As solar panels have grown cheaper and more ubiquitous, a growing chorus in environmental circles condemns efforts to pursue other forms of electricity generation, as if having more than one source of usable energy is a negative. Certainly, the relative success of solar power complicates the immediate economic picture for other energy generation methods, including both nuclear fission and nuclear fusion, but solar’s advantages remain incompletely addressed, including low conversion efficiency and intermittency. Battery technologies keep improving, but most require complex and hazardous chemistries to operate. The best situation we can pursue is one in which multiple energy generation technologies remain viable for different circumstances and applications, from conventional combustion-based powerplants, to traditional renewables like solar and wind, to geophysical sources like geothermal and hydroelectric, even incidental energy generation through piezoelectricity or triboelectricity. And, of course, nuclear power. I’ve written before about nuclear power, and my particular interest in the subject, and I encourage you to read that post if you’d like a refresher or primer on the basics of nuclear fusion and nuclear fission. As it’s been for the past decades, though, net-positive nuclear fusion energy generation remains always on the horizon.
That said, I’ve been seeing estimates in the ten-to-twenty-year range, instead of the thirty-year outlooks which have been common for about the last sixty. Encouraging results out of the National Ignition Facility in recent years have motivated research in laser-based compression techniques, but the scalability of such methods is unclear, and NIF’s applications are different from those focused specifically on energy generation. Tokamaks remain the preferred design for pursuing break-even fusion power generators, and the state of venture capital markets has enabled the rise of several private companies pursuing “ignition.” Amongst these is Commonwealth Fusion Systems, which recently released a bevvy of scientific papers regarding the work they’re pursuing, the design they’ve chosen, and the remaining physics and technical problems which must be solved.
For a team intending to achieve commercially viable fusion power generation before major government experimental tokamaks like the ITER project even come online, the papers highlight a concerning number of outstanding problems. As usual with these efforts, most have to do with maintaining the containment and uniformity of the plasma, but there are also problems remaining with cooling systems and the high temperature superconductors required for the supporting magnetic fields. To be clear, when “high temperature superconductors” are invoked in an application like this, it does not refer to materials which are superconductive at temperatures at or above what you would consider comfortable – they are only high temperature compared to other superconductors, maintaining their superconducting properties sometimes at temperature above -100C. Furthermore, anytime superconductors are used, there is risk of sharp, discontinuous quench events, when the superconductor fails and will have to be reset before its properties can be restored. In the case of a tokamak, quench events could be catastrophic…and their poorly understood dynamics are akin to those of the high-pressure plasma states which are also so difficult to maintain.
There are sound physics reasons to believe tokamaks can work and become power positive. The core physics are well understood, and many of the most significant problems have already been solved, but this is very much a problem set in which even the smallest of details are the difference between a tokamak which is a nice science experiment and a tokamak which is a commercially viable fusion reactor for power generation. Usually, when a series of papers is released like this in a splashy PR event (by the standards of scientific publishing), it is in support of a more corporate end than a scientific one, usually to justify continued work and funding. I’ve seen it before with fusion and other constantly-on-the-horizon technologies, like quantum computers. This is not to belittle the work of the scientists involved, or to suggest there is anything wrong with the contents of the papers, just that the timing of the release is deliberately designed to build excitement and a surge in momentum for a project. It goes hand-in-hand with what is probably an unrealistic timeline. Commonwealth Fusion maintains their experimental reactor will be ready in 2027, and their commercial reactor will be deployed in the early 2030s. The experimental reactor could just happen, reaching some kind of fusion by the projected date (if probably not break-even fusion), but I am highly skeptical of the timeline for the commercial reactor.
I don’t want to be skeptical about it. Fusion remains, to me, one of those core technologies which will change and enable so much, from terrestrial energy markets and applications to space capabilities and missions. However, between the technical and scientific hurdles which remain, the engineering challenges involved in making something that is not just workable but actually viable for at-scale production and implementation, and the unclosed economic case, I’ve learnt to temper my expectations. It seems to me a company seeking to viably pursue fusion power should begin with conventional, non break-even fusion, using the technology to produce and sell the byproducts of the fusion reaction, like rare isotopes of helium which have uses in cooling and instrumentation, and making progress towards break-even from there. So, although I hope I’ll be announcing commercial break-even fusion being deployed at scale ten years from now, I’m not going to hold my breath.
IGC Publishing 