Yes I won't disagree that the technology is getting better and that we are getting closer to achieving it. But a commercial fusion reactor in ten years seems very unrealistic with the current regulation and standards set by current government regulatory bodies.
When I was in school studying nuclear engineering, the running joke was that fusion will always be N amount of years away from happening. It seems like every year or so a new company or group of researchers has found a breakthrough that will allow fusion to happen in N amount of years even though we have yet to reach breakeven in a research setting.
But a commercial fusion reactor in ten years seems very unrealistic with the current regulation and standards set by current government regulatory bodies.
I think it would be too much of a competitive disadvantage for a country to not use fusion if it became practical.
There'd be some need for regulation but less than with fission. The only nuclear waste is activated reactor components, not transuranics and fission products. The reactor turns off like a light switch, with nothing to produce decay heat, and it has no potential for a runaway reaction. (It's hard enough to get the reaction going in the first place.) The only potential radiation release is small amounts of tritium, and there's no concern about fissiles getting diverted for weapons. Tritium has some weapons use if you're ready to progress to thermonuclear bombs, but in that case you hardly need fusion reactors to make it.
If we manage boron fusion, we'll be producing less radiation than burning equivalent coal, and won't have tritium. It's hard to see how anyone would justify regulating that for anything other than electrical safety, just like any other power plant, and for radiation standards on par with medical equipment.
People bring up that joke in the comments section of every fusion article ever published. The fact is, fusion has progressed exponentially since about 1970, about as fast as Moore's Law, despite a level of funding far below what those early optimistic advocates said we needed.
Just out of curiosity: what if fusion was perfected? what are the consequences? massive economic growth & population? Does the earth become an heat sink?
It's a heat sink right now. Hydroelectric generation aside, efficiency for electricity generation is pretty much always below 40%! That, however, is since almost all our plants use the Carnot/Rankine cycle heat engine.
Again though, even those watts of electricity eventually get turned back into heat. Gotta love entropy...
The consequences of us having fusion?
The good, we get cheap, abundant electricity for the entirety of the planet's lifespan with almost no harmful byproducts, made by a nuclear plant that's impossible to melt down or be used in the proliferation of nuclear weapons.
The bad, we have to build the plants, and possibly replace the old ones. That indicates a large shift in jobs, and makes you wonder how we can afford it (although improving economic conditions should make the latter less of a downside as fusion becomes viable).
There are power plants that hit 42% theremal and dump waste heat, others reuses that waste heat for things like home/office heating and hit 70+ efficiency. So really one of the best solutions is simply to find ways to reuse waste heat. Granted, you would still need massive shielding even with a tin can sized fusion reactor, but assuming ther safe enough to put near city's you could got a lot of winter heating practically for free.
Yes, that's called co-generation (or combined heat/power plants). I can't comment on fusion reactors, but this isn't really feasible with fission reactors, since the coolant becomes radioactive. Sure you could run it through several loops to bring it down to a safe level, but then you're losing efficiency at each sub-stage.
I'd also like to point out you can only achieve those high efficiency numbers when you're actually using the heat.
The coolant in the actual nuclear reactor itself is radioactive. But all the working fluid in the heat engine (including heat dissipation) is safe. Could you imagine how ridiculous it would be to do maintenance on your radioactive turbines?
For one thing (the one that's guaranteed), nuclear power would get a lot safer [1].
If our expectations about fusion's efficiency [2] are correct then in the long run we would have to worry much less about our conventional sources of energy and the environmental price that comes with using them. The questions of peak oil and CO_2 emissions would be at least partially defused regardless of how much of a threat they really represent.
Even if perfected it still wont be free. Creating it and then sending it all over the world will cost quite a bit of money. So we'll probably (hopefully!) just get cheaper energy.
And that's why I don't think it will impact economic growth that much. But it will hopefully reduce our CO2 emissions.
The reduced CO2 should make the climate colder. Continued economic growth will dump more heat into the air. But as we expect global population to peak at only a couple more billion people, would the energy humanity dumps into the air be comparable to how much the sun dumps into each square meter of the earth every day?
There are a great amount of powers that do not want cheap electricity for the world.
"Giving society cheap, abundant energy at this point would be the equivalent of giving an idiot child a machine gun." - Paul Ehrlich.
Or Amory Lovins, who was advisor to many U.S. presidents who said "If you ask me, it'd be little short of disastrous for us to discover a source of clean, cheap, abundant energy because of what we would do with it."
I completely disagree with the above sentiment, but you can be sure that energy companies will always try to limit supply so that demand can be set at the right price for them to make the profit they want. We're seeing it right now with natural gas cornering the american market. NG's prices are notoriously volatile because it's easy for the companies delivering it to change the supply until demand is where they want it.
The world changes in a very significant way. Three things become true:
1) Oil no longer has to be dug out of the ground, various long chain hydrocarbons can be created with the CO2 in the air and water.
2) Fresh water no longer becomes an issue because arbitrary amounts of sea water can be converted into fresh water.
3) Generally food becomes easier to produce as both more land is available for it (irrigate with desalinated water) and 'food products' like corn aren't used in energy products.
The other two fusion science experiments go under the monikers of 'polywell fusion' and 'focus fusion'. That stays away from the various "low energy nuclear" type devices which are currently considered hoax material (and popular on the e-cat site) by most scientists.
The discovery of a practical fusion system is one of the 'good' things that could happen in the next 50 years which would change the world in mostly 'good' ways (mostly because economies that depend on oil exports would lose pricing authority on oil and slowly collapse, leaving behind angry and often dysfunctional nation-states)
You seem to be assuming zero capital costs for fusion plants and hydrocarbon synth capacity. Think about how cheap those would have to be in order to make oil burning economically unprofitable. And what about after oil price adjusts to decreased demand.
The vast majority of oil production is profitable at very low oil prices (it was still making oil sheiks filthy rich at < $20 a barrel). So you'd need to get something like $5/barrel synthetic oil to stop a free market system from pumping up and burning the fossilized oil.
that's the marginal cost of new hard to reach oil. the existing established wells are on average cheap. eliminating just the hardest few percent of production doesn't help with our co2 problem.
Right, but I think the point was that oil prices will plummet in the presence of cheap fusion power because fossil fuels will no longer be competitive for electricity generation, drastically reducing demand and freeing up capacity for the remaining markets where hydrocarbons still make sense (not that all fossil fuels are fungible, but reallocating natural gas resources to power cars isn't a completely ridiculous idea).
Oil prices won't plummet with a lot less demand, they'll go higher.
There's no real ability for the oil industry to compete on price much below $50 to $60 / barrel energy equivalent. Even Saudi Arabia needs $85 to $100 oil just to pay for its budget these days. Since they can't actually afford to chase energy costs down, the industry would simply fold for the most part.
The volume benefit that oil derives is a critical part of its formula. If you remove the volume, you lose the efficiencies of the oil ecosystem as well. That means losing the pipelines, tankers, and global supply counters to the OPEC cartel (as many nations would give up on oil).
Most likely oil would move to being an expensive niche product, only supplied by those who can drill & ship it the absolute cheapest.
Focus fusion seems to be going really well, though running on a shoestring still causes problems. Polywell is getting a lot of research beyond the Navy project, which is still not talking. Other near-term hot fusion projects:
General Fusion (D-T, well-funded, plasma compressed by molten lead/lithium impacted by steam-driven pistons, the molten mix stops neutrons and breeds tritium)
Sandia's MagLIF (D-T, uses the Z-machine. Simulations say a particular configuration could break even with their current device, and a device three times larger would have 1000x energy gain. Experiments have started and match simulations so far.)
Tri-Alpha (aneutronic, very well funded)
Helion (somewhat similar to Tri-Alpha except I think for D-T, not currently funded but does have funding from NASA for fusion rocket work with similar tech)
Petawatt picosecond laser (only theory so far, the lasers have to get a bit bigger to try it, but recent papers say it'd make aneutronic only ten times harder than D-T, give a 10,000x energy gain, and produce power ten times cheaper than coal. It only takes one laser beam, igniting fuel from the side.)
There was also MIT's levitated dipole, which looked interesting and would work well for D-D fusion but sadly their funding was cut.
Google turns up lots of information on this stuff.
I suspect you haven't worked out the feasibility of large-scale desalinization for food crops in the US. It doesn't seem economically reasonable, at least not until food is an order of magnitude more expensive than now.
We pull out ~30 cubic km of water from the Ogallala Aquifer per year. Let's estimate how much power is needed to replace this with seawater.
At 2780 J/liter, this requires about 3 gigawatts, assuming perfect efficiency. Realistically it's more like 15 GW. Okay, that's doable. The US generates about 1TW of electric power, so 1% would go to desalinization.
Next, you need to pump it to the midwest. The second Los Angeles Aqueduct cost $90 million in 1965 dollars to carry water 137 miles. That's about $500 million in 2013 dollars. The entire Aqueduct transports about 0.4 cubic kilometers of water per year. You'll need about 10x the length to get from the Gulf to the aquifer, and 8x the volume. You'll also need a distribution network, which is likely another 4x to the cost, and you'll need to pump it uphill, which means there's more expensive upkeep.
This sets a low estimate of 300*$5 billion = $1.50 trillion in construction costs, and that's deliberately low-balling the estimate. The Ogallala produces about $20 billion in agriculture each year. I don't think it's financially reasonable.
Also, where do you dump the brine with all of the salt that you've extracted? Back into the Gulf? That's going to seriously affect the marine life. Or do you fully dry out the salt and use it in place of salt mining? I calculate this as 1 gigaton of salt/year, or about 5x the current world production of salt.
Even with free power, it doesn't seem that desalinization could replace the supply that we currently get from the Ogallala Aquifer. At least, not without having much higher food prices.
Instead, you'll have to relocate farming to some place closer to the sea which is also water restricted. In the US, this is ... where? More of the Central Valley? Where is the Nebraska-sized chunk of land by the coast that lacks only water in order to flourish?
Or we import more food from Australia, which seems the prime candidate for this approach.
Have you considered the ramifications of moving where farming is possible? The combination of desalinization and the ability to make long chain hydrocarbons (like fertilizer) means you can farm the San Fernando valley with seawater and take a tremendous load off of the California aqueduct system. Places in Mexico become targets for new farms. All freshwater in the southeastern part of Texas can come from the Gulf of Mexico. It is an interest experiment to look at a map of coastal areas with arid or desert climates, and think about those becoming farmland.
The brine issue is non-existent, as both Qatar and Saudi Arabia have demonstrated with their desalination plants you can pump a lot of sea water through them with the output water having only slightly more salinity than the input water.
That and the fact that fusion power is initially additive to the total power output rather than replacement power. The challenge is of course the numbers. The original Nuclear energy projection of power 'too cheap to measure' was based on an assumption that once nuclear power regulatory structures were in place, the cost to build a plant would converge to something close to the capital costs. That assumption turned out to be false. If it turns out to be false for fusion as well then we'll have different effects.
Well, I guess if it's almost dead then the effect of the brine has a less overall impact. What would the effect be on the shrimp industry in the Gulf?
Saudi Arabia produces 450 million liters per day. That's 5.2 m3/second or 0.16 cubic kilometers/year, or about 1/20th what the Ogallala Aquifer provides. I found that Qatar produces 1.5 million m3/day = 17 m3/second.
http://www.cvwd.org/about/agricultural.php says that the "Coachella Valley Water District delivers 280,000 acre-feet annually ... to irrigate nearly 60,000 acres of farmland." That's 11 m3/second on average, so about the same order of magnitude. Also, "Overall crop production exceeds half a billion dollars a year."
By comparison, Israel has about 460,000 acres of farmland and California has 9 million acres of irrigated land.
Now, how much will the infrastructure cost to build the desalination plants, and the canals, and the pumps needed to make the entire system work against gravity? Even if you assume the power cost is free, there's a lot of maintenance overhead, and the system is more fragile then a gravity fed aqueduct.
I'm definitely not saying that it isn't possible. I pointed out that Australia would be an excellent place for this. That's why I said that it wouldn't be that useful in the US. While you're correct about Texas, that's still only a small percentage of the US farmland, and Texas doesn't have the same weather that makes California so successful.
But using desalinated water for irrigation isn't free/cheap by far, and the cost of power is not the only constraint in making it successful. Any analysis which doesn't include the costs of moving water uphill and delivering it is necessarily incomplete and inadequate.
'fertilizer' -> Ammonium Nitrate - http://en.wikipedia.org/wiki/Ammonium_nitrate (NH4NO3) Nothing more than air (using the Nitrogen) and Water normally the Haber-Bosch process used natural gas as its source of H2 however it is also easily produced by splitting water if the energy is "free".
Sorry, I misunderstood your point. I thought you were saying that you couldn't make fertilizer at a desalinization plant being driven by a fusion reactor.
1960 to 2004 dollars : 650 million
X10 for 10x length 6.5 billion
X8 for 8x volume (pipes are not 2x cost for 2x volume but letes assume 8 pipes for redundancy): 52 billion.
X4 for distribution 208 billion.
Though, as you could just pump it back in the aquifer. And you don't needed redundancy if a the aquifer can provide plenty of buffer so 3x for volume 1.2x for pumping and 1.1 x for distribution is probably a better estimate. = ~25 billion. Assuming you can get the billing down.
As for farming elseware AZ, Texas, etc could grow a lot more crops with a little more irrigation, so could northern Africa and most of Mexico.
D'oh! I copied a "$500 million" as "$5 billion". That's the power of 10 error. Also, I used 1970 dollars since the source I gave said "started in 1965", "took 5 years", "cost $90 million." There's why you have the $650 instead of my $500.
Last time I looked, aquifer recharge was not a simple topic. If the ground has already settled then there isn't as much storage space. I also think you have to pump in from many different places, so there's still the distribution network. You can't fill it up in North Dakota and think of being able to fill up Nebraska as well.
My main point was to show that "Fresh water no longer becomes an issue because arbitrary amounts of sea water can be converted into fresh water." is not a true statement. Even with free power it's still expensive to bring that fresh water to Nebraska.
As I recall, Texas isn't as good a place as California. In "Cadillac Desert", the author, Marc Reisner, points out how the lack of rain in summer means that farmers in California can give exactly as much water as is needed to induce the crops to grow better. ("Better" in a production sense, of course.)
While in Texas, the intermittent rains and occasional downpours would not make that possible. I don't think that an irrigated Texas would have the same productivity as the Central Valley. But I don't know it that means 5% less or 50% less.
Otherwise, yes, I agree that Texas is the best place to take advantage of cheap desalinated water in the US.
No one can answer that question without knowing what "perfected" looks like. A Back to the Future-style Mr. Fusion, which can produce 1.21 GW in a volume the size of a household coffee grinder, is quite different than a large plant which produces the same.
The large power plants based on oil, coal, natural gas, nuclear, etc. are thermal power stations. They use heat to convert liquid water into steam, which then drives steam turbines. These necessarily (by the laws of thermodynamics) produce a lot of waste heat. More than half of the energy used to heat the water is not turned into power at the end.
The waste heat is dumped in the large condensers of the cooling towers, which often have the characteristic hyperboloid shape because it's the most efficient form. This requires a lot of space.
So a commercial fusion system for large-scale use, if it can be built, would likely be little different than a nuclear power plant now, because it requires a big steam turbine at a large facility.
On a smaller scale, you might replace a large ship's diesel engines with electrically-driven fusion powered systems. This would reduce ship pollution and reduce the number of times it needs to refuel. (Assuming that a perfected system needs little maintenance otherwise.)
We don't think it's possible to get fusion power to an even smaller scale, other than people whose proposals and work are difficult to distinguish from a perpetual motion machine scams.
If we did have Mr. Fusion, then it would be a game changer. We would be able to have airplanes and helicopters driven by electric motors, powered by Mr. Fusion. You could probably think about the other things possible of power were essentially free. What about heaters under the sidewalks to melt the ice? I loved going to the outdoor heated pools in Iceland, heated by cheap geothermal. With free power, we would see more outdoor pools elsewhere. More people would have hothouses for growing flowers and plants in winter. Canada could become a major producer of orchids. People in Haiti wouldn't have to strip their country of trees in order to get power. And so on.
Mr. Fusion isn't going to happen, at least not soon. We'll still need transmission lines. This sets a lower limit on the cost of power. Life would be like in Iceland or the Pacific NW, where power is cheap enough that aluminum smelters relocated there for access to cheap power, or where data centers get located in the Dells for cheap power and cooling for data centers. (And where farmers use the cheap power for moving water around.)
In other words, not much different than it is now. Except with less dependency on petroleum sources and the global politics that that entails.
Mr Fusion isn't going to go on board airliners any time soon if Mr Fusion is running on a De/T cycle reaction -- did you notice the He + n side of the equation? Fusion neutrons are not your friend, and a good chunk of the 'magic' of a working fusion reactor is going to lie in how it takes those neutral, uncharged, go-through-lead-like-it's-barely-there neutrons and turns them into heat (and thus electricity).
Note: Lead (and dense materials in general) are not known for their abilities to absorb or slow neutrons - typically shielding is composed of materials composed of a high proportion of light hydrogen atoms, such as water, wax, or plastic.
IIRC, trapping the neutrons in water or some similar compound is how the power is extracted from a D-T reaction. However, my ignorance exceeds my curiosity.
Some of the designs are pretty small-scale, though not Mr. Fusion size. The smallest is focus fusion. The reactor core is the size of a coffee can, and the complete power plant would be about half the size of a shipping container, and produce 5 to 20 MW. Since it would use (mostly) aneutronic boron fusion you could safely locate them near their customers, and remove most of the transmission cost.
They've published a couple papers recently in respectable journals so I think they're easily distinguished from perpetual motion.
By "smaller scale" I meant something smaller than a freighter. 5-20 MW is about what you would use for a freighter. A Liberty ship from WW2 generated 2MW of power.
I couldn't find the "complete power plant" you were talking about. 5 MW in a 0.5 TEU? That's 3m x 2.4m x 2.6m, which is rather small for a 5 MW plant. And rather large for something you want to drive about town in.
Especially since you still need to worry about cooling.
> According to the interview I did with inventor Eric Lerner back in 2005, which was featured at Slashdot, this technology could give birth to a non-polluting power plant the size of a local gas station that would quietly and safely power 4,000 homes
A "local gas station" is much bigger than 0.5 TEU, and a highly vague definition. Assuming a home consumes 2kW then that's producing 8 MW.
Any plans I can find are highly speculative. Where is the published journal article you're talking about? The only ones I can find report experimental measurements of a non-power-producing setup. Any extrapolation from that to a real-world power plant is as highly suspect as "sequencing the human genome will cure cancer within 5 years."
Anyone who sold you plans for a working 5 MW focus fusion generator is almost certainly in the same class as selling you a perpetual motion machine. The best would be "in our optimistic future, we think this might be possible", and not a serious estimate that you could use for planning purposes.
It was published in Physics of Plasmas last year and shows sufficient temperature (1.8 billion C) and confinement time for boron fusion, and also that the fusion is occurring in the confined plasmoid, not the beam, which is a necessary condition for this approach. The remaining hurdle is sufficient density. They think they can do it but we'll see.
I was not claiming that a complete working design exists, which obviously is not the case since they haven't yet achieved net-positive fusion in the lab. Nobody has managed that yet, but focus fusion's ratio of neutron count to input power compares pretty favorably with other approaches so far.
I don't think it's silly to make an informed speculation about what a power plant would look like, if the basic idea turned out to work. NIF for example has been doing a lot of that with their LIFE design, to the point of sourcing specific components.
In the case of focus fusion, most of the power is released as a pulsed beam of charged particles. You can get energy from that by aiming it through a coil, no heat engine required. The rest of the energy goes into x-rays, which can be captured photoelectrically by a foil "onion" around the reactor core. You also need some good switches, a pretty substantial capacitor bank, and cooling. When I said "not Mr. Fusion" I was meaning to imply this would definitely not be something you drive around town in.
Focus fusion certainly isn't something we can "plan" on, any more than a poker player can plan on winning a particular pot. But that doesn't mean it's not a worthwhile bet. The investment is low, the pot is really large, and the odds don't look that bad.
Then I was lead astray by the comment about the engine being 1/2 the size of a shipping container. Where is the source of that speculation and how informed is it?
How much energy can you get from a pulsed beam of charged particles? What's the efficiency level? The same question applies to getting power from X-rays. Photovoltaic is what, 20% at best? Certainly X-ray isn't that efficient.
Which means 5 MW of electrical generation is going to require, what, 20 MW of input power? 500 MW? No matter what, it's going to require a lot of cooling. Enough that saying that it fits into a container doesn't make sense.
And in any case, my statement was "We don't think it's possible to get fusion power to an even smaller scale [than a large ship's diesel engines]." You said "Some of the designs are pretty small-scale", but your example is already my example of a possible valid smaller scale.
So I think this is a case of one of those arguments where we're both on the same side?
The tricky point is the "80% energy efficiency recovery from the beam and X-ray pulse." That seems incredibly high, and it lacks any references. All I could find in my limited search was this paper http://adsabs.harvard.edu/abs/1977epfr.conf.1161Q which uses "X-rays heat a working fluid in a boiler". The Rankine cycle thermodynamics prevent this from having an 80% efficiency.
I used PV as an example because there's been a lot of work to make that efficient, and it's still only at 20% for commercially feasible cells.
Did you notice that for 5MW of electrical power production they are generating 3MW of "losses"? That's about 1,000 tons of cooling (in the wonderful units of cooling. See http://www.trane.com/COMMERCIAL/DNA/View.aspx?i=978 ).
"One TEU represents the cargo capacity of a standard intermodal container, 20 feet (6.1 m) long and 8 feet (2.44 m) wide.[1] There is a lack of standardisation in regards to height, ranging between 4 feet 3 inches (1.30 m) and 9 feet 6 inches (2.90 m), with the most common height being 8 feet 6 inches (2.59 m)."
So just the cooling for this thing will be more than 1 shipping container in size. It certainly wouldn't fit in my (ex-) garage!
That's pretty interesting on cooling. So, maybe gas station size after all. I suppose I can live with that :)
I wouldn't think that comparing to the efficiency of other technologies is really that informative. The nearest thing I can think of to extracting energy from the beam is a linear alternator, which, if the comment here is correct:
http://www.physicsforums.com/showthread.php?t=254589
...can have anywhere from 80% to 95% efficiency. I haven't found anything on the efficiency of photoelectric capture of x-rays, but from what I've seen Lerner seems to think that's the least of his worries. Perhaps he'll feel differently if he gets that far!
www.sunpower.com/library/pdf/publications/Doc0064.pdf says 92%, and higher is possible with more cost.
I really don't see how extracting energy from a charged particle beam can be compared to a linear alternator. The math is quite different. For example, you only extract energy from the front part of the beam, while in a linear alternator it slows down the entire piece of metal.
This causes a problem because when you extract energy from the particles you slow them down. These are charged, so they will repel the particles coming in from behind. The better you are at extracting energy, the more the charged particles get in the way.
The http://lawrencevilleplasmaphysics.com page that you linked to, with the Sankey diagram, does itself a disservice by giving numbers accurate in some cases to 3 significant digits when the error bars are so high, or even unknown. An excess of detail, not based on experimental values, happens to be characteristic of the free energy/perpetual motion machine crowd.
BTW, I misread that chart. It puts net energy at 24.7 kJ and losses at 42kJ, which means that 5 MW electrical production will generate 8.5 MW of heat. It'll need three times as much cooling as I thought it would. The predicted overall efficiency is about the same as other power plants.
Assuming 'perfected' means you could produce power effectively for free: global politics would change a lot, as coal, oil and natural gas prices would drop.
Also, power usage would skyrocket. Obvious growth areas would be flying cars, mining other than for coal/gas/oil (for example, somebody might think of ways to locate likely locations for dinosaur skeletons a mile down and start digging for them) and space exploration.
Flying cars could lead to people living more dispersed (with cars, there is pressure to live near a road; if everybody has a heli, pressure likely would be to not live too close together, as that would make flying your car more dangerous)
Environment-wise, I guess that spread of population would negatively affect nature. On the other hand, with free energy, we would not need fracking or other mining operations might be able to stop pumping up water, recycling it instead.
Chances also are that people would start terraforming on a small scale. For example, Egypt has pyramids and a few tropical beaches, but could have some closer by them. While at it, it also could have ski slopes next to them.
Additional heat production could become a problem, but that would only become problematic if energy consumption grew by huge factors. Solar irradiation in Wh currently is way higher than what is produced from burning coal, gas, etc, and we would produce way fewer greenhouse gases.
It also is fixable. For example, if we were to melt the ice caps because of unlimited energy use, we could paint the poles and, if needed, the Sahara, whiter than they have ever been, thus reflecting more of the sun's heat.
Eventually, I think we would either move mostly of the planet or change earth so much that nobody would recognize it anymore.
The short answer is that realistic fusion plants would have few advantages over uranium fission plants that exist today.
Long answer:
Fuel: Both are likely to use expensive but not scarce fuels but produce so much output from it that it doesn't matter.
Cost: Almost entirely in the plant infrastructure for both. Fusion is likely to be at a permanent disadvantage here, as both coal and fission plants are simple compared to hypothetical fusion plants.
Waste: Likely small advantage to fusion, as it probably won't produce proliferation-sensitive waste just a bunch of irradiated eqiupment and buildings that are easier to deal with.
Safety: It'll probably be more dangerous to work at a fusion plant than a fission one by orders of magnitude, but the negligible danger to people outside the plant will be lower. A Fukushima/Chernobyl situation at a fusion plant would be bad but less bad.
NIMBY: Equal for both, the scariness of an energy generating technology is inversely proportional to its practicality. Did you know that Einstein predicted that a fusion containment loss would cause the atmosphere to light on fire in a runaway reaction that kills all life on earth except for oil company executives and people who work in the advertising industry? Do we really want to take that risk with our children?
See other posts referencing D-T and other fuel cycles. The D is deuterium and the T is tritium. Hydrogen-Hydrogen fusion is more challenging than more exotic types. D-T is, in a sense, the easiest, but both ingredients have non-trivial costs.
The GP post is erudite on activation. Fusion creates a lot of neutrons, which will render the reactor assembly itself radioactive, especially on short timescales. The waste problem is smaller, especially when compared to non-reprocessed fission waste, but not zero. An upside to fusion is the lack of usable bomb material in the waste stream.
Deuterium is pretty cheap. It's 1/2500 of the hydrogen in seawater and easy to separate.
Tritium is bred from lithium, which isn't rare either. The main problem here is that tritium breeding limits the rate at which you can build new reactors. So tritium is going to stay pretty valuable for a while but that price will go down as we build more reactors breeding it.
Neutrons are definitely a problem, and that's one advantage of General Fusion's design, which has lots of lead and lithium to capture the neutrons. Of course the whole problem goes away if one of the boron fusion projects works out.
Looks like deuterium is ~$3000/kg, as heavy water is ~$600/kg [1]. Less expensive than I thought, but still far more expensive than hydrogen at <$0.01/kg when purchased from my local public utility.
It's unfair to compare with hydrogen though - this study [2] suggests that fusion and wind power are roughly comparable in cost.
I'm guessing your second link is based on tokamaks, which are generally considered likely to be far more expensive than some of the lesser-known designs. If they project tokamaks to be competitive with wind then I'm pretty encouraged.
It depends on what kind, as there aren't any viable fusion designs yet. If they involve gigantic magnets or largish amounts of material at surface-of-the-sun temperatures or incredible amounts of neutron flux, costs are going to be high and safety is going to be a problem even compared to fission.
If they can miniaturize it like the Lockheed guy in the OP wants then not so much but nobody really knows if that's possible.
A "fukishima/chernobyl" situation at a fusion plant simply cannot happen. Period. First off, containment is trivial because a shut-down fusion plant generates zero heat and pressure. Zero. Which means that even in a worst case scenario you can just press the big red button and walk away, then come back perhaps years later for any on-site mitigation work. Compare this to a fission reactor where the fission products will continue to generate enough heat to cause a lot of mischief if you don't apply active cooling continuously for decades.
Also, whereas in a fission reactor the byproducts tend to include huge quantities of the worst sorts of hazardous radionuclides such as Sr-90, I-131, and Cs-137 (which are picked up by the human metabolism and then happily radiate your vital organs from within until you die) in contrast a fusion reactor's load of hazardous isotopes is almost trivial. There's a small amount of "activated" isotopes formed by the neutron flux transmuting the structure of the reactor, but this is easily mitigated by picking low activation materials for construction and also by the fact that the materials will tend to be kept in place. The other major risk is Tritium release, but Tritium is not terribly dangerous (it doesn't bioaccumulate, it dilutes rapidly, and it does not stay in the human body long) and the amount that could be released is likely to be small.
Saying that a possible accident at a fusion plant would be "bad but less bad" than Chernobyl is like saying that a paper cut would be "bad but less bad" than a guillotine. They are simply not comparable.
Re "heat sink": Most of the global climatic effects of our current energy infrastructure are due to the greenhouse effect, not direct heating. This stops going, which can only be a good thing (though at this point, a lot of greenhouse gains are already "baked in", absent some significant, and hugely expensive, project to take the greenhouse gases out of the atmosphere).
Should probably get rid of whatever crap site this is... but here is the direct youtube video. He basically talks about a new kind of fusion reactor they've been working on in skunkworks and how it's different from the reactor people have been trying to build forever.
Plasma physicist Pekka Janhunen points out in the comments that the losses in a traditional magnetic trap are high, this is what the Tokamak was invented for in the first place.
I note that submarine reactors are typically on the order of 50Mw, and surface ships (CVNs -- aircraft carriers -- typically; also some Russian Arctic ice-breakers) are up to 100Mw per reactor.
I doubt it, but my understanding of the topic is limited.
AFAIK nuclear reactors are popular on naval warships because they dramatically reduce (and in some cases eliminate) the need to refuel. It's one huge factor crossed off of your logistics problems - modern CVNs can go literally decades without refueling, with the only resupply being jet fuel, munitions, and life support.
Doesn't fusion demand constant refueling (like most power plants)?
If it's possible to proportionally scale down that plant for the sub, then it would produce 50 MW for two decades on the same fuel. A nuclear sub weighs in the neighborhood of 10,000 tons, so 4 tons for fuel seems pretty easy to manage.
Obviously, all these numbers are very rough, but it's probably within an order of magnitude.
I'm a bit surprised about the Lithium use, that seems like a lot. Assuming that we spend the entire early production of Lithium we would only be able to feed 11.000 1GW powerplants.
Potentially. In practice it'd just sit in the reactor for most of the time, it's basically an up-front construction cost, not an ongoing consumable. Out of several tons of natural Lithium you're going to breed some amount of Tritium, but the reactor will only use a few tens of kg of Tritium a year. So in terms of consumables you are only using up a few kg of Lithium per year, not tonnes. Depending on how effective Tritium breeding is it's possible that not all reactors would need to employ the technique. In any event converting a kilogram of Lithium which costs about $100 into fusion fuel which has an energy equivalent to over 5,000 tonnes of coal (worth about half a million dollars) which seems like a pretty good use of materials. Even the cost of tonnes of Lithium would be paid off in the first year of operation several times over.
I think that, just like with fission, the point is that you get a huge amount of energi from very little fuel. So you take on a few kilos/liters of fuel and spend very, very little at a time.
The difference between fission and fusion is that with fission you just load all of it into the reactor at once. With fusion you'll need a "fuel-tank" and feed the reactor continuously, but it's just a few atoms each time.
This is how I understood the concept, it may very well be wrong.
>Doesn't fusion demand constant refueling (like most power plants)?
I don't think the half-life of deuterium/tritium is particularly long, so even if you could store it, it might not last decades before use. Though on the other hand, it's conceivable that you could design the reactor so that it produces deuterium/tritium on site from hydrogen cracked from seawater.
But realistically the reason we want fusion over fission in the first place is the proliferation concern. All of the other arguments against fission are NIMBY nonsense that could be applied equally to a whole swathe of chemical processing facilities that nobody seems to care anything about because they're not OMG nukular. And there is hardly a major proliferation risk from a reactor surrounded by military personnel on a vessel designed to securely carry actual nuclear bombs, so it makes the specifically military application kind of questionable.
We really need fusion for two reasons. 1) There is a better chance that we can actually build a large number of reactors without roving gangs of idiots destroying their cost effectiveness with gratuitous and intentional red tape, and 2) we can build them in countries we don't trust without making it easier for them to blow up the world, which will help to fight global warming vs. those countries continuing to burn oil and coal.
Deuterium doesn't decay, the half-life of tritium though is 12 years, which could be a problem. Though it's possible to breed Tritium from Lithium under neutron bombardment, which could potentially be a feature of a reactor design.
Deuterium is stable. Tritium has a half-life of 12.3 years. Like all proposed fusion reactors, you have to feed fuel in constantly rather than firing it up with a critical mass in situ, but you could store enough Tritium to run an aircraft carrier for a year in a smallish liquid gas cannister. (Smallish by aircraft carrier fuel tank standards.) ((With lead shielding. Lots of lead shielding. Tritium belts out about 9650 Curies of radiation per gram in the shape of beta radiation, which is enough to kill you really quick if you get it on or in you.))
Fusion is unlike fission in that it will require constant resupply of fusion fuels into the reactor during operation, whereas in a fission reactor the fuel can just sit in the reactor for potentially a very long time.
However, this is a distinction without a difference. Fusion fuel has an enormous energy density. For example, the fusion fuel capsule in a half megaton nuclear bomb is the size of a soda can, give or take. Deuterium-Tritium fuel has an energy density of around 3.4e14 Joules/kg or 94 million kilowatt-hours/kg. Even at a paltry 1% efficiency that means that operating a 50 megawatt output fusion reactor continuously for 10 years will only use about 50 kilograms of fuel, which is trivial to store.
Fusion reactors at that scale would revolutionize naval operations.
Right now the carrier is nuclear-powered and can cruise at high speed for as long as it wants. But in practice it can't because the rest of the carrier group runs on oil, and can't keep up. It would change things a lot if the whole group could keep up with the carrier.
This is probably why the Navy has been funding polywell research.
Just a decade away from commercial applications? Hmmm, isn't "the next big breakthrough" always a decade away?
A good rule of thumb: unless the technology has been proven to work and they are just working on commercializing it, "a decade" always means, "we have no idea when we will have anything, if ever."
86 comments
[ 2.2 ms ] story [ 202 ms ] threadhttps://www.solveforx.com/moonshots/ahJzfmdvb2dsZS1zb2x2ZWZv...
or http://www.youtube.com/watch?v=JAsRFVbcyUY
When I was in school studying nuclear engineering, the running joke was that fusion will always be N amount of years away from happening. It seems like every year or so a new company or group of researchers has found a breakthrough that will allow fusion to happen in N amount of years even though we have yet to reach breakeven in a research setting.
I think it would be too much of a competitive disadvantage for a country to not use fusion if it became practical.
If we manage boron fusion, we'll be producing less radiation than burning equivalent coal, and won't have tritium. It's hard to see how anyone would justify regulating that for anything other than electrical safety, just like any other power plant, and for radiation standards on par with medical equipment.
People bring up that joke in the comments section of every fusion article ever published. The fact is, fusion has progressed exponentially since about 1970, about as fast as Moore's Law, despite a level of funding far below what those early optimistic advocates said we needed.
Corollary, IPv6 is always only 5 years away from replacing IPv4
Again though, even those watts of electricity eventually get turned back into heat. Gotta love entropy...
The consequences of us having fusion?
The good, we get cheap, abundant electricity for the entirety of the planet's lifespan with almost no harmful byproducts, made by a nuclear plant that's impossible to melt down or be used in the proliferation of nuclear weapons.
The bad, we have to build the plants, and possibly replace the old ones. That indicates a large shift in jobs, and makes you wonder how we can afford it (although improving economic conditions should make the latter less of a downside as fusion becomes viable).
I'd also like to point out you can only achieve those high efficiency numbers when you're actually using the heat.
If our expectations about fusion's efficiency [2] are correct then in the long run we would have to worry much less about our conventional sources of energy and the environmental price that comes with using them. The questions of peak oil and CO_2 emissions would be at least partially defused regardless of how much of a threat they really represent.
[1] https://en.wikipedia.org/wiki/Fusion_power#Accident_potentia...
[2] http://focusfusion.org/index.php/site/article/its_not_fissio...
And that's why I don't think it will impact economic growth that much. But it will hopefully reduce our CO2 emissions.
The reduced CO2 should make the climate colder. Continued economic growth will dump more heat into the air. But as we expect global population to peak at only a couple more billion people, would the energy humanity dumps into the air be comparable to how much the sun dumps into each square meter of the earth every day?
Economic growth is hugely tied to energy costs.
The sun delivers a huge quantity of energy compared with that used by humans.
http://en.wikipedia.org/wiki/Earths_energy_budget
"Giving society cheap, abundant energy at this point would be the equivalent of giving an idiot child a machine gun." - Paul Ehrlich.
Or Amory Lovins, who was advisor to many U.S. presidents who said "If you ask me, it'd be little short of disastrous for us to discover a source of clean, cheap, abundant energy because of what we would do with it."
I completely disagree with the above sentiment, but you can be sure that energy companies will always try to limit supply so that demand can be set at the right price for them to make the profit they want. We're seeing it right now with natural gas cornering the american market. NG's prices are notoriously volatile because it's easy for the companies delivering it to change the supply until demand is where they want it.
1) Oil no longer has to be dug out of the ground, various long chain hydrocarbons can be created with the CO2 in the air and water.
2) Fresh water no longer becomes an issue because arbitrary amounts of sea water can be converted into fresh water.
3) Generally food becomes easier to produce as both more land is available for it (irrigate with desalinated water) and 'food products' like corn aren't used in energy products.
The other two fusion science experiments go under the monikers of 'polywell fusion' and 'focus fusion'. That stays away from the various "low energy nuclear" type devices which are currently considered hoax material (and popular on the e-cat site) by most scientists.
The discovery of a practical fusion system is one of the 'good' things that could happen in the next 50 years which would change the world in mostly 'good' ways (mostly because economies that depend on oil exports would lose pricing authority on oil and slowly collapse, leaving behind angry and often dysfunctional nation-states)
The vast majority of oil production is profitable at very low oil prices (it was still making oil sheiks filthy rich at < $20 a barrel). So you'd need to get something like $5/barrel synthetic oil to stop a free market system from pumping up and burning the fossilized oil.
There's no real ability for the oil industry to compete on price much below $50 to $60 / barrel energy equivalent. Even Saudi Arabia needs $85 to $100 oil just to pay for its budget these days. Since they can't actually afford to chase energy costs down, the industry would simply fold for the most part.
The volume benefit that oil derives is a critical part of its formula. If you remove the volume, you lose the efficiencies of the oil ecosystem as well. That means losing the pipelines, tankers, and global supply counters to the OPEC cartel (as many nations would give up on oil).
Most likely oil would move to being an expensive niche product, only supplied by those who can drill & ship it the absolute cheapest.
General Fusion (D-T, well-funded, plasma compressed by molten lead/lithium impacted by steam-driven pistons, the molten mix stops neutrons and breeds tritium)
Sandia's MagLIF (D-T, uses the Z-machine. Simulations say a particular configuration could break even with their current device, and a device three times larger would have 1000x energy gain. Experiments have started and match simulations so far.)
Tri-Alpha (aneutronic, very well funded)
Helion (somewhat similar to Tri-Alpha except I think for D-T, not currently funded but does have funding from NASA for fusion rocket work with similar tech)
Petawatt picosecond laser (only theory so far, the lasers have to get a bit bigger to try it, but recent papers say it'd make aneutronic only ten times harder than D-T, give a 10,000x energy gain, and produce power ten times cheaper than coal. It only takes one laser beam, igniting fuel from the side.)
There was also MIT's levitated dipole, which looked interesting and would work well for D-D fusion but sadly their funding was cut.
Google turns up lots of information on this stuff.
We pull out ~30 cubic km of water from the Ogallala Aquifer per year. Let's estimate how much power is needed to replace this with seawater.
At 2780 J/liter, this requires about 3 gigawatts, assuming perfect efficiency. Realistically it's more like 15 GW. Okay, that's doable. The US generates about 1TW of electric power, so 1% would go to desalinization.
Next, you need to pump it to the midwest. The second Los Angeles Aqueduct cost $90 million in 1965 dollars to carry water 137 miles. That's about $500 million in 2013 dollars. The entire Aqueduct transports about 0.4 cubic kilometers of water per year. You'll need about 10x the length to get from the Gulf to the aquifer, and 8x the volume. You'll also need a distribution network, which is likely another 4x to the cost, and you'll need to pump it uphill, which means there's more expensive upkeep.
This sets a low estimate of 300*$5 billion = $1.50 trillion in construction costs, and that's deliberately low-balling the estimate. The Ogallala produces about $20 billion in agriculture each year. I don't think it's financially reasonable.
Also, where do you dump the brine with all of the salt that you've extracted? Back into the Gulf? That's going to seriously affect the marine life. Or do you fully dry out the salt and use it in place of salt mining? I calculate this as 1 gigaton of salt/year, or about 5x the current world production of salt.
Even with free power, it doesn't seem that desalinization could replace the supply that we currently get from the Ogallala Aquifer. At least, not without having much higher food prices.
Instead, you'll have to relocate farming to some place closer to the sea which is also water restricted. In the US, this is ... where? More of the Central Valley? Where is the Nebraska-sized chunk of land by the coast that lacks only water in order to flourish?
Or we import more food from Australia, which seems the prime candidate for this approach.
The brine issue is non-existent, as both Qatar and Saudi Arabia have demonstrated with their desalination plants you can pump a lot of sea water through them with the output water having only slightly more salinity than the input water.
That and the fact that fusion power is initially additive to the total power output rather than replacement power. The challenge is of course the numbers. The original Nuclear energy projection of power 'too cheap to measure' was based on an assumption that once nuclear power regulatory structures were in place, the cost to build a plant would converge to something close to the capital costs. That assumption turned out to be false. If it turns out to be false for fusion as well then we'll have different effects.
The brine issue is not non-existent. http://www.thenational.ae/news/uae-news/environment/desalina... "Between the tankers, pollution from urban centres and the brine disposed from desalination plants, the Gulf is almost dead."
Well, I guess if it's almost dead then the effect of the brine has a less overall impact. What would the effect be on the shrimp industry in the Gulf?
Saudi Arabia produces 450 million liters per day. That's 5.2 m3/second or 0.16 cubic kilometers/year, or about 1/20th what the Ogallala Aquifer provides. I found that Qatar produces 1.5 million m3/day = 17 m3/second.
http://www.cvwd.org/about/agricultural.php says that the "Coachella Valley Water District delivers 280,000 acre-feet annually ... to irrigate nearly 60,000 acres of farmland." That's 11 m3/second on average, so about the same order of magnitude. Also, "Overall crop production exceeds half a billion dollars a year."
By comparison, Israel has about 460,000 acres of farmland and California has 9 million acres of irrigated land.
Now, how much will the infrastructure cost to build the desalination plants, and the canals, and the pumps needed to make the entire system work against gravity? Even if you assume the power cost is free, there's a lot of maintenance overhead, and the system is more fragile then a gravity fed aqueduct.
I'm definitely not saying that it isn't possible. I pointed out that Australia would be an excellent place for this. That's why I said that it wouldn't be that useful in the US. While you're correct about Texas, that's still only a small percentage of the US farmland, and Texas doesn't have the same weather that makes California so successful.
But using desalinated water for irrigation isn't free/cheap by far, and the cost of power is not the only constraint in making it successful. Any analysis which doesn't include the costs of moving water uphill and delivering it is necessarily incomplete and inadequate.
"In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon" - http://en.wikipedia.org/wiki/Hydrocarbon
"an organic compound (as acetylene or butane) containing only carbon and hydrogen and often occurring in petroleum, natural gas, coal, and bitumens " - http://www.merriam-webster.com/dictionary/hydrocarbon
(And it looks like I shouldn't have included oxygen.)
1960 to 2004 dollars : 650 million X10 for 10x length 6.5 billion X8 for 8x volume (pipes are not 2x cost for 2x volume but letes assume 8 pipes for redundancy): 52 billion. X4 for distribution 208 billion.
Though, as you could just pump it back in the aquifer. And you don't needed redundancy if a the aquifer can provide plenty of buffer so 3x for volume 1.2x for pumping and 1.1 x for distribution is probably a better estimate. = ~25 billion. Assuming you can get the billing down.
As for farming elseware AZ, Texas, etc could grow a lot more crops with a little more irrigation, so could northern Africa and most of Mexico.
Last time I looked, aquifer recharge was not a simple topic. If the ground has already settled then there isn't as much storage space. I also think you have to pump in from many different places, so there's still the distribution network. You can't fill it up in North Dakota and think of being able to fill up Nebraska as well.
My main point was to show that "Fresh water no longer becomes an issue because arbitrary amounts of sea water can be converted into fresh water." is not a true statement. Even with free power it's still expensive to bring that fresh water to Nebraska.
As I recall, Texas isn't as good a place as California. In "Cadillac Desert", the author, Marc Reisner, points out how the lack of rain in summer means that farmers in California can give exactly as much water as is needed to induce the crops to grow better. ("Better" in a production sense, of course.)
While in Texas, the intermittent rains and occasional downpours would not make that possible. I don't think that an irrigated Texas would have the same productivity as the Central Valley. But I don't know it that means 5% less or 50% less.
Otherwise, yes, I agree that Texas is the best place to take advantage of cheap desalinated water in the US.
The large power plants based on oil, coal, natural gas, nuclear, etc. are thermal power stations. They use heat to convert liquid water into steam, which then drives steam turbines. These necessarily (by the laws of thermodynamics) produce a lot of waste heat. More than half of the energy used to heat the water is not turned into power at the end.
The waste heat is dumped in the large condensers of the cooling towers, which often have the characteristic hyperboloid shape because it's the most efficient form. This requires a lot of space.
So a commercial fusion system for large-scale use, if it can be built, would likely be little different than a nuclear power plant now, because it requires a big steam turbine at a large facility.
On a smaller scale, you might replace a large ship's diesel engines with electrically-driven fusion powered systems. This would reduce ship pollution and reduce the number of times it needs to refuel. (Assuming that a perfected system needs little maintenance otherwise.)
We don't think it's possible to get fusion power to an even smaller scale, other than people whose proposals and work are difficult to distinguish from a perpetual motion machine scams.
If we did have Mr. Fusion, then it would be a game changer. We would be able to have airplanes and helicopters driven by electric motors, powered by Mr. Fusion. You could probably think about the other things possible of power were essentially free. What about heaters under the sidewalks to melt the ice? I loved going to the outdoor heated pools in Iceland, heated by cheap geothermal. With free power, we would see more outdoor pools elsewhere. More people would have hothouses for growing flowers and plants in winter. Canada could become a major producer of orchids. People in Haiti wouldn't have to strip their country of trees in order to get power. And so on.
Mr. Fusion isn't going to happen, at least not soon. We'll still need transmission lines. This sets a lower limit on the cost of power. Life would be like in Iceland or the Pacific NW, where power is cheap enough that aluminum smelters relocated there for access to cheap power, or where data centers get located in the Dells for cheap power and cooling for data centers. (And where farmers use the cheap power for moving water around.)
In other words, not much different than it is now. Except with less dependency on petroleum sources and the global politics that that entails.
No, it makes no physical sense. Perhaps it's a branding name, since "Mr. Zero Point Energy" doesn't flow as well.
They've published a couple papers recently in respectable journals so I think they're easily distinguished from perpetual motion.
I couldn't find the "complete power plant" you were talking about. 5 MW in a 0.5 TEU? That's 3m x 2.4m x 2.6m, which is rather small for a 5 MW plant. And rather large for something you want to drive about town in.
Especially since you still need to worry about cooling.
The closest numbers I could find was http://pesn.com/2011/01/12/9501741_Focus_Fusion_achieves_1-b... which said:
> According to the interview I did with inventor Eric Lerner back in 2005, which was featured at Slashdot, this technology could give birth to a non-polluting power plant the size of a local gas station that would quietly and safely power 4,000 homes
A "local gas station" is much bigger than 0.5 TEU, and a highly vague definition. Assuming a home consumes 2kW then that's producing 8 MW.
Any plans I can find are highly speculative. Where is the published journal article you're talking about? The only ones I can find report experimental measurements of a non-power-producing setup. Any extrapolation from that to a real-world power plant is as highly suspect as "sequencing the human genome will cure cancer within 5 years."
Anyone who sold you plans for a working 5 MW focus fusion generator is almost certainly in the same class as selling you a perpetual motion machine. The best would be "in our optimistic future, we think this might be possible", and not a serious estimate that you could use for planning purposes.
It was published in Physics of Plasmas last year and shows sufficient temperature (1.8 billion C) and confinement time for boron fusion, and also that the fusion is occurring in the confined plasmoid, not the beam, which is a necessary condition for this approach. The remaining hurdle is sufficient density. They think they can do it but we'll see.
I was not claiming that a complete working design exists, which obviously is not the case since they haven't yet achieved net-positive fusion in the lab. Nobody has managed that yet, but focus fusion's ratio of neutron count to input power compares pretty favorably with other approaches so far.
I don't think it's silly to make an informed speculation about what a power plant would look like, if the basic idea turned out to work. NIF for example has been doing a lot of that with their LIFE design, to the point of sourcing specific components.
In the case of focus fusion, most of the power is released as a pulsed beam of charged particles. You can get energy from that by aiming it through a coil, no heat engine required. The rest of the energy goes into x-rays, which can be captured photoelectrically by a foil "onion" around the reactor core. You also need some good switches, a pretty substantial capacitor bank, and cooling. When I said "not Mr. Fusion" I was meaning to imply this would definitely not be something you drive around town in.
Focus fusion certainly isn't something we can "plan" on, any more than a poker player can plan on winning a particular pot. But that doesn't mean it's not a worthwhile bet. The investment is low, the pot is really large, and the odds don't look that bad.
How much energy can you get from a pulsed beam of charged particles? What's the efficiency level? The same question applies to getting power from X-rays. Photovoltaic is what, 20% at best? Certainly X-ray isn't that efficient.
Which means 5 MW of electrical generation is going to require, what, 20 MW of input power? 500 MW? No matter what, it's going to require a lot of cooling. Enough that saying that it fits into a container doesn't make sense.
And in any case, my statement was "We don't think it's possible to get fusion power to an even smaller scale [than a large ship's diesel engines]." You said "Some of the designs are pretty small-scale", but your example is already my example of a possible valid smaller scale.
So I think this is a case of one of those arguments where we're both on the same side?
Here's a diagram showing the energy flow they expect, if things work out: http://lawrencevilleplasmaphysics.com/index.php?option=com_l...
Overall energy balance of focus fusion reactors would be somewhat marginal, nothing like the 100x to 1000x that Sandia's talking about for MagLIF.
In this diagram they mention "garage-size." The "onion" is photoelectric, not photovoltaic.
I used PV as an example because there's been a lot of work to make that efficient, and it's still only at 20% for commercially feasible cells.
Did you notice that for 5MW of electrical power production they are generating 3MW of "losses"? That's about 1,000 tons of cooling (in the wonderful units of cooling. See http://www.trane.com/COMMERCIAL/DNA/View.aspx?i=978 ).
If you air cool the system then you'll need a tower with dimensions about 14'x22'x19' ( http://www.trane.com/CPS/uploads/userfiles/chillers/coolingt... )
"One TEU represents the cargo capacity of a standard intermodal container, 20 feet (6.1 m) long and 8 feet (2.44 m) wide.[1] There is a lack of standardisation in regards to height, ranging between 4 feet 3 inches (1.30 m) and 9 feet 6 inches (2.90 m), with the most common height being 8 feet 6 inches (2.59 m)."
So just the cooling for this thing will be more than 1 shipping container in size. It certainly wouldn't fit in my (ex-) garage!
I wouldn't think that comparing to the efficiency of other technologies is really that informative. The nearest thing I can think of to extracting energy from the beam is a linear alternator, which, if the comment here is correct: http://www.physicsforums.com/showthread.php?t=254589
...can have anywhere from 80% to 95% efficiency. I haven't found anything on the efficiency of photoelectric capture of x-rays, but from what I've seen Lerner seems to think that's the least of his worries. Perhaps he'll feel differently if he gets that far!
I really don't see how extracting energy from a charged particle beam can be compared to a linear alternator. The math is quite different. For example, you only extract energy from the front part of the beam, while in a linear alternator it slows down the entire piece of metal.
This causes a problem because when you extract energy from the particles you slow them down. These are charged, so they will repel the particles coming in from behind. The better you are at extracting energy, the more the charged particles get in the way.
The http://lawrencevilleplasmaphysics.com page that you linked to, with the Sankey diagram, does itself a disservice by giving numbers accurate in some cases to 3 significant digits when the error bars are so high, or even unknown. An excess of detail, not based on experimental values, happens to be characteristic of the free energy/perpetual motion machine crowd.
BTW, I misread that chart. It puts net energy at 24.7 kJ and losses at 42kJ, which means that 5 MW electrical production will generate 8.5 MW of heat. It'll need three times as much cooling as I thought it would. The predicted overall efficiency is about the same as other power plants.
Also, power usage would skyrocket. Obvious growth areas would be flying cars, mining other than for coal/gas/oil (for example, somebody might think of ways to locate likely locations for dinosaur skeletons a mile down and start digging for them) and space exploration.
Flying cars could lead to people living more dispersed (with cars, there is pressure to live near a road; if everybody has a heli, pressure likely would be to not live too close together, as that would make flying your car more dangerous)
Environment-wise, I guess that spread of population would negatively affect nature. On the other hand, with free energy, we would not need fracking or other mining operations might be able to stop pumping up water, recycling it instead.
Chances also are that people would start terraforming on a small scale. For example, Egypt has pyramids and a few tropical beaches, but could have some closer by them. While at it, it also could have ski slopes next to them.
Additional heat production could become a problem, but that would only become problematic if energy consumption grew by huge factors. Solar irradiation in Wh currently is way higher than what is produced from burning coal, gas, etc, and we would produce way fewer greenhouse gases.
It also is fixable. For example, if we were to melt the ice caps because of unlimited energy use, we could paint the poles and, if needed, the Sahara, whiter than they have ever been, thus reflecting more of the sun's heat.
Eventually, I think we would either move mostly of the planet or change earth so much that nobody would recognize it anymore.
Long answer:
Fuel: Both are likely to use expensive but not scarce fuels but produce so much output from it that it doesn't matter.
Cost: Almost entirely in the plant infrastructure for both. Fusion is likely to be at a permanent disadvantage here, as both coal and fission plants are simple compared to hypothetical fusion plants.
Waste: Likely small advantage to fusion, as it probably won't produce proliferation-sensitive waste just a bunch of irradiated eqiupment and buildings that are easier to deal with.
Safety: It'll probably be more dangerous to work at a fusion plant than a fission one by orders of magnitude, but the negligible danger to people outside the plant will be lower. A Fukushima/Chernobyl situation at a fusion plant would be bad but less bad.
NIMBY: Equal for both, the scariness of an energy generating technology is inversely proportional to its practicality. Did you know that Einstein predicted that a fusion containment loss would cause the atmosphere to light on fire in a runaway reaction that kills all life on earth except for oil company executives and people who work in the advertising industry? Do we really want to take that risk with our children?
http://en.wikipedia.org/wiki/Fusion_power#Fuel_cycle
The GP post is erudite on activation. Fusion creates a lot of neutrons, which will render the reactor assembly itself radioactive, especially on short timescales. The waste problem is smaller, especially when compared to non-reprocessed fission waste, but not zero. An upside to fusion is the lack of usable bomb material in the waste stream.
So, safer, yes, but not completely safe.
Tritium is bred from lithium, which isn't rare either. The main problem here is that tritium breeding limits the rate at which you can build new reactors. So tritium is going to stay pretty valuable for a while but that price will go down as we build more reactors breeding it.
Neutrons are definitely a problem, and that's one advantage of General Fusion's design, which has lots of lead and lithium to capture the neutrons. Of course the whole problem goes away if one of the boron fusion projects works out.
It's unfair to compare with hydrogen though - this study [2] suggests that fusion and wind power are roughly comparable in cost.
[1] http://reactorscanada.com/2008/05/21/is-there-enough-heavy-w...
[2] http://www.energyresearch.nl/energieopties/kernfusie/achterg...
I'm guessing your second link is based on tokamaks, which are generally considered likely to be far more expensive than some of the lesser-known designs. If they project tokamaks to be competitive with wind then I'm pretty encouraged.
If they can miniaturize it like the Lockheed guy in the OP wants then not so much but nobody really knows if that's possible.
A "fukishima/chernobyl" situation at a fusion plant simply cannot happen. Period. First off, containment is trivial because a shut-down fusion plant generates zero heat and pressure. Zero. Which means that even in a worst case scenario you can just press the big red button and walk away, then come back perhaps years later for any on-site mitigation work. Compare this to a fission reactor where the fission products will continue to generate enough heat to cause a lot of mischief if you don't apply active cooling continuously for decades.
Also, whereas in a fission reactor the byproducts tend to include huge quantities of the worst sorts of hazardous radionuclides such as Sr-90, I-131, and Cs-137 (which are picked up by the human metabolism and then happily radiate your vital organs from within until you die) in contrast a fusion reactor's load of hazardous isotopes is almost trivial. There's a small amount of "activated" isotopes formed by the neutron flux transmuting the structure of the reactor, but this is easily mitigated by picking low activation materials for construction and also by the fact that the materials will tend to be kept in place. The other major risk is Tritium release, but Tritium is not terribly dangerous (it doesn't bioaccumulate, it dilutes rapidly, and it does not stay in the human body long) and the amount that could be released is likely to be small.
Saying that a possible accident at a fusion plant would be "bad but less bad" than Chernobyl is like saying that a paper cut would be "bad but less bad" than a guillotine. They are simply not comparable.
Here's a physicist doing the math: http://scienceblogs.com/principles/2013/02/19/direct-and-ind...
https://www.youtube.com/watch?v=JAsRFVbcyUY
(That's also what the Polywell tries to solve).
Haven't watched the video.
Anyone smell a [Naval] market?
AFAIK nuclear reactors are popular on naval warships because they dramatically reduce (and in some cases eliminate) the need to refuel. It's one huge factor crossed off of your logistics problems - modern CVNs can go literally decades without refueling, with the only resupply being jet fuel, munitions, and life support.
Doesn't fusion demand constant refueling (like most power plants)?
> A 1 GW fusion plant will need about 100 Kg of deuterium and 3 tons of natural lithium to operate for a whole year, generating about 7 billion kWh.
http://fusionforenergy.europa.eu/faq/
If it's possible to proportionally scale down that plant for the sub, then it would produce 50 MW for two decades on the same fuel. A nuclear sub weighs in the neighborhood of 10,000 tons, so 4 tons for fuel seems pretty easy to manage.
Obviously, all these numbers are very rough, but it's probably within an order of magnitude.
The difference between fission and fusion is that with fission you just load all of it into the reactor at once. With fusion you'll need a "fuel-tank" and feed the reactor continuously, but it's just a few atoms each time.
This is how I understood the concept, it may very well be wrong.
I don't think the half-life of deuterium/tritium is particularly long, so even if you could store it, it might not last decades before use. Though on the other hand, it's conceivable that you could design the reactor so that it produces deuterium/tritium on site from hydrogen cracked from seawater.
But realistically the reason we want fusion over fission in the first place is the proliferation concern. All of the other arguments against fission are NIMBY nonsense that could be applied equally to a whole swathe of chemical processing facilities that nobody seems to care anything about because they're not OMG nukular. And there is hardly a major proliferation risk from a reactor surrounded by military personnel on a vessel designed to securely carry actual nuclear bombs, so it makes the specifically military application kind of questionable.
We really need fusion for two reasons. 1) There is a better chance that we can actually build a large number of reactors without roving gangs of idiots destroying their cost effectiveness with gratuitous and intentional red tape, and 2) we can build them in countries we don't trust without making it easier for them to blow up the world, which will help to fight global warming vs. those countries continuing to burn oil and coal.
However, this is a distinction without a difference. Fusion fuel has an enormous energy density. For example, the fusion fuel capsule in a half megaton nuclear bomb is the size of a soda can, give or take. Deuterium-Tritium fuel has an energy density of around 3.4e14 Joules/kg or 94 million kilowatt-hours/kg. Even at a paltry 1% efficiency that means that operating a 50 megawatt output fusion reactor continuously for 10 years will only use about 50 kilograms of fuel, which is trivial to store.
Right now the carrier is nuclear-powered and can cruise at high speed for as long as it wants. But in practice it can't because the rest of the carrier group runs on oil, and can't keep up. It would change things a lot if the whole group could keep up with the carrier.
This is probably why the Navy has been funding polywell research.
A good rule of thumb: unless the technology has been proven to work and they are just working on commercializing it, "a decade" always means, "we have no idea when we will have anything, if ever."