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.

[null and void]

Note that I never said my system would pay for itself any time soon. I'd get better interest in a bank savings account.

That being said, I still favor solar power, not as a whole solution, but as part of a suit of solutions.

Further improvements in the whole system tend towards it becoming a larger part of the energy equation.

[MeekOneGOP]

[DB]

"It sure reminds me of trying to tell people about Jesus, which is what I should probably be doing anyway."

It must be your loving way...

[rollin]

Between 1980 and 1982, the Japanese spent US$75 million evaluating all types of alternate energy devices in actual working conditions.

At the end, the conclusion was not politically-acceptable. The only real solution is nuclear power or a variant.

While wind, solar, and water are pushed because of their so-called clean attributes, in the end, they don't have the capacity to provide the necessary wattage.

If you can get a copy from the Japanese Ministry of Trade, it would be a real eye-opener. But then, zealots are hard to convince particularly when they have an agenda to push and are unwilling to look at data.

[Saturnalia]

Damn, this thread pulled in the morons.
You two keep up the good work, it's nice to have intelligent people on.

[DB]

Well the efficiency is more than 15% higher than you claimed. And your claim was absolute. No room for any other thought.

From my first post on I never claimed solar electric was a good economic alternative as of today. I did say it was improving.

Things change. Just like the improved inverter performance you so refused to accept. New thin film PV technology is driving the price down as we speak. It uses much less material and energy to manufacture.

It is not unreasonable to think that PV cell costs could drop to a fraction of what they cost today with new technology and high volumes. Even without any improvements in PV efficiency (conversion efficiency only reduces the area for a given output power not necessarily the cost) a panel that puts out 100 W that cost $100 (the panel you said currently costs $700) with an inverter that costs $1 a Watt would pay for itself in 5 to 8 years at my home at current California electricity rates.

To make the demand that solar energy has to provide 100% of our energy demand or its useless is just plain BS. Using 50% percent of the roof area of my new home (submit to city next week) could provide 18 kW-h a day at 10 W per m^2 with 8 hour average sun availability. That would put a big tent in my electric bill. So the real issue to make it practical is PV cell cost. It needs to improve at least 5 to 1 to be cost effective for use at one’s home. That 5 to 1 cost improvement lessens as utility electricity costs increase. I don’t think it is improbable at some point in the future they will converge.

[DB]

So name names.

[PeaceBeWithYou]

Thanks.

Now that it is sourced, I can see that you used the maximum values for the losses, which makes this a fairly accurate Minimum Net Efficiency value for solar.

Solar is getting better, and cheaper. Should the InGaN full spectrum cells become reality in a thin film product, lookout.

BTW: Are your angle calculations based on flat surfaced PV's or did you consider the pyramidal and spiked surfaces that have been in use for about 12 years?

Thanks again for the work and effort you put into this.

[gogov]

Yea, but it spins your electric meter backwards and cuts the electric bill by at least 1/3. Return on investment is only 20 years, 10 years if you figure the state rebates!

[DB]

Interesting article, thanks.

[DB]

It looks like this thread ran out of photons... ;-)

[Boot Hill]

Here's one more photon...

DB says:   "I never claimed solar electric was a good economic alternative as of today."

Economics is the fundamental criteria for selecting a method of power generation. Every thing else is just sophistry.

DB says:   "Just like the improved inverter performance you so refused to accept."

Incorrect, the only thing we've been arguing is whether or not those higher efficiency units were qualified for connection to the public utility grid, not whether those higher efficiency units existed.

DB says:   "New thin film PV technology is driving the price down as we speak."

It is??? Somebody must have forgotten to pass that piece of wisdom on to the manufacturers. Here's some typical data from Shell Solar, one of the biggest producers of solar PV arrays.

	SP150 standard technology	ST40 Thin Film
$/watt	$4.62	$6.10
watts/m2	114 watts	94 watts
wattage warranty	25 years	10 years
Temp loss	.45%/ºC	.60%/ºC

DB says:   "To make the demand that solar energy has to provide 100% of our energy demand or its useless is just plain BS."

I'm not making that claim, but it is by examining the economies of scale that the absurdity of solar power can best be seen.

--Boot Hill

[biblewonk]

What? I am always a target of other peoples scorn on the topic of windpower. Look back.

[biblewonk]

I also shudder to think of all the fossil fuel used to create electricity to power their computers to chat about a utopian future which will never come to pass.

Ofcourse not, the end of the world draweth nigh.

[DB]

I'm referring to the scorn directed at me.

And I didn't even comment on the pro's or con's of wind power... I simply offered an explanation of how others were using the word “efficiency” and how it made sense in the context they used…

[DB]

I think a better summary would be:

You believe solar electric generation is a technology without a future.

I think it probable it does have a future.

Neither of us offered proof to the contrary. No fundamental reason it can't be done.

We both made misstatements of fact in the attempt.

Only time will tell whose opinion was closer to the truth.

[biblewonk]

Oh. I thought you were saying my ways were unloving like the rudeness of some of the people on this thread. Usually I mention windpower and the flamers fire up their torches. This thread was no exception but I suspect such flamers are very young and ignorant. They have just learned the republican party line and they are out trying to sound cool to the choir.

[biblewonk]

I hope I'm one of the 2.

[DB]

When I fire up my torch I usually just burn myself...

[biblewonk]

Me too. I prefer mature discussion.