nuclear fusion

The scientific community has long dreamt of bringing the sun to earth and thereby creating a nearly limitless source of clean, safe energy.

In 1920, British physicist Arthur Eddington hypothesised that our sun is powered by fusion: hydrogen nuclei combine in helium nuclei; the products have a lower mass than the reactants and that mass difference is found in the form of energy, including heat and sunlight.

This article was originally published as part of the PEI print edition in Smart Energy International Issue 3-2020. Read the full PEI section here, or subscribe to receive a print copy here.

Ever since then, nuclear fusion has captured the imagination of scientists, sciencefiction writers and the broader public.

Why? Because it combines the fascination of science (the energy of the stars!), the quintessential technological challenge and the promise of a nearly perfect energy source (see Box 1) for all mankind to benefit from. Fusion spinoffs made major contributions to other sectors as well, from medical imaging to robotics, new materials and aerospace, just to name a few. Fusion epitomises the word “moonshot” nearly as much as, if not more, than the space era.

Progress to make fusion a reality has been immense. The ‘triple product’ of density, temperature and confinement time grew exponentially between the 1950s and early 2000s, by a factor of 1,000,000 (one million). With yet another small increase in triple product, by a factor of 2 or higher, the reactor will produce net energy.

The large international ITER tokamak, under construction in France, is designed to start operations in 2025, and it will produce net power by 2035. Specifically, it will produce 500 MW of fusion power, amounting to 10x the power injected in the plasma to keep it hot.

Fusion is coming. Its scientific feasibility is finally in sight. The old joke that “fusion is 30 years away, and always will be” is about to be proven wrong: 2035 is not that far away.

The time is ripe to start tackling the next issues: economic attractiveness, industrialisation, commercialisation.

To be fair, none of these was a goal or constraint for ITER, hence its price-tag, and aside from obvious considerations on firsts-of-a-kind, they have no direct correlation with the projected cost of a fusion power-plant.

The excitement is palpable, as the baton is gradually passing to private companies: there are currently over 30 fusion start-ups worldwide. According to Fusion Energy Base, their number doubled in just four years, between 2016 and 2020.

Another indicator of excitement is the growing membership of the Fusion Industry Association, a nonprofit organisation advocating for “policies that would accelerate the race to fusion energy”.

The Association now counts 22 members and 13 affiliate members, including large non-fusion companies “working to support the fusion industry”.

Growing investments are a third sign of excitement: General Fusion, Commonwealth Fusion Systems and Tokamak Energy raised more than $100 million each.

TAE Technologies raised much more than that. Among the investors we find tech-enthusiast billionaires like Jeff Bezos (General Fusion), Bill Gates (Commonwealth Fusions System) and Peter Thiel (Helion Energy), but also energy giants like Eni and Equinor (Commonwealth Fusions System).

There are three main approaches to fusion. Within them, there are sub-categories. For example, within Magnetic Confinement Fusion (MCF), two companies are betting on the tokamak and two on the stellarator.

The authors of this article founded Renaissance Fusion, a stellarator start-up based in France and in the US. Each approach has pros and cons, and while everybody in the industry agrees on the feasibility of commercial fusion, nobody knows which technology will win the race, and which one will maintain a sustainable competitive advantage.

Therefore, everybody agrees that we still need a relatively broad portfolio of technologies – fusion is too important to bet on only one concept.

Despite the technical differences, fusion start-ups share similar traits: they are agile, open to technologies invented elsewhere, fast in identifying opportunities and inherently interested in collaborations and co-development.

Partly due to budget constraints, partly due to a sense of urgency, fusion start-ups are immune to the “not invented here” syndrome. Thus, High Temperature Superconductors are finding their way into MCF, and Chirped Pulse Amplification into ICF, just to give two examples.

There are certainly still a lot of challenges ahead. From a technical standpoint, tokamaks will have to avoid or mitigate an instability called disruption; stellarator coils will need to be simpler; pulsed ICF and MTF concepts will need high enough repetition rates, and the power injected in the device, e.g. by lasers, will need to be delivered to the plasma, instead of being otherwise lost. All fusion concepts will need special plasma-facing materials.

Financing will also be difficult. Start-ups will need between $600 million and $1 billion each, and none are sufficiently funded, as of now, to bring fusion electricity to the grid.

However, research intense start-ups are participating in grant proposals and in novel public-private partnerships with universities and public laboratories. In addition, financial research started agglomerating data and creating models for specialised fusion funds. The interest is building up.

Major competition will come from renewables, which are rapidly scaling up worldwide. However, renewables have their own weaknesses in areas (intermittency, land-use) where fusion is strong. Hence, fusion could very well complement renewables in a sustainable, dispatchable energy-mix.

Public acceptance might pose another challenge: fusion typically produces neutrons, which induce radioactivity in the solid parts of the plant. Public outreach will be key in differentiating fusion from fission.

Additionally, the low radioactivity of fusion could be further reduced to the level of a coal-plant or of natural radioactivity, by at least two techniques under study. In one technique, special liquid materials do not become radioactive. In the longer term, different fuels might be fused, not producing neutrons.

As mentioned, there are definitely challenges ahead, but the publicly funded ITER experiment is well on its way to prove the scientific feasibility of fusion by 2035.

Now is the time to gather private investments, talents, innovative ideas and business partnerships to prove the economic feasibility and make fusion smaller, cheaper and possibly faster, and to put its electricity on the grid.

It has been a long journey, a marathon involving three generations of scientists, but progress has been huge – by a factor of 1,000,000 in triple product – and huge will be the reward if we cost-effectively realise one final improvement, by a factor of 2 or higher. The final sprint is on.

About the authors

Martin Kupp is professor of entrepreneurship and strategy at ESCP Business School and advisor at Renaissance Fusion.
Francesco Volpe is the founder of Renaissance Fusion. He received his PhD in experimental physics in 2003 from the University of Greifswald, Germany.