Molten Salt-Based Solar Power Plant

rcastro0 writes "Hamilton Sundstrand, a division of United Technologies, announced today that it will start to commercialize a new type of solar power plant. A new company called SolarReserve will be created to provide heat-resistant pumps and other equipment, as well as the expertise in handling and storing salt that has been heated to more than 1,050 degrees Fahrenheit. According to venture capitalist Vinod Khosla 'Three percent of the land area of Morocco could support all of the electricity for Western Europe.' Molten Salt storage is already used in Nevada's Solar One power plant. Is this the post-hydrocarbon world finally knocking?"

Comments

sun renewable?

[achilles777033]

The system's main energy source, the sun, is renewable and costs nothing.

So Gene Wolfe was right?
http://en.wikipedia.org/wiki/Book_of_the_new_sun/
http://en.wikipedia.org/wiki/The_Urth_of_the_New_Sun/

Re:sun renewable?

[rustalot42684]

I got in trouble for that in grade 5 when I pointed out that the sun would eventually die out. I was told "Well, it's not going to die out in our lifetimes". I replied with "So are oil and gas renewable resources if they aren't depleted before we die?". The teacher put on my report card " ... seems to have trouble distinguishing between renewable and non-renewable resources."

Re:sun renewable?

[JoshHeitzman]

No she was not right. A renewable resource is one that we humans can currently cause to be renewed through our own actions. For example when we harvest plants we can plant new ones in their place. Wind, hydro, and solar power all come from the sun. Tidal power comes from the moon and a lesser extent the sun. Geo-thermal comes from the earth. We humans do not currently have the ability replace the sun or increase its life span. We also do not have the ability to prevent the earth and moon from becoming tide locked. Nor do we have the ability keep the Earth from eventually growing cold. Some day we may have that ability, but it seems likely that we will have developed fusion in order to supply the energy needed to implement those capabilities in which case we won't need energy from those sources any longer and we'll be pulling the matter we need to fuel the fusion reactors from the ocean and then quite probably gas giants. It's also interesting to note that we do have the capability of creating coal from wood (i.e. charcoal) so we could replace the coal we consume, there just isn't much of a point in doing so for most electricity generation as it would be better burn the wood directly (or use the same land to produce crop that yield more useable BTUs per acre). Similarly we can create crude oil from organic matter using thermal depolymerization. Never looked into the generation of natural gas or propane, so I'm not sure if that's feasible at the moment.

Re:sun renewable?

[Urkki]

No she was not right. A renewable resource is one that we humans can currently cause to be renewed through our own actions. For example when we harvest plants we can plant new ones in their place. Wind, hydro, and solar power all come from the sun. And just where do you think the energy for the plant to grow (form organic molecules for structure and energy storage) comes from?

There is no *real* renewable energy, laws of ethropy make that an impossible thing. A perpetual motion machine is impossible (as far as we know). That's why "renewable energy" means something else, basically an energy source that is not permanently depleted by us humans using it.

It's a bit of a definition issue really. For example there is some controversy wether peat should be considered renewable or non-renewable, as it takes hundreds or thousands of years for a peat swamp to accumulate. Still, if you count all the peat accumulated over a year, you can harvest an awful lot of it without taking more than is accumulated back.

So the teacher was right, but apparently she was unable to explain or understand the conecpt properly, which isn't very good either.

Re:sun renewable?

[Dorceon]

I guess the relevant terms should be exhaustable vs. non-exhaustable. Using sunlight for power doesn't change when the sun will die. Using fossil fuels for power changes when the fossil fuels will run out.

Re:sun renewable?

[Urkki]

The energy for the plants comes from light of course, but it doesn't have to come from the sun. Any light source emitting the appropriate wavelength(s) will do. Resource have other uses then energy such as lumber, paper, thread, drugs, etc. If we ever figure out controlled sustainable fusion we'll no longer be dependent on the sun as our primary energy source. I also didn't say that renewable resources were infinite, I merely said that we currently have the ability to replace those that we use which is something we can do for coal and oil but not for the sun. I'm not sure I understand what you are trying to say...

Synthesized oil or coal are not energy sources, they are ways to store energy. Energy for the synthetication must come from some actual energy source. Fossil oil and coal are energy sources for humans, but they are non-renewable because more of them will not appear from anywhere (not in human time-scales anyway), and they get less and less as we use them. And even though the energy for the fossil fuels came from the Sun, we are harvesting it from the fossil fuel, so the fossil fuel is considered to be the energy source for us (and same with wind power etc), even if it is originally the Sun's energy (which is originally energy from the Big Bang, which got it's energy from nobody-really-knows-where).

Also, plants grown with other than sun light aren't energy sources. Then the energy source is whatever is used to power the artifical lights for growing them.

Fusion energy will not be renewable either, because the more we use it, the less of it there is left. There's just so much of it (except usable reserves of the "ultimate fusion fuel", Helium-3, may be limited within our solar system) that we won't run out.

Sun's enegy output is the only known renewable origin of energy in our solar system, because it doesn't matter if we use it or not, there won't be any more or any less of it left, no matter how much solar energy we collect. Also, any energy source that uses the Sun's energy and grows/accumulates back in human time-scales, is considered renewable, such as wind or naturally (without non-renewable fossil fuel based fertilizers) grown biomass. They "come back" quite fast, and if we use it at most at that rate, we will never run out.

Pretty light on detail

[AshtangiMan]

Don't current adsorption chillers use solar heat/ molten salt? A pretty week summary but perhaps someone out there knows how this works . . .

Re:Pretty light on detail

[jcaldwel]

I'm with you, I wanted more info. I found a page with a little more technical information about how this works: http://www-stud.fht-esslingen.de/projects/alt_energy/sol_thermal/powertower.html

Re:Pretty light on detail

[bluelip]

The guy above me may be correct.

Specific heat capacity and the ability to move the energy store are more important than the rate at which the material conducts thermal energy.

Re:Pretty light on detail

[modecx]

Metals can be a great conductor alright, but most aren't all that great at storing heat, especially compared to water, which has every metal beat to a margin greater than 5:1. At any rate, you misunderstand the purpose of the molten salt. It's there to move heat alright, but not entirely through heat conduction. Heat conduction is far too slow a process be used in a multi megawatt power plant. The molten salt is there because it's pumpable, so that it can quickly gather up a bunch of energy from the reflectors, and just as quickly dump it through conduction when the heat is used to make steam. Water is king, in terms of storing heat, unfortunately it turns to gas at a relatively low temperature. Fortunately, it can be stored under pressure, unfortunately the pressure goes up very much at very high temperatures, which makes containing it more expensive, more dangerous and generally harder to do.

Heat engines also require a big temperature gradient to do work at high efficiency, which makes using steam directly a harder proposal. Molten salt is well understood in used as a coolant in some types of nuclear reactors, and it works well for this purpose, and that's why it's used.

Re:Pretty light on detail

[falconwolf]

The molten salt is there because it's pumpable, so that it can quickly gather up a bunch of energy from the reflectors, and just as quickly dump it through conduction when the heat is used to make steam. Water is king, in terms of storing heat, unfortunately it turns to gas at a relatively low temperature.

However in cases like the Nevada Solar One power plant, it's oil that is circulated through tubes and is heated. Then the heated oil goes through a heat exchanger where the heat is transfered to water which spins the turbines. Only if the heat can't be used right away will the heat be transfered to the salt, which stores the heat for later use.

Falcon

Re:Pretty light on detail

[ibbey]

I suspect that this is the difference between this latest invention and the the current tech, though it's certainly not clear from the article. The January '08 issue of Scientific American covers this topic, and they say that one of the breakthroughs needed for molten salt solar is to be able to directly use the molten salt as the transfer fluid. The article doesn't go into a lot of detail on this topic, but here's the quote:

Engineers are also investigating how to us molten salt itself as the heat-transfer fluid, reducing heat losses as well as capital costs. Salt is corrosive, however, so more resilient piping systems are needed.

The article is available online, and I highly recommend anyone interested in solar check it out. They outline a plan that could provide 69% of the countries electricity & 35% of it's total energy from solar by 2050.

Re:Pretty light on detail

[TooMuchToDo]

'Twas an excellent article, although I disagree with some of their points. While we should be building out renewable infrastructure as quickly as possible, we shouldn't put all of our eggs in one basket with solar. Also, they don't take base load into account. Yes, we're working on methods to store the solar energy during the night through molten salt, but if it's not quite there yet, we shouldn't base a plan on it that needs to work at all costs.

Re:Pretty light on detail

[TooMuchToDo]

Yes, I read the whole article (about 2 days ago, as I subscribe to SciAm). A recent Nature article has already noted that we've most likely hit a tipping point of CO2 parts per million in the atmosphere. Using natural gas is unacceptable, as any plan going forward has to eliminate CO2 emissions, not just reduce them. A more prudent solution would be for wind and solar to shave peak loads during the day, as well as charge electric vehicles, while nuclear and hydro would be base load for night power usage. I can't stress this enough though. CO2 emissions have to be eliminated due to how much we've already dumped into the atmosphere. Sounds crazy? Check back with me in 3-5 years when carbon sinks such as the ocean and rain forests refuse to absorb more CO2 because they've become saturated, and global warming accelerates.

Re:Pretty light on detail

[Mark_MF-WN]

The larger the plant gets, the more inefficient it gets.

Actually, this the exact opposite of reality. Larger plants are vastly more efficient. Otherwise, all of the world's power would be provided by trillions of 500 milliwatt plants rather than thousands of 500 megawatt plants.

Think about it -- these plants have to store heat; heat is proportional to mass, which scales as cube of diameter. Meanwhile, they lose heat at a rate that is proportional to surface area, which scales as the square of diameter. You need only the most basic math skills to see that this results in VASTLY better efficiency at larger sizes.

But, no, I'm sure you're much smarter than... you know... the actual engineers and physicists who designed this plant. Or the people who built any of the nuclear plants that pump liquid salt to transfer heat. Those silly people, they've probably never even HEARD of using oil to store heat!

Solar panels and cells are expensive to produce, and the process uses tremendous amounts of energy. After all, it requires producing perfectly pure silicon, not a trivial task. And a huge amount of waste is produced in the process.

That's not to dismiss solar cells -- but we need to explore every avenue. And at the large scales where power plants become commercially viable, heat engines rule. Coal and gas-fired reactors, as well as nuclear plants, they're all just big heat engines. Heat engines have over two centuries of engineering research and development behind them. And Semiconductors just can't be produced in large enough quantities cheaply enough (yet).

Re:Pretty light on detail

[ibbey]

Thanks for your input. Some quick googling suggests that the current state-of-the-art hydrogen conversion is approaching 75% efficiency (See http://www.qsinano.com/white_papers/2006_09_15.pdf, note this is lab efficiency, not truly applied yet). Assuming that the efficiency continues to improve, I would expect that that value will rise notably by 2020 and beyond. When you factor in the NG used, transmission losses, etc., compressed air is only about 80% efficient (see post 101 of the SciAm discussion), so it would seem that hydrogen might be feasible as a replacement in the not terribly distant future.

Since there would also be lost efficiency going the other way (hydrogen > electricity), it probably isn't a very good sole storage solution, but it would seem to be a good solution to burn hydrogen in place of the NG. That would obviously result in further reduced efficiency, but would remove any Co2 from the equation. I'm not a chemist, physicist, or really any other -ist, but it seems like there is at least some potential there.

Re:Pretty light on detail

[Chandon Seldon]

Why don't they build it with solar panels that convert solar energy to elctricty so they don't have to pump any salt? Seriously, ones that run on just heat are such a bad, inefficient idea.

It seems like that would be true, doesn't it. Luckily, engineers use actual science to design stuff rather than just gut feelings. Solar to concentrated heat to a steam engine (or similar) is actually still a bit more efficient and cheaper than photovoltaics, but the real killer bit here is overnight storage and generation.

How do you store electricity? Batteries - which are ridiculously expensive and wildly inefficient.

How do you store hot liquids? In a thermos - which ends up being really, really efficient.

Nuclear's the future.

[urcreepyneighbor]

Is this be the post-hydrocarbon world finally knocking? A "post-hydrocarbon world" has been available for a long time - nuclear. She's been knocking for so long that her hand is sore.

While I would love to believe some form of solar power would meet the world's needs, it simply isn't feasible with current technology.

We'll probably have wormholes, sexbots and universal prosperity before solar can meet the demand. :)

Re:Nuclear's the future.

[Smordnys s'regrepsA]

Ah, but didn't you hear, the sexbots will meet the demand!

Re:Nuclear's the future.

[B3ryllium]

With apologies to The Tick ... Fission is a harsh mistress.

Re:Nuclear's the future.

[soul_well]

Not so. Solar is closer to meeting our needs than you may realize. Nanosolar has been in the news recently for producing its first runs of third generation solar panels. These are essentially printable sheets of foil that are cheap and easy to produce.

The NYT quotes Nansolar's founder and CEO Martin Roscheisen saying, "With a $1-per-watt panel, it is possible to build $2-per-watt systems." That $2-per-watt figure comes from the Energy Department, the cost of building a new coal plant.

source

The future is here, and it isn't nuclear.

Re:Nuclear's the future.

[jcaldwel]

While I would love to believe some form of solar power would meet the world's needs, it simply isn't feasible with current technology.

Much of the argument against solar is one of economics, but a company called Nanosolar has recently produced solar panels making energy more cheaply than coal. "Current Technology" is a moving target.

post hydrocarbon already here

[thule]

" Is this be the post-hydrocarbon world finally knocking?".....

It was here 50 years ago with nuclear power. Thankfully, it's finally getting attention again.

Re:post hydrocarbon already here

[BlueParrot]

On a related note, nuclear engineers were using molten salts decades ago, and even developed a special corrosion resistant alloy, Hastelloy-N, to deal with the corrosion problems. However, the molten salt system turned out to be more expensive than water based technology, thou this may change if thermochemical production of hydrogen kicks of.

Essentially, proponents of solar power usually like to fantasize about theoretical advances in solar technology, while simultaneously refusing to recognise advances in nuclear technology. As an example, electric cars are usually touted as being CO2 neutral "if the electricity comes from renewables". It is outright obvious that this remains true with nuclear as well, but that is scary and hence rarely mentioned. Similarily advances in electric storage is usually touted as a means of allowing solar to be used for baseload, but rarely is it pointed out that the same tech coudl allow nuclear to deliver peak-energy at increased efficiency by running the plant at its maximum output even when demand is low.

Re:post hydrocarbon already here

[jonwil]

Unfortunatly, nuclear power will never be as good as it could be as long as the energy companies are not allowed to use technologies like breeder reactors and reprocessing because one of the steps just happens to produce something that could be used in a nuclear bomb if the wrong people got their hands on it.

Of course, the same people forget to mention that a breeder cycle with reprocessing will produce less waste that needs to be stored.

Re:post hydrocarbon already here

[darklordyoda]

That is true, that molten salt is more expensive, but look at the overall picture. Although the working fluid is more expensive than water, water has this pesky habit of undergoing phase change, and pressures are MUCH higher. This means the cost goes into transporting the water/steam and even pressurizing whole structures, and ultimately it gets pretty hairy.

Molten salt, on the other hand, if chosen well, will not expand as it heats/cools and can flow slowly, reducing the engineering hassle for a reactor. In other words, the molten salt requires a larger initial investment, but upkeep is lower. This solar system they are talking about seems like a variant of these molten reactors, only replacing the core with a solar concentrator/collector.

Re:post hydrocarbon already here

[greg_barton]

It was here 50 years ago with nuclear power. Thankfully, it's finally getting attention again.

Back in 1960 my grandfather patented a fuel creation process for molten salt reactors while working at ORNL. These days my uncle is carrying the torch for green nuclear power, and fighting the good fight to get people to accept it as a viable power alternative. It's an uphill battle. Folks on the left are terrified of nukes. Folks on the right are in bed with the oil and coal industries. Thankfully the technology is all there, so when the environmental and peak oil shit really starts hitting the fan nuclear power will be up to the task. It'd be nice if we could be ahead of the game a bit more, but that's OK. The solution is there. We just need to be sufficiently motivated to do it.

Waste salt

[Threni]

I hope they don't start dumping waste salt in the oceans...

I am be

[mi]

Is this be the post-hydrocarbon world finally knocking?

Slashdot editors are be the worst ever...

SciAm article

[snaildarter]

Yes, hot salty, um, fluid is real solution to the world's energy problems. There is an excellent article in Scientific American about it in the latest issue.

http://www.sciam.com/article.cfm?id=a-solar-grand-plan

Unfortunately, it will take massive investments to make this stuff really viable. Fortunately, some European governments are stepping up with real money. Unfortunately, America hasn't for about a decade.

vinod is late to the game

[WindBourne]

There are a number of companies doing this. One is looking to work in conjunction with POwer plants esp Nukes. The waste heat can actually kick the salts up a bit, and then solar pushes is that much higher. The nice thing is that this can be used on really hot days as a means of cooling off the waste heat from the nuke prior to putting in streams. Where this might get really interesting is to combine with geo-thermal power. The same sets of solar concentrators can be used to kick up heated water/steam from the ground and make the generators more efficient. During the daytime, the generators can run at full tilt, while at night, when it is just geo-thermal, then generators run at less efficient speeds.

I know this is somewhat OT

[MichaelCrawford]

Nuclear reactors can be made smaller and more efficient if they use liquid sodium for cooling. I think this may be because they can run at a higher temperature, which is more harmonious with the laws of thermodynamics.

But the US Navy refused to build any sodium-cooled submarine reactors. Finally a Congressional committee hauled Admiral Rickover in to a hearing to testify as to why he wasn't making better use of taxpayer's money.

To which he replied "This is what happens when sodium gets wet," and he threw a chunk of sodium into some water.

Re:I know this is somewhat OT

[MBCook]

There WAS a liquid sodium reactor in the US. The seals in the cooling system seals started to fail leading to severe consequences. See Wikipeida.

Re:I know this is somewhat OT

[BlueParrot]

To which he replied "This is what happens when sodium gets wet," and he threw a chunk of sodium into some water.

Care to guess what happens when 300 C warm and radioactive water goes from 15 mega pascal to neutral pressure within a fraction of a second after a coolant pipe bursts? No matter if it is sodium or water primary coolant leaking is a Bad Thing (tm) , and sodium has the advantage that you don't have to keep it under pressure, thus reducing the chance of a leak greatly.

In addition sodium is practically non-corrosive to steal, while boric-acid spiked water at 300 C is quite agressive. Sodium also has a much better heat conductivity than water, so the reactor won't melt down if the primary cooling pumps fail ( natural convection of the coolant is enough to cool the spent fuel once the chain reaction has stopped, as it will do due to thermal expansion of the fuel rods ).

Having said this, my favourite candidate for coolant is molten-lead. Like sodium you don't have to pressurise it, it doesn't react with water or air, it won't boil even if you overheat teh ractor so much that the steel melts, and it is an excellent radiation shield against gamma-radiation. Main issue is corrosion, but 20+ years of research has produced alloys that are very stable in molten lead, so you could expect comercial plants using it within a deacde or two.

Re:I know this is somewhat OT

[Rob Riggs]

You admit that it's somewhat OT, but did you also know it's mostly BS?

Two competing concepts for cooling nuclear submarine reactors were available, cooling by pressurized water and by liquid metal. Rickover wanted to try both of them, so he arranged with Westinghouse in 1949 to investigate the pressurized water approach, and with General Electric in 1950 to pursue a liquid sodium approach.

Rickover's faith in nuclear submarines was vindicated in January 1955, when the USS Nautilus reported that it was underway entirely with nuclear power. The Nautilus employed the pressurized water method of reactor cooling. The Navy's second nuclear submarine, USS Seawolf, was powered by a reactor using liquid sodium.

http://www.u-s-history.com/pages/h1857.html

Article reads like a business deal.

[Kuukai]

If you're more interested in the technology, try looking at this. It doesn't work "like a hydroelectric plant." (spinning a turbine doesn't = "hydroelectric") It simply uses an array of mirrors to aim sunlight at salt and heat it. The molten salt can then be used to steam water and turn a turbine, or saved for later.

Still limited by Carnot efficiency

[compumike]

Any system that does a thermal -> mechanical conversion is limited by the Carnot efficiency. This system would be limited by the temperatures of the hot side (sun's heating of the salt, balanced with losses from the pipes) and the cold side (presumably atmosphere or a cold river). In contrast, a solar cell directly rectifies electromagnetic field energy (light), so it doesn't obey the Carnot limit. That's why for a system like the one in this article, there's a need to push the operating hot-side temperature up as much as possible.

--
Educational microcontroller kits for the digital generation.

Re:Still limited by Carnot efficiency

[GameMaster]

That will only matter if we actually manage to develop, and mass produce, photovoltaic cells that reach anywhere near the efficiency of traditional heat engine generator facilities at a reasonable price per watt over the life of the panel. Much like the fuel cell, we've had the photovoltaic technology for a very long time and have yet to produce any truly efficient products that weren't extremely high priced specialty items for things like satellites and such. It would be great if we manage to come out with an economical device, but past experience suggests that we shouldn't hold our breath for a major breakthrough anymore than we should for other similar technology such as fuel cells, fusion power, or Artificial Intelligence (all of which are perpetually X years away from becoming practical and X never seems to shrink).

Re:Still limited by Carnot efficiency

[Rei]

Huh? Have you compared what people were paying for solar cells back in the 70s to what they are now? And even today's prices are inflated by manufacturing shortages (the market isn't stable). If manufacturing actually met demand, we'd be paying about $3/W today, not $4.80/W. And this ignores CIGS production like NanoSolar's that's just now coming online. NanoSolar claims $1/W would still be profitable for them. The other CIGS manufacturers also (quite reasonably) anticipate very low production costs. Sure, indium is rare (about as common as silver), but you only need a tiny amount of it.

As for the necessity of high efficiency, it's not neccessary. Even if just a small fraction of the world's urban area was paved with inefficient solar cells, it'd still power the world. I don't care to repeat this calculation yet again (I do it about once a month it seems), but look up China's total urban area (just China's) and do the math with 10% efficient cells (less than NanoSolar's) at, say, 20% coverage and an average 100W/m^2, then compare that to the entire world's electricity demand.

As for what potential efficiency we're capable of, it's actually looking up. But not for CIGS -- for more conventional semiconductor cells, which aren't likely to be cheap enough to panel the world. We're up to a staggering 42.8% now (Honsberg and Barnett) -- and the record keeps growing at a rather surprising clip. And there's more potential for that number to keep growing up to 60-70% or so. There are three technologies pushing this -- the ability to get multiple electrons out of a single photon, the use of integrated beam splitters so that different parts of the cell can be optmized to specific parts of the solar spectrum, and the use of phosphor coatings that can be excited to release photons in a desired energy range. These technologies may not end up running our grid, but they'll be running our satellites, our malibu lights, our self-illuminated highway signs, and so forth.

Back to the initial topic: Just to drive home the point as to how much photovoltaic prices have been dropping, let's put in some historical price points (in non-inflation-adjusted dollars):

1956: Bell solar cell: $300/W .
Early 1970s: Bergman's improvements lowers the price from then $100/W to $20/W

Specifically (in 1994 dollars):
1976: ~$51
1977: ~$38
1978: ~$27
1979: ~$21
1980: ~$18
1981: ~$15
1982: ~$14
1983: ~$11
1984: ~$11
1985: ~$10
1986: ~$9
1987: ~$8
1988: ~$8
1989: ~$8
1990: ~$8
1991: ~$7
1992: ~$7
1993: ~$6
1994: ~$6

In non-inflation-adjusted dollars, solar prices were at a minimum in the early '00s (~4$/W, if I recall correctly), and rose up until this summer due to supply shortages, when they started to go down again. And with the CIGS companies, the prices can be expected to go down a lot over the next several years. Anyways, I really don't see how anyone can look at the numbers and act like solar hasn't been advancing by leaps and bounds since it was first turned from a laboratory curiosity into a commercial product in the '50s.

Might be better with smart power...

[tempest69]

The concept is this.. The power company auctions off power in real time to devices which automatically bid for "cheap energy blocks" The cheap energy blocks never exceed the price of standard energy. This allows the power company to adjust load based on production from non-predictable sources. So when a windfarm starts going crazy with power, the air conditioner in your house can go full steam for quarter price. As the number of smart devices increases, the prices can auction to higher values. As smart devices get more vogue, we can rely on sporadic power generation more and more. Right now, the power companies predict usage, with little control, with smart energy, they can tune usage much more efficiently.

The concept of storing the energy as thermal is fine, but reducing the amount of energy swaps is going to be the more efficient way to use the power. The efficiency that they can store energy and re-convert it is going to determine how low a cheap power block can sell for.

Anyway, just a crazy rant.. enjoy,

Storm

Re:Electricity for the masses.

[Rob Riggs]

On a more serious note, 3% of Moroccos land mass could provide power for ALL of Western Europe? Can I ask what possible reason there could be beyond corruption and greed for this NOT to be used? Somehow I think that this kind of technology, no matter the initial cost, would be an absolute boon and can see no reason why it shouldn't be adopted.

Well, according to the article it is being used and will be used more in the future. The issue is that it takes time, money and a lot of land (3% of Morocco may seem small (446,300 km^2 * .03 = 13389 km^2), but it's larger than some European countries (think countries that start with the letter "L") and about 1/3 of the size of the Netherlands.

It may take Hamilton Sundstrand and others quite a few years to ramp up production to the point where they can consider converting even 100 km^2 of land over to solar energy production.

Time to re-think the cost justification model

[oldenuf2knowbetter]

Articles on massive scale solar power systems almost inevitably include some sort of a comparison showing that solar power generation is not cost-competitive with systems which burn oil or natural gas as fuel. The implication is that solar systems will force consumers to pay more for electricity, thereby discouraging their construction.

There are two critical issues that such cost comparisons ignore:

1) They never account for the long-term costs of pumping more carbon dioxide (plus various pollutants) into the atmosphere and,

2) They never tell us the price of crude oil used for the cost justification.

It is extremely unlikely that any such comparison will give oil quite so much of an advantage if computed at $100+ per barrel (today's price) for imported crude. Or at $200 per barrel. Or if imported crude isn't available at any price.

Yes, I know that I ignored coal as a fuel. I live in California and every fuel-burning power plant around here runs on oil or natural gas depending on weather conditions. Coal isn't an option for pollution reasons. And we do have thousands of square miles of desert that are ideal for solar power plants.

Nothing new here. See Solar Two Mojave

[John Sokol]

I will just dump a mess of links from an old E-mail I did on this some time ago. It's all good stuff, Solar two in Mojave was also molten salt based. I knew someone who bought it after it failed and got to explore it before it was partly dismantled.

---------

Solar two was a flat mirror array.

Search google image search with
            "solar two" Mojave

http://maps.google.com/maps?f=q&hl=en&geocode=&q=yermo,+ca&ie=UTF8&ll=34.871919,-116.83416&spn=0.005915,0.010042&t=h&z=17&om=1

Take the link above and zoom out, just below and to the right is a Parabolic glass mirrors plant

http://en.wikipedia.org/wiki/Solar_Two

http://www.powerfromthesun.net/Chapter10/Chapter10new.htm

http://en.wikipedia.org/wiki/Image:Solar_Two_2003.jpg

http://en.wikipedia.org/wiki/Image:Solar_Two_Heliostat.jpg

http://theothersolar.com/?m=200702

http://www.commondreams.org/headlines06/1101-10.htm

http://www.global-greenhouse-warming.com/solar-central-power-towers.html

http://www.ldeo.columbia.edu/edu/dees/U4735/projections/pitman/solar.elec.jpg

http://fixedreference.org/2006-Wikipedia-CD-Selection/wp/s/Solar_power.htm
(search for "Solar two")

http://www.reia-nm.org/HTML_Docs/Solar_Thermal_Electrical.html

http://greatgreengadgets.com/gadgets/category/solar/

http://www.answers.com/topic/solar-thermal-energy

http://blogs.business2.com/greenwombat/2006/week44/index.html

Excellent page on many technologies - Sorry it's in Spanish.
      http://g3nergy.blogspot.com/2006_11_01_archive.html
      Search for "Australia to Build 154 MW Solar Energy Plant"
      This one is identical in design to the one in the Mojave Dessert here.

http://ludb.clui.org/ex/i/CA4965/ Abandoned Solar Power Plant

Re:Danger Will Robinson!

[MachineShedFred]

While I'm sure your post was in joking fashion, Rocketdyne was the company who made the five F-1 motors in the first stage of the Saturn V.

I know, I know... why ruin jokes with facts! Why, indeed - I'm an ass. That's why!

Re:No, it be the grammuh police

[UbuntuDupe]

I'm more more surprised that no one has yet made a grammar comment with a mocking pirate theme, like,

"Arrr, I think this be post-hydriecarba world knockin on 'r door, matey! It be a danger too, since less global waaaarmin means less 'f us!"

O&M Expense

[sphealey]

Molten salt heat exchange technology isn't new, and has been tried in various forms of electric generating plant for at least 25 years to my memory (and probably a lot longer - they tried a lot of odd stuff in the 1920s and 1950s). The think to keep an eye on is projected operating and maintenance expenses over the long term. Molten salt is nasty stuff and does a lot of damage to everything it touches. Major components such as pumps have to be considered replacement rather than repair items for example. So the O&M cost projections are critical.

sPh

Re:Electricity for the masses.

[WaltBusterkeys]

Don't forget transmission costs--even if Morocco produced enough power for western Europe, the power would still be in Africa instead of Europe. Long-distance power lines are expensive, vulnerable to failure, and lose (at best) 10% of power transmitted. There's water between Europe and Africa, meaning that they'd either have to string really big lines across Gibralter or run a giant copper cable. Going underground through cable is expensive and leads to larger power losses because you can't run the same high voltages in the middle of a salt bath as you can from high-tension wires.

All of that assumes that having a single point of failure for all power in western Europe would be a good idea. Seems like it would make a lucrative target for political disruptions, a massive piece of negotiating leverage for Morocco, and vulnerable to all kinds of natural disasters.

And don't get me started on microwave power transmission. Haven't we all played enough SimCity to know how that can go horribly wrong?

If it really were that easy then greed would have caused Bronson (or somebody else) to have done it already. He's incredibly greedy but usually tells established business to go bugger itself and launches disruptive technologies when there's an opportunity to undercut the market.

Re:Electricity for the masses.

[vijayiyer]

Except that you can't easily get electricity from Morocco to Europe. Transmission of electricity isn't lossless or free.

and without subsidies!

[MrKaos]

I'm wondering if this is result of carbon taxes becoming inevitable. It would seem to me that some companies are positioning themselves to take advantage of funding and tax breaks that hopefully will become available in a carbon trading world. Even if the project can only address peak power demands it's certainly appears capable of offsetting a large amount of carbon production during peak energy demand times.

If this is project is feasible and is what can be achieved without subsidies I wonder what solar energy projects (and indeed other alternative energy projects) can be created with funding.

Nuclear is not the future..

[cybrthng]

The energy cost with refining, processing, storing and disposing of nuclear materials makes solar look like a bargain. Nuclear fanatics seem to forget the process it takes from digging up something that is one of the rarest elements on our planet and then disposing of such elements when we are done.

Re:Nuclear is not the future..

[Entropius]

What are you smoking?

It requires an absolutely tiny amount of uranium to run a nuclear plant, compared to the 10,000 tons/day that a 1GW coal plant uses. Uranium is rare, but you don't actually need that much *of* it. 95% of the fuel used in fission plants can be reprocessed. Coal producers are chopping off the tops of entire *mountains* in Appalachia;

"Disposal" isn't as big a problem as it's made out to be; reprocessing reduces the amount of waste produced tremendously, and storing a little waste for a time is a whole lot better than *not* storing it and dumping it into the atmosphere, as we're doing with coal.

There are other forms of power generation than nuclear, but at the moment it is the only proven, scalable, clean, and economical alternative to fossil fuels for power generation. Perhaps solar-thermal (as in this article) or geothermal or tidal power or some sort of wind power can be used to carry a lot of the load, but nuclear power is available now, and the only thing lacking is the political will to implement it.

France had that political will, and now they have the cheapest power and the cleanest air in Europe.

Re:Nuclear is not the future..

[linzeal]

It is not just that they are chopping whole mountains off it is that there are 1000's Coal Fires in mines underground that are adding anything from 1-5% of the worlds Co2.

Re:Nuclear is not the future..

[AJWM]

so you need a lot of high quality ore to get fuel in an expensive and energy intensive process (eg. heat a heavy metal all the way to a gas and centrifuge it).

Um, no. You only need to do that if you're planning on building bombs. (And anyway, gas centrifuges don't heat the uranium to a gas but chemically convert it to uranium hexafluoride before centrifuging.)

There are plenty of reactor designs that run on unenriched uranium, including most of the nuclear power plants in Canada (CANDU) and places to where Canada has sold reactors.

Re:Nuclear is not the future..

[AJWM]

and requires the heavier isotope

Oh, and actually it's the lighter isotope (235 vs 238) that's the one of interest.

Re:Nuclear is not the future..

[gambolt]

To anyone who has ever smoked an unfiltered gauloises, the reason for this should be obvious.

Re:Nuclear is not the future..

[falconwolf]

"Disposal" isn't as big a problem as it's made out to be; reprocessing reduces the amount of waste produced tremendously, and storing a little waste for a time is a whole lot better than *not* storing it and dumping it into the atmosphere, as we're doing with coal.

The French, who have come the farthest in reprocessing, are finding out it's not as simple to reprocess as many would have you believe. IEEE's magazine "Spectrum" has a good article on this: "Nuclear Wasteland". However another /.er brought up the Candu reactor in Canada a few weeks ago. I don't know much about it so I can't say whether there are any problems with the design or waste, or whether its economically feasible. However nuclear power isn't really needed, not in the US. The Rocky Mountains alone contain enough potential wind power to supply the 48 continuous states with electricity. Add OR, CA, AZ, NM, and Texas along with some offshore sites from Cape Cod to the Mid Atlantic and much more can be generated by wind. Also many megawatts of potential power goes up smoke stacks daily as Waste Heat. Combining wind, solar power, cogeneration or waste heat recovery and conservation negates the need for nuclear power. The alternative power sources, both listed above and others, have a distinct advantage over nuclear power, while it can take years and years for a nuclear power plant to be constructed and brought online, these others can be added immediately. Wind generators and solar PVs can be made from raw material and brought online in months, and can be sited closer to many of the placed where the energy is needed. Besides PVs on roofs a farmer in the Adirondack Mountains in New York can provide electricity to NYC. The farmer would then have a second source of income.

Falcon

Re:Nuclear is not the future..

[Arthur Grumbine]

Although your exaggerations do allow for a much more pronounced emotional impact on the reader, if you were interested in perspective (i.e. proper science) here's what your source's source has to say:

1. Coal fires are a natural occurrence albeit aggravated, and sometimes caused, by human mining.

2. In China, which has the by-far greatest collection of coal fires, "estimated" 20 - 200 million tons of coal burn every year in coal fires. That is an incredible range... 20 to 200...mmm... that's some good science. Assuming 200 million tons of coal, and all of it man-caused, you get "nearly" 1 whole percent of the carbon dioxide emissions "due to fossil fuels being burned".

As a side-note, "the world's Co2" weighs in at about 3x10^15 kg, or 3x10^12 tonnes, or 3,000,000 million tonnes, or 3,000 billion tonnes. All of human activity (fossil fuel burning and everything else) produces 27 billion tonnes of CO2 each year. That's right. ALL human activity contributes less than 1% to "the world's Co2" each year.

Please do not let Wikipedia think for you. The FSM did not bestow brains (the very image of His Compacted Noodlieness) upon us so that we might neglect our duties to rigorous science (or in this case, simple math).

Re:Nuclear is not the future..

[Mark_MF-WN]

Anti-nuclear cowards seem to forget that nuclear power's main alternative -- coal -- requires destroying vast swaths of land to extract, and releases far more radioactive waste into the atmosphere than nuclear releases into manageable steel drums.

I know that YOU probably enjoy acid rain, mercury poisoning, and the pulmonary disorders that are inextricably linked to the emissions from coal plants, but I don't. Meanwhile, nuclear plants produce well-contained waste that can be reprocessed, and use tiny amounts of fuel. And once we finally get past this kind of pathetic cowardice, we can finally start putting serious investment into research into nuclear power -- and get ideas like the Thorium and Actinium fuel cycles into practice, allowing nearly perfect reprocessing and allowing the exploitation of Thorium, which is incredibly abundant. And uranium isn't exactly rare -- it's just uranium 235 that's rare, and we don't even need to use enriched uranium in many reactor designs.

Seriously, what's wrong with you people? No one questions the value of solar, but it's not a panacea. We need more than one energy source. It's that kind of ridiculous thinking that got us into this situation where we're overly dependent on fossil fuels. We should have been diversifying our sources of energy all along, not wimpering in the corner because of paranoid delusions about t3h rad1at10n coming to get us.

Re:Nuclear is not the future..

[dbIII]

As an engineer with a background in power generation (but ten years out of touch and most of the nuclear power plant guys I worked with were Russian and Indonesian) I'd say what we'll be using in the future as in the past is a mix of a lot of things depending on what is easiest in specific locations. There are solar thermal baseload designs that usually run on the principle of having a big heat reservoir (in this case molten metal salts) to run stuff around the clock but they all have to be large so there is resistance to building them. Your average thermal plant can run for quite a while after you stop shoving in fuel because there is so much steam in the system so this is expanding on the idea (ie. being able to give you a full nights worth of steam after the power is cut). What most people miss is that the real problem in electicity generation is covering the peaks - and they almost always happen in daylight anyway.

This is going to take years and it's a matter of people seeing a lot of solar hot water collecters on rooftops before governments decide it is a safe bet to go for large solar power projects - I think industry on it's own will hit exactly the same problem the nuclear power advocates have. For really big thermal plants they want government money because they can't get commerical finance. Electricity is heavily regulated in most places anyway so it usually takes government involvment to just get a foot in the door. This sometimes involves convincing relatively old people who did not have the benefit of finishing high school of the merits of a project - hence the delay until solar thermal (eg. hot water) comes into the personal experience of the people regulating things.

Re:Nuclear is not the future..

[Phanatic1a]

The French, who have come the farthest in reprocessing, are finding out it's not as simple to reprocess as many would have you believe. IEEE's magazine "Spectrum" has a good article on this: "Nuclear Wasteland"

That article doesn't support what you claim.

The French experience clearly does show that reprocessing need not be the dangerous mess that other countries, including the United States, have made of it [see photo, "Blue Glow of Success"]. The U.S. military used reprocessing for several decades to separate plutonium from spent fuels, providing fissionable material for bombs. The result was widespread contamination--which has been in some cases irremediable--in the central Washington desert and the South Carolina coastal plain.

France, in contrast, now reprocesses well over 1000 metric tons of spent fuel every year without incident at the La Hague chemical complex, at the head of Normandy's wind-blasted Cotentin peninsula. La Hague receives all the spent fuel rods from France's 59 reactors. The sprawling facility, operated by the state-controlled nuclear giant Areva, has racked up a good, if not unblemished, environmental record.

[...]

Nevertheless, although it may be safe to proceed with reprocessing, France's experience suggests that reprocessing as done now is not ready to catalyze a full-blown nuclear renaissance. The problem in a nutshell is that without breeder reactors, which can break down the most long-lived elements in nuclear waste, reprocessing comes nowhere near achieving Finck's 100-fold reduction in that waste.

It's not the reprocessing that's the problem, it's the lack of economical breeders. More research into things like the IFR is most definitely called for.

A few notes and questions

[stomv]

1. Nuclear power is not carbon neutral. Uranium is mined, and nobody is running mining equipment on biodiesel, nor are they transporting it to power plants using biodiesel, ethanol, or even renewable generated electricity on electric locomotives. To be sure, the amount of carbon is extremely low per kWh of electricity generated, but very small > 0, even for very small cases of very small.

2. As you know, nuclear proponents continually ignore the major immediate problem with nuclear power -- waste storage. Nobody wants more glass-encased nuclear waste in their neighborhood, and presently nobody wants some other neighborhood's nuclear waste being transported through their neighborhood. The nuclear industry has got to find technical and political solutions to these problems before society will embrace nuclear as a green solution. I'm not arguing that burning coal or oil is safer or cleaner than nuclear, just that any change to a status quo requires more than a slight or obscured imbalance, which is how the public currently perceives the status quo.

3. What is Hubbart's Peak for uranium? I have no idea, but it surely must have one.

4. Which nations have substantial amounts of useful uranium? What would the balance of power be if those nations became the new Saudi Arabia of energy?

5. Solar off-peak is simply not a problem, not for a long time. Peak demand is highly correlated with sunshine in most of the world -- solar could serve quite effectively as the peaking plant, relying on other types of generation for base load. Electric storage is just not a major issue for solar -- it might become one for wind but it wouldn't be that hard to operate other green energy plants in a negative correlation to wind, ie burn woodchips when the wind isn't blowing, but not when the wind is blowing.

6. That said, plug in cars might change that formulation substantially, since most people would plug in their cars at night thereby adding demand off-peak [and off-sun]. If/when that happens, much of (5) becomes moot and there'd be some shifting of nighttime use [industrial, it's cheaper] to daytime and there'd be encouragement for folks to charge during the day [plug in jacks at car parks] to help keep demand during the day higher, when production due to solar is higher.

7. Ultimately, this doesn't matter. Solar production in the US is well less than 1%. Even at 10% there won't be a necessary substantial change in infrastructures or demand shaping. So, until then, more of every kind of renewable electricity generation is better, and none of it will create challenges. And, of course, nuclear may or may not be greenish, but it is not renewable.

Re:A few notes and questions

[Rei]

3. A long, long way away when you consider seawater extraction, and even further with breeders, incl. thorium. Sure, it's quite expensive in comparison to mining, but the cost of fuel isn't the real cost in nuclear power -- it's paying for your reactor construction and decomission that kills you.

4. Ignoring seawater? Australia by far, at 24% of known reserves. Other significant sources include Kazakhstan, Canada, South Africa, Namibia, Brazil, Russia, the US, and Uzbekistan.

Re:A few notes and questions

[radl33t]

A commonly employed tactic, you have just narrowed your scope such that you can criticize nuclear energy. 2. Not a problem. More people would understand this if fear hadn't reigned and nuclear research didn't take a nose dive decades ago. 3. Also not an imaginary problem. Proper (well documented) reactor design will eliminate this concern. IT would be a done deal if we maintained the nuke program from the 60s through today. Even existing tech would allow us to burn other elements, which are more plentiful than uranium. On second thought, why aren't you concerned with Hubbert's Peak for the sun or the universe? The timescales of these peaks are not really of a concern same as those for uranium, unless you really think you can plan for 100+ generations out. 4. There is enough unused "waste" sitting around for thousands of years. Plenty hiding around down under too. 5. Actually the lack of off-peak energy is a massive problem, mostly for economic reasons. IT is probably the single largest cost barrier for both wind and solar, which typically enjoy moderate to peak output less than 20% of the time. In other words, to reach cost parity with coal they actually need to be 5 times cheaper. 6. Ultimately it doesn't matter? Um, yes of course if you are so narrowly focused that you don't consider things like economies and social welfare. Why isn't nuclear renewable? Just as renewable as our sun if you ask me. p.s. pv isn't carbon neutral either p.s.s. Life is destructive. take it or leave it. Don't kid yourself. Nuclear energy is at least as good an option as solar or wind for decades. At least until fancy PV arrives at 100s of GW of annual production. But then again theres no difference between fear of nuclear energy and whatever other boogieman is out there.

Re:A few notes and questions

[sholden]

1. Solar cells are made from silicon, which carried in trucks and hence not carbon neutral. Every power source is not carbon neutral since it has manufactured components that were transported at some point. Of course once you have plentiful power from the nuke plants you might change that...

2. It'd be mighty expensive but you could just mix it back with the non-uranium rock you dug out and put it back where you found it... A lot of that waste also isn't waste, it's fissionable material that politically isn't used (because doing so gives you plutonium easily used in weapons).

3. In 20 years we'd run out if we just used uranium in nuke plants for all our electricity. Again allow breeding to plutonium and it turns into 2000 years...

4. The top 5 known recoverable uranium holders are: Australia, Khazakhstan, Canada, USA, South Africa - they make up about 2/3rds of the total. From a Western world perspective, that's a much nicer set then the oil top 5: Saudi Arabia, Canada, Iran, Iraq, Kuwait...

Re:A few notes and questions

[sploxx]

1. Solar cells are made from silicon, which carried in trucks and hence not carbon neutral. Every power source is not carbon neutral since it has manufactured components that were transported at some point. Of course once you have plentiful power from the nuke plants you might change that...

And to further elaborate on this: There is this concept called Energy Returned on Energy Invested. (And even more refined indicators).

I have heard this flawed argument against nuclear power so often that it is not really funny anymore.

Re:A few notes and questions

[Bender0x7D1]

I would encourage you to read up on nuclear power - while a lot of what you are saying is true, it really doesn't capture the reality of the situation.

1. No, nuclear, by itself, is not carbon neutral. However, neither is any other alternative energy. However, when you have the extra electrical power, you can construct "factories" that will scrub the carbon dioxide out of the atmosphere. Now, we might not have the political will to carry it out, but nuclear alone is still way better than what we have now.

2. Fast breeder reactors can run on our current nuclear waste and the waste from those reactors doesn't last nearly as long. So we get to reduce the amount of waste and what's left doesn't last as long. The reason we don't use them is that reprocessing can create weapons-grade plutonium. Again, this is a political issue instead of a technological one.

3. With today's "wasteful" reactors using Uranium-235 it is estimated between 80 and 300 years. If we use breeder reactors so we can use U-238 and Thorium, it can be billions of years at current energy levels.

4. If necessary, fuel can be extracted from sea water making it a moot point.

5. There is also a peak in the evening when everyone turns on lights and TVs. Also, winter means a lot less sunlight in many populated areas so more demand for lighting and heating.

6. Moving power around might help, but there are just too many hours when power is needed and solar isn't available. Also, cloudy days affect production and can't be planned around. Limiting solar farms to areas with minimal cloud cover means increased losses from transport.

7. Nuclear doesn't have to be renewable if we have a few billion years, (or even a few million), years available. If we can assume a technology level that can protect us from extinction due to an asteroid or comet in that time period, we can assume a technology level that can mine the moon, mars or asteroids for more nuclear material.

While nuclear has its problems, they are really political instead of technological. I really hope we get past our fears of nuclear power so we have a chance of keeping our planet habitable for humans.

Re:A few notes and questions

[Rei]

Range and charge time are both insufficient, and are likely to remain so for the foreseeable future.

Huh? Fast charge li-ion batteries will be out in the next few years -- several companies (including big players like Toshiba) have already announced them. We're talking 5-10 minutes for a full charge. As for range, didn't you see the Stanford study headed by Yi Cui that got 10x the lithium ion density in the anode with silicon nanowires? The team estimates it'll take about 5 years to commercialize that with conventional cathodes, giving "several times" better energy density than current li-ion. Most research has been on the anode; there's tons of room for improvement in the cathode, so that likely means the potential for improvement to a full 10x energy density. Even with just 3x, that'd mean in 6 years or so, we'll have electric vehicles meeting or exceeding the performance of gasoline vehicles in both respects.

Arrays of nuclear power plants could be constructed for the express purpose of electrolyzing water and creating hydrogen, which could then be shipped around and sold at stations as fuel currently is. With an energy density of 143MJ/kg, hydrogen compares very favorably to gasoline, which only stores 46.9MJ/kg.

Hydrogen has horrible energy density, and the system efficiency of hydrogen vehicles is pathetic incomparison to electrics. Improve the density with a storage medium and you make the efficiency even worse. And let's not even talk about safety.

Advances in li-ion technology have essentially rendered hydrogen obsolete before it even got a real chance.

Re:A few notes and questions

[yariv]

Canada and Australia currently supply more then 50% of the uranium in the world. Australia also holds about 40% of the known reserves. I think I can live with them as "the new Saudi Arabia of energy".

However, in the long run, we'll have to use other sources of energy. Solar and fusion, simply because we'll probably run out of cheap uranium before the 23rd century. (unless we'll be able to extract the uranium from the seas, then we'll probably have enough for several thousand years).

Re:A few notes and questions

[Rei]

Where are you going to get the power to charge the batteries in 10 minutes?

Wow, there are still people out there asking this question? It's really, really simple. There are three ways to charge.

1) Slow charge overnight. Anyone can do this without any specialized hardware.
2) Fast charge at gas station. Truck stops already have a lot of power going to them, as do many gas stations, and few would hestitate to upgrade their wiring if it adds another revenue stream.
3) Fast charge anywhere using a fast charger. The same batteries used in your vehicle can charge your vehicle. They slow charge from the wall, and when you plug in, they charge your vehicle. While it's an extra purchase cost, it also provides further advantages: A) automatic grid power load balancing (a favorite of power companies), and B) home backup power

Even if the battery technology was here today, the power distribution infrastructure isn't, and isn't on its way either.

Yes it is, and yes it is (and why don't people look this up first?) Let's do the math: the average car goes something around 40 miles a day. EVs are typically 120-200Wh/mi, so that's 4.8-8kWh/day. Let's go with the high end, 8. That's 240kWh a month. At 10 cents per kilowatt hour, that's $24 a month. Compare that to your monthly power bill, and notice something? Your existing power usage almost certainly dwarfs that which would be used by an EV, especially in the summer (midday during the summer most accurately reflects our generation baseline). Even if you merely use 20% less power at night during the day (as opposed to the more typical usage of several times less power at night than during the day), that right there is enough to charge your vehicle.

Even if this *wasn't* the case, it's much easier to build power generation and transmission infrastructure than it is to replace aging oil infrastructure and develop new fields, so it's a rather dumb argument to make to begin with.

You didn't even discuss range, yet claimed that it will remain insufficient without any evidence to counter what I wrote. No surprise there.

Re:Colonial Thinking Not Dead

[Bryansix]

British people are totally backwards. For proof look at their use of "Fanny Fun" to refer to straight sex between a man and a woman. The only Poofters are the ridiculous people who use such a word.

salt - water heat exchanger: tricky

[smellsofbikes]

Here is a shorter, and in my opinion, more informative summary. They're heating up sodium chloride salt, then using that to produce steam from water, which drives turbines. That's nice, because molten salt is fairly nasty stuff to work with.
Anything has its chemical activity rise exponentially with temperature (the Arrhenius equation) so as things get hotter, they get more chemically aggressive. Molten glass will dissolve bricks and mortar. Molten sodium and chlorine ions are even nastier -- a sodium ion is a very small object, only a little larger than hydrogen -- and can diffuse into metals, weakening them and creating leaks.

Re:salt - water heat exchanger: tricky

[Dunbal]

Here's an even shorter summary:

"I've discovered perpetual motion^H^H^H^H^H free renewable energy, send me money".

Come on. Use sunlight to melt salt to heat water? Why don't you just use sunlight to heat the water directly. Every step you add just increases your heat loss and decreases your efficiency, because no single step will ever be 100% efficient. There's nothing magical about salt, molten or not. And you can't beat thermodynamics. Ever.

Re:salt - water heat exchanger: tricky

[smellsofbikes]

They're using the sodium chloride as a thermal reservoir -- heating it and relying on its high temperature to make up for its so-so specific heat. Water's specific heat isn't much different, but it's difficult to contain as steam. So they heat up the salt -- or anything else -- and let it gradually cool down, extracting heat from it by vaporizing water and reclaiming the energy through turbines. That way they can produce power all night off the heat saved during the day.
It's not a bad idea if they have a good insulated container for the molten salt. It introduces a lot of waste because of the cumulative inefficiency of heat transfer between the different systems, but it allows a system based on this to provide more reliable energy -- energy that's closer to being on-demand, rather than just when the sun is shining strongly enough.

Several liquid metal cooled reactors, actually

[mbessey]

The first US nuclear power reactor (EBR-1) was a liquid-metal cooled breeder reactor, as was the Fermi 1 reactor near Detroit, Michigan. The Fermi reactor had a minor meltdown accident in 1963. Overall, the safety record of liquid-metal reactors hasn't been particularly impressive, at least in the power-generation arena.

Yes, Solar is great...

[Anonymous Coward]

when the sun is out, and Wind is great when the Wind is blowing, but they are not viable for providing base load power needs.

Nuclear is ideal for providing base-load power (30-40% of peak capacity), suplemented by Solar, Wind and Tidal power.

Re:Yes, Solar is great...

[MrKaos]

Nuclear is ideal for providing base-load power (30-40% of peak capacity), suplemented by Solar, Wind and Tidal power.

Geothermal is ideal for providing base-load power (30-40% of peak capacity), suplemented by Solar, Wind and Tidal power.

Fixed that for ya, Mr AC.

Great, for places with lots of sunshine

[Mr. Roadkill]

The future world will have to depend on a mix of energy sources, most renewable, some probably not.

This kind of thing will work great for Las Vegas, and a number of Moroccan arrays would be great for Western Europe with submarine cables across the Mediterranean. Hell, there's lots of great possible sites for this kind of thing in Australia too - even more, if we look at things like using the peak to do things like pump salt water up hill, or store pressurised air, where a couple of days of cloud cover and peak demand won't result in solidification of your thermal reservoir.

But what about Galena, Alaska? With places like that, the options are probably need to either continue shipping in hydrocarbons (either fossil or renewable)or ship in a micro nuclear plant.

I know this is going to sound like some bizarro socialist mish-mash, but what just might be needed is a pricing structure for energy that's in part based on actual costs, in part based on environmental impact, and in part based on the practicalities involved in providing power in a particular location. Under such a scheme, Las Vegas might pay an absolute fortune for electricity generated from natural gas fuelled turbines (a.k.a. ex-airliner jet engines) but very little for solar - enough to make solar the far more attractive option, but allow the gas turbines to be kept available for peak demand (e.g. aircon load on the hottest days, because a couple of arrays are down for maintenance). Galena, however, would probably pay cost of production + shipping + reasonable profit margins for the biodiesel used to fuel its generators, plus maybe a very small surcharge for any mineral diesel purchased and cycled through as reserve stocks (due to biodiesel's shorter storage life). What this would involve is some proper resource planning, above and beyond just what's going to provide the biggest return to investors over the next three to five, and that's why I don't hold much hope for it happening. If we're smart as a species, though, we'll look carefully at how we can reduce our dependance on fossil fuels while still holding them in reserve for emergency power uses or using them for specialised purposes - feedstocks for manufacturing, for example, rather than as a general source of power.

Not that new...

[zippthorne]

This kind of thing has been suggested for use in high-power spacecraft, and it's not necessarily sodium salt that's the storage mechanism.

I don't see why you'd lose much efficiency. You'd chose a salt that was molten over the operating range, and no matter what, you cannot exceed the temperature limitations of the other materials you've built the thing from, so that's your design temp. Because of the T(t) smoothing effects, you'd be able to run the generator at maximum efficiency for most of the time. Thus, you can size your machinery to the average capacity rather than the peak available solar input. Not spooling the generator up and down as the sun waxes and wanes is great for efficiency.

For instance, you might pick a salt that has a liquid-solid transition just below your desired T_hot, ensuring even temperature until all the salt solidifies. This has the added benefit that, depending on the expansion characteristics of the salt in question, you have a number of ways to evaluate the remaining generating capacity.

With good insulation, and a fixed installation can be made arbitrarily well insulated, you would lose a lot less energy than storage in batteries, and it scales very well: the larger the installation, the thinner the needed insulation is relative to the total volume.

The main loss would be radiation from the absorption patch. Presumably you'd mitigate this by having some kind of louver or hatch that you could close to insulate that during the night and overcast days. You could also take advantage of the much lower-than-the-sun temperatures, and use a covering that is transparent to visible light, but reflective to lower frequency light. Although there would still be a fair bit of radiation in the visible at reasonably efficient temperatures.

Learn about what you advocate

[dbIII]

While I would love to believe some form of nuclear power would meet the world's needs, it simply isn't feasible with current technology.

There are some promising possibilities (pebble bed is at an advanced stage now, and accelerated thorium shows potential) but TRY PAYING ATTENTION - Iran and North Korea's efforts have been headline news for some time and should highlight that what we have today is a dual use compromise that could be better. If the focus was primarily on electricity generation like some of the newer and UNTESTED concepts it would be more than using a bomb materials plant to boil water which is what most of our 1950's derived plants really come down to.

There are a lot of good uses for nuclear materials but we are not yet very good at using them to boil water, and the "nuclear batteries" while they rule their niche scale up no better than photovoltaics.

Photos what you've all been looking for.

[AbRASiON]

What is it with intetnet sites (slashdot, news sites, digg etc) having fascinating articles but no cool pictures to back them up?

Did anyone else groan intensely last year when 'worlds largest squid has been caught!' articles came up with no pictures?
"Meteor smashes into datacentre"
"Worlds largest seal clubs man in Alaska"
"100ft tall hot woman with massive breasts seen naked crossing major highway"
"Worlds coolest event happens! No pictures here!"

Anyhow to get the rant over with,.........
http://ucdcms.ucdavis.edu/solar2/photos/

That site is an existing site with one of these fascinating reactors, I found the site some time last year (and had a hell of a time finding the damn link in my history too) check it out purely for the cool factor, good stuff.

Correcting misunderstandings in parent post

[Eivind Eklund]

We can deal with the production of power in the day and consumption at night by using power storage. This can presently be done at about 80% efficiency, through the use of water storage (you pump water up into a reservoir when you have surplus power, and release it when you need to draw power).

The difference in consumer voltage between Europe, Japan and the US is a non-issue - we transport electricity at a much higher voltage, and then transform it down close to the point of use. The same isn't quite true for frequency - it is synced at 50/60Hz in the grid - but there are production facilities in operation that produce it at a different frequency and convert it to the grid frequency using a frequency changer. You can read more about in Wikipedia's utility frequency article.

The main problem with interconnecting the continents is the power loss associated with long distance transmission. As far as I understand, this makes interconnection impractical at the moment - local storage (as in the reservoirs described above) being more economical. Superconductors may some day change this.

Eivind.