Slashdot Mirror
World's Largest Solar Array to use Stirling Engine
An anonymous reader writes "Stirling engines are not a neglected or forgotten technology after all, according to a story at PESN. With 20 years of in-the-field fine-tuning, Stirling Energy Systems is now ready to go big -- real big. They signed a purchase agreement Tuesday with Southern California Edison (SEC), to install a 20,000 dish array that will cover 4,500 acres and will be capable of generating 500 megawatts of electricity -- more than all other U.S. solar projects combined -- making this the largest solar installation in the world. Each collector has a 37-foot-diameter array of mirrors to focus the sun's rays on the Stirling engine, which turns the heat into rotational torque for electricity generation. According to a spokesperson for SCE, this purchase will be in their commercial interest, requiring no subsidy in order to compete, implying that the efficiencies of the technology will give them an edge in the market."
I'm not surprised stirlings are finally profitable.
But those giant dishes look expensive and complicated.
Doesn't anybody have a way to make large parabolic reflectors cheaply? Or isn't there a way to do away with the tracking devices?
"I assumed blithely that there were no elves out there in the darkness"
Counting or not counting the uranium mines, heavy water refineries, and spent fuel storage facilities?
"I'm not impatient. I just hate waiting." - My Dad
If anyone is wondering, 500 megawatts can power about 500,000 homes.
I worked on projects for large methane->power facilities in California (and across the US), which turned landfill belchings into fuel for large engines. One of these facilities, in a dinky little building, put out about 6MW all day long. Not quite 500MW, but it was pretty impressive given that it was methane that would otherwise have been flared off uselessly.
For context, typical new nuclear power plants produce around 600-1200MW.
Touche. Which is why I think we should be focusing research and energy on nuclear fuel reuse [waaaay unexploited in the US] and disposal techniques.
I know some knowledgeable Slashdot reader can help me here. What I want to know is, what is the drawback to such a power system? It sounds like it generates quite a bit of power, and looks like a completely clean source. Are these things super expensive to build? Is it really hard to keep these things lined up with the sun to produce optimal power?
There is the issue of not being able to produce any power at night. But intelligent use of battery stores along with some supplemental traditional powered generators might take care of that, especially since power draw from the grid is (I'm guessing) much less at night.
So - what's the catch? Why aren't fields of these things going up like crazy?
Now that Bush signed the 'Energy Bill' we have this gigantic solar project, underwritten by a big utility. Coincidence?
The voters here in Colorado were suckered into an initiative requiring the utility companies to get 15% of their power from renewable sources whether it made economic sense or not.
The spin you put on this makes it seem bad, however, relatively speaking our idea of efficient alternative energy is less efficient than coal mining and what have you. So, sure, it might not make economical sense compared to non-renewable energy, but that doesn't mean it's a bad thing!
Another reason this whole thing isn't that bad is because it forces companies (Xcel, etc.) to actually work on R&D for making their energy production more efficient - they now have a vested interest in it. If that were not the case, they'd just be burning the candle at both ends with oil/coal and worry about the future when the future came about. Xcel has been putting in a lot of wind generators in SW Minnesota, and they're not done. I love to see those generators every time I travel through there - it means something is actually getting done.
As for the voters in Colorado getting suckered in, well, I hear you, they're not the smartest...
Comment removed based on user account deletion
If nuclear plants can prove to be finacially viable on their own then I am all for lifting the regulations against new ones. The problem I have is that US population essentially pays all of their liability insurance; in that there is a federal law mandating that they don't have to have any. If they had to pay that liability and still could be finacially sucessful I would think they would have reached a pretty safe point. If they are as safe as everyone says then why do the need us to pay their insurance?
--
WHO ATE MY BREAKFAST PANTS?
From the description of the system, the plant will only produce power when the sky is clear during daylight hours. Has anyone seen information regarding how much time the solar plant will be online and how much time it will spend offline due to night or cloud?
Is the only backup to this system the electric grid as a whole, or will the solar plant include some kind of heat sink or other way to store energy which can be drawn on when the sun isn't shining?
We used to think that all 'organic' compounds were organic in origin. We were wrong. 'Organic' compounds have been observed in space and on other planets. It's not a huge stretch (especially given other evidence) to wonder if these vast pools of hydrocarbons under the Earth's crust might be from some source other than decaying vegetation. That doesn't mean we have an unlimited supply of course .
Photovoltaic cells have no moving parts. Anything with moving parts _will_ wear out faster than a solid-state solution. I wonder how competitive the industry will be in the future...
I can't find the reference, but part of the problem is that the US nuclear regulatory regime is designed around the assumption of monolithic, large light-water reactors. The idea of a modular system where you can add another reactor module quickly doesn't fit in with the approval process, removing one of the biggest advantages.
Secondly, US companies aren't developing PBMR designs; South African and Chinese ones are. Funnily enough, the subsidies for nuclear R&D and deployment currently floating around Washington are aimed at the American nuclear power industry, not its foriegn competitors.
Mind you, if Westinghouse's cost estimates on its new AP-1000 power plant design turn out to be it's going to be pretty competitively priced anyway. Pebble beds aren't the be-all and end-all. One concern is whether there'll be enough helium available to run them...
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
A few years in Spain, a new series of solar pilot plants was built that does break even. They learned from California's problems. Advanced engineering on these new plants allowed them to use hot air rather than high temperature hot oil. Silicon carbide collectors allowed beat various engineering problems. Their next step is to scale up to fullsize installations.
You're right. I studied desert ecosystems before I changed my direction in college. They are quite sensitive, and over millions of years many of the little critters in those areas have become quite dependant on very certian conditions, and very precise timing of monsoons and changes of the season--which greenhouse warming is bound to affect drastically anyway.
I say put these collectors as individual units in people's yards--if they agree--and give them a percentage off their electricity bills as lease for the land. They get the power to run their AC for free, and they contribute to the power grid, win/win.. It's basically the same deal with cell towers. We have one on one of our properties, and we get $2,000 a month for it. Best tenants we've ever had, I must say!
Of course, they'd have to be almost completely maintance free so you don't need a horde of technicians running all over fixing them. In this way, the environmental impact will be mitigated, as there are already people in the area with houses and paving and all of that... But that's good also because distributed power grids are much more reliable (and probably more efficient) than grids depending on only a few sources.
This could be quite popular all over the southwest if it were economically feasible.
Constitutional rights may be respected, repealed, or modified; but they must never be ignored.
Gas will be available as long as there is any demand for it. Because of collectors cars that means close to forever. It will be pricy though.
I see it more like this. 30 years from now I'll be able to stop at the classic gas station and top off my '62 Alfa Romeo with some high test gas for roughly $20 a gallon (current dollars, who knows then).
I am not a script!
The Preamble -
Let me cut out the unnecessary stuff here -The preamble explains why 'We the People' adopted the Constitution. It has nothing to do with any powers delegated to any branch of government beyond hinting that the power is derived from the people.
While I agree that your interpretation has been used, it is so laughably off from the plain text of the preamble that it should never be given a first thought, let alone a second one.
Laws are horrible moral guides, moral guides make even worse laws.
Sure, if all you do is try to collect it near the surface like we do now. All you have to do is drill deeper to find more. The Russians are currently pumping oil out of wells 8 miles deep. The stuff we're pumping out at the top is only that little bit that seeps into easily reachable pockets.
Secondly, you find remains of plants in oil, which almost makes you wonder how they got the idea it came from a biological source, not
You don't so much find "plants" in oil, you find "organic matter". Biogenic fuel theory says it's from zooplankton and phytoplankton. The reason abiogenic petroleum theory was initially rejected was that in the 19th century it was believed that microbial life could not exist in such extreme conditions, thus the petroleum itself must have come come from decayed organic matter. We've since discovered numerous extremophile forms of microbial life, but the whole "fossil fuel" notion has become so ingrained that the loss of a major part of it's theoretical underpinning has essentially been ignored.
If a job's not worth doing, it's not worth doing right.
As an old Navy Nuclear technician that was personally involved in atleast one radiation clean-up, I would imagine he had some very good reasons for doing that at the time. Would you happen to know his reasons for banning them and if they may still be valid?
Money for nothing, pix for free
I think the solar tower that you are looking for is here
A 188.pdf
A 197.pdf
http://www.wentworth.nsw.gov.au/solartower/
Going forward to http://www.enviromission.com.au/
They are talking of a 25MW station
http://www.enviromission.com.au/financial/EVM%20C
and site in the USA ie Arizona
http://www.enviromission.com.au/financial/EVM%20C
...for a power plant covering 4500 acres (or approx 7 square miles). In contrast, a typical 500MW standard-fuel (gas, coal, nuke) power plant would typically cover a few acres including parking facilities. :) Solar energy just isn't as efficient as a burn, which is why it needs to be scaled up dramatically and captured through an efficient process (like a Stirling) to work.
:)
Fortunately, as a previous poster said, there is a *lot* of unused land in the US. Fly over the country sometime and look down - most of the land is completely unspoiled, not even a home or farm in sight. There is plenty of room to absorb this energy and convert it.
Who knows, maybe stealing a little of the earth's solar energy will slightly abate global warmimg at the same time.
The amount of energy in sunligt at noon at the equator is approx. 1 kW/M^2, so the theoretical maximum of energy reflected is somwhere around 100 kW.
Getting 25 kW out of that seems quite good. If the 25 kW is average and not peek, it seems even more fantastic...
--- Henrik
Actually they ARE pretty much the same thing.
Heliostats are just mirrors with trackers. Each SES unit is.... a mirror with a tracker.
The only difference is that the SES system has the heat engine attached to each unit while the Solar One "power tower" configuration has only heat engine. Molten salt is used as a storage and transport technology but the real engineering is in the steam turbine, a technology which is extremely mature.
While sterling engines and steam turbines work differently, they are both heat engines and are subject to the same limitations (moving parts and Carnot efficiency).
The tracking is more difficult for the heliostats - I agree there - bank shot versus a straight shot. No combustion takes place in either system. Combustion requires the oxidation of fuel, no?
Anyway I have my degree in EE and work at a company that has invested billions into power projects so I do know this field. Power towers (solar one), linear concentrators (trough concentrators), and these sterling units are generally grouped together as solar thermal. They all use solar energy to heat a transport fluid which in turn powers some sort of heat engine to run a generator. While the implementations are different, the various methods share a great deal of technology and none of it is especially hi-tech.
Solar suffers from the fact that insolation has low power density. Concentrating that power has efficiency and cost challenges which point to clever uses of low-tech materials and mechanisms, not hi-tech ones. For instance in Solar One it is the heliostats that cost the money and most of that is in the mechanics of the tracker. A single computer can control any number of trackers and the calculations are quite simple geometry, so the "bank shot" problem need only be solved once for any size system.
Extracting power from hot fluids has been mature for some time now with only incremental improvements possible due to the Carnot limit. Molten salt as a transport fluid and the elevation of the target are not, in any way, major challenges. Wind turbines are far taller, heavier and more complex. Lots of mainstream heat exchange systems operate at higher temperatures and pressures.
Solar One exists on a grand scale already and is an important project but shouldn't be treated with undo reverence. It is just one step towards practical solar power and may in fact be a dead-end.
These Sterling units are self contained and modular. You can add power incrementally, as needed. With power towers you need to size the target and generator according to a certain power level and then deploy all the required heliostats to maximize efficiency. With these you just keep adding modules.
I think we agree more than disagree. I think the power towers *are* a dead end - the working fluid is heinous to handle, the plant itself is much more vulnerable to single points of catastrophic failure, it brins NIMBYs the dishes don't, and it's not that suspectible to manufacturing economies of scale. I think it's a bad application of big power plant thinking to a diffuse and distributed resource.
Where I will argue with you is that the economic failure (and failure they were) of a hundred=plus kW power tower has any bearing on the prospects of a field of dozens of 25-kW engines operating on entirely different principles throughout...
I posted something similar a few days ago but got no replies, and I think this is the most overlooked effect of nuclear energy (including fusion btw, but maybe less so, and except maybe the cold variety ;)
Nuclear power leads to a militarization of society due to the huge risks involved, and adds tremendously to a concentration of power - electrical, political, and economical - due to the high complexity and costs, and necessary scale involved.
The first big post-war waves of increased police and governmental control in Europe were pushed through by using precisely these threats, even before terrorism (another kind: RAF and Brigate Rosse, both with well-documented help by the police and secret services btw) played that role for the first time, but of course then the two scares worked together.
Add to that how nuclear power contributes to political instability in the world, and adds danger to the already existing instabilities (take this week's developments in Iran).
"When I first heard Daydream Nation it quite frankly scared the living shit out of me." -- Matthew Stearns