Since the 1930s, nuclear fusion has been seen as the holy grail of renewable energy sources. Hans Bethe’s Nobel-winning research into the fusion reactions that power the hearts of stars (including our sun) started a race to provide viable energy production making use of those reactions – one that continues to this day. Now, with an increasing number of private firms entering a previously institution-dominated space, the competition is starting to heat up. James Midgley reports.

 

Just months ago, Google published results from its first contribution to the effort to achieve viable energy production through nuclear fusion.  Partnering with California-based Tri Alpha Energy (TAE), the tech giant has developed an innovative machine learning algorithm designed to speed the processing of enormous amounts of data concerning the behaviour of plasma (the superheated fuel) in fusion reactors.  The ‘Optometrist Algorithm’ takes preferences from human operators and transforms those broader brushstrokes into iterative solutions.  So far, the system has achieved an astonishing 50-per-cent reduction in energy loss. 

 

Google and TAE’s partnership points towards a new era of fusion research which is only just beginning.  This era sees private firms – of all sizes – taking the reins from institutional titans.  The competition brings surprising innovations, as well as claims of scale-reduction previously thought impossible.  

 

An alternative nuclear history

 

The history of nuclear fusion runs more or less in parallel with that of its more widely known counterpart, fission.  The first major scientific steps in both fields were made in the 1930s, and while the astonishing and controversial power produced by splitting the atom would be made quickly apparent thanks to the Manhattan Project, fusion has been a much slower burner. 

 

Initial clues as to the power of nuclear fusion arrived from observations of our most important energy source – the sun.  Positively charged hydrogen nuclei which would otherwise repel each other are squeezed together by the immense pressures at a star’s core, releasing large amounts of energy as a by-product.

 

After first demonstrating fusion in the laboratory in 1932, to this day scientists continue to try to bring it to practical applications.  Fusion reactions in our sun take place in a superheated plasma of deuterium and tritium (hydrogen isotopes) under conditions of almost unimaginable pressure and heat.  The challenge is no less than to replicate the conditions found in the centre of a star.

  

Until now, all efforts have been met with limits in plasma temperature, density and length of stability.  Most importantly, no one has yet reached the sought-after ‘break-even’ point at which a reactor produces as much energy as it consumes.  But there is hope on the horizon, with projects underway that look not only to meet that requirement, but to push well beyond it.

 

The ‘holy grail’ of clean energy

 

Why pursue fusion at all? The answer is several-fold – compared with its distant fossil fuel relatives and closer cousin fission, fusion is far safer, potentially much more efficient and may eventually (a long time down the line) become more commercially viable.

 

“Fusion has intrinsic safety,” emphasised Prof.  Steve Cowley, CEO of the UK Atomic Energy Authority, speaking to the Guardian.  “[It] produces energy without making long-lived radioactive waste, without making CO2.”  While tritium – one of the fuels used in many fusion reactors – is indeed radioactive, the amount used is tiny.  Any leakage into the environment would be rapidly diluted.

  

The other fuel with which tritium is reacted, deuterium, is readily available in seawater.  Using nuclear fusion, a single glass of seawater could produce as much energy as a barrel of oil, with minimal waste.   As Prof.  Cowley pointed out, “There is 30 million years’ worth of fuel in seawater.”  Tritium, on the other hand, is exceedingly rare and expensive, with maybe as little as 20kg on the planet – and most of that is already inside nuclear warheads.  Usually, tritium must be created through nuclear reactions – in itself a potentially waste-producing and expensive method.  Thanks to this, the hunt for alternative fuels and alternative fuel-acquisition methods continues. 

 

Some companies, such as New Jersey-based LPP Fusion, have looked to hydrogen-boron fuels to power their reactions.  Helium-3 – a helium isotope which tritium itself decays into – may be another option.  The catch? It too is exceedingly rare on Earth.

 

Nuclear fusion promises the possibility of considerably greater energy production than fission since it fuses lighter materials, while fission splits much heavier elements.  There is also no chance of catastrophic nuclear meltdown.  With the Fukushima Daichi power plant disaster of 2011 still fresh in the minds of many, and the Chernobyl nuclear accident more than three decades ago now approaching a kind of mythologised status, fusion’s infinitely safer credentials make it a very attractive goal.

 

The ‘pinch’ method and other solutions

 

Institutional efforts towards fusion have mostly progressed at a slow pace over the last half-century, although things now appear to be speeding up.  Tokamak reactors evolved from early ‘pinch’ methods, using magnetic fields to compress and contain the plasma at their hearts.  Perhaps the most prominent tokamak project is ITER (International Thermonuclear Experimental Reactor; the acronym is also Latin for ‘the way’), dubbed ‘the world’s largest fusion experiment’.

 

An international scientific and engineering megaproject, ITER is currently under construction in southern France.  Completion is slated for 2021, with costs already sitting at over US$14 billion.  The internationally-funded experiment hopes for the first time to produce more energy from fusion reactions than it puts in – 500MW output from 50MW input to be exact, over an operation time of around 20 minutes.

   

Other kinds of magnetic confinement reactors exist, such as the Stellarator.  The design is a US proposition from 1951, facing off against the Russian-designed tokamak at the beginning of US-Soviet tensions (although at the time unbeknown to either party).  The German Wendelstein 7-X and the Large Helical Device (LHD) in Japan are both Stellarators.  The e1.06 billion (US$1.25bn) W7-X is hoping to show the viability of continuous operation, while the JPY 50 billion (US$440m) LHD is exploring confinement solutions. 

  

In Livermore, California, the largest laser in the world is put to the task of a quite different method of fusion exploration.  The National Ignition Facility (NIF) is the largest inertial confinement fusion device in the world.  Energy from its laser rapidly heats the surface of a small spherical pellet of fusion fuel, turning its surface into plasma and driving the remains inward to a point of extreme density.  The immense scale of the NIF is mind-boggling – more than 73,000 cubic yards of concrete, 7,600 tons of steel rebar and over 5,000 tons of steel had gone into its construction by 2001.  The scale, cost and sheer energy usage required by the lasers make it a less than ideal proposition outside of experimental conditions.

  

Though differing in their goals and technologies, all these projects are alike in their enormous costs and their gargantuan physical proportions, factors long associated with nuclear fusion that have meant only governments and institutions have been able to make much headway – that is, until recently.

 

The rise of private fusion firms

 

Alongside enormous institution-led projects comes the bureaucratic encumbrance of red tape – a fact which, combined with the notion that there might be better prospective technologies out there, has encouraged an increasing number of private ventures to take on the challenge of nuclear fusion.

  

Companies have also sought miniaturisation of the technology – borne both out of funding limitations and simply out of a desire to show that it can be done.  Back in 2014, Lockheed Martin’s Skunk Works team kicked up a stink by claiming they would have a truck-sized fusion plant functional within a decade.  

 

Other private firms have followed suit, including some seemingly unlikely propositions.  At the end of 2014, reality TV star Richard Dinan of Made in Chelsea fame founded Applied Fusion Systems.  This year he announced that he was seeking £200 million (US$264m) in investments to construct two reactors based on the Tokamak model.  “Technology has moved on considerably since ITER was designed,” said Mr Dinan to the BBC.  “I have no new physics for the world.  My trick is that I can build technology quickly and cheaply.”

 

That sentiment is shared by many in the new wave of fusion ventures.  “If you do the same as the other guy, and he’s [spending] billions of dollars on it, you’re not going to beat them – but if you do something slightly different, it has a chance of working,” explained Dr Michael Laberge, founder of General Fusion, to the BBC.  General Fusion has already attracted over US$100 million of funding – including backing from Amazon CEO Jeff Bezos.  The firm is experimenting with a fusion concept first explored in the 1970s by US Naval Research Laboratory, a somewhat self-sustaining model using a liquid lithium liner and high-pressure helium. 

 

“How can we succeed if the government has spent billions on fusion and worked on it for decades?” asks Ms Lili Gomez of the Focus Fusion Society.  “We’re using the natural instabilities of plasmas to concentrate the energy – the government-sponsored programmes have been fighting these instabilities.”  The project’s President and Chief Scientist, Dr Eric Lerner, agrees:  “Guide the plasma’s instability; don’t fight it,” he recommends.  New Jersey based LPP Fusion, the company behind the project, is exploring a small-scale Dense Plasma Focus (DPF) device.  Notably, this open-handed approach to the superheated plasma is the same philosophy as that supported by Google’s ‘Optometrist Algorithm’.

 

A competitive landscape

 

Until a few years ago, TAE – backed by Google and PayPal cofounder Peter Thiel – worked more or less under the radar, with not even a website to its name.  Yet more competitors seem to join the race to fusion every day, with announcements from an increasing number of firms coming thick and fast.

 

“While publicly-funded laboratories excel at fundamental research, the private sector can innovate and adopt new technologies much more rapidly,” commented Dr David Kingham, speaking to the Guardian.  Dr Kingham is CEO of Tokamak Energy, a UK firm which has just recently achieved ‘first plasma’ in its ST40 reactor – with the intention of reaching 100 million degrees Celsius by 2018. 

 

Last year, on its final day of operation, MIT’s Alcator C-mod tokamak reactor set the world record for plasma density, achieving over two atmospheres of pressure for the first time.  In December, researchers at the KSTAR reactor (Korean Superconducting Tokamak Advanced Research) broke another fusion record, maintaining ‘high performance’ plasma in a stable state for over a minute – the longest time yet for maintaining such a reaction.

   

Smaller projects have recorded groundbreaking results as well.  The aforementioned LPP Fusion, which has received only around US$5 million in funding, published results in 2012 in the scientific journal Physics of Plasmas showing that its DPF device had achieved ion energies of over 260keV (equivalent to 2.8 billion degrees kelvin) – yet associated claims of the firm’s proximity to viable fusion have been met in some quarters with considerable scepticism. 

 

It is not only the lure of clean, efficient and cheap energy that drives fusion research.  The technology has immense application for related fields of science, too – not least for space exploration.  NASA’s Direct Fusion Drive concept is one example.  Such a device could enable a spacecraft and lander to reach Pluto in as little as four to six years.  Further-more, establishing a base on the Moon would permit access to invaluable quantities of helium-3 deposited in the lunar dust by solar winds.  Such mining operations could provide fusion projects with an abundant alternative to radioactive tritium.

 

What is certain is that nuclear fusion – long seen as commercially prohibitive – is finally starting to get some market forces working on its side.  The differences between the diverse players now making headway in fusion energy experimentation, alongside the growing potential for convergence, are sure to speed development in this field to the finishing line.