Solar Power: Flat-Out Wrong For All Time

This is a guest piece from regular reader OBloody Hell, prompted by a post earlier this month about the over-hyped claims of cost-effective solar power on the roof of the Denver Museum of Science and Nature:


UPDATED: below



As expected, President Obama is pushing for more "renewable" and "sustainable" energy sources. The underlying justification--beyond the Green assertion "we can't do this forever!!" (as though any product of civilization is perpetual... rode on a chariot lately? Climbed on a horse to get to work?)--is the unproven and questionable reasoning of Anthropogenic Global Warming. The claim is, if we continue to put CO₂ into the atmosphere as we have, using fossil fuel sources (i.e., coal and oil/natural gas), the CO₂ released will drive the earth's temperature rapidly and uncontrollably upward.

Ignore the seldom-mentioned science that CO₂ represents only 5 percent of greenhouse gases. Never mind that there is limited evidence for the notion that CO₂ forces temperature. Overlook the reality that global temperatures aren't increasing very fast at all. Forget the fact that a proven technology, nuclear fission, can easily meet all the world's energy needs for an indefinite period of time without producing so-called greenhouse gases. Any or all of these points suggest that the current energy sources are adequate--or would be if we exploited all available resources and the price of oil stays relatively high.

Still, the Greens say only solar and wind are "clean" enough. Now, the "cleanliness" of solar power is unproven, dependent on ignoring two entire segments of the total energy cycle -- the creation of and disposal of the solar power mechanisms. Also, a strong case can be made against wind power, but it's not as clear and self-evident as the case against solar. But those aspects are beyond the scope of this discussion.

And enviros also say that the under-performance of renewables--including solar--is a product of the energy industry's lack of incentives. This presumes that profit-making corporations aren't interested in profits. That alone explains why renewables require subsidies for the last 40-odd years, and want more. Now, if renewables haven't been viable without tax dollars for that long, there must be something wrong. One obvious conclusion is that the left doesn't understand economics at all.

In support of this conclusion, we find that Obama has increased the subsidies for Wind Power and Solar Power. "Hundreds, even thousands of new, Green jobs!!" we are promised. And yet all of them are dependent entirely on undeveloped technologies which don't currently exist, and, given the history, aren't going to exist. This is unlike nuclear, which would certainly and unquestionably promote a vast array of high-paying technical and skilled-labor positions -- a "maybe" job vs. a known certainty job... and one with excellent pay.

"Pie, meet sky. You two should have a lot in common."

But there's a more fundamental and insoluble flaw in the entire notion of solar power as a large-scale energy source -- one which flies in the face of Green "common sense." (Come on -- how often do you actually encounter real "sense" in a liberal position? I mean really.) This post shows that solar is unlikely ever to be a large-scale, cost-effective energy source at all -- because, in simple fact, the energy in question is far, far too diffuse..

The absolute maximum amount of power available from the sun at the earth's surface is called the solar constant. It represents how much solar energy is directed toward the earth, without consideration of the atmosphere, cloud cover, or the conversion efficiencies of solar systems. It's the best-case amount of energy one could realize in ideal conditions, after applying all possible human ingenuity anyone can ever -- ever -- apply to the problem. It's a physical ceiling; without space-based collectors, as unavoidable a limit as the speed of light. Just as E=Mc² is the maximum possible for any matter-to-energy conversion, so, too, the solar constant defines the maximum possible energy derivable by the conversion of solar power.

It's true that "solar constant" is a bit of a misnomer, since it's not really "constant" but varies consistently (within a few percentage points) based on the actual brightness of the Sun (which varies) and the Earth distance from the Sun (which also varies -- the Earth's orbit isn't a circle but an ellipse, as you might recall from science classes). But it averages a bit more than 1.3 kW/square meter, measured outside the atmosphere. When you also take into account the absorptive qualities of the atmosphere (not including cloud cover), it drops to roughly 1 kW/m² at high noon with the Sun directly overhead. The sun's apparent position at noon varies from 23 degrees South (December) to 23 degrees North (June). It's less at other times and other locations, especially beyond the tropics, where sunlight is filtered by still more atmosphere. But, I'll presume the 1 kW/m² estimate for solar energy at the earth's surface under ideal conditions--it's close enough to the top end to be just and fair, and it does make the calculations a bit easier.

Now, the total power generation capacity of the USA from all sources, is just a hair short of 1 TW (terawatt). Assume for a moment that we could convert 100 percent of the sun's energy striking the earth into power (somehow). One TW divided by 1 kW/m² means that powering America by solar--under perfect conditions--would require not less than 1 BILLION square meters of solar collectors. Let me restate that: one Billion. It really is that simple.

Just for simplicity's sake, let's abbreviate a "Billion Square Meters" as a "Giga Square Meter", or "Gsqm". So, to restate the issue, to replace U.S. generators with ideal solar power would require a collection area of not less than a full Gsqm.

Of course, ideal solar power doesn't exist in the real world. So 1 Gsqm underestimates the actual area required, for several reasons:

1. Cloud cover: Hugely significant, but not easily estimated, since it depends on where we situate the solar collectors and so forth, plus the type of cloud cover affects the level of power output possible. I'm going to set this aside as an exercise for the reader, since other impediments, as we will see, will be adequate to make solar power blatantly unattractive even without considering this.



2. Day/night cycle: The Sun's only there about 50% of the day. Indeed, in the winter, when power demand is most critical, it shines a lot less, as little as 35% of the time in many US latitudes. Taking the average leads to an obvious 50% factor, which means we're going to have to cover 2x as much area -- so now we're looking at two Gsqm.



3. Conversion efficiency: When Greens promote solar power, they usually focus on one of two approaches: solar thermal or solar cells (several other options typically are ignored, including one which has far more potential than either of these two). Solar thermal uses the sun's energy to heat something (often water) in a conventional generator, often concentrating the sun's rays in a small space using mirrors and such. Solar cells directly convert the sun's energy into electricity, bypassing a conventional generation system.
   
   Both suffer from unavoidable technical limitations on the efficiency of converting sunshine into power. Solar thermal conversion efficiencies range (depending on how measured) from under 3% to just over 30%. Solar cells (photovoltaics) typically operate at conversion efficiencies of around 25%, with best case currently around 40%. And best case, large-scale, practical engineering limits for all energy types, not just solar, seems to be in the vicinity of 60% to 70%.
   
   Let's be generous and presume solar cells that can produce 50% conversion efficiency AND be manufactured in industrial, high-volume quantities (there's a toxic waste issue I'll mention later in regards to this, but we'll ignore it for the moment). Even with that optimistic assumption, though, that means we'll have to lay down TWICE as many cells, so that we're now talking about four Gsqm.



4. Transmission-line losses: As of 1995, these were about 7.2% -- that is, for every 1kW you pump into the grid, your plug at the other end only gets about 928 watts out. Small, but hardly trivial. And 92.8% efficiency means that we'll need 4.3 Gsqm covered.



5. Storage inefficiencies: That day/night cycle means you're going to have to do something about the other 50% of the day. People still need power, even when the Sun is down. Assume that, oh, 30% of your total power is used at night. The average storage system at best tends to get about 50% creation-to-storage-to-reuse efficiency -- which means that you're going to have to generate an additional 15% just to deal with that problem. That bumps up the required area to 4.96 Gsqm. -- round it to "5 Gsqm" for simplicity.

So, accounting for some of the real world -- but not cloud cover -- we would need to find five billion square meters in the U.S. where we could deploy "little blue cells." That's a huge number, hard to really wrap one's head around. Five billion square meters is a lot of meters, we grasp, but, really, what "is it" in real-world terms. A big pond? Central Park in NYC? A big lake? What?

Well, the conversion factor for a million square meters is 0.386 square miles -- so, since five billion is 5,000 million, that means that 5 Gsqm is 5,000 x 0.386, or about 1,931 square miles of area. But again -- how much is that?

It's bigger than a park or a lake. To put in perspective, the STATE of DELAWARE is only 2,490 square miles. So we're talking about covering NOT LESS than 4/5ths of the land area of a small state with solar material. And this estimate still omits the effects of cloud cover, hardly negligible. Picturing the Earth with the clarity of a school-room globe ignores the weather. This is more typical:



So, once again, that number will go up, and substantially. I think a factor of 25% is hardly unreasonable. Shall we aim, then, to cover the ENTIRE state of Delaware?

What do you think the response of the Greens would be to a proposal to do that with concrete?? And no -- I, frankly, don't think that spreading it over a hundred locations would moderate the reaction. You make THAT announcement and they will scream loud enough to wake the dead. We know what Ted Kennedy did attempting to block construction of just one wind farm.

And imagining concrete isn't so far from the mark, either, since these panels do require a support infrastructure beneath them, which also require building and maintaining. Did I mention maintenance costs, yet? Because solar panels have to be cleaned fairly regularly, even if you ignore all the other matters. And, did you know what is the third most common cause of accidental death in the USA, behind automobiles and poisoning? Accidental falls, that's what.

How many more will die falling off a roof while cleaning solar panels? "Safe" energy, indeed.

"Head, meet Concrete. You should make quite an impact together."

Now, let's consider a couple of related issues:

1. Pollution: Solar cells are basically computer chips. Production of computer chips necessarily produces a substantial amount of toxic wastes. Right: "solar cells" are hardly the "clean, benign, environmentally friendly" thing they're sold so commonly as by the Greens. In reality, they produce some of the worst wastes on the planet. And we're talking here about an incredibly massive ramp-up of production quantities. Will our speculated "new" 50% efficient cell ALSO be much, much greener? Possibly, but that's yet another constraint you're placing onto two fairly big constraints, already: "50% efficient" AND "reasonable costs in industrial quantities".



2. Input: Production of computer chips is energy intensive. It takes energy to make them, and generally not a small amount. You have to obtain, smelt, and refine both some pretty common stuff (like sand) but also some fairly rare stuff (The term "Rare Earths" isn't always deserved, but is there for a reason. You can't walk around most places and grab chunks of rare earth materials for production). Why does that matter?:
   
   
   • You have to transport these materials to wherever you are going to make the chips/cells. Hardly cheap in industrial quantities.
   
   
   • Are these sources US sources? Are you going to trade in being dependent on oil producing nations for being dependent on rare earth producing nations?
   
   
   • This is not a trivial question, either -- there is substantial evidence that current cells (not the "optimal" ones we're assuming) are actually net energy sinks -- that is, the amount of power derived from them, from production to destruction, all things included, is actually less than the energy used to make them and dispose of them. That's current cells, but it's instructive about what needs to be considered here, which is usually called the "Total Power Cycle." In assessing cost effectiveness, one must include the energy required to create and dispose of your energy generation system, not just the active operating costs. Typical claims of solar power as "clean" and "cheap" entirely ignore the setup and disposal issues, which are hardly small. Once more, we find that the Left and the Greens fail utterly in basic economic concepts.



3. Lifespan: The typical fossil fuel power plant has a lifespan of about 40-50 years before it gets decommissioned as decrepit and/or overtaken by new technologies to the point where it might as well be decrepit. Solar cells, too, suffer from a life span. The functional lifespan of current solar cells is on the order of 20 years, after which the efficiency tends to drop off radically. This varies with cell type, but... were you planning on adding a FOURTH criteria to those ever-more magical 50%/cheap/green solar cells: longevity??? And this leads us to. . .



4. Disposal: We don't generally worry that much about disposal of solar cells, yet. But much like NiCad and Lithium batteries, we're going to have to recycle or dispose of these cells about every 20-30 years (let's be generous once again), and we're talking here about the open disposal/recycling of not less than 2000 square MILES of fairly nasty materials, and the replacement of same -- more often than we replace power plants in general.
   
   And that's just the USA. The USA's power production is about 4.2 TWhrs (Note: Watt-hours, not Watts, this is production, not capacity), China's is only a bit less, at 3.3, Europe's at 3.1, Japan at 1.2, Russia at 1.0, India at 0.665, and so on. What happens when the per-capita power demands of the world ramp up, to match the USA's? Current world power demands are 19 TWhrs, or almost 5x that of the USA -- so we're talking, about the world alone -- today, of covering FIVE DELAWARES with little blue cells. That's far more than the entire surface area of Lake Erie!!
   
   And where is that demand going to go when the third world stops wanting to suck on hind teat? How much land area are we going to cover with these things? How much toxic waste will it produce, both in creating and destroying them?

The fact is, the whole concept is just too inefficient.

This means that the money being spent is being utterly wasted. It cannot and will not produce either the kind of jobs it claims (those which are "sustainable" themselves because they pay for themselves without constant government subsidy) nor will it come even close to satisfying the growing worldwide need for more power. The same monies, put into encouraging a standardized nuclear design, with safety-inherent design features, would go far further towards both enhancing the US and world economies, but also towards solving the problems of getting the rest of the world up to the kind of standards of living we, in the USA, consider minimal. As NOfP previously has posted:


source: Wondermark, May 2, 2008

Such a standardized nuclear design could be a source of steady income for the USA for the indefinite future, and become the heart of a thriving industry in exporting parts and/or minor design mods for locale-specific conditions. Furthermore, this would this resolve any concerns about global warming, should they have any basis at all in fact. Instead of China and India having to choose between building the wealth of their peoples and producing greenhouse gases, they could, instead, license the design from the USA and produce power as needed. They could have both.

"Peasant, meet Cake. You'll like one another's company."

So, the notion of solar power panels or mirrors as a major energy source is not just questionable -- it's blatantly wrong-headed, based on myths, whims, desires, and a whole host of failed understandings of what the Sun is, how it warms the Earth, and how that might be utilized. There ARE ways to utilize the Sun which MIGHT be cost-effective -- but neither of the two obvious ones -- SPS and Ocean Thermal -- are getting much attention.

SPS requires a functional, industrial presence in space (which is one reason it might pay for itself, though it is a risky and expensive proposition and I'm not openly advocating it here).

Ocean Thermal might work and requires less pie-in-the-sky investment, because it essentially uses the vast ocean surface of earth as an undedicated collector of energy. For it, the diffuse nature of solar power doesn't matter, at least, not as much. The efficiencies it operates at isn't trivial engineering, but they are possibly cost-effective without magical tech developments like 50%/cheap/green/long-living solar cells. If we put money into development of this, it might bear worthwhile fruit.

Conclusion: Solar power, excepting possibly Ocean Thermal (and maybe SPS), can never be, and will never be, a serious, significant component of any rational power generation scheme in the USA or any other post-industrialized nation.

What Obama should be doing is to increase development of nuclear power by making the process of raising capital to build new plants easier, by streamlining the insane regulatory process (does it REALLY require hundreds of regulatory permits to be passed and signed off on, just to stick the first shovel into the ground? Could this not be reduced to a dozen or so covering exactly the same details?). To encourage the design and development of a standardized, safety-inherent system which could be mass-produced and mass-utilized. And to reverse course and sign off, finally, on a disposal process (presumably the one at Yucca) rather than decrying it.

Instead, as I have shown, what Obama is doing is pushing pie into the sky, trying to create a mythical "green" energy source from something which is anything but, and, more critically, anything but practical.

I mean... Delaware?

In better keeping with his goals, then, Obama probably should probably order the Department of Labor to introduce regulations creating and funding the Catapult Construction Corps. They can be manned by members of ACORN, with pies created by the NEA in new mandatory Home Economics classes ("Full employment for Home Ec Teachers!! Compulsory Civil Service For All Our Young Citizens!! The New O-Pie Corps!!").

Well, that would work at least as well as the current plans of the Administration, any way... And at least then we'd get to stand downrange of the catapults and get something nice to eat.

MORE:


Case in point. I repeat: go and tell the Greens you're going to cover Delaware with concrete, then sit back and watch their heads explode. It should be a great improvement on the next Rob Zombie or Uwe Boll film.


(edited for style, and substantial links added, by Carl)