Here is what the acolytes of solar power don't want you to know...

self | July 15, 2003 | Boot Hill

[Boot Hill]

Here is what the acolytes of solar power don't want you to know...

These are the essentials you need in order to appreciate the absurdity of using solar cell power systems as any kind of sensible alternative. After you read this, ask yourself again how much sense solar power really makes.

THIS IS WHAT HAPPENS TO THE SUN'S ENERGY WHEN
WE USE SOLAR CELLS TO GENERATE ELECTRICITY:

	SOURCE	LOSS - %	POWER - W/m2
1.	solar constant	--	1370W
2.	atmosphere	27	1000W
3.	clouds	21	790W
4.	sun angle1	49	403W
5.	night2	50	201W
6.	cell efficiency3	85	30W
7.	dust/reflection4	10	27W
8.	packaging5	20	22W
9.	DC to AC inverter	25	16W
10.	storage	30	11W
Source Notes: 1.   Calculated for both hour angle and a latitude angle of 37º. 2.   See link. Continental U.S. average sunshine is 4.8 kilowatt-hours/       square meter/day, or 200 watts/square meter. That value is nearly       identical with total losses shown for items 1-5 above. 3.   See table on linked page. 4.   Dust, bird droppings, scratches, etc. estimated to be about 4%.       Reflections, per Fresnel's Law, would be another 6%. 5.   See link for data sheet on typical solar panel. Data shows an       overall efficiency of 10.3%, at nominal conditions. This is       nearly identical with total losses shown for items 6-8 above.

Net efficiency = 11.4 Watts/m² or a mere 0.83% (!)

But read on, it gets worse.

• The current average rate of U.S. energy consumption is about 3.3 trillion Watts. Based on the above efficiency data, we would need to cover the entire state of New Mexico with solar cells just to generate this amount of energy!   [+]

• And because of the 2% annual growth rate in our energy consumption, in only 35 years we would also have to cover the entire state of Arizona as well!   [+]

• And the irony is that the environmentalists, who are so obsessed with the use of solar power now, would be the first to scream bloody murder at the idea of such large areas of wild lands being permanently covered over with solar generating plants!   [+]   [+]   (Note: Both articles are written by the same author!)

• Worse still, the entire world-wide production of photovoltaic (PV) cells is so small (300 MW) that it can't even keep up with the annual U.S. growth rate in energy consumption (66,000 MW), much less produce enough PV cells to supply the base amount of energy that we currently use (3,300,000 MW). To do that, PV cell production would have to ramp up over 100,000%!   [+]   (Scroll down to chart)

• The initial capitalization cost of a solar PV generating plant is at least 10 times the cost of a large conventional plant. And that is exclusive of the mammoth land acquisition costs necessary to accommodate the vast expanse of solar cells.

  Here is an example:
  Siemens Solar (now Shell Solar) produces a popular line of large solar arrays intended for commercial, industrial and consumer applications. A big seller is their SP-150, supposedly a 150 watt unit that measures 1.32 square meters. The problem is, it only produces 150 watts under carefully controlled laboratory conditions where the incident light intensity is boosted to 1000 watts per square meter (unrealistically high, see items 2 and 3 in above table) and the PV cells are artificially cooled to 25º C. But when Shell tests that same unit under more realistic conditions of 800 watts per square meter and little cooling for the PV cells, the output drops to 109 watts. When sun angle and night time are factored in (see items 4 and 5 in above table), the average level of power production drops to a piddling 28 watts. (That is only 21 watts per square meter(!) which is nearly identical to the value shown for item 8 in the above table.)   [+]   [+]

  In quantity, this unit sells for $700. That calculates out to $25 per watt. By way of comparison, the initial capitalization cost for a conventional power plant is on the order of $0.75 to $1.00 per watt. That makes the solar "alternative" 33 times more expensive than the conventional power plants of today, and we haven't even figured in the additional cost of the inverters and power storage systems that solar needs (or the land acquisition costs).

  Solar proponents would be quick to point out that, while the capitalization costs may be higher for solar, they don't need to purchase the expensive fossil fuels that conventional plants use. While that is true, what they aren't telling you is that the cost of financing the much higher initial debt load for solar, is greater than the cost of the fuels that conventional plants use. (TANSTAAFL !)

• PV cells have a limited lifetime. As a consequence, manufacturers offer only limited warranties on power output, some as short as 20 years.   [+]

• A violent storm, such as a hail storm, can decimate a solar power plant. A storm covering only one square mile (the size of a small 50 MW solar plant) could destroy a half billion dollars in solar panels.

• PV cells have a nasty little habit of loosing conversion efficiency when you put them out in the warm sunlight. A hot day can lower the output power by up to 20%!   [+]

• A solar PV generating plant is not without maintenance. How are you going to wash the tens of thousands of square miles of PV cells of the dirt, dust and bird droppings that will collect over time? How will they be kept free of snow and ice during winter? A 1000 MW solar plant can lose 40 MW of power (retail value, about $50 million per year) by failing to keep the PV cells clean of dirt. Losses would be even greater for snow and ice.

• Solar PV generating plants incur inefficiencies quite foreign to conventional power plants. First, there is no need for energy storage in a conventional plant, as night time doesn't affect generating capacity. Second, there is no need for an inverter to change DC to AC. The inverter is a bigger deal than it first appears to be, because the inverter for a public utility must produce a very pure sine wave and that is much harder to do while still maintaining high conversion efficiency.

• The consumer that purchases a solar power generating system for home installation pays only a small fraction of its real cost, often as low as only 25%. That is because every sale is subsidized by direct payments of your tax dollars and by the government placing un-funded mandates on utility companies, requiring them to push the solar power "alternative". These unfunded mandates are re-paid by the rest of us in the form of higher utility bills.   [+]

Is there any use for solar power that makes sense?
Yes, solar power makes sense in those limited applications where the customer does not have convenient or economic access to the power grid, such as with remote country or mountain top homes. It is also useful for powering mobile or portable equipment such as utility, emergency, scientific devices, etc., where it is not otherwise feasible to hook to the power grid.

But other than those narrow exceptions, it makes no economic, engineering, ecological or practical sense to use solar power as a replacement for, or even as a compliment to, conventional power plants. Solar may have its' own specialty niche, but in no way does that rise to the level of an "alternative" to conventional power plants.

[autoresponder]

great post!

Wind powered generators to power the USA would require a full 25% of the total acreage of America.

Also constant and high winds

These are the reasons that wealthy lib venture capitalists do not invest in and build these alternate energy projects

Being inefficient and impractical they would lose money

As much as rich libs say they love paying taxes it does not wash

Note Bill Clinton's recent purchase of a golf course condo in Ireland will probably "tax-shield" him from his $10,000,000 book deal taxes.

Ireland has special tax exemptions for the "artist community" so many American and other artists, musicians, and writers now have homes there to evade income taxes.

So now Bill Clinton's book will claim to have been written by him alone just since he bought a home in Ireland.

[Boot Hill]

kezekiel says:   "Like in [distributed generation] applications, which is what solar is best at."

Gosh how solar advocates love to throw that silly phrase around. Problem is, it is meaningless (for all practical purposes). Please provide us with a sound and rational explanation why you feel we should distribute our energy production through economically unfeasible methods such as solar, wind, fuel cells, bio-mass, etc.

--Boot Hill

[Boot Hill]

Are you sure you're not confusing switching between PV array power and utility grid power and the synchronous transfer of power between PV array and utility grid?

--Boot Hill

[Boot Hill]

Thanks for those words. I lay the blame for much of the misinformation being spread by these alternative power guru's at the feet of the public education system.

--Boot Hill

[ggekko]

Your analysis is cogent. The problem with all "alternative" energy sources at this point in time is that they scale up VERY POORLY. This is true of solar power, biomass and wind power. The growth in power consumption also makes alternative energy even more of an exersize in green fantasy.

The real answer is nuclear power to be used as a bridge to produce hydrogen as a byproduct. Nuclear power actually has the smallest environmental footprint of all energy technologies but the greens have been so successful in demagoging this issue the public seems oblivious to this fact.

The actual result of the greens cripling the nuclear power industry has been a greater use of coal-based power plants. This is a result that no one should be happy with.

[Boot Hill]

ggekko quips:   "...an exercise in green fantasy."

Nicely said.

--Boot Hill

[Jeff Gordon]

I know a start up company that will be producing thin film, flexible solar cells that cost less than 2% of the current panels.

No. I can not provide a link. The technology is propriatary at this point.

[DB]

"This is not a true sine wave inverter. True sine wave inverters (often called synchronous inverters) are required for a utility grid tie in and run at far less efficiency than the unit you cite. Inverters running at the level of efficiency you referenced, are designed with switching power supplies that include heavy amounts of low pass filtering in order to simulate (but never actually achieve) a sine wave output. They are not capable of being tied to the utility grid, and either run as "stand alones" or tied only to a local power grid."

Not true. Here's one example that is designed for utility tie in that is 90% efficient and uses a switching design:

http://www.xantrex.com/support/docserve.asp?id=220

I do not understand what you mean by "Inverters running at the level of efficiency you referenced, are designed with switching power supplies that include heavy amounts of low pass filtering in order to simulate (but never actually achieve) a sine wave output." What does “but never actually achieve” mean??? One percent distortion, 0.001% distortion??? It is all a matter of degree. There are no limitations on how "pure" a sine wave a switching supply can produce. Now you're in an area of electronic engineering I know something about. PWM can achieve very low distortion sine waves at high power levels at high efficiencies. The amount of "low pass" filtering required is primarily defined by the ratio of the AC output frequency to the switching frequency and the desired amount of attenuation to that switching frequency and its related sampling artifacts.

[Wonder Warthog]

"I thought you were the bandleader for the hydrogen parade; what is it, photons or protons?"

Actually, "Professer", its photons, protons, and neutrons.

[Wonder Warthog]

"The same roof collector surface that forces you to use air conditioning is what you propose to use to offset it?"

Tell me, "Professer"---what were you "Professer" of?? Basketweaving?? Surely not any field of science or engineering to judge from the above comment.

[DB]

I wonder how much of a heat sink ground water would provide.

I always thought it would be interesting to circulate water through a heat exchanger in the ground, ideally in the water table. In some places around here anyway the water table is as shallow as 50 feet. No, I’m not suggesting wide scale use. Just thought it would be interesting to try and would use far less energy than a compressor based heat pump.

[DB]

Did you even bother to read the first link I provided?

Here's the manual for the GC 1000:

http://www.advancedenergy.com/Doc/gc1000installationmanualv2.31.pdf

It is in fact a grid tie inverter qualified for use in California. It does connect and back-feed into the public utility grid just as the original poster claimed. If your solar or wind array generates more power than your home needs it feeds the excess power back to the public grid just as he claimed. Using a switching supply and all… And over 90% efficient in the process… And that “super” pure sine wave required looks to be around 5% total harmonic distortion (total harmonic content of less than -26 dBc). Not all that pure in electronic land.

[wita]

Wind is intermittent in some places, which is why studies are done as to the most efficient place to put this at present, inefficient system. Enviros don't like it because it kills birds, and I don't particularly like anything, subsidized by government.

I don't believe for one second that even congress is able to hide a 35 billion black lung benefit, when if anything it might be a few million, however, I am listening. Are underground coal miners still getting black lung after years of study, research, and development of safety measures? I would have thought many or most of the older black lung sufferers would by now be long gone.

I lived in an underground coal mining town in Germany in the early sixties. There were quite a few staub lunge sufferers, but still plenty of miners, and that was forty years ago. A little research along the way indicates black lung should have been done away with, but widespread cheating on dust tests, in US underground non-union coal mines says otherwise.

[Wonder Warthog]

"I wonder how much of a heat sink ground water would provide."

Actually, it provides an excellent one.

"I always thought it would be interesting to circulate water through a heat exchanger in the ground, ideally in the water table. In some places around here anyway the water table is as shallow as 50 feet. No, I’m not suggesting wide scale use. Just thought it would be interesting to try and would use far less energy than a compressor based heat pump."

You can buy systems today. They are called "ground-coupled heat pumps", and are used to drastically increase the efficiency of compressor-based heat pumps. They are the best choice for new home construction in the 'burbs or out in the country, but more expensive than regular air-exchanged heat pumps.

Heh--where I grew up in south Louisiana, the water table was usually about ONE foot down (sometimes it was one foot UP!).

[biblewonk]

I read about it in a windpower magazine, did a search on Yahoo for "black lung benefit billion" and found it right away.

[biblewonk]

Coal, wind, hydro and bio fuels are my ideal energy solution. No more nukes, save gas for home heating and wait for a better idea on solar.

[DB]

Cool (pun intended ;-) do they require ground water or does typical soil 15 feet down or so work well?

I’m working on my new house plans I write... The building site is up on a mountain with no hope of usable ground water nearby. I’ll have to do some research on this and see if it is practical, as I didn’t know this was actually done.

Use the septic tank leach field? Probably a bad idea…

[DB]

I see there is lots of information available for "ground-coupled heat pumps". Thank you.

[kezekiel]

In quantity, this unit sells for $700. That calculates out to $25 per watt.

Well, there's where you said it. As for the cost of building a solar plant, we priced out construction of a 25 MW solar farm, so I know what I'm talking about.

As for solar cells having a limited lifetime, well what the flip doesn't? Certainly every other power generation technology that I can think of has components that have a limited lifetime. By the way, the warranties for modules typically state that the module will produce at least 80% of its rated output after 20 years... that's hardly the same thing as expecting the module to croak after 20 years. These things can last decades.

As for the lowered cost of PV systems, I find it odd that I am being asked to do your own research for you. I have seen prices fall just in the last six months as the industry gets bigger and more competitive. Anyway, I have signed contracts and have built systems for $6-$8 watt, so I know it can be done, and I know that with newer products coming on the market, it can be done for less than that.

As for one "concrete and realistic advantage" to using solar for on-site DG is that is the only renewable, clean technology available for companies or homeowners that want to reduce their consumption of grid power or go completely off the grid. Diesel generators are restricted in Southern California to running no more than 200 hours per year for pollution control. What's more, solar systems run with no fuel costs and very low maintenance cost.

The downsides, about which we are very open with potential clients, is that solar takes up a lot of roof space and has a high initial cost and payback relative to other technologies. However, the cost is coming down, and efficiency is rising, so the technology has promise, and it is working well for a lot of people here in California where air pollution is a constant concern. I remember what it was like growing up in the 60s and 70s, when the air could get so unhealthy that they actually recommended that children not go outdoors. Solar-generated power doesn't pollute the air, as even "clean-burning" natural gas plants do, and around here that counts for a lot.