Nuclear fusion 'will work' (auto-starting audio)
news.bbc.co.uk
news.bbc.co.uk
The question really isn't "will it work?", but rather "when, how much will it cost to develop, and (most importantly) will commercial power production via fusion ever be cheaper than the alternatives?"
I see no indication tokomaks will ever be commercially viable, even if they can be made to work. The up-front cost to construct a plant will be ruinous under the rosiest of scenarios. It would probably be cheaper to fake base load power with solar cells backed by lead-acid batteries.
And laser ignition? Who knows? I would like to see someone ask these guys "Okay, assume all the technical problem are resolved the way you expect, how much is it going to cost to build a commercial power production plant?"
The fact that this looks difficult from where we sit is not a good reason to not do the research. Many of the biggest discoveries in history looked impossible before they became ubiquitous.
You missed the point entirely. Billions of dollars in research, even if successful, will have no positive effect whatsoever if they don't lead to a commercially viable means of generating power. It's not enough to get to break even. The end result has to be cheaper than the alternatives.
I'm not a big solar power fan, in general, because I think it's too expensive. But if we're going to pretend cost doesn't mean anything, we'd be far better off taking those billions and building out a solar infrastructure with technology we have today rather than taking a dodgy gamble on something that a) may never work at all and b) probably won't be cheaper than solar if it does work.
Solar energy has already reached grid parity¹ in Australia².
[1] http://en.wikipedia.org/wiki/Grid_parity [2] http://www.abc.net.au/news/2011-09-07/solar-industry-celebra...
Anyway, if we go by straight cost/benefit, nearly all of the viable alternatives are polluting. And it's a fantasy to assume that we'll completely replace our energy consumption with renewables.
Projects like NIF and ITER aren't basic research, and in any case there are all sorts of competing interests when it comes to research - we'll get better bang for our basic research buck funding, say, the Web telescope or something like the LHC. The argument for ITER and NIF has always hinged on the promise that they'll be able to produce something useful within a few decades.
Anyway, if we go by straight cost/benefit, nearly all of the viable alternatives are polluting. And it's a fantasy to assume that we'll completely replace our energy consumption with renewables.
It's not a fantasy because we can't do it. It's a fantasy because we can't do it for a price we're willing to pay. But what fusion advocates are asking is we instead pay for something that's going to be even more expensive.
1. Neutrons rapidly destroy any kind of containment. He-3 is seen as some kind of holy grail here. Unfortunately it's incredibly rare. The best source is probably the Moon (which, with no atmosphere, has had billions of years of solar winds to collect non-trivial amounts of He-3); and
2. To sustain a fission reaction any current research reactor I can recall reading about uses probably radioactive isotopes (most likely tritium ie H-3) or at least somewhat uncommon isotopes (ie deuterium, H-2).
Fun fact: per cubic foot compost generates more power than an equivalent volume of material from the Sun's core [1]. What makes stars such great energy producers isn't fusion per se, it's their sheer size and fuel supply.
Fusion goes hand-in-hand with the Utopian concept of "free energy" because obviously water (and thus hydrogen) is abundant. But no energy will truly be "free" although it may be cheap enough to have the almost the same impact as being free.
There are four component costs in energy:
1. The cost of building a device that produces energy;
2. The cost of maintaining that device;
3. The R&D required to bringing that device to market. Obviously, over time, this cost diminishes to zero; and
4. The cost of extracting, storing and transporting whatever fuel is required.
So for hydrogen, assuming a fusion reactor doesn't use sea water, you must first extract hydrogen. This is actually relatively expensive. Hydrogen extract is seen as a way of smoothing out power generation from renewable sources (most often wind power) [2].
Sure a fusion power installation could produce the energy for this but remember that any power system needs to produce more power than it uses or its largely worthless (barring corner cases like producing energy in portable form, which is the entire model for batteries). With hydrogen extraction, you've just raised the bar on how much power than reactor needs to produce.
Likewise, hydrogen storage is non-trivial. It's flammable and hard and expensive to store in liquid form (compared to, say, liquid nitrogen [3].
Energy needs to be produced in many forms. Fusion is on the scale required for power stations but that's only one of our needs. What about vehicles? It's really hard to beat the amount of energy stored in oil (by mass or by volume) and the ease with which it is extracted.
I see a long term solution to this in genetically engineering microbes to produce readily consumable compounds for abundant and sustainable inputs. Another fun fact: if you've read Neal Stephenson's Anathem you'll probably recall his mention of "fuel trees" that suggest this kind of approach.
In the far distant future I see the only viable power source that would allow us to live in space, let alone cross interstellar space, to be black holes [4].
[1]: http://en.wikipedia.org/wiki/Solar_core
[2]: http://en.wikipedia.org/wiki/Wind_hybrid_power_systems
[3]: http://hypertextbook.com/facts/2007/KarenFan.shtml
[4]: http://io9.com/5391989/a-black-hole-engine-that-could-power-...
This technology is not a matter of 'is it possible?' but 'is it technically feasible?' And the scientific community has been chipping away at the latter for a long time.
I'm not saying it's a valid goal - just until the technology is useful, it's not yet viable.
Compare to unified field theory, the Higgs boson and string theory.
A pessimist is an experienced optimist :)
http://en.wikipedia.org/wiki/Sun#Core
The Sun is not like a nuclear bomb going off. It's just a big radiating compost heap. Its huge energy output is due to its large size, and not the intensity of its reaction. (If the Sun's reaction were like a nuclear bomb, the solar system would be destroyed in a supernova-like explosion.)
In other words, nuclear fusion at the Sun's scale isn't very intense a reaction. Why do we expect it's a good idea for a power plant? Do we expect to get significantly hotter than a star? Significantly more dense? It makes sense how nuclear power works. Fusion power, it's not so clear.
Of course, there are fusion bombs as well, but aren't those set off by nuclear bombs?
What the "blanket" does at this point is exert pressure on the "core", which would be beginning to blow apart in a conventional nuclear device. Keeping the "core" together for just that small bit of time longer allows it to remain supercritical for just that small bit of time longer, with the energy release growing exponentially with a time constant of 10^-7 seconds.
where, as the diagram shows, fission comes up from the heavier elements (less energy difference) and fusion from the lighter (greatly more).