Fusion power will be well worth the wait

Since the dawn of the nuclear age, scientists have been working to tame the fusion reaction that powers the sun and give us a concentrated energy source here on Earth. Fusion has been around since 1952 in the explosive form of the H-bomb. But a controlled reaction capable of generating electric power has remained tantalisingly out of reach — despite expenditure of billions of dollars on research and development by governments around the world.

After years of frustration and disappointment, the field is now experiencing a justified return to optimism, driven by improvements in fusion technology accompanied by an influx of funding from public and private sectors. The latest £220m investment, announced this week by the British government, will enable the UK Atomic Energy Authority (UKAEA) to design a fusion power station called the Spherical Tokamak for Energy Production — a “Step” towards the anticipated completion of a commercial-scale plant by 2040.

A tokamak is a round vessel originally conceived in 1950s Russia and still the most popular type of fusion reactor. It holds a plasma of deuterium and tritium in place with powerful magnetic fields, while the gases are heated electrically above 100m Celsius. Then the atomic nuclei begin to fuse together, releasing far more energy than the fission reaction that powers existing nuclear plants.

The mother of all tokamaks will be the gigantic Iter machine, under construction in southern France by a global government consortium. Budget overruns and delays — the current cost estimate is $22bn with first experiments in 2025 — had threatened its very existence but fortunately Iter’s management seems to have brought the project back under control.

Nuclear scientists see fusion as a goal worth pursuing because it offers carbon-free energy from plentiful materials — more safely and with less radioactive waste than today’s atom-splitting fission reactors. Fusion power may turn out to be unattainable at reasonable cost, for technical reasons that have yet to emerge. Yet the chances of success are high enough to justify significant spending on the development of an energy source that might make a huge contribution to the battle against climate change later this century.

Although Iter will be the main test bed for new technologies needed for fusion power, such as magnets and reactor materials, the world will benefit from a diversity of approaches to see what works best. Tokamaks come in different shapes. While Iter looks like a huge doughnut, the planned UK spherical reactor is more like an apple with its core removed.

Other varieties of reactor are being developed by a welcome influx of companies into nuclear fusion, particularly in the US and UK. They are backed by investors who believe that the private sector can develop commercial fusion plants more quickly and cheaply than the large public projects.

Two companies are based close to the UKAEA in the Oxford area. One, called Tokamak Energy, aims to have a power plant connected to the grid by 2030. The other, First Light Fusion, uses a quite different technique to achieve the extreme conditions required to initiate fusion, by firing a large number of projectiles simultaneously at tiny pellets of reactor fuel.

We should wish the fusion contenders, public and private, success in eventually overcoming the charge that fusion is a technology that always seems to be 30 years away. Whenever it opens, the first commercial fusion plant will represent a huge advance in energy generation.

Letter in response to this editorial comment:

Dutch have the answer to clean power generation / From Saul Levickas, St Maarten, Dutch West Indies