The Sun and other stars are enormous fusion reactors using their immense gravity to create compressive forces so great it forces light atomic particles like hydrogen to fuse together releasing vast amounts of energy.

How dense does the Sun’s internal environment have to be to produce a fusion reaction? Measured in grams per cubic centimetre, that number is 160. How does that measure against atmospheric pressure at sea level? An air density of one atmosphere when measured with an ambient temperature of 15 Celsius (59 Fahrenheit) translates to a weight pressure equivalent to 0.002695 pounds per cubic centimetre. If that doesn’t sound like a lot of pressure, you are right. It’s pretty tame stuff and no atoms swirling around under those conditions would fuse together despite what cold fusion advocates espouse even if we were to apply an external heat source to raise the temperature by a factor of one thousand or more. The difference-maker is gravity and we cannot create that physically here on Earth without applying all manners of technology.

In the current race to build a commercial equivalent to the Sun, companies and universities on both coasts of the United States, and in Canada, China, France, Germany, Japan, and the United Kingdom are in a horse race using a variety of novel technological solutions including:

• Tokamaks, powerful magnetic fields to contain hot plasma under very high atmospheric pressures,
• Stellarators that feature complex coiled configurations of tubes that serve to confine hot plasmas,
• Lasers that use pulsed energy beams to initiate sustained fusion,
• Acoustically-driven magnetized fusion that uses hundreds of synchronized pneumatic pistons to create pressures within a confined sphere to superheat plasma.

In the Sun’s high-density core, temperatures reach 15 million Celsius (27 million Fahrenheit). Hydrogen and helium, the two lightest atoms, become a plasma with the end result, a chain reaction that sees hydrogen fuse into deuterium, and helium to beryllium with excess amounts of energy released at every stage. Fusion in the Sun continuously combines lighter atomic elements with each other until the star’s engine produces iron. To create elements heavier than iron, the Sun would need an additional energy source of input as would be generated if the star were to go supernova. The energy produced at every stage of the fusion chain reaction is measured in mega-electron volts or MeV. Each MeV equals 1,000,000 electron volts (eV).

The technology that CFS has developed is a high-temperature superconducting (HTS) magnet, seen in the image above. In the latest test, the HTS was able to create a sustained magnetic field of more than 20 Tesla (a measure equal to one volt per second per square metre), or enough force to confine and compress a plasma field within a tokamak to create a net energy yield from a controlled fusion chain reaction. The tokamak being used is the SPARC which was developed at MIT. Smaller than the CERN ITER, the experimental fusion reactor project that has involved a number of countries and has endured endless delays, SPARC with HTS magnets is on track to be completed by 2025.

Achieving net energy output greater than energy input is the goal of every organization playing in the fusion reactor game. In a September 2021 news release, Bob Mumgaard, CEO of CFS was quoted stating, “The world needs a fundamentally new technology that will support efforts to decarbonize on a timeline that can mitigate climate change. This test of our magnet proves we have that technology, and we’re on our way to producing clean, limitless energy for the entire world.”

If successful, CFS will be one of two front runners in creating the first viable commercial fusion reactors. The other in this horse race is General Fusion, the Canadian company that is currently building a demonstration project near Oxford, in the United Kingdom.

The SPARC will be housed in a commercial fusion power plant called ARC. Mumgaard claims that CFS has the lead now with “the fastest path to commercialization of affordable fusion energy” in the world.

Last year I read an article that forecasted 2025 as the year for the arrival of the first commercially viable fusion reactor. I thought, how could that be when every time fusion reactors come up in the news it seems that commercial versions still lie decades ahead.

Nuclear fusion as opposed to fission is very attractive if we can pull it off. Why? Because a mere 30 grams (one ounce) of the fuel used for fusion reactors produce the energy equivalent of 9,000 litres (304,000 ounces) of heating oil. That’s a 304,000:1 payback which makes the quest to harness this technology a worthwhile endeavour. Then add two other benefits that put fusion well ahead of fission: the former produces zero radioactive waste, and it will never in an accident lead to a meltdown such as occurred at Chernobyl and Fukushima. Instead, the fusion reaction will just die.

The technical and material problems, however, remain significant. These include:

• the need to create a stable magnetic field that can endure and be maintained for a sustained period that can contain a gas plasma heated to 150,000,000 degrees Celsius (270,000,000 degrees Fahrenheit).
• the need to produce more energy output than input. At best today, experimental fusion technology produces marginal positive output but nothing to write home about.
• the need to source supplies of tritium and other materials needed in fusion reactors. Some of these materials are not naturally occurring in the real world. For example, tritium is so rare that today most of what is in use is produced by existing fission reactors. In the future fusion reactors may be able to produce their own material requirements by the very nature of the chemistry and physics within them (the fusing of atoms to create new elements).

Fusion reactor design has been a challenge. The most common model has been the doughnut-shaped vessel called a tokamak. The European Union is the home of the ITER, a tokamak that when it finally gets working will produce between 2,000 to 4,000 megawatts of power.

The tokamak isn’t the only concept design on the market. For example:

• A Vancouver company backed by Jeff Bezos is developing magnetized target fusion.
• A California company is pursuing a design called Norman, combining particle accelerator technology with plasma physics.
• Another backed by Peter Thiel is developing something called the Fusion Engine, a thousand times smaller, and 500 times cheaper than the competition.
• Lockheed-Martin skunkworks is tinkering with a truck-sized fusion reactor for portability.
• And an Oxford, UK-based company, Tokamak Energy, is building a reactor called the ST40, a miniature version of the ITER.

Not to be outdone by commercial enterprises, universities and research institutes are also in the race to perfect fusion reactors. For example:

• The University of Illinois at Urbana-Champaign and University of Chile, are working together on a project they call the Quantum Controlled Fusion reactor using laser pulses.
• The Laser Inertial Fusion Energy (LIFE) reactor is being developed at the Lawrence Livermore National Laboratory.
• The University of Washington’s Spheromak is a plasma nuclear reactor that its developers say can produce a billion watts of surplus power output at a cost less than the building and operating of a single coal-fired power plant.
• Two competing designs are vying each other from the engineers at the Massachusetts Institute of Technology (MIT). The first is the Alcator C-Mod reactor that uses deuterium, hydrogen and a pinch of helium-3 as fuel, and the second is the SPARC (Smallest Private-Funded Affordable Robust Compact) reactor, designed to achieve sufficient heat to keep a fusion reaction going without requiring external energy input. The SPARC project team claims it will have a finished product by 2025.
• The Max Planck Institute in Germany has been building and provided proof-of-concept for a very different fusion reactor design called the Stellarator. The current version is called the Wendelstein 7-X.

So it would seem we have both a commercial and academic fusion reactor arms race on the go that could allow us to transition away from carbon-generated energy even faster than previously estimated. Where ITER had set a 2040 target date, these competing designs appear to be a decade ahead or better which is encouraging news. With nuclear fusion added to the mix, the intermittency issues of renewables like solar and wind no longer pose a problem for our clean energy future.