“The whole planet needs a lot of energy,” begins Michel Laberge, in an understatement. So far, he says, we’ve been running on fossil fuels, and it’s been difficult to find something as cost-effective to replace them. Laberge is a fan of nuclear power, which he thinks is the best solution to that problem in the long run.
There are two ways to produce nuclear power: fusion and fission. Right now, all of our nuclear plants use fission, where you take a big nucleus, like uranium, and break it apart.
In fusion, by contrast, you take two very small nuclei, hydrogen, and push them together. As Laberge says, “This is nature’s way of producing energy. The sun and all the stars in the universe run on nuclear fusion.” The other reason to like it (the main reason really) is that a fusion power plant would be very safe. It can’t melt down, and it produces only short-term radioactive waste. The fuel is water, so we can get fuel from the ocean, at a potential cost of 1/1000 of a cent per kilowatt hour.
So, “If fusion is so great, why don’t we have it?” The answer is that it’s really hard to do. The two nuclei that you need to push together are electrically charged, which means they repel each other. You have to push them together to get past that electrical repulsion before the nuclear attraction takes over. To do that you need a temperature of about 150 million degrees centigrade. That’s hard.
Laberge got interested in fusion as a PhD student, but he went to a postdoc that led to him making laser printers for a big company. At 40 he had a midlife crisis. As he said, “Some people get a Porsche, some get a mistress. I decided to solve global warming and make fusion happen.”
He knew that there are currently two methods for producing fusion. The first involves a big magnetic ring; you trap a hot gas inside a magnetic field and heat it up into plasma inside the ring. The second way is with laser fusion — you shoot a bunch of lasers into the center of a sphere. Enough power from the lasers, and you can produce fusion.
Now, there’s a perception that fusion is going nowhere. But as Laberge points out, people have actually been making a lot of progress, and are in fact getting near to the point where fusion is possible as power generation. He showed a plot of power generated from fusion, and compared it to the famous curve of Moore’s Law, which it closely tracks. Current projects are now near the line where more power is produced than is put in.
Recently projects have been delayed, for reasons that Laberge describes as political rather than scientific. For example, an international collaboration, ITER, will be the first to produce more energy than is put in. It could have been built in 2005, but has been delayed by political problems (such as, it took three years to decide where to build it).
Fusion is also often criticized for being too expensive. It’s $1-2 billion per year, but as a comparison, the effort to produce today’s microchips has cost a total of about a trillion dollars. “Considering that fusion could solve all the world’s energy problems, I think it’s short change” to not fund new efforts.
Laberge points out he is biased, as he founded a small fusion company. Knowing he couldn’t compete with the big international projects, he went for a different solution. It’s called Magnetized Target Fusion. The idea is to take a big vat of liquid metal, spin it to produce a vortex, and push it in with a piston. That compresses the metal and causes it to ignite. The liquid metal gets hot, and you can use that to drive a turbine. The original version, developed many years ago, didn’t work. The pistons couldn’t push fast enough. So he introduced a design change — the piston in his new machine hits an anvil, which means that it deposits all its energy at once.
They built a machine in a garage, and produced about 100MW of power. His company is now up to 65 people working on prototyping all the parts of the new reactor. They have work to do before proving that the machine works — in particular in producing a plasma that lasts long enough, and in making the implosion symmetric, so that the plasma can’t escape out one side.
The point, though, is that fusion is coming. The thinking, Laberge says, has changed from “Can it be done?” to “How can it be done cheaply? Fusion is getting very close. We’re almost there.”