We might very well be on the verge of producing a clean, safe, small, and unlimited supply of electrical energy.

It has been almost sixty years since we were first told that a clean, safe, and unlimited supply of electrical energy from nuclear fusion was only ten to twenty years away. Yet here we are, ten years into the twenty-first century, and instead of the Mr. Fusion reactors we were promised in Back to the Future, we are opening new coal plants and digging deeper into the oil sands to try to satiate a hungry world's appetite for energy.

Nuclear fusion is our species' attempt to tap into the process through which most of the universe's energy is generated. Hydrogen, the most abundant of the elements, is unstable under conditions of sufficiently high pressure and temperature. In places where these conditions are met, the centre of the sun for example, two hydrogen nuclei can come together to form helium, releasing massive amounts of energy in the process.

And by massive, I mean ridiculously massive. Two grams of the stuff would be enough to power the average car for twenty years. It is no surprise, then, that the first application of fusion was to give an extra bit of kick to the world's nuclear arsenals, creating bombs about 100 times more power than the fission-based one that levelled Hiroshima.

Unfortunately, efforts to create a controlled nuclear fusion reaction that creates net energy, the kind that can be safely housed inside an electrical generating station, have so far been unsuccessful, despite billions in investment and years of work from some of the smartest brains in physics and engineering. It is the carrot that keeps dangling just outside the reach of the world’s scientific community.

It isn't that fusion is all that difficult to achieve. Dozens of different kinds of working fusion reactors have been built. The simplest of them, the Farnsworth-Hirsch reactor, fits on a table and can be built for a few hundred dollars. There is even an active community of amateur nuclear fusion enthusiasts who build such contraptions in their basements and swap tips over the internet.

The problem is that these devices are incapable of producing a net surplus of energy. Without exception, they require a large amount of energy to be put into the material undergoing fusion and too great a loss of that material as things start to heat up.

To be a viable energy source, a fusion scheme must be capable of producing far more energy than is required to run it. So far, there are two technologies that have the capacity to achieve this goal.

The more mature of the two is magnetic-confinement fusion, a technique wherein hydrogen is heated to several million degrees and kept confined by magnetic fields. There is a massive US$10 billion project currently underway in southern France that is attempting to build magnetic confinement capable of producing as much power as a small fission reactor. It is scheduled to be completed in 2018. If it works, it could well provide the template for large-scale fusion reactors around the world.

But 2010 is the year in which the fusion community will find out about the viability of the second approach, inertial confinement fusion. In the coming months, all eyes will be on the National Ignition Facility at Lawrence Livermore National Laboratories in Stanford. There, scientists are aiming the world's most energetic laser at a capsule of frozen hydrogen about the size of a peppercorn.

For a brief billionth of a second, the laser will direct power equivalent to the total output of all the electrical plants in North America at this tiny capsule. The blast will cause the outer layers of the capsule to explode and the inner layers to be compressed. This compression and heating will cause the hydrogen to fuse together and release energy. Each little peppercorn should produce as much energy as a barrel of oil.

The lab has set itself the goal of achieving such a reaction, called ignition, this year. Last month, they showed that they can create explosions in the outer layers that symmetrically compress their capsules. The next step will be putting the hydrogen inside and seeing what happens.

Admittedly, it isn't Mr. Fusion, but if ignition is achieved this year, it opens up the possibility of cheap, small nuclear fusion. And if we want to kick our fossil fuel habit for good, that is very good news.