It's a nuclear race like no other, involving billions of dollars and hundreds of scientists from across the globe.

Their aim is as ambitious as it is monumental: to replicate the energy source that powers the solar system, effectively building a mini sun — a swirling mass of super-heated atomic plasma so hot that it can only be contained by a magnetic field.

The process is called nuclear fusion.

Scientists believe that if fusion technology can be successfully harnessed as a human energy source, it could help save the world from future environmental catastrophe.

From vision to construction

Just outside the port city of Marseille in the south of France work is underway on a giant nuclear fusion test facility known as ITER — Latin for "the way".

Its construction is being funded by an international collaboration between 35 nations, and it's expected to cost somewhere between $27 billion and $36 billion when completed.

Construction continues at the ITER site in France. ( Supplied: ITER )

Australia isn't a member of the consortium, but it does have a research relationship with the project involving both the ANU and the Australian Nuclear Science and Technology Organisation (ANSTO).

"It's called the largest scientific engineering project in the world," says ANSTO's Richard Garrett.

"The site is many hectares. The tokomak itself — the doughnut-shaped chamber the plasma will be confined in — is just enormous, 100,000 kilometres of superconducting cable, because it uses superconducting magnets to confine this plasma as tightly as possible.

"It's about three or four Eiffel Towers' worth of steel.

"In fact, I think the world's production of superconducting wire had to be increased about 10 times to supply ITER."

In Italy a D-shaped coil for ITER is inserted into a structural steel case manufactured in Japan. ( Supplied: Manuela Schiara and Fabrizio Giraldi/ITER )

Fusion versus fission

Conventional nuclear reactors harness energy from a process called fission, which involves splitting the nucleus of a large atom.

Nuclear fusion, on the other hand, works by forcing atoms together in order to release energy.

British physicist David Kingham says fusion technology has significant benefits over its established counterpart.

"The advantages of fusion are: no risk of meltdown — it's very easy to stop it safely — no production of radioactive waste, and a very high energy density of the fuel," he says.

"In some ways fusion has all the advantages of nuclear fission without any of the drawbacks like risk of meltdown or long-lived radioactive waste."

But generating energy from nuclear fusion has proved far more difficult than scientists initially thought back in the 1960s when it was first mooted as a serious future energy source.

Early test reactors managed to produce a fusion reaction, but not one that was sustainable or energy efficient. In other words, it took more energy to produce the reaction, than the reaction itself produced.

A model of ITER shown at an expo in China in 2011. ( Getty Images: VCG )

ITER was originally launched way back in 1985, amid great expectation. Its collaborative structure was designed to ensure the whole world would eventually benefit from the technology, not just one or two nations.

But the initial stages of the project were problematic. On-site construction didn't begin until 2010. And even then, it was slow to get going.

"I think fundamentally that tells us that these international collaborations are quite difficult to achieve," Professor Garrett says.

"Five or six years ago, ITER was not in a good shape. It was late, it was over-budget. But a new directorate was put in on the project and they have really got the thing moving in the right direction."

The first plasma experiments are now expected to begin in 2025.

For ITER to be considered a success, according to Professor Garrett, it must demonstrate that it can achieve an energy gain of a factor of 10.

"ITER consumes 50 megawatts of power to produce this plasma at 150 million degrees, and the goal is to produce 500 megawatts of power from that plasma," he says.

"The second goal is to be able to maintain that condition for many minutes at a time, so maybe 10 minutes, up to an hour, and that's what you would need for a steady-state power reactor."

Scale and manageability

ITER isn't the only nuclear fusion initiative underway.

In both North America and the United Kingdom there are numerous projects operating on a smaller scale.

One of them involves the company Tokamak Energy, whose executive vice chairman is Dr Kingham.

"I think private investors can see solid scientific foundations for the business," he says.

Tokamak Energy is yet to produce a fusion reaction at its test facility in Oxfordshire.

Tokamak Energy's spherical tokamak chamber ST40. ( Supplied: Tokamak Energy )

But that's not the immediate priority, Dr Kingham says.

The company's researchers are using a spherically shaped tokamak chamber that they hope will deliver greater efficiencies than the donut-shaped one designed for ITER.

The aim is to increase the plasma temperature during the fusion process.

Plasma inside Tokamak Energy's spherical ST40 tokamak. ( Supplied: Tokamak Energy )

"The next big milestone for us is to achieve a 100 million degree (Celsius) plasma temperature," Dr Kingham says.

After that, they'll then need to demonstrate that the enhanced superconducting magnets within the tokamak have the strength required to effectively contain the plasma.

Dr Kingham expects both of those milestones to be met by the end of next year.

He says the company will then need to raise the additional investment necessary to fast-track the development of a small fusion demonstrator device by 2025, the same year that ITER expects to begin its initial plasma testing.

The United Kingdom Atomic Energy Authority is also seeking to outrun ITER in designing its own fusion reactor.

Known as STEP, the UKAEA research collaboration has recently received a $430 million investment from the British Government.

Inside China's Experimental Advanced Superconducting Tokamak (EAST), dubbed the 'artificial sun'. ( Supplied: Institute of Plasma Physics Chinese Academy of Sciences )

Prime Minister Boris Johnson even made it part of his re-election pitch during December's election.

Like Dr Kingham, STEP's boss Howard Wilson is cautiously critical of the approach taken by ITER.

"It looks like if you go down that route alone you'll end up with a very expensive solution which won't be commercially deployable, and that's why we are keen on innovations which will reduce the cost," he says.

He also agrees with Dr Kingham that a focus on developing high-temperature superconducting magnets is a priority.

"If you can double the field strength of your device, reduce the size substantially, it becomes a lot cheaper but it can produce the same amount of power," he says.

"That really makes the difference to commercial deployability of the technology. We've got to be cost-competitive with oil, gas, coal and renewables."

Future focused or fantastic folly?

Proponents of nuclear fusion believe it will end the world's dependence on fossil fuels once and forever.

But the catch is that no-one involved in the research believes a fully operational, commercially viable nuclear fusion reactor will be operating before at least 2050.

That fact has seen some question the level of financial investment, including Sir Chris Llewellyn Smith, the director of Energy Research at Oxford University and a former director general of CERN.

He once managed the UK's fusion program, but two years ago, in an interview with the Simons Centre for Geometry and Physics, he expressed doubts about ITER and the viability of the industry in general.

"I used to think that there was a reasonably good chance that fusion could compete with other low carbon sources of power, but while I would not say that it's impossible, the situation has changed," he said.



"The cost of wind and solar power has decreased faster than anyone could have dreamed. Meanwhile ITER has gone way over budget. Fusion reactors will be intrinsically more expensive than we thought a decade ago."

Renewables like solar and wind power have become cheaper. ( Supplied: Lothar M Peter )

He argues that ITER needs to go ahead, but that a final cost comparison with renewables should be conducted before any construction on a full-scale reactor is begun.

Dr Kingham understands the argument, but he believes the long-term economics still make sense.

"The point with renewables is that large-scale transmission of power across the world is not necessarily going to be feasible, and extremely large-scale storage looks prohibitively expensive and perhaps even technically not feasible," he says.

"So, I think fusion in the long-term sits alongside renewables as part of the low carbon solution we need to be developing and deploying."

An aerial shot of construction on ITER in France. ( Supplied: ITER/EJF Riche )

Professor Wilson adds that all projections indicate global energy needs are likely to dramatically increase as more and more people are lifted out of poverty in the developing world.

"Even now, Delhi consumes something like seven gigawatts of power," he says.

"That is a very high power density. It's hard to imagine delivering that through wind and solar."

Planning now for the mass energy requirements of the future, he argues, makes for prudent policy.

"We need to develop technologies, otherwise all we're doing is delaying the problem… leaving a problem for the next generation to try and fix," he says.

"Fusion is really the only clean reliable way of doing that. That's the gap that fusion is aiming to fill."