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Largest US Power Storing Solar Array Goes Live
Lucas123 writes "A solar power array that covers three square miles with 3,200 mirrored parabolic collectors went live this week, creating enough energy to power 70,000 homes in Arizona. The Solana Solar Power Plant, located 70 miles southwest of Phoenix, was built at a cost of $2 billion, and financed in large part by a U.S. Department of Energy loan guarantee. The array is the world's largest parabolic trough plant, meaning it uses parabolic shaped mirrors mounted on moving structures that track the sun and concentrate its heat. A first: a thermal energy storage system at the plant can provide electricity for six hours without the concurrent use of the solar field. Because it can store electricity, the plant can continue to provide power during the night and inclement weather."
The plant doesn't really store electricity. It can however, store heated salts that can be used to generate electricity well after sunset.
So I'm not going to respond to the first post because it makes no sense. But I'll happily use the "first reply" spot, thank you very much, to actually say something. This $2 billion plant breaks down to close to $30,000 per home serviced. Seems a wee bit excessive, considering the average home electric bill in Arizona runs something like $200 (I researched the web for a few minutes to estimate this). Consider that installing a home solar system would run something like $10-$20k at most in a sunny place like Arizona (considerably less w various tax incentives). Looking like a bit of a boondoggle?
http://en.wikipedia.org/wiki/Solana_Generating_Station
Interesting that the wholesale price of this electricity is 14c/kWh. The overnight residential rate in Phoenix is about 7c. I guess they're hoping to resell a lot of this to businesses during the day, or they're just going to eat the price difference (over nuclear, gas and coal) to meet the 15% renewable energy mandate for 2025.
But the demand is typically down significantly 6 hours after sundown.
The real question is, can it withstand fracking underneath?
Nighttime lasts longer than that.
RTFA - "These six hours will satisfy Arizona's peak electricity demands during the summer evenings and early night time hours . . "
Someone do the math. $2 bil over 30 years for 70k homes.
The plant doesn't generate solar power, the plant generates electricity.
Are you sure? TFS said it was a first. If the LHC can make a contain a black hole, then a small star should be doable. How else are you going to generate solar power at night. ;-)
I'm not saying it's useless, but I am curious if there's some fundamental limitation that's caused this. If you want base load power, you'd probably want more like 12 hours of storage and it seems strange they wouldn't go for that, since they're half way there. If you're only going for intermittent power, this system is more expensive to build and operate than a photovoltaic system would be, but it makes sense if you add energy storage to the picture.
I already did. It's $0.11 per kWh with no operating costs or interest added in. Or it's about $1000 per home per year (again no operating costs or interest payments).
And since they're selling the power to APS at 14c/kWh, it seems like a good plan...
In Arizona, we use most of our power during the day, cooling homes.
Solar power is currently cheaper than wind energy.
Wind energy is currently cheaper than oil and competitive with non-subsidized coal and gas.
Any questions?
The invisible hand already weighed in, and resistance is futile.
-- Tigger warning: This post may contain tiggers! --
I did the calculations and it is around 1200 square feet per household that this project is powering. I'm not sure this type of land use could really scale.
Economics. You don't need nearly as much power between midnight and 6 (7? 8?), during which time the nukes and coal, which can't be throttled too much, will oblige. Designing heat storage capacity for around-the-clock is wasting money, at least in the current grid configuration and state of the tech.
Few people here turn their cooling systems OFF during the day. Also, the hottest days of the year here are in the summer, where a lot of families have kids at home. YES, there's absolutely a spike in electricity around 4pm (when it's still hot and people come home), but businesses (which a lot of us go to during the day) have air conditioners too.
Nighttime lasts longer than that.
Or more likely, they did some demand modeling and found some value that made the economic sense?
Electricity demand follows a predictable pattern, with the lowest demand between 10pm and 7am. If surplus power (to storage) were to transition from positive to negative in the early evening, then 6 hours of stored capacity might work out pretty well.
Yes, night is longer than the 6 hours mentioned in the story summary. But the story summary is a bit misleading.
That is six hours running at full capacity and also running entirely from the salt tanks. Neither of those conditions are likely to be true overnight.
Solar plants continue operating at reduced power during cloud cover and at night time. Even at times of reduced sunlight or at night there is still energy available. It does not need to run entirely from the salt tanks.
Secondly, nighttime is not peak usage hours.
The Solana salt tanks are about 740 cubic meters so they could probably store around 16TJ of energy. (For physics impaired, 1 joule per second == 1 watt.) That is a lot of power. Since it will mostly be relying on that stored energy at night and not running at full capacity, that stored energy could reasonably last through the night and on through a good portion of the following day.
//TODO: Think of witty sig statement
As an Arizonan, I assure you, we have no use for any of the land between Phoenix and Yuma sans that which the Palo Verde nuclear plant sits on -- and there's a lot of it.
Technically nothing stores electricity except for super-cooled superconductors. Batteries "store electricity" in the form of chemical energy and even capacitors only "store electricity" as two charged plates. But I think we all know what they meant, that it was storing the potential for electricity.
Yea solar plants are soooo ugly. Not like coal power plants which are scenic wonders.
http://en.wikipedia.org/wiki/File:Grand_Junction_Trip_92007_098.JPG
That's really small, in fact it's less than the average size of a home. Considering you have a lot of otherwise unusable desert out west, this sounds like a great use of land.
Well after sunset?
Actually, when you read up on it, the storage capacity is exhausted shortly after sunset. 6 Hours max.
The efficiency falls off at low sun angles.
Sunset usually happens right at peak demand time, evening cooking, and late afternoon air conditioning.
Plus the site has high ground to the immediate west, sunset comes earlier for them.
Don't get me wrong, this is an impressive feat of engineering.
It was installed very fast, hacked out of prime farm land (or as prime as it gets in Arizona).
Google Maps Satellite view, with imagery dated 2013 http://goo.gl/maps/Qh7e5 shows nothing
but desert with truck roads laid out, and now they are up and running.
(Either that or Google is Playing Fast and Loose with image dates, because Google Earth shows the same
images but has a 2010 date on them)
Sig Battery depleted. Reverting to safe mode.
it also seems stupid to use a turbine that requires water in the middle of a desert and is subject to the energy lost in conversion. I'm a fan of the "by all means necessary" approach to solving our energy problems but this is just a huge waste IMO. Perhaps it has use as a prototype, otherwise I'm not convinced it's a good idea, at all.
Can you think of another way of generating electricity from heat on a commercial scale?
According to this it is a bit lower than that at about 94.2%. It is also a bit skewed by the fact that Seattle is close to mountain ranges with lots of valleys that can produce hydroelectric power. If you remove the hydroelectric, 89.8% the percentage drops to 4.4%.
Not everyone lives in an area that has plentiful hydroelectric generation. It is like Arizona touting how much solar based electricity they are generating and slagging Seattle for falling behind.
Meanwhile, I just shelled out $150 to buy one unit of the Seattle Aquarium solar panel array, which will reduce my annual already green electric bill by about $46 until around 2035.
That is only because you are getting credited for $1.15/KWh when electricity sells locally for $0,0672. You are being paid over 17 times the going rate. Making money due to tax incentives really skews the picture.
By the way according to Seattle Power the credits amount to "an estimated annual credit of almost $29 per solar unit"
I really don't think comparing a highly subsidizes small , 49 kW, project with al large commercial project is very valid at all.
What I don't get is why they only went for six hours of storage capacity? A few years ago, a friend of mine described an idea to me for a salt tank system that would take days to come up to working temperature, and days to cool off. You'd just add heat whenever you could, and draw power whenever you needed it. His estimate was that the power would end up costing 3 to 4 cents per KwH.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
Shhh... Don't argue. The average slashdotter has a lot better technological insight than what "stupid" people with a paltry $2000000000 credit line could ever access.
Those education cuts really did hurt :(
The efficiency falls off at low sun angles.
It falls off faster for solar hotwater (like this plant) than for photo-voltaic.
You start drawing on your stored heat WELL BEFORE sunset, usually several
hours before sunset, because as I pointed out that is the peak demand period, and your
storage is exhausted in 6 hours, from the time you start drawing.
So maybe two or three hours after sunset your storage is exhausted.
Its a long time till sunrise.
Sig Battery depleted. Reverting to safe mode.
News just in - big stuff costs a lot, big stuff that is a cutting edge experiment even more so.
Also I suggest you look at the fine print and breakdown of those numbers you've quoted - I'd say they are assuming the tenth plant or so of a type where savings can be made due to already sunk expenses and from experience. For the China number I suggest you use a real plant instead of a wild estimate. They some AP1000s almost ready to go, a couple of years behind the initial plan and a few billion over expected budget but real things instead of rubbery numbers with an implied attack at "regulation costs". I suspect a lot of those extra costs are really due to China not having so many parasitic "horse judges" doing a "heck of a job" in the businesses involved with construction. I'm not suggesting that China is not corrupt, simply that the US nuclear lobby is vastly more so.
Not at large scales. PV does not scale well since if you double the size you only double the output. With thermal solutions of all types you can get a lot more heat out of stuff if you have a lot of hot stuff, so doubling the size gives you more than double the output due to an increase in the amount of energy you can get out. For example, if you don't have much steam you can only have a high pressure turbine but if you have a lot you can use the leftover steam that comes out of the first turbine and feed it into another with a different blade pattern to extract more energy and so on.
With thermal it has to be big so you have an enormous capital cost, but if it's big enough PV just will not match it. A 500MW PV array would cost a vast amount more than a 500MW thermal solution.
China 2007:
Tianwan Nuclear Power Plant
$3.3 Billion for 2,120 MW
$1.56 Million/MW
US 2013:
Solana Solar Power Plant
$2 Billion for 280 MW
$7.1 Million/MW
And we wonder why we keep having to borrow money from them?!
-- "Government is the great fiction through which everybody endeavors to live at the expense of everybody else."
Yes, but during our horrible, soul-killing abominable summers (6 months out of the year) AC usage 24/7 is pretty well required. How many nights a year does the overnight low not dip below 100? (I moved to phoenix from oregon, i might be .. exaggerating, but shit summers be hot here.)
Except the collectors, although not operating at peak efficiency, due to the sun light passing through more air (but the effective surface area is still the same, since the mirrors rotate to track the sun) they still provide heat energy to the molten salt, right up until sunset.
What's the total cost of the fuel used by the combined cycle plant during the first 10 years? 15 years? 20 years?
Is there any solar power that is not a blight on the land?
Where I live, in San Jose, California, they install solar-PV panels over parking lots. They look nice, generate power, and provide shade for the parked cars.
Do you think they vent the steam to the atmosphere? Or do you think they might put it in a closed loop so they can reuse the water?
That was the turning point of my life--I went from negative zero to positive zero.
Most of you don't work weekends, and probably half the homes have somebody home during weekdays (retired people, unemployed people, stay at home parents, latch key kids), and it's hotter during the day than the evening, so you need a lot of daytime power still.
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More storage capacity beyond peak hours probably isn't profitable. You want to sell electricity during peak because that's when you're getting the highest dollar value for your power. They probably designed the salt storage, so the total output of the plant was extended long enough to generate during those peak evening hours, and no longer, so baseload power takes over. The smaller your storage is, the less power you would put into storage and the more power you put into spinning your turbine.
Helps to read this in the voice of Sheldon.
Well, that's all well and good for you people in areas that don't have 99.8 percent green energy like we in Seattle do.
How can you breath with all the smug in the air up there? Do you have any figures on how many are lost per day due to self righteousness?
Right, and that is another reason this plant is way more efficient than roof top collectors.
It can make the best use of early morning and late afternoon sun, even when there is much more air the light has to go through.
Sig Battery depleted. Reverting to safe mode.
Technically nothing stores electricity except for super-cooled superconductors.
Depends on how you define electricty I suppose. If "static" electricity isn't really electricity, then you have a point. We refer a lot to "electrical flow" as if there is a thing called "electricity" that is made up of electrons, rather than electricity being the flow itself. If you think of electricity as an "electron fluid" then it's still electricity even when it's just has a potential to flow as in static electricity. If you think of it the way you're thinking of it (which is more technically correct) then only actual flow of charged particles (which don't just have to be electrons) is electricity.
Still, you're ignoring ways other than superconductors that you can "store" electricity. Cyclotrons, for example. Or natural magnetic artifacts like the Van Allen belts. For that matter, I'm not sure there's such a thing as a perfect insulator, so "static" elecricity isn't really truly static, it's just that the flow is very slow. So capacitors and Leydon jars, etc. can be said to be "storing" electricity by slowing it down, just as pretty much any vessel "storing" water actually allows the water to flow out of it very, very slowly.
In any case, it's always tricky to talk in absolutes. You always find yourself having to invent arbitrary constants and cutoffs or applying "I know it when I see it" style reasoning.
However the amount of electricity produced is not. You can recover energy more energy from a vast amount of steam pushing a series of turbines around to drive generators than you could from the electrons coming from the PV cells coving the same area.
Make it bigger and those costs come down. Of course the sensible thing is to solve a lot of problems by building a pilot plant such as this before you build the large plant - hence this project. It's not big but it's big enough for a proof of concept.
So in other words this thing makes perfect sense and bitching about it is like complaining that the Wright brothers didn't start off with a SR71. Why should they have bothered when airships existed?
Unless there are some nuclear reactions going on in there, I really don't think it is creating any energy at all, much less "creating enough energy to power 70,000 homes".
Solar energy converts energy from the nuclear reactions in the sun into electricity. Ok, conversion.
Hydroelectric - captures energy stored from gravitational potential energy and converts it using a turbine into electricity. Fine, conversion again.
Coal/Nat. Gas - takes stored energy in the form of deposits of oil, coal and natural gas and uses them to drive turbines... oh, you get the picture. Check, conversion of energy again.
Clearly nuclear energy reactions "create energy" - no wait, it's converting stored energy in the form of nuclear bonds into radiation, which can then be captured as a heat energy which can then drive a steam turbine turning into electricity.... uh... huh.
Conversion is all we can do apparently. We might want to thank/curse this lousy law [1] .... who's with me for repeal?!?
[1] http://en.wikipedia.org/wiki/First_law_of_thermodynamics
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Except for the fact that, in the southwestern US, peak power demand tracks sunlight pretty well. And that peaking plants (run on coal) are fairly expensive. And that all that solar power can simply displace daytime use of hydro, which can fill-in the shortfall on cloudy days of high demand.
So, you're just *completely* wrong... That's not too bad here on /.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
No matter what the power plant... No matter how clean and low-impact it is, some moron ALWAYS has to find something stupid to bitch about.
Are you suggesting that a nuclear power plant would be a scenic tourist attraction, right at home inside Yellowstone? How about a coal power plant, along with the huge open-pit mine where the coal comes from? Or maybe some nice tar sands right outside your back yard?
If you don't like the fact that electricity generation is going to use some land, then cut the power lines coming into your house and live in the nice, scenic, non-blighted dark and cold.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
No, TFA clearly says that it can run for 6 hours after sunset, not six hours from some indeterminate point where the sun reaches a low angle before sunset.
Anyway, peak time is during the day, not the evening. It's when people need air-con and industry is active. In the evening it gets cooler and commercial buildings shut down.
You also make the classic mistake of judging the technology as if it were the only source of energy, which of course it isn't and was never intended to be.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
In 2010 there were 114,800,000 U.S. households, 114,800,000 / 70,000 powered homes = 1,640 of these facilities at 3 square miles per facility = 4,900 square miles! Airizona is 114,006 square miles, that is 4.2% of the state covered in panels....or roughly the entire state of Connecticut if you have some room for growth.
neorush
A loan guarantee is not financing. The DOE has provided no money. The financing is from private institutions.
The loan guarantee means the private institutions get paid even if the project fails, true. But why should the project fail? This is proven tech that's cost competitive. It would take some true catastrophe for the loan guarantee to ever be called on.
"with their freedom lost all virtue lose" - Milton
And how do you think they extract electricity from nuclear fission plants?
Fission -> Heat -> Steam -> Turbines -> Electricity
This solar setup does the same thing, except replaces the heat source with sun / molten salt.