, it will be capable of not only managing and confining plasma to create the conditions necessary for controlled fusion, but also of developing more energy than will be absorbed, thus demonstrating the feasibility of the project to achieve controlled fusion. The knowledge gained through the trial will enable CFS to design and build ARC, the first reactor capable of outputting energy from fusion to the grid. If all goes to plan, ARC will be ready  by 2033. Thanks to super magnets with HTS (High Temperature Superconductors) technology, which was successfully tested in September 2021, SPARC will be five times less powerful than ITER, but will be much smaller and simpler to build. The tokamak will have a radius of about 3.3 metres, which compares to about 8.5-9 metres for DEMO, and a substantial reduction in the size of the auxiliary plants. The entire reactor will be sixty-five times smaller and will be able to work with magnetic fields that are four times more powerful.

In addition to CFS, we also have cooperation agreements in place with ENEA and CNR. With ENEA, we are collaborating on the Divertor Tokamak Test (DTT) project conducted at the ENEA Centre in Frascati. This programme is investigating techniques for managing the excess power (heat and particles) produced in the tokamak and aims to determine the best possible design of the tokamak in terms of structure, magnetic field configuration, materials and operating parameters. The DTT project has close links to the ITER-DEMO project and involves Eni and MIT studying the design and physics aspects of the Divertor, the reactor component where the power that is produced is managed and extracted. Other areas of great interest involve the physics of plasma and managing its natural instabilities. At the joint Eni-CNR "E. Majorana" centre, mathematical models for these and other processes are being investigating, as well as new superconducting materials for confinement magnets.

Developing magnetic confinement fusion is a global challenge that will involve a wide range of international talent in industrial science and technology. Everyone will have to put his skills and experience to use in the service of this revolutionary technology. At Eni, besides working with big research bodies, we have handed our HPC5 supercomputer to researchers, who will use its huge calculating power for highly complex mathematical models that will describe the physics of plasma and simulate its behaviour. When we get fusion to a mature enough point that it can be used in industry, the stage will be set for unprecedented things. We will finally have a widespread supply of clean, safe, sustainable energy. Power stations fed by fusion reactors could meet the growing demand for energy at big production and population centres while maintaining high sustainability. Smaller stations, on the other hand, integrated with renewable sources, could make it easier to provide energy to small communities and off-grid businesses.

The energy produced in the fusion process is virtually infinite, is safe and releases no emissions of climate-altering gases or pollutants whatsoever. Consider that to get the same energy produced by 8,500 tonnes of petrol, you need just 1 kg of “fusion fuel”, which has the added benefit of not releasing any greenhouse gases. The road to this technological revolution is long, but by taking it we are heading for a more sustainable future.