Fusion, what is it good for?

Nuclear fusion has been described by the World Economic Forum as being the Holy Grail of energy, a technology that will provide unlimited, cheap, clean power.

Fusion is the process that powers the Sun and the stars. The often-quoted vision for fusion is that it will provide clean energy in perpetuity, like our sun does. This vision has inspired fusion research since the 1940s. There was a joke in scientific circles, about when fusion energy would become applicable. The answer was always 30 years in the future, regardless of when you asked the question.

Nuclear fusion is a process where hydrogen isotope nuclei combine to form a heavier nucleus – helium – while releasing immense energy in the process.

Globally, many public and private sector research organisations are making this fusion technology vision a reality. China, for example, has joined the fusion race with an estimated $1.5 billion budget.

And in a recent BBC interview, Chris Wright, the US secretary of energy (and former fracking business executive), said that nuclear fusion may provide carbon-free energy within eight-15 years, that is, between 2033 and 2040. His timeline is viewed in the field of fusion development as being overly optimistic.

Given the recent rapid uptake of cheap clean solar, wind and hydro energy, it is uncertain to what extent we will need fusion technologies to solve the problem of global warming emissions. These already-established and cheaper technologies are likely to play a central decarbonisation role in the critical decade between 2030 and 2040.

The use of these well-established sources of renewable energy technologies has already resulted in the plateauing of global emissions in 2025 according to the International Energy Agency. This plateau in emissions flow is significant as the first step in restoring the global climate.

However, the second and final step of reducing the concentration of historical carbon dioxide in the atmosphere, by companies such as ClimeWorks and 1Point Five, is in its early stages and will eventually require massive amounts of power during the next few decades. Full-scale fusion in the long term (beyond 2040) may hopefully play a critical role in achieving that long-term critical objective of remediating the planetary climate for humanity.

The fact that many big technology companies (Google, Microsoft, etc) and prominent figures (Gates, Bezos etc) are the major investors in fusion facilities indicates that the fast-rising demand for future AI data centres will be a key driver for future fusion growth.

The complex processes involved in fusion reactors can be understood in stages that have been summarised clearly in a schematic reported in Time magazine in July 17: “A doughnut-shaped vacuum chamber contains hot tritium and deuterium atoms; high temperature superconducting magnets confine and control the plasma within the chamber; particle beams heat the plasma to more than 100 million degrees centigrade which allow the atoms to colloid and fuse; the energy can then be converted into heat that produces steam to drive turbines and so generate electricity.”

A spinout company of Massachusetts Institute of Technology, Commonwealth Fusion Systems announced last year that it plans to build the world’s first grid-scale fusion power plant in Chesterfield County, Virginia, which will generate 400MW output, enough to supply power to 150,000 homes in the early 2030s. This output is comparable to that of a typical medium-sized solar farm such as the one being constructed at present in Waikato by Genesis.

We can expect such small-scale fusion reactors to appear in international laboratories from 2030 to 2040. These small reactors are important stages in the development of large practical reactors for various applications. Therefore, a great deal of development will be required before large-scale fusion reactors appear.

The leading fusion development projects in 2025 involve several international government agencies and a range of private sector innovators. The leading fusion development laboratories are in Europe (ITER), Japan, China and Korea (Tokomak), France (the largest fusion consortium), USA (Inertial confinement and Tokamak), and Germany/Japan (Stellarator). China appears to have drawn ahead and may have grid-connected fusion years ahead of the other countries involved, including the USA.

There are also about 50 private companies of many sizes involved in fusion development and investment with funding up to US$1 billion. This level of investment has encouraged a diversity of approaches thus increasing the prospects of breakthroughs and efficiencies.

But there are serious challenges remaining. An extensive review of the technical disadvantages and issues relating to fusion technology was reported in Bulletin of Atomic Scientists in 2017 by scientist Daniel Jassby who worked on nuclear fusion experiments for the Princeton Plasma Physics Lab for 25 years.

It is a long and very technical report. A more accessible summary is available using ChatGPT on ‘nuclear fusion primary disadvantages’ including the following bottom line text, “Fusion has huge promise (virtually unlimited, low-carbon energy with no meltdown risk), but cost, complexity, materials, and timing are the biggest disadvantages.”

In conclusion, it is feasible that small-scale fusion reactors such as the prototype small fusion power plant being built in Virginia could start to play a minor role in decarbonisation alongside dominant renewables around about 2040. These early prototypes might find applications that are more local and regional in nature. Could this include New Zealand?

But for fusion to play a major future role in global decarbonisation, it would need to compete in terms of cost, simplicity, and waste with ascendent cheap, clean renewables such as solar, wind and hydro.

On the other hand, by 2050, large fusion reactors may well play a key role in our power-hungry AI future, and hopefully to even play a key role in the processes of Climeworks and 1PointFive, which seek to reduce the concentration of historical carbon dioxide in the atmosphere to restore the planet’s climate.