US approves world's biggest solar energy project (Update)

When the banks pay back the 600 Billion it can be spent on 600 plants at one billion dollars each... end of energy problem for most of North America. The money is obviously available since it is used for financial problems easily enough.

I don't see how you can equate the waxing and waning of solar power to the power output of a nuclear powerplant, unless you take the word "roughly" quite literally.

In any case, all the best for the project. Wake me up when they've figured out how to smooth the output without using "virtual batteries" (aka. coal power running somewhere else)

The reason being that all the solar energy in the world can't break the dependence on fossil fuels unless you figure out a way to put sunlight in a bag and release it when needed.

Eikka - the current need for power is during peak hours, not at night. It would be extremely expensive to build a nuclear plant and use its power only half the day. Solar works great for peak hour supply.

Output is smoothed via inverters on panels. It doesn't matter if one or a few panels are temporarily shaded.

Finally, we know how to store energy. We've been using pump-up storage for a hundred years. We built quite a bit back when we were building nuclear in order to time shift nuclear plant output. We're building more.

(Not that we need storage for solar at this time. The grid can adjust for varying inputs/outputs as it already does.)

easiest way to smooth out the output is ... and the type of solar plant is not mentioned --- but to built a solar concentrator. These plants tend to be the most expensive type of solar plant to built. They basically fous the sun's rays on a column of salt and make that baby boil. The boiling salt puts pressure into the system and drives turbines and keeps energy production going well into the night.... It's not perfect but it smoothes out that curve for you.

Or heating a salt mine in the ground and using that pressure when night comes to provide extra long lasting power throughout the night.

The only question is how economic these technologies are.. and how low the cost can go with more and more development.

Eikka- So essentially your gripe about this is that it isn't perfect. You want us to wake you up when there aren't any flaws with this method? Have fun Mr. Van Winkle. Building a nuclear plant may cause somebody to state "wake me up when it doesn't have nuclear waste products" or "wake me up when there isn't a threat of a meltdown". The fact is, every method has its pro's and con's and certain groups will value some pro's more than another. We must recognize that this will not in any way hurt our energy needs and should be welcomed as a new addition to our diverse energy grid.

easiest way to smooth out the output is ... and the type of solar plant is not mentioned --- but to built a solar concentrator. These plants tend to be the most expensive type of solar plant to built. They basically fous the sun's rays on a column of salt and make that baby boil. The boiling salt puts pressure into the system and drives turbines and keeps energy production going well into the night.... It's not perfect but it smoothes out that curve for you.

Or heating a salt mine in the ground and using that pressure when night comes to provide extra long lasting power throughout the night.

The only question is how economic these technologies are.. and how low the cost can go with more and more development.

@El Nose,

My thoughts Pie-zackly.

And high time, too!

This is a proposed concentrated solar power plant, NOT photovoltaic plant. Which highlights the lack of energy knowledge in this country, even among the highly educated.

http://www.energy...dex.html

trekgeek1:

Wake up, nuclear power.

Closed fuel cycle, no meltdowns.

http://en.wikiped..._Reactor

If these numbers are accurate, these plants are extremely cost-effective compared to the stuff I've seen in the past. At this price, it would only cost an initial ~390 billion to supply all residential power needs for the U.S...for the next 25 years...(excluding maintenance and such.)

Compared to the amount of money the government is throwing around is useless "top down" stimulus programs, this is peanuts...

(Not that we need storage for solar at this time. The grid can adjust for varying inputs/outputs as it already does.)

That's the "virtual battery" again.

Not only does it prevent other viable energy sources from entering the grid, it binds existing power capacity into a non-stop up and down adjustment cycle and makes us more dependent on fossil fuels.

You don't understand that when there's 1000 MW of highly variable power in the grid, there must be 1000 MW of highly adjustable power to back it up, and that invariably means either coal or natural gas, in the most inefficient way because these plants have to be kept on standby.

Pumped hydro storage is peanuts compared to what you'd actually need to smooth the output from solar and wind. You got minutes of power, and you'd need a week of it.

Eikka- So essentially your gripe about this is that it isn't perfect. You want us to wake you up when there aren't any flaws with this method?

I want you to wake me up when this method of energy production is actually scalable and sustainable beyond the 1% margin where it can exist as noise in the electric grid without causing too much trouble.

To make these systems cost-effective, you have to push all the energy they can produce into the grid, whenever it comes, however much of it comes. Otherwise the energy is lost, so the whole grid has to dance to their tune.

Only Reebs is awake it seems. This Blythe plant is a solar concentrator ie thermal plant, not photovoltaic. No tune to dance Eikka.

Eikka - the current need for power is during peak hours, not at night.

How about early mornings and afternoons, and early evenings? The power demand doesn't just die off as the sun does.

Output is smoothed via inverters on panels.

That suggests you didn't even understand the question.

Finally, we know how to store energy. We've been using pump-up storage for a hundred years. We built quite a bit back when we were building nuclear in order to time shift nuclear plant output. We're building more.

Raising a ton of water 300 ft high will only give you 0.3 kWh of energy, from which you can recover perhaps 0.2 kWh. That's why pumped hydro storage is only viable for smoothing small variation. You need a truly massive reservoir to get e.g. 1 GW for 24 hours, and places for those are hard to come by. And it's not particularily friendly to the environment to flood out huge areas of land, because the reservoirs emit methane.

Only Reebs is awake it seems. This Blythe plant is a solar concentrator ie thermal plant, not photovoltaic. No tune to dance Eikka.

Are you claiming that using a boiler instead of a solar panel somehow allows this plant to generate energy without the sun shining on it?

Sure, there's the molten salt method which allows you to generate a little bit of energy and extend the peak operation couple hours beyond midday and early afternoon, but that's not really what I was talking about. That's just cutting the blanket at one end and sowing it onto the other, because the molten salts need more time in the morning to heat up, just as the demand is rising, so while your solar concentrator is warming up like a lizard in the low hanging morning sun, coal plants are used to meet demand.

Eikka, you are obviously a troll. Each response has met your lofty claims, your short sightedness is rather appalling. You ignored the "Peak Usage" comment and, you started adding methane to the mix. I think you should crawl under your bed till the bogey man leaves.

CouchP, yeah, he's a troll, gotta be.

meanwhile, the last paragraph of the first link at the "more info" refs:

The Blythe Solar Power Project uses parabolic trough technology where rows of parabolic mirrors focus solar energy on collector tubes. The tubes carry heated oil to a boiler, which sends live steam to a turbine to produce electricity. A new 230 kilovolt (kV) transmission line will be constructed to connect the Blythe Solar Project to the Devers-Palo Verde #2 500 kV line at the Colorado River substation.

ultimately, I reckon, large scale heat storage around the world will be attained by using reservoirs of salt wherein the best advantage will be in the heat of solidification/melting at about 801DegC. I think that in the long run Stirling engines will come to be the primary drivers of generators for these purposes.

That's politics alright; this move is only logical if public opinion is your main objective. We are just about to develop more effective ways of gathering solar energy (molecules capable of storing heat energy indefinitely, nanofibers mater...ials capable of capturing heat and convert it into electrical power,... ) and yet instead of financing researches that may make a huge difference, the US prefers to throw away 6 billions in a project that may very well be archaic in a few years...BUT it is a big improvement of this country's politics.

Why not use some the power to make hydrogen. Then when needed, burn the hydrogen to balance output. Heck you even end up with distilled H2O.

Are you claiming that using a boiler instead of a solar panel somehow allows this plant to generate energy without the sun shining on it?

Huh... let's think about that for a second. Lets say for some strange reason there's isn't a huge peak energy demand this day. You heat the salt up to boiling. You heat huge reservoirs with superheated liquid salt. The sun stops shining...

So the salt immediately drops to freezing because the sun isn't shining? No. I don't think so.

Yes of course it means that the heat can be used to turn turbines whenever anyone desires... For the most part during the peak at mid-day.

If you need 1GW of nuclear/fossil backup for every 1GW of solar then solar is going to take 50% of the market eventually. Not bad.

I was saddened to see that a US company wasn't lead but rather a German company. I hope this infrastructure project hires a lot of Americans as touted.

@Eikka,

when there's 1000 MW of highly variable power in the grid, there must be 1000 MW of highly adjustable power to back it up, and that invariably means either coal or natural gas, in the most inefficient way because these plants have to be kept on standby.

First of all, you aren't going to have peak demand at night. And during the day, you are never going to generate 0 power even from a highly-intermittent solar source (BTW, this one is located in a sun-drenched desert.) So your 1000 for 1000 figure is wrong. Probably, it's more like 600 MW (or less) of backup for every 1000 MW of variable capacity.

Secondly, coal vs. natural gas generators are exactly the opposite of each other. Coal plants are baseload providers, whereas gas plants are usually designed SPECIFICALLY as peak load providers. Meaning, they are DESIGNED to be intermittent, and they are most efficient in that actual regime.

You heat huge reservoirs with superheated liquid salt.

The problem in your solution is the quantity of molten salt required. Existing system proposals speak of couple hours of backup at feasible prices. The system efficiency is also somewhat low, as the stored molten salt is at a lower temperature than what you get directly out of the solar concentrator when it is operating normally.

If you need 1GW of nuclear/fossil backup for every 1GW of solar then solar is going to take 50% of the market eventually. Not bad.

It doesn't work quite like that. If you expect 1 GW of steady production, but the solar plant produces full power for 4 hours around midday, you end up running the conventional powerplant 20 hours a day to meet the demand.

Of course you can think of it as a replacement for the peaking powerplants, but the difference between the midday peak and afternoon/evening demand isn't that great, and you'd still have to run on coal most of the day.

First of all, you aren't going to have peak demand at night.

Not all night, but the typical demand curve extends steadily to well past 11 pm before it starts the decline towards the early morning minimum.

Meanwhile your solar powerplant will produce its peak at 10am - 2pm and then drop steadily. With thermal energy storage, you can shift this peak 2-3 hours forwards, but then it drops more dramatically as there is no more sunlight at late afternoon.

Here's an example from France:
http://i122.photo...neelo/ET graphs/Nuclear/RTE_PowerCurves-07-2010v2.gif

trekgeek1:

Wake up, nuclear power.

Closed fuel cycle, no meltdowns.

http://en.wikiped..._Reactor

I agree nuclear is fine and meltdown isn't a huge concern. The point was that no method is perfect and somebody will always dislike certain methods for different reasons.

"7000 acres of public land" -- What a sorry joke...Remember that the promoters of these types of wasteful boondoggles are the same Sierra Clubbers who would absolutely abhor disrupting "pristine" nature by construction of water project for irrigation. The Parsons engineering firm put together a project called the North American Water and Power Alliance years ago that would supply abundant fresh water and power to the entire western parts of Canada, US and Mexico. Look it up...

All of this will be economic roadkill in 5-10 years.
So far, aside from the bother of having to upgrade state-of-the-art switches to cope with the current involved, the fusion mini-generator being developed here LPPhysics.com (booster site at focusfusion.org ) is on track to hit "scientific break-even" early next year.

The mini 5MW generators will go in place almost anywhere, and cost 1/20 best current North American retail (i.e., about 1/50 Ca.'s costs). Output could be sold profitably at well under ½¢/kwh.

They will be able to power fusion torches to reduce all the solar and wind hardware back to valuable elements, though, so all the current spending won't have been totally wasted.

Edit;
Sorry, was getting erroneous HTML "missing style for page" error message.

@Eikka,

Meanwhile your solar powerplant will produce its peak at 10am - 2pm and then drop steadily.

That's probably not quite true with this particular design. Here you have parabolic concentrators, which rotate to track the sun across the sky. The atmospheric attenuation isn't that dramatic until you hit really low incidence angles; I expect the power plant will generate near-peak power almost from dawn to dusk. Or at least, more like 9am-3pm in the winter (and much longer than that in the summer...)

Here's an example from France:

I see enough room in the chart for a good 20% of solar sourcing between 9am-4pm, with no impact on base capacity. (Don't forget the location, also: same latitude as LA, where the shortest day of the year -- sunrise to sunset -- is 9 hours, 52 minutes long; the longest is 14 hours, 25 minutes.)

electric cars have the potential to contribute significantly to the reserve grid power. You would leave it plugged in all the time, tell if/when you expect to need a full charge so it's ready. You could make money from it/reduce you power bill by having it charge up during off hours and discharge to grid during peak. This is all already being designed and beginning to be implemented.

The Blythe plant is a distasteful joke.

$6 billion for a project that will generate a projected 2.1 TWh/year. That's $25 000 per kW.

If you need 1GW of nuclear/fossil backup for every 1GW of solar then solar is going to take 50% of the market eventually. Not bad.

Except the "backup" is running most of the time and the solar is running whenever the sun shines. If you can find someone who will commit economic harakiri you might eventually get something like 30% of your power from solar in California and about 5-10% in a place like Sweden where every other day is over cast and most power demand is in the winter.

electric cars have the potential to contribute significantly to the reserve grid power.

Not really. That would require some kind of battery technology that's not even on the horizon.

You could make money from it/reduce you power bill by having it charge up during off hours and discharge to grid during peak.

No, you can't. You can only lose money by doing that. The cost of storing 1 kWh in a vehicle battery is on the order of 10 cents. In order to make money electricity would regularly have to fluctuate in price by more than 10 cents per kWh and the grid would have to be redesigned to cope with this kind of flow on a large scale.

You'd need something like EESTOR(but you know, not a fraud) to do that profitably.

they figured out how to "store" the sun. look up the work of the nocera group at MIT
http://outsideonl...era.html

they figured out how to "store" the sun. look up the work of the nocera group at MIT
http://outsideonl...era.html

Well, sorta maybe someday. Depends on the availability of Lithium-6 hydride as a catalyst. Which remains a thermonuclear-weapons-exclusive material legally. Unless you make your own with a particle accelerator.

Smooth power with flywheels.
"Flywheel energy storage works by accelerating a cylindrical assembly called a rotor (flywheel) to a very high speed and maintaining the energy in the system as rotational energy. The energy is converted back by slowing down the flywheel. The flywheel system itself is a kinetic, or mechanical battery, spinning at very high speeds to store energy that is instantly available when needed."
http://www.beacon...eels.asp

Smooth power with flywheels.
"
...
The energy is converted back by slowing down the flywheel. The flywheel system itself is a kinetic, or mechanical battery, spinning at very high speeds to store energy that is instantly available when needed."
http://www.beacon...eels.asp

IMO, the issue is capacity. The stored power required to keep a city going overnight is would require a s***-load of flywheels!

Yay! Lets build the biggest solar plant in the most broke state around! Score one for Odumba!

On a side note, encouraging @home energy storage sites could both save alot of money and help against those annoying black outs that occasionally happen.

Tucson Electric Power had a program for their customers to purchase a 1kw panel for their roof, but they could not store the power.
The cost for such a panel would require 10-20 years for roi.
I would have leased my roof to TEP for them to install their panels.
Apparently TEP couldn't get a good ROI either.

@wwqq,

$6 billion for a project that will generate a projected 2.1 TWh/year. That's $25 000 per kW.

What the hell are you talking about? The article above says the $6 billion buys you more than 3 GW of generating capacity. That's less than $2,000 per kw. You'd have to assume less than 10% average output relative to nameplate, to arrive at you $25,000 figure.

Except the "backup" is running most of the time and the solar is running whenever the sun shines.

Bullshit, and bullshit. This power plant is being built in a desert, where the sun is shining most of the time. And it's a southern desert, where days are long.

You'd need something like EESTOR(but you know, not a fraud) to do that profitably.

So maybe we should throw a few hundred $Billion into advanced electricity storage research... before we wind up buying THAT too from the Chinese.

When the banks pay back the 600 Billion it can be spent on 600 plants at one billion dollars each... end of energy problem for most of North America. The money is obviously available since it is used for financial problems easily enough.

Last time I checked, the banks are well ahead of the payback plan (taxpayers are less than 50 billion on the hook currently), and within 9 months the program will in fact have made taxpayers a profit. Reality strikes again!

I think the days of centralized power generation are limited.How about systems like the Bloom energy product,which uses fuel cell tech to produce electricity on site.You can even use biogas as the fuel.No more widespread blackouts,and terrorists cannot take the system down.

The energy crisis is over. Shale gas is everywhere!
http://www.thegwp...ver.html
The warmistas and their burgeoning nomenklatura will continue to try and leverage the CO2 scam, but cheap NG into the most distant foreseeable future means that the egregious and inane economics of renewables will get shorter and shorter shrift.
Economics and Reality will have their Bite!

Economics and Reality will have their Bite!

They will, indeed.

With these new sources, we'll quite likely far exceed CO2 emissions of even the most dire IPCC projections -- with all the attendant consequences.

Economics and Reality will have their Bite!

They will, indeed.

With these new sources, we'll quite likely far exceed CO2 emissions of even the most dire IPCC projections -- with all the attendant consequences.

Yes, further improvement in agricultural yields!

Each of the above problems mentioned now has a viable solution. It may mean investors will choose between several good ideas,not one cure all option.There is no reason to think the utilities and ratepayers should divest themselves of a working grid for this would be like digging up all the roads and pushing everyone into a unique vehicle.Instead,the utilities and ratepayers should be looking for new more efficient battery chargers for automobiles, more efficient appliances,furnaces, air conditioners,and Scandinavian window treatments which save vast amounts of thermal energy.
The internet allows us to tap into the wonderful solutions being created around the globe,and allows investors and the utilities many opportunities to examine the proven, cheaper solutions available.

Economics and Reality will have their Bite!

They will, indeed.

With these new sources, we'll quite likely far exceed CO2 emissions of even the most dire IPCC projections -- with all the attendant consequences.

Use all that shale gas to power your own home and charge your electric car.

The article above says the $6 billion buys you more than 3 GW of generating capacity.

No. The article says that the Blythe project alone costs $6 billion, other sources say the Blythe project will costs $6 billion, you're wrong.

2.1 TWh per year is the amount of power they expect to generate; that's a capacity factor of ~24%.

That's less than $2,000 per kw.

No, that's $6 000/kW of capacity and $25 000/kW of average power.

This power plant is being built in a desert, where the sun is shining most of the time.

With a north-south single-axis tracker, which a parabolic trough effectively is; you get approximately 50% more power in the summer than in the winter in California. This is a good match with demand profile only for poorly insulated houses. Concentrating solar can't use diffuse light, it takes very little cloud cover to noticably reduce output.

And it's a southern desert, where days are long.

About 8 hours of useful power output.

Yes, further improvement in agricultural yields!

Most of the things we like to eat either are grains or are fed grains. Grasses are adapted to the low levels of CO2 we've had the last few tens of millions of years and don't benefit much from higher CO2, but weeds do.

CO2 is in most cases not going to be the constraining resource; it's water, availability of which is going to be reduced in many of the most fertile areas of the planet.

Increased temperature is going to push he areas in which you can grow staple crops like wheat towards the poles. But those places tend to have soils of low fertility, like taiga and podsol.

AGW is a disaster for farming. Adaption may sound romantic, but the reality of adaption is that it will be more like triage and misery.

No. The article says that the Blythe project alone costs $6 billion, other sources say the Blythe project will costs $6 billion, you're wrong.

My apologies. I must've misread the article, or perhaps I read it prior to the "Update"...

Wikipedia says it's a 968 MW (nominal? effective?) project.

2.1 TWh per year is the amount of power they expect to generate; that's a capacity factor of ~24%.

I still can't figure out where you get your figures (my web searches have come up empty.)

you get approximately 50% more power in the summer than in the winter in California.

How come? The summer-winter difference in insolation at LA's latitude is just 22%:

http://www.solar4...dow.html

Parabolic troughs shouldn't be sensitive to elevation of light source, as long as the incident "rays" remain correctly oriented with respect to the parabolic surface when projected onto the plane containing the parabolic cross-section.

In any case, all the best for the project. Wake me up when they've figured out how to smooth the output without using "virtual batteries" (aka. coal power running somewhere else)

My, there's a lot of misinformation in this thread. As has been mentioned before, and despite the misleading photo, this plant is to be solar thermal, and not photovoltaic. It's really the only sane way to do a large solar plant. And in addition to its other benefits... efficiency, for example, it also makes storing large amount of energy simple. One of the best ways we have of storing energy is in the form of steam. It's not really that much of a problem to store days' worth of energy output in steam tanks. And a properly designed steam tank exhibits only about 1% per day in thermal loss. So Eikka's objection is really a non-issue.

I still can't figure out where you get your figures (my web searches have come up empty.)

The Blythe project fact sheet at energy.ca.gov: http://www.energy...me_I/2.0 Project Description.pdf

Parabolic troughs shouldn't be sensitive to elevation of light source[...]

Light that is scattered by any kind of aerosol haze, light wispy clouds at great altitude, particulate pollution or sand becomes diffuse rather than direct, and therefor unusable by concentrators.

Elevation affects opt

PinkElephant, ignore my last post immediately above, it got malformated from a too long URL, and it ate half my post when I tried to correct it.

Go here for blythe project fact sheet(tinyURL because of formating problems): http://preview.ti.../3xcexlj

I used http://rredc.nrel...ble.html for January and June with North-South Axis Tracking Concentrator Tilted at Latitude.

Light that is scattered by any kind of aerosol haze, light wispy clouds at great altitude, particulate pollution or sand becomes diffuse rather than direct, and therefor unusable by concentrators.

Elevation and seasonal variations in weather affect optical depth.

...
AGW is a disaster for farming. Adaption may sound romantic, but the reality of adaption is that it will be more like triage and misery.

Uh-huh.

Under higher CO2 levels, crop plants showed a notable increase in reproduction while wild plants did not. On average, crops produced more fruits than did wild species (28 percent higher in crops vs. 4 percent higher in wild plants) as well as seeds (21 percent higher vs. 4 percent higher, respectively).

Individual crops varied in their response to increased CO2 levels. Rice seemed to be the most responsive, as its seed production increased an average of 42 percent. Soybean followed with a 20 percent increase in seed, then wheat (15 percent increase) and, finally, corn (5 percent increase).

While crop plants and wild plants had similar increases in total growth (a 31 percent increase), crops allocated the additional weight to reproduction, while wild plants seem to funnel

-cont-

--cont---

funnel much of it to tasks other than reproduction, Curtis said.

“Wild plants are constrained by what they can do with increased CO2,” he said. “They may use it for survival and defense rather than to boost reproduction. Agricultural crops, on the other hand, are protected from pests and diseases, so they have the luxury of using extra CO2 to enhance reproduction.”[/q} [/blockquote]

-cont-

much of it to tasks other than reproduction, Curtis said.

“Wild plants are constrained by what they can do with increased CO2,” he said. “They may use it for survival and defense rather than to boost reproduction. Agricultural crops, on the other hand, are protected from pests and diseases, so they have the luxury of using extra CO2 to enhance reproduction.”

researchnews.osu.edu/archive/co2plant.htm

Sorry for the dupes. Kept getting HTML style error messages.

@wwqq,

Thanks for the excellent links.

I guess it remains to be seen what the actual output of that plant will be. The projected 24% capacity factor still seems suspiciously low to me; it could be that the projections are overly conservative (i.e. focusing on lower bounds.)

But upon reviewing the document you linked, I agree that this project seems too expensive for the output it provides. Then again, I don't quite see what should be so expensive about it. Fundamentally, the technological pieces are not that exotic (glass mirrors? Tubular steel? Gas boilers? Heat exchangers? Filters?) Perhaps part of the plan is to ramp up the manufacturing volumes and pay down R&D costs/debts, which would make similar subsequent projects significantly cheaper.

Regarding 50% variation December vs. June, I agree it's quite extreme. More than I'd have expected for such a southerly location. Then again, most of the electricity in the area probably goes to AC in the summer...

Also, looking at the NREL site, a north-south axis tracking flat plate seems to be more efficient, while a two-axis flat plate completely dominates (and features smaller spread between December/June average numbers.)

That leaves me wondering, why the emphasis should be on solar concentrators, rather than flat plates.

...
That leaves me wondering, why the emphasis should be on solar concentrators, rather than flat plates.

Reduced complexity and cost, I think.

The projected 24% capacity factor still seems suspiciously low to me[...]

Sounds about right to me. They're not using any kind of molten salt heat storage and they're only using a little bit of natural gas(keep the salt liquid over night, rapid start-up in the morning).

Then again, I don't quite see what should be so expensive about it. Fundamentally, the technological pieces are not that exotic (glass mirrors? Tubular steel? Gas boilers? Heat exchangers? Filters?

The same is true of a nuclear plant. It's mostly just concrete, steel, steam generators, steam turbines, plumbing. And yet, putting a few tens of millions of dollars of material in the right shape and configuration to do something useful costs a few billion dollars.

Why? Labour is expensive.

The Blythe project is 7000 acres that have to be leveled, sprayed with binder, covered by steel and polished reflectors which have to track the sun with few mechanical breakdowns regardless of sand and crud.

That leaves me wondering, why the emphasis should be on solar concentrators, rather than flat plates.

Because unless you're satisfied with low-grade heat(e.g. hot water heating) flat panels have to be slabs of semiconductor, commonly multicrystalline silicon.

Silicon is cheap as dirt, it's 28% of the Earth's crust by weight.

Yet to make a solar panel of silicon it has to be extremely pure. First you find high-purity quartz, reduce it at ~1900 degrees C in an arc furnace with coal. This gets you a lump of 98% pure metalurgical silicon.

You convert this silicon into trichlorosilane, fractionally distill it and slowly deposit/decompose it on high purity silicon rods at 1150 degrees C in the siemens process. This gets you to 1 part per billion of impurity.

You slice these rods up into wafers with a diamond saw in clean room conditions; then there's all that doping, surface patterning, contacts and antireflective coating(often silver, palladium and titanium).

The Blythe project is 7000 acres that have to be leveled, sprayed with binder, covered by steel and polished reflectors which have to track the sun with few mechanical breakdowns regardless of sand and crud.

Right, but by the same token with $6 Billion, you could build 12,000 very nice houses (with a ~half-acre plot for each) on those same 7000 acres. Which undertaking should be more complex and labor-intensive?

unless you're satisfied with low-grade heat(e.g. hot water heating) flat panels have to be slabs of semiconductor

Well I was indeed thinking of heat rather than PV (PV only captures a small fraction of the spectrum, anyway.) Good point about low-grade heat; it would kill thermal efficiency for a heat engine...