On a platform inside a laboratory not far from Oxford sits a device that is roughly the shape of a giant beer barrel, but will certainly never be going into a pub cellar. For one thing, it has hosted temperatures of up to 15 million degrees Celsius and, for another, its steel walls are 30 millimeters thick to withstand forces 5,000 times greater than those in a Formula 1 racing car engine.
The ST40 fusion reactor built by U.K.-based Tokamak Energy Ltd., with its inner and outer vacuum chambers, “poloidal and toroidal” field coils and inner plasma, is designed to bring about the same process that fuels the sun – and point the way to the generation of clean, safe and abundant heat and power on Earth.
Fusion energy has been on scientists’ radar for decades, and has yet to make a decisive breakthrough. However, David Kingham, executive vice-chairman, told BloombergNEF in an interview that Tokamak Energy’s high-temperature superconducting magnets could transform the outlook because they make it possible to use a much smaller reactor.
Compared to ITER – the multibillion-dollar inter-governmental project in the south of France to develop a fusion energy reactor – Tokamak Energy’s device will be “at least ten times smaller by volume, at least ten times cheaper, and potentially almost ten times quicker to develop,” said Kingham.
Magnets are used in tokamaks to contain very hot plasma at high pressure for long enough for fusion reactions to occur—where hydrogen atoms combine to form helium atoms and huge amounts of energy are released. Tokamak Energy says its magnet is unique in achieving a magnetic field of more than 20 tesla, operating in warmer conditions than conventional superconducting magnets allow. Consequently, “there is less cost associated with cooling and the mechanical engineering is easier,” Kingham said.
In addition to scaling up the size of the test magnet, scientists at Tokamak Energy are working on increasing the maximum temperature of the plasma in order to proceed to demonstrating net energy generation by 2025. By 2030, the company aims to deploy “the first-of-a-kind fusion power reactor” that delivers electricity into the grid, Kingham said.
Tokamak Energy, now 10 years old, has raised 50 million pounds ($63 million) so far from investors including Legal & General Group Plc, and is pursuing another fundraising round.
BNEF’s Bryony Collins spoke with David Kingham and his team in a site visit on June 28:
BNEF: Scientists have been trying to develop fusion energy for many decades. Why is there a better chance of it happening now?
Kingham: High-temperature superconducting (HTSC) magnets are a game changer – they enable the scaling-down of the device. [So we get} the performance of ITER in a device that is at least ten times smaller by volume, and at least ten times cheaper, and potentially almost ten times quicker to develop. That means that instead of it being in the realm of government laboratories and inter-governmental collaboration, it’s in the realm where the private sector can make a big difference.
Q: Where has Tokamak Energy come in the last few years?
A: Since 2012, we’ve been focused on spherical tokamaks with HTSC magnets, with a goal of fusion energy.
The really attractive features of fusion energy are very high energy density for the fuel, safe operation with no risk of meltdown and no long-lived radioactive waste, and very plentiful fuel so that if and when the technology can be mastered, it can be an energy source for millennia and scalable to deal with a very significant fraction of the world’s energy needs.
Although wind and solar are making big inroads in many countries into electricity production, there is still a huge demand for energy for industrial heat, and for home heating and industrial processes like agriculture that is going to need new energy sources at the latest in the 2030s.
So our business plan targets the delivery of fusion energy at scale in the 2030s.
Q: What is the purpose of magnets in a tokamak device, and what is the significance of having one that operates at a slightly warmer temperature?
A: The magnets are crucial for holding a high-temperature plasma at high pressure, for long enough for fusion reactions to occur. So we want the strongest possible magnetic field in a relatively compact magnet and we don’t want to waste a lot of energy cooling the magnet down any more than is necessary.
Our latest magnet has proven that we can [reach a magnetic field of over] 20 tesla at 20 [degrees] Kelvin.
That’s a unique result that unlocks our commitment to invest another 5 million pounds ($6 million) in developing the next magnet.
Q: So operating the magnet at a slightly warmer temperature means that there’s less cost to cool and it’s easier to maintain and keep stable?
A: It’s the ideal material for compact tokamaks that can be developed quickly. And we’re also now confident that there are manufacturers around the world capable of making material of the right quality.
The best we can do with our current tokamak using copper magnets, is to operate the plasma for about one second – long enough to prove the physics of the plasma and the fusion reaction, but it’s not viable as a power plant. We have to replace copper with superconductors, and to do so economically it has to be HTSCs. They don’t heat up and they can hold the reaction essentially permanently. A magnetic field can be sustained permanently with very little energy input.
Q: So your next step is to build a bigger HTSC magnet with 1.5-meter diameter to be operating next year?
A: Yes – it will be by far the world’s largest HTSC magnet. In 2021, we’ll be able to say to investors that we’ve demonstrated both key bits of technology at scale. The ST40 will have delivered close to energy-gain conditions, and the HTSC magnet will have delivered 20 tesla at 20 [degrees] Kelvin, at scale. That means we will proceed with our next device, which will deliver fusion power at industrial scale by 2025. And when that works, we will proceed immediately to deploy the first-of-a-kind fusion power reactor, aiming for electricity into the grid by 2030.
Q: Where has your financing come from?
A: We’ve raised a total of 50 million pounds to date, mainly from private individuals [and] this year, we’re aiming to raise 200 million pounds. We also have an investment from Legal & General, who want to be investing in new energy technology.
Q: What are the advantages of developing ground-breaking technologies in the private sector with smaller organizations, rather than doing it with large-scale government organized programs like ITER?
A: We have benefited hugely from publicly-funded research in fusion energy, having emerged from Culham Laboratories just outside of Oxford, a world leading center for fusion research. In terms of physics validation, we look at Culham, at ITER and at Princeton Physics Laboratory in the U.S. So that gives us a lot of confidence that the scientific basis of what we’re doing is understood and the performance of the device is good enough to deliver fusion energy.
We’re not trying to compete with publicly-funded research – we want to interact and learn from it.
Q: In 2025, you hope to achieve net energy with your tokamak. How much energy will you put in relative to the energy you get back out?
A: We are aiming to put in no more than 10 megawatts for 100MW out.
Q: Do you see the tokamak being used just to produce heat – for industrial processes as you mentioned – rather than having an aim to produce electricity?
A: Traditionally, fusion is seen as a way to produce electricity, but there is increasing interest in using fusion as a way to produce heat – to produce hydrogen, or for industrial heat purposes. That could be the most important application of our device.