Fusion is what powers the sun and the stars. Scientists have been trying to replicate the same on the Earth for nearly a century now, but with little success. It is a running joke that fusion is always some 30 years away. Still, the idea of virtually limitless clean energy, which is several million times more efficient than coal, is something hard to overlook. 

Last year was an exciting one for fusion. Fusion startups collectively raised more than USD 2.6 billion in venture funding in 2021, including Commonwealth Fusion Systems’ massive USD 1.8 billion raise. Commonwealth Fusion Systems and TAE Technologies also announced breakthroughs during the year, while General Fusion announced plans to develop a fusion demonstration plant in the UK. 

How would these developments shape the fusion landscape for the next decade? Can fusion energy materialize by the 2030s as promised? Let’s discuss.  

“Fusion” is a new form of nuclear power.

The traditional approach to nuclear power is known as “fission”. This already accounts for around 20% of the US' electricity-mix. Fission generates energy by splitting radioactive atoms (like Uranium) into two. More specifically, when an (external) neutron is made to collide with a Uranium atom, it splits the atom into two, releasing a massive amount of energy in the form of heat. This heat is utilized to convert water into steam, which is then used to generate electricity by turning a turbine.

Fusion is literally the opposite of fission. It is when two atoms collide to form a heavier atom while releasing energy in the process. Typically, two hydrogen atoms (more specifically, isotopes of hydrogen such as deuterium or tritium) fuse together to form a helium atom. Fusion is what powers the sun and all other stars in the universe. At every second, the sun transforms around 600 million tons of hydrogen into helium, generating virtually limitless light and heat.

For a start, the amount of energy released from fusion is around four times higher than from fission. To put things into perspective, fission itself can generate around a million times more energy than coal.

But better energy efficiency isn’t the only reason why the world is pursuing fusion. It is also 100% renewable and clean. The problem with fission is that it requires uranium as fuel, which is limited in supply (so, not exactly renewable). Fission doesn’t emit any greenhouse gases, but it leaves behind nuclear waste (so, not exactly clean either). In contrast, deuterium and tritium (extracted from lithium) used in fusion can be readily extracted from seawater. Meaning, there is enough fusion-fuel to power the earth for millions of years. And of course, no radioactive waste.  

Simply put, we are yet to produce a fusion reaction in an energy efficient way. The heat and the pressure required to create the fusion reaction consumes more energy than what it produces. This ratio of energy to form the reaction versus what it produces is referred to as the “gain factor”, and is expressed by the symbol “Q” (Q=1 means breakeven; Q>1 means energy creation; and Q<1 means loss of energy). The current record for Q is 0.7, and was set by the National Ignition Facility (NIF) in August 2021, only marginally bettering the long standing record of 0.67 set by the JET tokamak reactor (UK) in 1997.

In fusion, the idea is to fuse two atoms together. There is one big problem with this. Atoms usually repel each other. So, in order to fuse them, the two atoms need to collide at a speed that can overcome the natural force of repulsion. This speed is generated by heating atoms to an extreme temperature. On Earth, this temperature is estimated to be around 150 million degrees Celsius or around 300 million degrees Fahrenheit (putting things into context, this is around 10 times higher than the temperature at the center of the sun; the higher surface pressure in the sun, compared to the earth, allows it to create fusion at comparatively lower temperatures). Reaching temperatures of such scale requires A LOT OF ENERGY! 

Other challenges include the need for significant design and engineering innovation and the high cost of development. 

There are currently three approaches under consideration: magnetic confinement, inertial confinement, and Z-pinch.

The magnetic confinement approach uses large donut-shaped reactors called “tokamaks” to facilitate fusion. These devices, as the name suggests, are equipped with large electromagnets. Why magnets? Well, when the atoms are heated to extreme temperatures, they reach a super hot plasmic state. There is no known material in the universe that can hold this super-hot plasma. Hence, electromagnets are used to confine it inside a magnetic field. The donut shape of the tokamak is also critical to maintain the magnetic field, although some variations of the design are also being explored. Magnetic confinement fusion (MCF) is the most sought-after of the three approaches and is the underlying technology of almost all major fusion projects at present.

The inertial confinement approach uses pulses from super-powered lasers to heat the fusion-fuel. The fuel is heated instantly to facilitate the reaction, hence, unlike in magnetic confinement, there is no need to hold plasma for longer periods. The approach is somewhat less popular because super-power lasers are not easy to build. The US Department of Energy (DOE) funded NIF is one such large inertial confinement fusion device, located at the Lawrence Livermore National Laboratory in California. NIF reported a Q of 0.7 in August 2021 and is considered the highest ever achieved by a fusion experiment. However, in the three experiments carried out since, NIF has reportedly fallen short of the level achieved in August. British company First Light Fusion is a leader in inertial confinement fusion (ICF). 

Z-pinch is a variation of magnetic confinement. However, instead of relying on an external electro magnet, the machine sends pulses of electric current along a column of highly conductive plasma, creating a magnetic field that simultaneously confines, compresses, and heats the ionized gas. The process is still mostly experimental and has been the focus of fusion startups like Zap Energy. 

The recent USD 1.8 billion funding round has made Commonwealth Fusion Systems (CFS) the highest funded fusion startup. This, coupled with the recent breakthrough in technology, puts CFS at the front of the fusion race, at least in these very early stages. General Fusion’s affiliation with the UK Atomic Energy Authority (UKAEA), the former record holder for the Q, puts the company in a strong position too. The international megaproject ITER leads in terms of the proposed scale and the budget. Some of the other notable fusion startups are TAE Technologies, Helion Energy, and Tokamak Energy, each having raised more than USD 100 million in funding.   

ITER is an international megaproject to test MCF at a massive scale. The project aims to build a test facility in southern France that is capable of achieving a Q of greater than 10. The project is a collaboration between China, the EU, India, Japan, Russia, and the US. The construction is currently underway, with the expectation to produce first plasma in December 2025, and then ramp-up to full operation by 2035. 

The total cost at completion is projected to be around USD 22 billion. The US DOE estimates the cost to be around USD 65 billion (which ITER has disputed). Either way, ITER will be one of the most expensive science projects to have been ever carried out, placing it somewhere in the middle between the International Space Station (USD 150 billion) and the Large Hadron Collider (USD 5 billion) in terms of the budget. 

The flip side of the above is to go smaller. MIT has proposed a design for a compact tokamak fusion reactor that is 2% the size of ITER. The design attempts to create a stronger magnetic field using high-temperature superconducting tapes. This stronger magnetic field allows plasma to be confined in a smaller unit. The smaller size also means that the system is less expensive and faster to build. MIT has spun off Commonwealth Fusion Systems (CFS) to develop its technology. The company’s SPARC reactor is expected to be built by 2025 and produce commercial fusion energy by 2030. Despite its smaller size, the SPARC reactor also attempts to reach a Q of more than 10. 

The project recently had a breakthrough with MIT+CFS reaching and maintaining a magnetic field of more than 20 teslas in steady-state for about five hours in September. This is considered to be the strongest high-temperature superconducting (HTS) magnet in the world and is also large enough (when assembled in a ring of 17 identical magnets and surrounding structures) to be fitted onto the SPARC reactor. 

Following this breakthrough, CFS raised USD 1.8 billion in Series B funding to build its reactor. This was the highest amount raised by a fusion energy startup in a single round. With this raise, CFS also topped TAE Technologies as the highest-funded fusion energy company. 

UKAEA is the UK's national research organization responsible for the development of fusion power. It operates the Culham Center for Fusion Energy (CCFE), a fusion research laboratory, located in Culham, Oxfordshire. It is the site for the infamous Joint European Torus (JET) experiment, which, until recently, held the record for the highest Q.

Since June 2021, General Fusion has been in partnership with UKAEA to build and operate a fusion demonstration plant (FDP). General Fusion is expected to enter into a long-term lease with UKAEA to host the FDP at Culham. The construction of the FDP is expected to begin in 2022 and operations three years later. In November 2021, General Fusion raised USD 130 million to build the facility. The company expects to commercialize the technology by the 2030s.

TAE Technologies takes a somewhat different approach to fusion compared to most others. It focuses on a linear reactor compared to a donut-shaped tokamak. In April 2021, the company announced that it has hit a milestone by achieving the necessary temperatures to make its reactors commercially viable. The announcement followed a USD 280 million funding round. The company has raised USD 917 million in total funding to date and expects to be operating at a commercial scale by the end of this decade. 

Helion Energy is another fusion startup focusing on a linear design. The company focuses on using deuterium and helium-3 as its fusion fuel (in contrast to deuterium and tritium). Helion’s latest prototype has reached temperatures of over 100 million degrees Celsius and expects to demonstrate net electricity by 2024. However, it has not disclosed a timeline for commercial scaleup. One of the other major differences between Helion’s and other approaches to fusion is that its design is able to directly generate electricity from fusion (as opposed to the heat-to-steam-to-electricity approach followed by the others).

Almost all leading fusion companies are now considering the early 2030s for commercialization. This is quite encouraging, given that, up to now, the fusion timelines had been at least a few decades into the future. But how realistic is commercialization by 2030?

For a start, none of the fusion experiments have been able to break even yet. In fact, despite the recent advancements in technology, fusion experiments have only bettered the record for the Q only once in the past 25 years. Climate technologies are known for some pretty steep learning curves, but an improvement of such an enormous scale looks somewhat of a stretch. 

That being said, there are a few key milestones in the fusion space to watch out for over the next few years. Most of these are related to developing demonstration facilities as proof of technology. Having developed the magnetic field required for its SPARC reactor, CFS will now look to complete its development by 2025. General Fusion has also raised the preliminary funds to kick start the construction of its demonstration plant. Two of the other well-funded fusion startups, TAE Technologies and Helion, have also reached the necessary temperatures for fusion and will now look to test out the technology. ITER’s construction is also underway, with expectations to complete in 2025.

Fusion’s progress, like any futuristic technology, needs to be looked at gradually—one small step at a time. The next big challenge for the fusion projects would be to complete developing the demonstration plants as planned by the mid-2020s. If this is achieved, we have the slightest hope of at least breaking even by the early 2030s.