The Spheromak Approach To Fusion • CTFusion

The world is moving towards clean energy sources. (Image: CTFusion)
The world is moving towards clean energy sources. (Image: CTFusion)

Fusion is a suitable replacement for fossil fuels because it is carbon-free and provides equal or greater reliability with higher power density working in concert with conventional renewables to provide deep decarbonization across the entire energy ecosystem. This is the future that CEO Derek Sutherland, VP Chris Ajemian, and COO Scott Brennan of CTFusion are working towards.

Fusion is Different from Fission

Fission is conventional nuclear energy, taking heavy elements like uranium and splitting them apart into lighter ones, releasing energy in the process via a nuclear chain reaction. These lighter products are radioactive and require long-term storage, and the nuclear chain reaction creates a risk of meltdown.

Fusion is also a nuclear reaction, and its process is essentially the opposite of fission. Instead, it generates power by combining light and everyday elements, like hydrogen, into heavier ones and releasing energy.

Fusion has Important Advantages Over Fission

Fusion is safer, cleaner, and uses low-cost fuel sources to work. It provides a similar power density as fission, but does not rely on a nuclear chain reaction, thus there’s no risk of a meltdown because it’s physically impossible. Additionally, fusion produces no long-lived radioactive waste with minimal health, safety, and environmental concerns. It’s like fission because it’s carbon-free and creates a lot of energy in a small package, but it’s simply a better product overall if it can be successfully commercialized.

Fusion’s History

Fusion started back in the 1950s and has continued to be a humbling work in progress. What began as something that was thought to be squared away in a decade turned out to be a grand challenge in need of vast amounts of research. Essentially, plasma physics had to be invented in order to make the system work.

The ability to run a fusion power reactor for an extended period of time has been so far away from reality that the most successful versions still haven’t made it past the fictional realm of Marvel movies.

In parallel, computing ability also needed to mature to develop fusion. As computing power developed, so has the field’s ability to simulate and understand how to optimize system performance. This increase in computing power has allowed a better design and optimization of fusion devices. This capability has allowed fusion technology to more rapidly advance towards net-gain, meaning the system makes more power than is put in, which is the basic requirement for any power plant.

Now that the knowledge and systems have matured, the challenge faced by CTFusion and other fusion start-ups is making the technology financially viable.

CTFusion’s Approach

CTFusion uses less superconducting coils than competitors, which lowers cost and space requirements.

Differences in fusion companies are based on technical approaches. There are multiple private fusion companies that are going for net-gain in the 2020’s. With the first commercial units connecting to the grid in the 2030s, fusion is on the precipice of being realized.

Fusion is more or less an artificial sun. There’s a quantity called the Lawson Criterion, which is the plasma density – think of it as the number of particles per cubic meter in this artificial sun, multiplied by the temperature of the fuel and the energy confinement time, which is how well the heat of that sun is retained. As long as the product of those three quantities is high enough at a given temperature, the system can produce net power output. There’s a lot of different approaches to those quantities and that’s what sets companies apart.

In general there’s three main camps of fusion:

  • magnetic fusion energy
  • magneto inertial fusion
  • inertial fusion energy

Each are different ways to balance plasma density and heat retention time. CTFusion belongs to the magnetic fusion energy camp, and is specifically developing the spheromak approach to magnetic fusion energy. Spheromaks are a type of fusion that uses a magnetic bottle to confine a really hot plasma that’s fusing and making power, which is more compact and simple than other approaches.

Consequently, this allows them to have a more compact system which drives down the CapEx required and lowers the projected levelized cost of electricity (LCOE). Since the OpEx and fuel costs are relatively low, reducing capex will reduce the overall cost and make the technology more commercially attractive without sacrificing other features.


With the looming threat of climate change, fusion is gaining momentum as a potential solution to meeting global energy demand. While hurdles in development, public acceptance, and implementation remain, fusion shows potential to fulfill a large market need, that is a clean and safe replacement for fossil fuels with the same level of consistent and reliable energy generation. If the team at CTFusion can reach net-gain and commercialize nuclear fusion, it may very well be the technology that eliminates fossil fuels and paves the way to a carbon-free future.

About The Author

John Doctor

John Doctor

NNSA Fellow at Pacific Northwest National Laboratory

John currently works at the Pacific Northwest National Laboratory as an Engineering Analyst Fellow. He has his master’s in Biotechnology, Sustainability, and Entrepreneurship from Northwestern University and has conducted research on microbial wastewater mitigation, soil batteries, and biomass chemical conversion and valorization. His goal is to help the world develop, understand, and embrace solutions to the climate crises. In his spare time he enjoys trail running, cycling, rock climbing, reading books, and playing the banjo.

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