In Showtime’s limited series The Man Who Fell to the Earth, genius alien protagonist Faraday attempts to save his home planet and Earth from the ravages of climate change by developing a successful quantum fusion solution, which can power entire continents when operating correctly.1
While quantum fusion is a slightly different type of nuclear fusion than what we’re talking about today (more on quantum if interested), we can draw many parallels between this sci-fi film and our reality.
For decades, scientists and researchers have been chasing the dream of nuclear fusion: the clean and efficient energy source that could solve our planet’s energy crisis. With fusion, many believe we can finally reduce our dependence on fossil fuels, decrease the impact of climate change, and improve the global standard of living. But the reality is, the technology to harness the energy in the same way as our Sun has eluded us for years.
The concept of nuclear fusion was first proposed by British astrophysicist Arthur Eddington in 1920. Eddington suggested that the energy emitted by stars, including the Sun, could be a result of hydrogen nuclei (protons) undergoing a fusion process to form helium. He proposed that this fusion process released a tremendous amount of energy, providing an explanation for the vast energy output of stars.
Interestingly, this was even prior to the discovery of nuclear fission, the process of splitting atomic nuclei. Fission was first experimentally observed by German scientists in 1938 and became the basis of the atomic bomb.2 After the discovery of fission, research and development efforts largely focused on fission-based technologies, such as nuclear power and nuclear weapons. Fission offered more immediate applications and demonstrated the potential for practical power generation. Unfortunately fusion, being a more complex process, received less attention and resources in the early years.
While nuclear fusion occurs naturally in the Sun and the stars, replicating it on Earth is much more challenging than fission. Fusion requires achieving and maintaining extremely high temperatures and pressures (like that found on the Sun) to overcome the electrostatic repulsion between atomic nuclei.
The most well-known approach so far has been to use magnetic confinement fusion, which aims to achieve fusion by confining a hot, ionized plasma (i.e., hydrogen atoms converted into an electrically charged soup) using strong magnetic fields. The two primary methods within this approach are:
- Tokamak, which uses a toroidal (doughnut-shaped) chamber to confine the plasma using magnetic fields and absorb the heat using its walls
- Stellarator, which uses complex magnetic coil arrangements to confine and control the plasma without the need for large plasma currents
In southern France, 35 nations are collaborating to build the International Thermonuclear Experimental Reactor (ITER) project (image: left). ITER will be the largest of more than 100 fusion reactors built since the 1950s, with 10x the plasma volume of any other tokamak operating today.3
Despite the numerous obstacles, the quest for fusion energy continues. There are many potential benefits: fusion produces no greenhouse gasses, doesn’t produce the same harmful radioactive waste as nuclear fission, and doesn’t have the same potential meltdown risks as current nuclear reactors (if the precise conditions of temperature and pressure are not maintained, the fusion reaction simply stops). Additionally, the fuel sources for fusion – deuterium and tritium (isotopes of hydrogen4) – are much more abundant and could last for thousands of years.
Check out this great infographic for a comparison between fission (current state) and fusion (future state).
The challenge now is finding a way to make the energy output exceed the input required to produce it, a process known as achieving net energy gain (in industry jargon, Q > 1).5 This is where advances in technology, such as the use of superconductors, will be vital. After a big scientific breakthrough in December 2022 in which this threshold was crossed for the first time at Lawrence Livermore National Laboratory in California6, the US Department of Energy accelerated its investment into innovators in the field, pumping $46M into 8 companies developing nuclear fusion power plants.7 The US government aims to achieve a pilot-scale demonstration of fusion on an incredibly fast timeline that’s within a decade.8 These projects and others cropping up are leveraging a mix of public and private investment to accelerate development and experiment with various fusion approaches.
I had a chance to tour the sparkling Devens, MA, campus of Commonwealth Fusion Systems (CFS), one of the 8 DOE grant recipients. CFS claims it will have a working demonstration plant within the next decade, with the goal of building 10,000 zero-carbon ARC fusion power plants delivering electricity to 20% of humanity by 2050.9
Another recent advancement is the use of AI in enhancing the various fusion approaches. DeepMind, the subsidiary of Google focused on AI, is using deep reinforcement learning to improve control over the magnetic coils in a tokomak, which typically require constant monitoring and manipulating at a rate of thousands of times per second.10
In terms of the potential impact of fusion energy, it’s difficult to overstate it. Clean energy could help mitigate the negative effects of climate change, reduce dependence on fossil fuels, and improve the quality of life for people around the world. However, there are still challenges to be overcome.
Public perception is the first roadblock - nuclear in some sense is stigmatized from historical events like Three Mile Island (1979), Chernobyl (1986), and Fukushima (2011) - but that is quickly changing with the public and private sector support. Fusion reactions do not have the same inherent risk of runaway chain reactions or meltdowns as fission reactions, which were the primary causes of the accidents at the aforementioned fission reactors.
Funding is still a concern, and there’s a gap between the current state of technology and the potential future advances. Even once we achieve a viable source of energy, we’ll need to adapt our energy infrastructure to make use of it. But with the progress we’ve made so far, it’s clear that the dream of nuclear fusion is not far off.
Sources:
1 https://thecinemaholic.com/the-man-who-fell-to-earth-episode-3-recap-and-ending-explained/
2 https://www.osti.gov/opennet/manhattan-project-history/Events/1890s-1939/discovery_fission.htm
3 https://www.iter.org/proj/inafewlines
4 https://www.energy.gov/science/doe-explainsdeuterium-tritium-fusion-reactor-fuel
5 https://www.futurelearn.com/info/courses/frontier-physics-future-technologies/0/steps/228802
6 https://www.energy.gov/articles/doe-national-laboratory-makes-history-achieving-fusion-ignition
7 https://www.energy.gov/articles/doe-announces-46-million-commercial-fusion-energy-development
8 https://www.theverge.com/2023/6/1/23745233/nuclear-fusion-energy-department-funding-millions
9 https://cfs.energy/technology/#arc-commercialization
10 https://www.engineering.com/story/could-ai-help-finally-unlock-fusion-power