Bell Curve The Law Talking Guy Raised by Republicans U.S. West

Wednesday, October 18, 2006

The Outside Gamble

Fusion is the turtle in the race to develop sustainable energy; it is the outside gamble that just might win.

In November, seven of the largest and richest nations in the world (China, India, the U.S., the E.U., Russia, Japan, and South Korea) will sign the final agreement to begin work on the $12 billion international thermonuclear experimental reactor, ITER. (Incidentally, the acronym no longer officially stands for anything: apparently, they decided "thermonuclear" was bad marketing.) You can find descriptions of ITER from the official ITER website, from the AAAS, and from Wikipedia.

First proposed in 1985, the giant tokomak in Cadarache, France will take 10 years to build, assuming the project stays on schedule. Second only to the International Space Station, ITER will be the most expensive international experimental collaboration in history. If ITER succeeds, its successor (oddly dubbed DEMO) should be a commercial fusion power plant up and running by 2040. The catch is that nobody knows for sure if ITER will work. It's not called "experimental" for nothing.

So far, no tokomak has ever generated more power than it consumes, but the bigger the plasma chamber, the more efficient it has become. The working assumption therefore is that if you just build one big enough, you'll get a working fusion reactor. The largest tokomak currently in existence, JET, has a plasma volume of about 40 cubic meters and produces at best 16 MW of power, only 70% of what it takes to run. ITER will have a plasma volume of over 800 cubic meters and is predicted to produce 500 MW of excess power--a tenfold amplifcation of the input power.

There are a number of physicists who believe this is the wrong approach. They worry that instabilities in the plasma field will inhibit power production; they worry about safety. They believe that the attempt to make the equivalent of a toroidal stellar core is not the way to go: instead, they believe a fundamental breakthrough in thinking--such as perhaps extremely high-powered lasers pummeling puffs of gas--might permit tabletop fusion. (Anyone remember "Mr. Fusion" from Back to the Future?)

Still, the scientific community has decided to back the horse they know best and have pushed hard for two decades to get the consortium of seven nations to pony up the billions needed for the ambitious experiment. It is astonishing to me that so few people know of this vast undertaking. Turtle though it may be, fusion is the only power source that has potential to up-end geopolitics and re-write the rules of global climate change. If ITER succeeds, November 2006 may go down in history as the beginning of the end of the era of fossil fuels. Of course, ITER will require sustained political will to see it through to its planned operational date of 2017.

Let's just hope "Cadarache" is not French for "Waxahachie."


Anonymous said...

Fusion reacters with electric cars.

What if we took all the money we are wasting on biofuels and put into research on the "Mr. Fusion" option as an addition to the ITER approach? 

// posted by RBR

Anonymous said...

We know fusion works. It heats my house all summer (sadly, not in winter when I would prefer it). The problem seems to be our distance from the reactor and the inefficiency of transmission. Wouldn't better learning to harness solar power be a better investment than trying to recreate the sun on earth?

Sorry, Dr.S, I know that's, er, raining on your parade. 

// posted by LTG

Dr. Strangelove said...

LTG is right to focus on solar power. Of the alternative sources, only solar could--even in principle--provide enough energy to support the world's current level of energy consumption. Here's a quick calculation.

1. Earth receives a total of about 120 PW of solar radiation.
2. The maximum theoretical efficiency of conversion to useful energy is about 1/3 (actual commercial cells are more like 10% these days). We'd also probably lose a minimum of 1/2 on top of that for transportation and storage.
3. Current total human energy consumption in 2006 is about 14 TW.

So in principle we could get all the energy we need now if we consumed about 0.07% of all incoming solar energy... though in practice it could easily be two to three times more. And unfortunately, energy needs are growing. The U.S. uses energy at about six times the average rate per capita, and U.S. energy consumption increases by about 2% annually (though it varies a lot). If the rest of the world were to catch up with current U.S. levels of energy use, we'd need to use 0.42% of all incoming solar radiation. And now we're really starting to risk global climate change.

So solar power is a more conventional solution to current problems, with lower risks and lower rewards--but still very worthy of investment!--while fusion power is a worthy longer-term investment for the future. Solar power can produce the energy we need for the near and medium-term, but fusion is the only source capable of producing virtually unlimited energy for the long-term. Fusion is as close to free energy as anyone has plausibly described. It's worth investment too.

Anonymous said...

Again I'd say invest in all of these: solar, big fusion and table top fusion. What we should be clear about though is that we will never combust our way out of climate change. Burning biofuels still burns fuel and dirties the air - just at a slightly slower rate.

I like the comment about relocating the Sun, LTG. Very witty.  

// posted by RBR

Anonymous said...

What's a PW? What's a tokomak?  

// posted by Anonymous

Dr. Strangelove said...

Wikipedia describes a tokomak better than I can. It's basically a doughnut-shaped chamber which uses strong magnetic fields to confine incredibly hot gas that would otherwise explode. PW and TW stand for "petawatts" and "terawatts" respectively. The SI or metric system uses Watts (symbol: W) to describe power. Peta (symbol: P) is a prefix meaning 10^15; Tera (symbol: T) means 10^12. So 120 PW is 120 quadrillion Watts, while 14 TW is 14 trillion Watts. For comparison, the two reactors San Onofore Nuclear Generating Station each produce about 1 GW (gigawatt, or billions of watts) each, and supply energy to about 2.75 million households in all.