Arnold Kling  

Solar Dreams

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The U.S. Department of Energy reports,


Acciona Energy announced on June 7th that Nevada Solar One, a 64-megawatt solar thermal power plant near Boulder City, Nevada, is now online. The new facility is the largest of its type to be built in the world since 1991...The Nevada Solar One plant consists of 47 miles of parabolic mirrors arranged in a grid and will produce enough power to supply 15,000 average U.S. homes.

Let's see. 47 miles of mirrors per 15,000 average homes. To get to 150 million homes we would need 470,000 miles of mirrors? The entire area of the U.S. is 3.5 million square miles, and it's not all as sunny as Nevada.

CORRECTION: Some overly picky readers clicked all the way through to the press release of the company and found that the footprint of the plan is 1.3 million square meters, which converts to about 0.5 square miles. So we need only 5000 square miles of mirrors. That we can find.

The press release says that the plant costs $250 million to build and produces 134 million kilowatts per year. That makes the economics seem dicey. The retail price of a kilowatt is about ten cents, which means that the unsubsidized wholesale price would be less. But at ten cents, the annual revenue is $13.4 million. Assume a 5 percent cost of capital, and the annual interest expense is $12.5 million. Then there are operating expenses, depreciation (what if the useful life of the plant is only 25 years?), etc.

This story says that more Americans expect solar power to be the leading source of energy in 15 years than any other source.

Maybe in 20 years. Maybe. Over the last two years, my faith in solar has been going down.


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COMMENTS (24 to date)
Buzzcut writes:

There's a lot of open desert out in California, Nevada, Arizona, etc. Even the high plains has a lot of sun: Kansas, Nebraska, etc.

The downside of these plants is that they more or less destroy the wilderness. You might as well be a "Pave the Earth!" advocate, because one of these plants is not much different than a parking lot.

Al Abbott writes:

That 47 "linear" miles (of unstated width) is about 16 feet per house. If this is the case, seems like the environmental impact would be less if these were mounted on the roofs of the houses instead of spread out over the countryside and requiring lossy transmission over considerable distance. Perhaps the mechanisms for actual power generation would be way too expensive to be replicated house by house. I agree that for now and the next few decades [at least], solar energy is going to remain a niche product.

Ryan Fazio writes:

I think that the market is being tricked by politicians and by environmentalists, which is for instance why the price of ethanol skyrocketed last year. These alternative energy sources are being hyped like crazy causing government and businesses to invest much more than should be invested in these fringe sources in order to achieve a sort of green reputation. but all the while that diverted investment takes away from the energy sources which actually work well--oil, for one.

Now when we talk about improving our energy sources we never talk about improving our access to fossil fuels. there is a reason that oil is the main source of energy in our lives--it works--the market wouldnt invest such a large portion of itself into oil if it did not work.

There is still room for innovation in petroleum--such as in deep sea drilling and tar sands. And of course it would be so easy to make an immediate impact if the government just let us drill in ANWAR, the eastern gulf of mexico, and on the pacific continental shelf for starters.

Matt writes:

I got about .35 square miles for 15,000 homes, assuming the mirrors are about 40 feet wide.

So, 150 million homes comes to 3500 square miles. (Did I make an error?)

For comparison, if we could grow algae properly, about 15,000 square miles covers our oil imports.

Bad solar is the photo-voltaic, which are very inefficient. Prabolic mirrors are very efficient with solar, more efficient then growing algae. Back to physic, the higher the temperatur differential, the more efficient. 750 degrees is a very hot fluid.

Lake Meade, in Nevada, which is a third generation man-made environment, could theoretically be converted in a biodiesel factory and cover our imports. But we need some genetic engineering to get algae working the way we like.

Chuck writes:

According to the press release (click through from the linked article) the plant covers half a square mile (1.3 million sq. meters). The Mojave desert is 22,000 square miles. If we turned the Mojave desert into 100% solar thermal plants, that would be enough energy for 330 million households. (If I calculate correctly.)

Not saying that is practical, desirable, etc, but I don't think available space makes solar thermal a pointless endeavor.

The human intestine is 22ft long, and yet humans are only 6ft tall. What gives!

Chuck writes:

Skeptics of alternative energy should keep in mind that the reason what we've got works well is that we've been doing R&D on it for decades in addition to building our lives around it.

Technology that we discarded several decades ago may be viable now. For example, one aspect of solar thermal plants is having the mirrors track the sun. Back when controls were pneumatic instead of electric, that wasn't really practical.

(If we built our lives around electric cars, the short range wouldn't be an issue, we'd be able to plug in at our commuting destinations, and use other means for long distances, like trains, or cars!.)

I'm not saying I have the answers, it is a complicated problem. But it is also the kind of complicated problem that markets are good at figuring out, as long as we price in all the costs, including the environmental ones.

Tom Myers writes:

The area required by their troughs is given at NREL: TroughNet - U.S. Parabolic Trough Power Plant Data as 357,200 square meters; a little over 1/7th of a square mile. Multiply by 10,000, as you say, and we're up to a square almost 40 miles on a side, yes? (They seem to be depending on very efficient [37.2%, v.good but not outlandish] steam engines.) The power is certainly available, and I personally expect that in a few decades we'll be collecting it, but about any given project...well, we'll just have to see, won't we? (Is my arithmetic off again?)

Gerry Wolff writes:

"… analysts evaluated the solar resource in the Southwest [of the US] and … found that [concentrating solar power] could provide nearly 7,000 GW of capacity, or about seven times the current total US electric capacity." ("Tackling Climate Change in the US", American Solar Energy Society, January 2007, page 17).

Further information about concentrating solar power (CSP) and highly-efficient HVDC
transmission of electricity may be found at:

http://www.trec-uk.org.uk/index.htm

and

http://www.trecers.net/index.html

and

http://www.trec.net.au/

randy writes:

i read recently about some advances in the efficiency of solar panels. there was some recent breakthrough that pushed the percentage from something like 25% up to 75%. email me if you want me to dig it up. and yeah maybe it hasn't been reproduced yet but there may well be a discovery in the future that makes solar a viable option.

have you ever looked up at that thing in the sky. it is BIG and it is HOT!

Bob writes:

We're all biased toward solar because we'd love to see it work and magically solve our energy problems. But solar (and fuel cells) have consistently remained 5-10 years from widespread use for at least 20 years (I did not get formally exposed to alternative energy technologies until 1985 so I can't speak to before this). As much as I wish otherwise, I'm reluctant to count on any new energy technologies having a meaningful impact in a reasonable time frame.

aaron writes:

What if the coming decades happen to be far cloudier than recent ones?

jim writes:

One of the neat tricks of "solar thermal" systems is making power at night. Nevada Solar One uses some of the heat during the day to melt salt (I don't know which type of salt) and recaptures the heat at night.
Thus they expect only about a 2-3% need for backup electrical supply from conventional power.

There is a presentation online by David Rutledge of CalTech where he indicates a square of southwestern desert about 125 miles (I recall) on a side could cover current electrical usage of the USA.

Dewaine writes:

Solar energy is used by large power companies only as a public relations activity. It makes soccer moms feel warm and fuzzy, or something. Solar power is not a reliable product; to be reliable it would require the use of massive batteries, which would completely reverse any cost or environmental advantages.

ed writes:

I'm not sure how efficient solar will ever be, but at least spending money on this type of thing isn't a complete waste. Imagine if we had taken the >500 billion spent on the Iraq war and instead built a couple thousand of these type of plants? And it's hard for me to believe that the 1000th plant wouldn't be a lot cheaper and better than the first one (at least if we got the incentives right).

Dewaine writes:

Would you want to have your hospital powered by this solar power, while you were having cardiac surgery in the hospital? If not, why not?

Chuck writes:

I would be fine with a hospital being powered with this type of electricity, because I know that they'd have diesel powered backups *just like they do today.*

Dewaine writes:

A city full of diesel-powered backups would also function well with solar power.

dearieme writes:

"..the plant ..produces 134 million kilowatts per year. ..The retail price of a kilowatt is about ten cents": you say kilowatts - do you mean kilowatt-hours?

Eric H writes:

75%? No, I think the maximum QE of photovoltaic cells is somewhere around 40%. At best, you can get about 1200 W/m^2 (noon, no atmosphere). Big PV farms are not going to work.

The future is going to be (a) distributed, and (b) multitech. Wind is more promising (despite the Kennedys of the world), concentrated thermal solar is not bad, PV prices are set to fall in the next few years, so we're going to see a little more of several different technologies in yards and on roofs, with wind and concentrated thermal plants powering industrial sites (cogeneration).

Algae can be grown in effluent streams. Any idea how many thousands of square miles are available that way?

Matt writes:

Cities are already hotter because concrete and asphalt trap more heat than dirt and grass. If there are huge solar fields out west trapping solar heat, will that cause global warming? What's the ratio of heat to power?

aaron writes:

Very good question. I thought of asking myself. What you are referring to is called the albedo of the surface, and changes have a major impact on climate and warming.

Don't know what the effect is, but I would imaging that channelling nearly all the light of such an area into a highly absorbtive object would greatly decrease albedo and would certainly affect on the region. But I don't know if changes to that size of an area would have much effect on global temperature.

I don't know if anyone has looked into it.

(I find it amuzing that GHG-AGW proponents often point to studies that show big human impact on climate, they often don't address GHGs, but rather changes to terrain.)

Leif writes:

Just anecdotally, my parents live in socal and recently purchased some solar panels for about 13k, and haven't paid more than a couple bucks in electricity bills since they got them installed this spring. So if you live in a lovely enough climate, it can be worth it. Unfortunately theres a lot of regulations/paper work/headaches in obtaining them - they def. need to be opened up the mainstream/retail market. If that ever happens then I don't see why, in a decade or so, homeowners in appropriate climates won't jump on board.

aaron writes:

My electric bill is about $400/yr.

Was that 13K before or after tax credits/rebates?

30 years seems like a long payback period. Do they last that long, does performance drop off, require maintenance?

William writes:

I have a better idea. Lets us not invest in solar energy nor wind power, heck, recycling is not even necessary! Burn all the carbon we want, it does not end up in the air we breath.

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