When I was a boy I thought that oil/gas would be gone in a couple of decades. Then we would build some fission-plants untill we found out how to do fusion and Presto! The future, with free unlimited energy, was here.
Then Tsjernobyl happened, oil prices skyrocketed and oil-reserves seemed to be almost constant. So none of that came true.
But the basic idea stays the same, right?
I need to get some more facts/ideas to correct/supplement my childish views on nuclear fusion.
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[li]Is it likely we (humanity) will succeed in getting an economically viable fusion-based powerplant running in the foreseeable future?(will it happen?)[/li][li]How far are we from realising such? I know you don"t really know but what would be your WAG?(when will it happen?)[/li][li]How much are we (humanity) spending on research?(why/how will it happen?)[/li][li]Am I correct in thinking that if we DON’T succeed in realising economically viable nuclear fusion soon we’ll [/li]A) burn all the oil/gas/coal, succesfully achiving every goal on our path to a beachresort on Antarctica. (and kill 3/4 of humanity.)
B) build so many nuclear fission plants that the chance of one blowing up in your neighbourhood becomes 100%. (and kill 3/4 of humanity.)
C) find a way do do A and B simultaniously. (and kill 3/4 of humanity.)
D) have to revert from our wicked ways, do what Greenpeace says (and kill 3/4 of humanity.)
E) have to accept that we’re f*cked.
Needs an essay to answer this properly, but here’s a quick stab.
Unlikely I think. Energy-yielding reactions are achievable, but we’re a long way from building a useable reactor. The required materials simply don’t exist, and we don’t know how to manufacture them.
Possibly never. As I understand it, one of the biggest unsolved engineering problems is extracting the energy from the reactor to do useful work. You can’t simply stick a pipe through it and use it like a big kettle.
Fossil fuels will eventually be depleted, coal will last the longest. Even then, renewables and nuclear power will give us a useful energy budget to work with, and there is a lot of scope for us to become more efficient. I’m very concerned about the impact of energy scarcity on the world economy and agricultural output, but I’m not expecting armageddon.
The first and last questions are kind of GD territory, but here’s some quick thoughts on the other two:
The old joke is that fusion power has been N years away for the past M years, where M is at least twice as big as N. I think I’ve heard “20 years away for the past 50 years”, but it may have originated with other numbers.
In addition to ITER, which is a “classic” tokamak design, there’s also the National Ignition Facility in California, an experimental inertial-confinement facility that was recently completed. Total cost: $4.2 billion.
Unfortunately that is not a joke. Sober physicists and engineers were giving the estimate of “ten to twenty years, more likely twenty” back in the 1960s when I was a teen first getting interested in these sorts of questions. The estimate hasn’t changed – it’ll be ten to twenty years.
It’s my understanding that government support for controlled fusion research has been consistent – and consistently cheap (meaning greatly underfunded). Some have attributed this to the influence of lobbyists for Big Oil, though I think there’s no or inadequate evidence to convince most people of that. (That’s not intended to be heading to GD territory but to be a statement of a relevant fact: “allegations have been made, but with insufficient evidence to convince most people.”)
As freido pointed out, a fusion reactor run a lot hotter, at something like 100 million K. For comparison, the core of the sun is only about 15 million K, fusion occurs there at a lower temperature due to the vastly higher pressure. The plasma is magnetically confined, so it isn’t in contact with the reaction vessal (otherwise, it would melt).
Reading up on DEMO, the planned successor to ITER, most of the energy produced by the reaction is in the form of high-energy neutrons. As they are electrically neutral, they can pass through the confinement field. The plan is to absord them into tons of liquid lithium as it is pumped around the outside of the reactor. The heated lithium can then be used to heat water, ultimately powering steam turbines.
The big problem at the moment is that no known materials can withstand the levels of neutron bombardment they will be subjected to for a period of time. That’s why ITER is only specced to run for 1,000 seconds.
I wouldn’t call US funding for fusion research over the last few years consistent - check the history of US support for ITER - but I don’t think you have to look for the influence of lobbyists to explain the limited funds (relative to the total energy budget) going into fusion - this is explained by the already mentioned timescales. Generally politicians can’t look passed the next election, a far sighted statesman is one that might look forward 10 years. Until recently, with fusion 40 years away and no worries in the US about burning coal and oil, there was no political incentive to put money into fusion research.
From what I can tell, we’re 30 years away from knowing whether fusion will be viable. If ITER’s results in 30 years are ideal, then we’ll be 20 years away from a real reactor - but add at least 10 more years for NIMBY (not in my backyard) syndrome - everyone will want a reactor, just not here. If ITER’s results indicate that new designs need to be tested, then we’ll be 30 years away from knowing whether fusion will be viable with those designs.
I feel pretty confident that we’ll have fusion working (one way or another) within 80-100 years and that it won’t be a major contributor to world energy for at least 120-150. I also think fusion will be a lot like fission - a significant producer, but not a stand-alone solution. This will be due, at least in part, to the fact that most fusion reactor models still have radioactive waste being produced as neutrons bombard whatever surface lines the reactor, and we’ll have to replace that lining periodically.
Whether funding for fusion technology is underfunded or not is subject to interpretation, but I would tend away from unfounded conspiracy theories and closer to MarcusF point that politicians aren’t generally amenable to consistent long-term funding of large technology development programs with an uncertain timeframe and result. Thus far no one has yet demonstrated a practical means for controlled over-unity fusion, and indeed, there is disagreement among physicists and engineers working in the field about even the basic criteria for what energy yield would give practical and cost-effective energy generation via fusion, much less resolved the materials and energy conversion problems of fusion power generation. It is really anyone’s guess as to when practical fusion generation will be both technologically and economically feasible.
This doesn’t mean that energy production via fusion is not-viable, however, in a hybrid fashion. There are several informal proposals to use a Farnsworth-type electo fusor for neutron generation to power a subcritical fissile reactor using readily available fertile materials like [sup]232[/sup]Th. This yields an energy-positive reaction with the advantage that it can be configured to run until all energetic conversions have occurred and the resulting fuel waste is radioactively benign. Of course, you still have the problem of neutron embrittlement of structural materials and the possibility of in-process leakage of radioactive coolant into the environment, but it largely gets you away from the fuel production cycle with highly toxic and caustic byproducts, and the reactor is inherently fail-safe, as the reaction is not self-sustaining.
There is, of course, another way to make both direct and indirect use of fusion power; the waste energy given off by the Sun both showers the Earth with almost limitless energy, and drives the hydrological and meteorological cycles, giving us waves and wind, not to mention the gravitational gradients that give us tides (though the Moon is more significant to us in regard to the latter). While current technology won’t let us replace anticipated energy demand with completely renewable sources, it can certainly supplant a significant amount and reduce demand on fossil and non-renewable sources. Improvements of this technology plus surge energy production storage methods, and more efficient means of distribution and end usage can all go a long way toward reducing the use of fossil fuels.
As for question #4, these claims are hyperbole at best. Even the worst projections of global climate change do not predict the deaths of 4+ billion people. It is even possible that warming may have the eventual beneficial effect of providing more fresh water to regions that currently engage in agriculture only at the expense of depleting non-replenished underground aquifers or severely strained river systems, although the transition will be problematic to say the least. “Our wicked ways,” of energy usage have permitted us both the leisure to develop insight into the underlying interactions in the ecology and the means to protect and restore from both natural and anthropological impacts on the ecosystem. This couching of humanity as some kind of virus upon the planet is nothing more than post-New-Age-ish self-flagellation. The reason to care of the environment and conserve resources not some Good-versus-Evil conflict that many make it out to be; it is for the same reason you don’t take a shit in the middle of your kitchen.
Although I have read in various sources that US government investment in fusion has been 100 times that of investment in solar, despite solar actually producing some degree of power for decades. So “underfunded” is kind of subjective.
If we got really serious about it, we probably could get fusion working in twenty years. The thing is, though, we’ve never gotten anywhere near as serious about it as we would need to. The funding just isn’t there.
Which, of course, completely leaves aside the question of whether the funding should be there. It’d certainly be a better use of our money than some things the government spends on, but it won’t necessarily be better than research into other energy technologies.
I’m a supporter of R&D into fusion but in my view we need more funding to encourage all forms of clean energy - fusion, fission, solar, wind, clean coal, etc, etc. The difference between fusion and solar and wind is that solar and wind are fairly mature and they need, and receive (at least in Europe) subsidies to encourage use, not basic research. On the questions in the OP I’m not as pessimistic as Alka Seltzer and Stranger On A Train but, given its potential benefit, as long as there is a greater than zero chance of success, it is worth the investment.
That’s my opinion so to bring in so facts, see these presentations by Prof. Sir Chris Llewelyn Smith (then Director of the UK Fusion lab at Culham and former Director General of CERN). They’re from a couple of years ago but still relevant. (Warning .ppt files)