New Scientist has a run down on recent developments in fusion - producing energy by squeezing atoms together - that suggests things are looking up in the field. Star power: Small fusion start-ups aim for break-even. (free on-line sign up needed to view article)
Break-even is the holy grail of fusion research - it refers to being able to get a fusion reaction going that yields as much energy as it takes to get the reaction started in the first place. No one has done it yet, but there are some new players in an effort where success has been "just around the corner" for decades. The focus on breaking even is simple - from there it should be a small step to achieving fusion that yields more energy than it consumes, and Bingo! The world will have a new source of energy.
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Some Background (Skip Ahead if You've Heard This Before.)
Let me start out by saying the N word - Nuclear Power. Fusion is the Other Nuclear Power, or could be, and it's fundamentally different.
At the moment, every nuclear power plant in the world, every nuclear powered ship or submarine, uses nuclear fission to make power. If you take the right kind of atoms - massive, prone to spontaneously split (fission) - you can assemble a bunch of them in a reactor where that splitting can be cranked up into a chain reaction. (I wrote this up in a 5 part series back in 2008 - part 2 goes into a lot more detail explaining it. Hopefully, most of the links still go somewhere useful.)
A key thing to remember about nuclear fission reactors is that keeping that chain reaction under control is a balancing act - the nuclear fuel in a reactor is already slowly breaking down just sitting around - bringing it all together to increase the rate of fission can get out of control if safety systems fail - as happened at Fukushima. Further, fission reactors by their very nature use hard to obtain elements for fuel that are dangerously radioactive, require lots of shielding to contain radiation, cooling to deal with heat, and generate a variety of very radioactive wastes.
So, why would anyone build a fission reactor? A variety of reasons: 1) Power in concentrated form versus huge amounts of oil or coal for the same amount of energy. 2) Energy not dependent on supplies in areas of the world that are politically unstable. 3) No green house gasses. 4) More controllable than dealing with the vagaries of wind, water, or sun. 5) Side benefit of nuclear weapons programs, science efforts.
So, what it advantages 1,2,3,4 could be obtained without the hazards - and what if the supplies of suitable fuel were potentially abundant and non-hazardous? That's why the interest in nuclear fusion instead of fission; why people have been chasing the dream for decades now.
Fusion - Tomorrow's Energy Real Soon Now?!?!??
If nuclear fission involves assisting really big and unstable atoms to break down in a controlled way to release energy, nuclear fusion is all about squeezing small atoms into slightly larger ones, while the leftover bits get released as energy. The Sun does nuclear fusion 24/7 - but making it happen on Earth at a smaller scale under control has proven to be quite a bit trickier - at least if you want to get more energy out of it than you put into the process. (It turns out to be easy actually, if you don't want/need excess energy - a high school student can do it on a table top!) I did a run down of the different approaches being taken to making fusion work in part 3 of that 2008 series. Which brings us up to today, and the New Scientist article by David Hambling:
Nuclear fusion will cost a fortune – or will it? A new wave of upstart companies think they've found cheaper, quicker ways to build a second sun
A VAST earth platform looms into view above the treetops of Cadarache in France's sultry south-east. It measures 1 kilometre long by 400 metres wide, and excavators dotted around it are digging out pits to be filled with massive, earthquake-proof concrete foundations. These foundations need to be strong: 18 giant, supercooled superconducting magnets, each weighing 360 tonnes, will be part of a payload totalling 23,000 tonnes. This is the site of ITER, an international scientific collaboration with funding of €15 billion.
Meanwhile, in an undistinguished building 9000 kilometres away on an industrial park in Redmond, Washington state, a handful of researchers are gathered around a slender cylindrical apparatus about 16 metres long. There are no massive foundations and no expensive cryogenics. The object of the researchers' interest is smaller than one of ITER's magnets.
The disparity in scale is striking, especially when you consider both pieces of kit have the same goal: to harness the awe-inspiring power of nuclear fusion. Which project is more likely to realise fusion's promise of clean, nigh-on inexhaustible energy? ITER certainly has the funding and the physics and engineering expertise. It would be most people's bet. Yet some diminutive upstarts are now challenging that assumption.
The article goes on to spell out the progress ITER is making, and discuss the new challengers taking different routes to fusion. ITER is a brute-force approach, building on years of ever more expensive and complex ways to almost break even. It's huge, and is going to run on a mix of tritium-deuterium fuel, which has inherent problems. (Part 3 of my series gives a run down.) Nonetheless a lot of hopes are riding on it.
In contrast, Helion Energy is trying to do fusion on a smaller scale smashing clouds of plasma together in pulses. A Canadian firm General Fusion is taking a different approach involving molten metals, acoustic compression waves, and more plasma collisions.
New Scientist spells out the practical implications:
The simplicity and smaller size of fusion reactors based on the new technologies - the companies are aiming for something on the 100-megawatt scale, rather than the gigawatts that are ITER's ultimate goal - could be their great advantage. "It's a size that allows for factory construction of systems rather than site-specific designs," says Delage. Wallace agrees. "ITER is not the sort of thing you could easily roll out in, say, Nigeria - but we can go anywhere," he says.
The timeline More Lows Than Highs in the New Scientist article makes passing mention of my own favorite in this horse race, the Polywell design developed by the late Dr. Robert Bussard. I wrote it up in Part 4 of my series. Funded by the U.S. Navy, progress has been hard to judge because of an embargo on releasing results so long as the Navy is funding the work. But, based on what has been released, I regard it as the most promising because among other things it might be capable of fusing protons and borons together in a reaction that might allow direct conversion of nuclear energy into electrical energy. The fuel is abundant, non-radioactive, and fusing it does not produce the neutrons you get with deuterium-tritum fusion, avoiding radiation problems. The details as of 1998 and revised in 2007 were written up here in a pdf file.
Bottom Line, For Now...
The fact that multiple programs are tackling fusion by different routes, by a mix of private, private-public, and government funding reflects the need for a new source of clean energy AND indicates progress seems to be picking up. Again from the New Scientist article:
But - and here's the surprise - it's hard to find anyone in the know with anything bad to say about the physics behind the new reactors. Even ITER scientists admit that the technology is credible and superficially attractive, if still immature. "The tokamak is fairly complicated; some other approaches appear simpler and that appeals," says Campbell. "They look like a more direct route to fusion."
The time estimates are converging; if we can just keep from screwing up the world in the next few years, we might yet have a shot at turning things around.
Update: Here's where Polywell fusion was back in May, 2011.
The last little experiment?
Park figures that the money provided under the WB-8 contract should last until the end of the year, depending on how efficiently the EMC2 team is able to stretch the money out. By then, the engineers in New Mexico and their backers in the Navy should know whether it's worth going ahead with the next step, perhaps even with the big demonstration reactor. Park hopes that WB-8 will be the last small-scale experimental machine EMC2 will have to build.
"This machine should be able to generate 1,000 times more nuclear activity than WB-7, with about eight times more magnetic field," said Park, quoting the publicly available information about WB-8. "We'll call that a good success. That means we're on track with the scaling law."
Don't expect weekly updates about EMC2's progress. "Currently all our funding comes from the Navy," Park said. "That's our customer. Our customer desired that we keep most of our progress confidential. ... They're somewhat concerned about making too much hype without delivering an actual product."
But if WB-8 and the follow-up studies are successful, the Navy won't stand in EMC2's way.