Laser quest: The scientist with a planet-saving plan straight out of Spider-Man

Clean energy forever. That, in a glorious theoretical nutshell, is what nuclear fusion – the reaction that gives stars and hydrogen bombs their immense power – could deliver. The urgency of the climate-change debate and the renewed impetus to tackle the 21st century's glaring energy problems have put fusion back on the agenda... and, thanks to key contributions from the British-trained scientist Dr Brian MacGowan, the highly volatile process may be harnessed to provide us with a viable source of green electricity sooner than previously expected.

Staff at the National Ignition Facility (NIF) in central California are confident that some time in 2010, they will create a fusion reaction by focusing 192 intense ultra-violet lasers on to a tiny golden pellet, recreating the energy of the sun for a fraction of a second, thereby paving the way to a carbon-neutral future without global warming or nuclear waste. If all goes to plan, the implications would fairly reflect California Governor Arnold Schwarzenegger's recent description of the project as "monumental". Fusion, we're told, could be mankind's salvation – but what are the chances of translating theory into practice?

From the outside, NIF – based within the grounds of the Lawrence Livermore National Laboratory – doesn't look much: a big aircraft hanger, you might presume, or an oversized warehouse. Surrounded by the bucolic Tri-Valley region hills, half-an-hour due east from San Francisco Bay, it sits unassumingly between the high-street wine bistros of Pleasanton (once labelled "The Most Desperate Town in the West") and Altamont Raceway Park, where the Rolling Stones played their infamous free concert in 1969. NIF's exterior offers little clue to what goes on there – but inside, it's a different story.

Once granted security clearance – which, for a non-US national, means draconian passport checks – I'm taken to meet Dr MacGowan, 49, the man in charge of those lasers. A family man with two grown-up kids and a home in San Francisco, he was born in West Germany (his father was in the RAF) and raised in leafy Maidenhead, Berkshire. He attended Imperial College, London, before writing his fusion-related thesis at Rutherford Appleton Laboratory, Didcot. Drawn to the US by the promise of access to new experimental facilities, he relocated in 1985, and carried out specialist work in X-rays and plasmas before devoting his attention to fusion.

At 6ft-plus, MacGowan has a willowy frame, and a pallid complexion exaggerated by his silvered hair: it seems that the serious business of harnessing the power of the sun means lack of exposure to its tanning rays. Appropriately enough, he tends to make unblinking, laser-like eye contact. "When I look forward to what my grandkids are going to be faced with, I really worry about fuels," he admits. "People talk about renewable energy – solar, waves, wind – but that's a tiny fraction of the amount of energy we really need. Even if you leave aside global warming, it's just really scary. So the fact that there's this possibility [of fusion], even though it might be really hard to implement, just gives me hope that we're not heading for some kind of nuclear winter-type environment out of an old science-fiction movie."

Measured and thoughtful in his responses, MacGowan makes no attempt to evade the scepticism brewed by talk of the quest for so-called "holy grail" energy sources, fusion in particular, but there's no mistaking the glimmer of optimistic conviction in his eyes: "People say about fusion energy that it's 30 years away and it'll always be 30 years away, but I think that if we demonstrate that we can make it work, and understand how to make it work better, it would change the whole complexion of that discussion."

Currently, nuclear power stations provide about 16 per cent of the world's electricity by means of fission – the splitting of atomic nuclei – a process that produces great ' energy, with the downside of long-term radioactive waste. The advantages of fusion – the joining of nuclei – are almost too good to be true: no greenhouse-gas emissions; less hazardous radioactive by-product; no danger of meltdown; and the fuel is... sea water. A third way exists, still in the theoretical stage, christened LIFE – Laser Inertial Fusion-Fission Energy – which combines the best aspects of both processes and uses nuclear waste as fuel: an appealing way to possibly shrink spent nuclear stockpiles.

Specifically, MacGowan is dealing with Inertial Confinement Fusion (ICF), in which his lasers "ignite" two microscopic isotopes of hydrogen – deuterium and tritium – creating helium and unimaginable energy, in line with Einstein's E=MC² equation. It's not that much different, on the most basic theoretical level, to igniting petrol. "If you had a can of gasoline and dropped a match in, you'd get more than the energy of the match. You'd start to burn the fuel." In terms of ICF, no one has yet achieved sufficient ignition to burn the atomic fuel – something MacGowan hopes to change – but in the realms of science fiction, it's a fait accompli. I'm surprised to discover that one recent Hollywood version of a fusion reaction has a solid basis in fact. "Spider-Man 2 has been used multiple times in scientific presentations," says MacGowan, referring to the scene where Alfred Molina's Doctor Octopus proclaims access to "the power of the sun in the palm of my hand" as he shows off a freshly summoned ball of pure, roiling, nuclear energy. "That's a reasonable analogy to the implosion we do – the challenge is to make it as spherical as possible. Of course, [at NIF] this is all happening at [tiny] 100-micron-type scales."

The equipment required for fusion is, however, anything but minuscule. Two mirror-image structures, 10 storeys high, house the most precise laser ever built: a jaw-dropping assemblage of pipes, tubes and ducts are used to focus the required 192 laser beams on to a tiny point at the heart of the target chamber – the business end of the equipment – where MacGowan hopes to ignite his isotopic fuel. More than 30ft in diameter, the chamber resembles a hollow version of the Death Star from Star Wars, lined with dark louvred panels, and portholes for diagnostics. Just standing in front of it makes you want to reach for a lightsaber.

In the target bay, which encases the chamber, there is all the yellow-and-black hazard tape you'd expect from any self-respecting Bond villain's secret training base. Cage-style elevators sound an alarm whenever you enter or leave them, and the floor outside each entrance is covered by a sticky white mat, like flypaper, to trap shoe dust. Everyone wears a hairnet, hard hat and – in a reassuring throwback to O-level chemistry – protective glasses.

Employee family portraits, with the target chamber as backdrop, serve to mellow the undeniable severity of the place, as does the appearance of a technician in a dorky Einstein T-shirt, as he lopes past pristine silver gun-like structures – the vast final optics-assembly cannons. The whole set-up has the menacing look of high-tech weaponry and, although the NIF lasers could not be fired in anger, there is a military connection. "One of the reasons NIF was built was to study the physics of nuclear weapons," says MacGowan. "It's part of the long-term ability of the United States, and other countries, to understand them. NIF uses a pulsed laser system, which isn't to say that, if it was run into you, it wouldn't hurt: it's just that it's not a very practical weapon."

On 10 March 2009, at 3.15am, MacGowan and the NIF team reached a world-first power milestone by successfully testing the laser beams at the 1.1 megajoule level – that's an ignition-worthy degree of energy, the culmination of 15 years' work. An adrenaline rush followed. "To be brutally honest, what I felt was incredible fear," admits MacGowan. "The things that I'm responsible for are now coming on to the front burner, and we have a lot of stuff to do in a short amount of time. But I also felt incredible pride in [everyone's] work. The laser pulse that we put in is a few billionths of a second, and within that pulse shape, there are features that have to be adjusted very precisely."

When MacGowan refers to "precision", he means it in the most meticulously calibrated sense. We're not just talking about a neatly slotted pass from midfield, or a nice piece of parallel parking... this work demands accuracy on a scale that's barely conceivable by everyday standards. The lasers take 90 seconds' worth of charging power from the national grid and compress it into a pulse that lasts for about a 10th of a billionth of a second. Only at that astonishingly brief moment are the conditions right for ignition.

Admittedly, the untrained, un-beautiful mind tends to glaze over, numbed by the sheer technological difficulty of what's being attempted, and – aware that my host is simplifying incredibly complex work for a physics dunderhead such as myself – I struggle to disguise the fact that the teacher-toddler dynamics of the nursery school have just been successfully recreated in a laboratory setting. NIF brings on a feeling of bewilderment in the face of incredible physics, but it also offers an opportunity to wade through dense thickets of acronyms and collect mind-blowing analogies, so that the world of the layman might have some point of contact with that of the hardcore, life-changing scientist.

The accuracy of MacGowan's lasers, according to NIF's brochure, "can be compared to standing on the pitcher's mound at AT&T Park in San Francisco and throwing a strike at Dodger Stadium in Los Angeles, some 350 miles away". Elsewhere, I'm told to digest the idea that a dollar bill (or a paperclip) contains the energy of one nuclear explosion, and I'm also asked to imagine the pressure of 10 aircraft carriers on my thumb... which I imagine equates to the same levels of duress under which MacGowan habitually works. So, how does he deal with the stress?

"I worry – that's what I do. A lot of people on this project are working under a lot of pressure. It's been a long time duration, and it's increasing now. I try to make a break at the weekends and get away, but then I still find myself working. I do a lot of running. If I find that if I have a lot of issues, I go out for a run, and about halfway through the run I start to figure out solutions. Another way of dealing with the stresses is to work as a team, support each other. Other than that," he concedes, "I worry."

So, will Inertial Confinement Fusion really work? "When we do our first ignition shot [in 2010] we'll be very confident we'll succeed," says MacGowan. "We have a series of about 100 experiments to do before then, which will establish that we've adjusted the laser and the target, and the design of the target, sufficiently well to have a high confidence of ignition. It's not like, now we've built NIF, we'll just start shooting hit and miss."

MacGowan believes NIF's major contribution to fusion energy will be demonstrating the fact that it works, and – all being well – he expects a "prototype energy production capability" to follow by 2020. "[Before building] the internal combustion engine, you demonstrate the principle that if you put a spark plug in a mixture of gasoline and air, it will release energy, right? Once you've shown that it works, then building the pistons and the drive train and all that stuff is just a different engineering problem. The whole world is watching us – the Japanese, the Europeans, other people in the States – because NIF will establish the credibility of the things they want to do, to develop [fusion] as a power source."

One final question remains: if NIF cracks ignition, how will MacGowan celebrate? A look of uncertainty crosses his face. Then a smile. "Actually," he says, "I can't imagine."

Dr Brian MacGowan's guide to nuclear fusion

ITER International Thermonuclear Experimental Reactor

Location: South of France

Method: Magnetic confinement fusion

The basic idea: Vast magnets are used in a doughnut-shaped machine that generates temperatures of tens of millions of degrees and confines fusion fuel as a plasma, rather than compressing it with lasers in the manner of NIF. The first ITER fusion reaction is anticipated in 2022

Doc MacGowan's verdict: "We're about 15 years ahead of ITER. But after we have demonstrated the credibility of ignition, ITER might compete with us to get to a prototype fusion power plant"

HiPER High Power laser Energy Research

Location: TBC (probably UK)

Method: Fast ignition fusion

The basic idea: Like NIF, HiPER is a laser-driven inertial confinement fusion system in which smaller lasers (hence lower construction costs) are aimed at pellets of hydrogen fired across a steel vacuum chamber. Construction should start around 2015, with operation forecast for the early 2020s

Doc MacGowan's verdict: "HiPER, and FIREX, which they will build in Japan, is geared toward fast ignition – and may be really promising"

LENR Low Energy Nuclear Reactions

Location: Multiple laboratories worldwide, but no major single programme

Method: Cold fusion

The basic idea: The process, discredited in the light of unprovable claims made by the electrochemists Stanley Pons and Martin Fleischmann in 1989, is based on the belief that heat-giving nuclear reactions can be stimulated at room temperature

Doc MacGowan's verdict: "I don't think it's a serious competitor. It's important to be creative, but you should be careful taking results and extrapolating them too far"