When James Watt’s first commercial steam engine was installed in March 1776 at Bloomfield Colliery, Tipton in the West Midlands, it was hailed as a mechanical marvel. Yet few could have anticipated the way steam engines would change the world. Developed initially to pump water from mines, the technology was adapted across so many industries and applications that it sparked the Industrial Revolution. Now, according to those working on the development of fusion energy power plants, we are on the cusp of a similar transformation. “I see this whole endeavour as having the characteristics of a general purpose technology in the same spirit as Watt,” says Lu-Fong Chua, chief strategy officer of TAE Power Solutions in Birmingham. Fusion is the energy-generating mechanism that makes the stars shine. The cliche is that human-engineered fusion on Earth is always “30 years away”. But if we can make it work, it promises such quantities of clean energy that we will finally be able to leave fossil fuels behind. Large, state-sponsored efforts and, increasingly, private startups are reporting breakthroughs that many in the industry now think will lead to viable fusion energy. Underlining their optimism, in 2022 the UK government announced the site for the Spherical Tokamak for Energy Production (STEP) project, at West Burton in Nottinghamshire. This demonstration plant aims to supply electricity into the national grid by the 2040s. And in developing such fusion power plants, we are creating new technologies and solutions that can reach far beyond the task of energy generation. For example, TAE Power Solutions is a spin-out from America’s TAE Technologies, which was founded in 1998 to develop commercial fusion power. Obliged to invent a way to collect and store 750 megawatts (the power needed to spark their experimental reactor into life) from a commercial electricity grid only capable of delivering 2 megawatts, the firm is now adapting its breakthroughs to provide more efficient batteries for the next generation of electric vehicles. “We don’t see these as side projects; we see these as happy byproducts that have very high intrinsic value on their own for problems and challenges beyond energy generation,” says Chua. In the UK, the Atomic Energy Authority (UKAEA) has established the Fusion Cluster at Culham in Oxfordshire to stimulate the growth of a fusion industry. Since its establishment in 2021, the cluster has grown from a handful of companies to more than 200. While the key goal remains the development of the skills and technology necessary to build a UK commercial fusion power plant by the 2040s, commercialising the spin-offs is also a high priority. “One of the roles the Fusion Cluster plays is telling people that not only is fusion coming, but there is value from it even years before we’ve got the first fusion power plants, because we’ve got these enabling technologies emerging,” says Valerie Jamieson, the centre’s development manager. It’s a message that stimulates investment, as Greg Piefer, founder and CEO of Shine Technologies, realised in the early 2000s when he saw that developing commercial fusion power was going to be a long and costly path. It led him to think of how the technologies being developed could be deployed for profit along the way, so that investors could see a more immediate return on their money. “It’s hardcore essential to the mission of commercialising fusion,” he says. There are currently four key areas in which fusion spin-off technology is playing a key role. Propulsion One of the seemingly impossible things that a fusion reactor must do is confine a gas at around 100m celsius – hot enough to melt any material. Fortunately, at that temperature the gas becomes electrically charged and so can be controlled by magnetic fields. The strength of the field determines the size of the reactor, and therefore how cost-effective it is to build. So, creating highly efficient magnets has been a core goal of Tokamak Energy, part of the Fusion Cluster and headquartered at Milton Park, Oxfordshire. In 2023, they announced the creation of a new generation of high-temperature superconducting magnets that deliver stable magnetic fields 10 or even 20 times stronger than existing technologies. Not only do such magnets open a path to a viable fusion machine, but they “can transform [existing] markets and create new markets”, says Warrick Matthews, CEO at Tokamak. One such area is the creation of magnetohydrodynamic (MHD) drives. Known to theoreticians since the 1950s, MHD drives use magnetic fields to create jets of an electrically charged fluid that propel a vehicle. The beauty is that they have no moving parts, so suffer no wear and tear. Marine applications are particularly attractive because seawater conducts electricity far better than freshwater. Since the engines are silent, they promise a big cut in the damaging noise pollution affecting marine environments. In the 1990s, Mitsubishi built the world’s first prototype MHD ship, the Yamato 1, but the programme was abandoned when its top speed proved to be just 15 km/h (just over 8 knots). By providing much higher magnetic fields, and therefore more thrust, Tokamak Energy’s magnets should be game-changing. The company is currently collaborating with the US Defense Advanced Research Projects Agency (Darpa) to prove the concept with a demonstration device. Medical applications There are several possible reactions that a fusion machine can use to generate energy. In 1998, TAE chose to pursue the fusion of boron atoms with protons, which opened their eyes to an old research programme into curing cancer. Atomic pioneers in the 1930s showed that boron possessed a strong affinity for reacting with neutron particles to split into lithium and helium. In 1936, Gordon Locher of the Franklin Institute in Pennsylvania pointed out the reaction’s potential for destroying cancerous cells. As the lithium and helium recoil, they deposit their energy over a range of about 5-9 micrometres, the size of a typical cancer cell. This sudden release of energy destroys the cell. While the boron can be introduced into the patient with drugs, finding a suitable source of neutrons in the mid-20th century was a big problem. Historically, the patient had to be taken to a nuclear reactor and exposed to the neutrons from its core. Hardly ideal. Now, the problem is all but solved. A key innovation from TAE’s fusion programme has been the creation of compact particle accelerators that can be used to generate tightly focused neutron beams. In fusion they are used to fuel the reactors. “We’re able to take those beams and reconfigure them for medical purposes,” says Rob Hill, CEO of TAE Life Sciences. The company is currently in discussions with university hospitals Birmingham and University College hospital London to install experimental apparatus. Meanwhile, Shine Technologies is producing lutetium-177, a medically useful isotope, in its facilities at Janesville, Wisconsin, and Veendam in the Netherlands. The lutetium is also used to target cancer, similarly delivered on a drug that binds to cancer cells. Unlike boron, it does not need neutrons to activate it. Instead, it is radioactive and decays with a half-life of around six-and-a-half days, emitting a high-energy electron that rips the cancer cell apart. It also emits a gamma ray, opening the possibility of a medical imaging device that can track the progress of the cancer and the effectiveness of the treatment. Having such a short half-life, however, means the isotope does not exist in nature and so must be created using fusion technology. Industrial imaging One method of igniting fusion is to use lasers to compress and heat a pellet of hydrogen fuel. While researching the lasers needed to do this in the early 2000s at the Lawrence Livermore National Laboratory in California, physicist Markus Roth and colleagues discovered that if they changed the target to a thin foil of material, they could accelerate particles from the foil to huge velocities. In 2021, Roth established Focused Energy in Darmstadt, Germany to develop a laser system capable of accelerating a neutron beam with 100 times the intensity of existing technologies. Neutrons can be used like X-rays for imaging but are more penetrating, meaning they can see inside denser materials, and Roth is currently in discussions with civil engineering firms to deploy the system to inspect the steel inside concrete buildings and bridges for signs of corrosion. The same technique can also produce particles called muons, opening up even bigger imaging projects. Muons are created naturally when particles from the sun strike atoms in the Earth’s upper atmosphere. They have tremendous penetrating power and were used after 2011’s Fukushima nuclear accident to locate the molten reactor core. A similar set of detectors revealed a previously hidden chamber in 2017 in Egypt’s great pyramid of Giza. Geologists have used muons to investigate the movement of magma in volcanoes before eruptions. The downside is that the amount of naturally occurring muons is relatively low. Hold your hand up to the sun and just one muon will pass through your palm every second. As a result, it took five months to image the Fukushima core. Roth’s laser method could improve on the number of muons by a factor of 10,000, tremendously speeding up the imaging process, although the development of systems large enough to study volcanoes currently lies somewhere in the future. Nuclear waste handling At present, the biggest spin-out project for Focused Energy is a contract with the German government to build the first laser-driven neutron source for examining nuclear waste containers. Having shut down its last remaining nuclear power plants in 2023, Germany must now deal with the waste, which has been piling up for decades. Focused Energy’s imaging system will determine the contents of the barrels, and what condition the waste is in, so that they can be safely and finally stored. Across the Atlantic, Shine is planning to take this one step further. Instead of using neutrons to image the waste, if the neutron beam can be made more intense, it can transform the waste into less harmful substances. For example, traditional nuclear reactors split uranium-235 or plutonium-239 to produce energy. The waste product is iodine-129, with a half-life of more than 15m years. However, if it could be bombarded with a high-intensity neutron beam, it would be transformed into iodine-128, which has a half-life of just 25 minutes. “You can be rid of this 10 million-year problem in a day,” says Piefer. It turns out that the kind of neutrons necessary to do this will be made in abundance in many fusion power plants. So the reactors of the future will not only solve the world’s energy problems, but can be harnessed to help clean up the dirty legacy of the first nuclear reactors. “I believe that fusion, ultimately, will be a gamechanger similar to the steam engine,” says Roth. “We will be able to do a lot of things in our society that were not possible before, and that starts with cleaning up a lot of the mess from the Industrial Revolution.”