To the untrained eye, the power station of the future will not look very different externally, from current ones. A series of blocky buildings, cooling towers, a distribution sub-centre. We probably won’t even see much difference to our lives, energy will still flow from magnetic coils, through electricity grids to our homes.
But inside, these power stations will be very different. There will be no furnaces and probably no enormous stainless steel bucket of a nuclear reactor. Instead, the heart of the system may be a large stainless doughnut shaped vessel, in which the most extreme conditions in the universe will be recreated. Temperatures from near-absolute zero will help generate titanic magnetic fields that will control a sparse quantity of electrically-charged gas inside the spherical vessel. This insubstantial wisp of matter will be heated to temperatures in excess of 100million°C, so that atomic nuclei fuse together, spraying out sub-atomic particles at staggering velocities – producing far more energy than was put in.
The result? The energy of those speeding particles will heat water to spin turbines, in the fashion that has been used to generate electricity since the early 20th century. But this electricity, generated by the processes of nuclear fusion, will create no greenhouse gases, and hardly any waste. The fuel will be derived not from coal or uranium, but water.
The tokamak – the heart of future power stations
For a vision of this future, watch the movie Iron Man, which portrays a spectacular energy generation system called an arc reactor. Production designers based its look upon the device at the centre of a putative fusion power station.
Originally invented in Russia in the 1960s, this device is called a tokamak: a Russian acronym for ‘toroidal chamber with magnetic coils’.
Tokamaks, or other fusion concepts, are likely to contribute to the biggest changes of any infrastructure sector over the next decades. Whilst the next 20 years will see growth in renewables, the biggest change to the energy sector by mid-century is expected to come from fusion energy.
After a long wait, fusion – the process by which stars derive energy – is now approaching a state of readiness. Of the 20-odd companies currently developing fusion reactors, most expect the first commercial fusion power to feed the grid sometime in the 2030s, according to an industry survey by the Fusion Industry Association (FIA)1.
The technologies of our fusion-powered future
Getting here has proven challenging. But progress – decades in the making – is now happening fast.
Fusion involves fusing the nuclei of atoms – a process that releases huge amounts of energy. Forcing them together means overcoming strong electrostatic repulsion. There are two main approaches in development. Inertial confinement uses powerful lasers to heat and compress small pellets of fuel.
Magnetic confinement, used by the tokamak, deploys powerful magnets to squeeze a cloud of charged particles (ions and electrons).
An enormous international project to build a demonstration fusion reactor in southern France, called ITER, is now well into its construction phase, albeit behind schedule and over budget. ITER’s first operation is scheduled for 2025, but first fusion is not scheduled until after 2035.
However, numerous private-sector fusion projects are working on a more ambitious schedule. Leading the pack in the UK is Tokamak Energy (TE), based in Didcot, Oxfordshire. Tokamak Energy is developing a spherical tokamak, a smaller, more compact, efficient version of the conventional tokamak. “We're looking to start roll out in the 2030s,” said Tokamak Energy Chief Executive, Chris Kelsall. “I envisage the 2040s as a decade of significant scale up in deployment. That scale up curve is difficult to predict, but certainly we have bold ambitions.”
There has also been much fusion research in Asia, with tokamak projects in China, South Korea, Japan and India, all of which are involved in ITER.
Tokamaks are not the only game in town. Canadian company General Fusion (backed by Jeff Bezos, among others) plans to build a different fusion power demonstrator using a technology known as magnetised target fusion (MTF). This will be built at Culham, Oxfordshire, alongside the UK’s publicly-funded projects, with construction beginning in 2022 and start-up targeted for 2025. MTF uses mechanical steam-powered pistons to compress fusion plasma and, like ITER, the plant is intended to be a demonstration unit, rather than a full-scale power station.
Kelsall welcomes the establishment of the General Fusion facility nearby “There are going to be numerous techno-commercial procurement, supply chain, and regulatory advantages arising from a fusion hub developing further, here in the UK,” he says. However, he believes that Tokamak Energy’s spherical tokamak approach has the potential to dominate. “We believe spherical tokamaks are going to be the most cost-effective and most commercial solution, due to the design features.” The UK government shares his belief, setting up a project called STEP (spherical tokamak for energy production) in late 2019, which aims to construct a demonstration fusion power station by 2040.
The challenges of delivering a fusion reactor
For all this to become real, there are still engineering challenges to overcome. The tokamak needs magnetic coils built from superconducting materials, requiring near absolute zero temperatures. And they need materials that can survive the extreme conditions of fusion reactions, and a heat extraction technology that can effectively capture the heat of the reactions.
TWI is an important partner in making these advances, supporting with expert advice and technology for materials selection and structural engineering, as well as partnering on the development of the future skills the fusion industry will need.
TWI already works with the nuclear industry, looking at methods for joining metals with high integrity and verifying their reliability. Kelsall believes that it will be equally as important for the fusion sector. “I would very much like to see that relationship evolving and developing further, while identifying the best collaboration opportunities to support our growing industry,” he says.
Part of a bigger picture
Fusion could be a genuinely transformative technology which one day provides a significant proportion of the world’s power. But no one technology is a panacea.
“When I view future net-zero greenhouse gas emission energy grids” says Kelsall, “there's inevitably going to be a blend of complementary technologies. Clearly, there will be renewables, solar, wind and batteries. That said, I see fusion sitting alongside those technologies, as a very significant, complementary partner in delivering clean energy at scale. Future clean energy grids will need to be diversified, in order to be resilient under variable and challenging conditions. If all goes to plan, we could see fusion generating over 50% of the world's total energy needs in the second half of this century.” Bloomberg New Energy Outlook 2020 predicts that in 2050, 24% of electricity will still be produced by fossil fuels. That’s a market that fusion needs to address urgently.
Looking further ahead, plasma physicist Dr Melanie Windridge, UK director of the Fusion Industry Association, adds: “When it comes to decarbonizing, electricity is not the only thing. Electricity at the moment is only about 20% of global primary energy demand. So there's a huge amount of work that needs to be done in addressing the other 80%, which is fuels for aviation and shipping, and heat for industry.” In particular, Kelsall sees a critical need for fusion energy solutions to power the hard to abate industrial sectors that require intense heat in large quantities, over long periods; such as iron and steel smelting. Decarbonisation of these sectors will be a key element in achieving netzero targets.
Windridge adds, further: “So we could produce hydrogen from fusion reactors, and from there you can produce ammonia, which can be used for shipping. This all requires a lot of energy, so these are markets where fusion could be helpful. But I think that’s going to be in the longer-term future. For fusion, there are studies that show that the most promising early market for fusion is electricity and that's because of the costs. But the costs are going to come down over time.”