What is fusion?

Fusion is the reaction
that powers the sun
and all other stars

And now we’re working to harness it on Earth, to create a world powered by clean, limitless energy for all.

How does it work?

Power is generated from the energy released when two lightweight atoms are fused together into heavier atoms. It’s the same reaction that powers stars – including our sun.

Fusion requires extreme temperatures and pressure to occur but it produces more energy per gram of fuel than any other fuel source on the planet.

Engineer operating remote handling equipment watches screens

How do we achieve it?

There are several ways to achieve fusion on Earth. The most common approaches use the heavier forms of hydrogen deuterium and tritium. They fuse to produce helium and neutrons.

Record-breaking amounts of fusion energy have been created by heating deuterium and tritium gases to temperatures 10 times hotter than the sun inside a vessel called a tokamak.

Once the science and engineering is proven, a large commercial fusion powerplant will need just 400 kilograms per year of deuterium and tritium fuels – 10 million times less than the amount of fossil fuels used to generate the same amount of electricity.

The interior of JET, with plasma present in the tokamak during experiments

When will it be possible?

As soon as we can make it happen

Fusion won’t be immediate. There are still challenges to overcome. But for the first time practial fusion is within our reach. Addressing these challenges has led to innovations and breakthroughs (in fusion and beyond). That’s why this cluster exists – more innovation, more breakthroughs, fusion faster.

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The history

Fusion has a long history built on pioneering work in atomic and nuclear physics. It's now moving from the era of research to the era of commercialisation.

1920 — 1930

Understanding the stars and the atom

How stars shine was a complete mystery until the 1920s. British astronomer Arthur Eddington proposed that a star's enormous energy mostly comes from hydrogen fusing into helium.

The idea was boosted in 1932 when Australian physicist Mark Oliphant fused hydrogen in the lab at Cambridge for the first time.

German physicist Hans Bethe later won the Nobel prize for physics for his detailed work on energy production in stars in the 1930s.


Enter the fusion machines

Fusion research in the UK began in earnest in the 1940s and 1950s. Around the world, various designs for fusion machines emerged. While many research programmes had military applications, others recognised the potential for fusion to generate electricity.

1970 — 1980

Designs on JET and beginnings for ITER

The worldwide oil crisis of 1973 prompted governments to step up research into alternative forms of energy, including fusion. Europe began an ambitious project to design a large, multinational tokamak. The machine came to be known as JET - the Joint European Torus. Culham was chosen to host JET in 1977 and the first plasma was produced on 25 June 1983.

Two years later in 1985, a collaborative international project to develop fusion energy for peaceful purposes was proposed. Conceptual work on ITER began in 1988.

1990 — 2000

JET record and a home for ITER

JET made headlines around the globe in 1991 when it became the first machine to achieve controlled fusion. It went on to set a world record for power produced from a fusion plasma in 1997. Since then it has continued to refine the tokamak concept, preparing the way for its larger international successor, ITER.

In 2005 an international consortium agree on a home for ITER. Building work began in Cadarache in the south of France in 2010.

JUN 2021

General Fusion to build its fusion demonstration plant in the UK

Private fusion companies started to spin out of national programmes. General Fusion is a Canadian company founded in 2002. Their approach is called magnetised target fusion. In June 2021, General Fusion announced that the company will build its fusion demonstration plant at Culham in the UK.

FEB 2022

JET breaks fusion energy record

The JET experiment set a new record for fusion energy, producing 59 megajoules from fusion for over five seconds. The previous record was 22 megajoules, also set by JET in 1997.

MAR 2022

Tokamak Energy achieves plasma temperatures of 100 million degrees

UK fusion company Tokamak Energy announces that plasmas inside its spherical tokamak have reached 100 million degrees, a new record for a spherical tokamak.

APRIL 2022

First Light Fusion proves their projectile approach to fusion

First Light Fusion near Oxford succeeds in fusing fuel using its innovative projectile approach