Talk:Photovoltaic array/Archive 1

message: Solar panels used for thermal collection (heating applications), a part of active solar is not mentioned here.  Perhaps solar panel, solar cell and active solar need to be reconciled for consistency.  -User:RatOmeter
It says 'photovoltaic meaning literally "light-electricity"'. As far as I know, the 'voltaic' part comes from Alessandro Volta, an Italian scientist who invented the voltaic pile. Thus, 'voltaic' does not mean 'literally electricity'.
:At this point the entire world solar electricy production is about the same as one large windmill produces.
What kind of windmill is that? Strange figures and really hard to believe. The second question is whether other solar plants are counted (those where sunlight is focused on water pipes). Paranoid 20:02, 22 Jun 2004 (UTC)
replies: text: I second this suspicion. At the very least I would like to see a link to a reference that can be verified. Also the abbreviation MWp should be explained. I guess Mega Watt peak but cannot be sure. 85.164.66.66 21:30, 12 May 2005 (UTC)
thread_title: Miscellaneous

message: Has anybody read:  Schaeffer, J. Solar Living Source Book  11th Edition (2001)  Vermont, California: Chelsea Green Pulishing Co?
This page is seriously out of date, or purposely written from a very negative POV. --Nigelj 15:37, 2 Apr 2005 (UTC)
thread_title: Solar panels in Spain

message: The picture of a laundromat that is "powered" by solar panels, and named
Image:Laundromat-SolarCell.png is certainly a photo of solar thermal; the large panels, white insulated pipes, and the pipes inside the panels give it away.
Merphant 05:46, 15 November 2005 (UTC)
thread_title:  Laundromat picture is wrong 

message: Extra commenting to this recent change of mine, that belongs here, in the discussion section:
"Accordingly, at the current $0.08/kWh, a square meter will generate up to $0.06 per 24 hr day, and a square kilometer (250 acres) would generate up to 30 MW, or $50,000/km²/day. For reference, the unpopulated Sahara desert is over 9 million km², with less cloud cover, giving closer to 50MW/km², or 450TW (terrawatt) total. The Earth's current energy consumption is near 12-13 TW at any given moment (including oil, gas, coal, nuclear, hydro.) 
The real issue with solar panels is the capital cost, as shown at the net energy gain article, requiring up to over 7 years recovery period before any profit is made, out of a 40+ year useful life. In contrast, nuclear or coal plant recovers its capital cost in under a mere month, not considering the limited fuel supplies and thus fuel cost. Solar energy is not bound by limited reserves, at least not for a good while."
Reading numbers such as $0.06/m²/day and 7+ years of investment recovery period before any profit is made are extremely depressing. It's like having an egg that you have to sit on for 7 years before it hatches, then you get a 30-50 year life out of it. Just like eggs, solar panels are fragile things, hail hits them and they crack, and now there you go. 
But here are some more arguments from the pro side:
* Unless we succeed in developing fusion, what else are you gonna do in the long run? Having a means of energy production that profits energy wise after 7 years beats not having anything at all. (Yes, coal reserves may last quite a few years, but not without even more greenhouse gases, and even then, sooner or later you still have to find a suitable longterm solution. Wind power is relatively cheap and profitable to harness, though it has moving parts unlike solar cells, but there may not be enough wind on the planet to supply us all, but there is enough sunshine for the long run, even if solar has horrible profitability compared to wind and everything else.)
* After 40-80 years? (nobody knows exactly because the very first solar cells are still going and going and going) of solar panel service, if diffusion effects mingling the p-n junction or whatever reasons make the cells inefficient and unproductive, they don't require the same energy to produce again, because the raw material, silicon, is already there, so to reprocess them into brand new cells would have a recovery period of say, 3 months. Same goes with hail damaged cells, though too much upkeep and maintenance might drive the whole thing unprofitable. For desert areas with lots of hail causing wind, windmill/solar panels might work together nicely, in the same area. Start with cheap windmills (2.5 MW/100m diameter ≈ almost 2 acre swept blade area), and invest the gained energy into silicon to build up the solar panels. Mauritania-Morocco seem close to desertous areas with lots of wind power at the same time, though the type of sand and its ore potential available there is unknown to me. 
* Coupled with solar tower designs, silicon solar panels could be the backplate to heat the air under a glasshouse, and thus, besides the direct photovoltaic efficiency, there could be extra thermal energy milked, though also some energy lost due to reflection off the extra layer of glass. Under a glass house protection the silicon solar panels would be less affected by hail.
* NASA has a competition going for lunar oxygen extraction. Oxygen combines with hydrogen in a stoichiometric ratio of 16 g O2/2 g H2, so the bulk of weight in spaceships is liquid oxygen, 8x as much as hydrogen. An efficient method to extract oxygen from lunar silicate rock would cut down space mission costs tremenduously, which have a fuel cost of about $5,000-30,000/lb of payload (or fuel). The byproduct of this lunar oxygen extraction would be generation of silicon, aluminum, etc. Down here on Earth, the same process would generate unprofitable (cheap) oxygen, and we'd only care about the silicon and aluminum. So in space mission context silicon solar cells could be much better justified than the dismal $0.06/m2/day or 7+year capital cost recovery numbers we have to deal with down here on Earth. Lifting bodies off the Moon's surface into space is less costly also, and could provide for infinite area solar panel building that are unaffected by day/night/weather/reflection cycles because they follow a south/north orbit, never in the Earth's shadow, and only very occasionally in the Moon's shadow. In weightlessness, the Czochralski and float zone processes might be able to process 2-100 meter diameter perfect single crystal wafers instead of the measly few centimeter limit allowed by gravity down here on Earth's surface. (May need a rotating space station to generate some centrifugal force acting as artificial gravity that may still be needed, and you could have any small gravity value set by the speed of rotation, including 0.)
*Even if done on Earth, silicate extraction yielding other important materials, could allow the silicon as a cheap byproduct. For instance, the JSC-1 lunar simulant contains 5.6 ppm thorium and 1.5 ppm uranium. I believe this material is a typical magmatic eruption material, representing the average composition of Earth's and the Moon's crust, and if we can successfully process this, we'd have unlimited nuclear fuel for millenia to come. The nuclear fuel present, though minute, it's just enough to provide the chemical energy needed to break the other bonds, and generate the silicon, besides the valuable aluminium, magnesium, titanium. So the 7-year payback could be repayed instantly in conjuction with nuclear reactors, and then you'd start with profitable silicon solar panels from day one, besides getting the valuable aluminum, if only the suitable technology were available. As of now, silicates are unprocessed/unprofitable, and most ore materials are weathered oxides/carbonates, including bauxite, thoria, rutile, dolomite. But there are no weathered materials on the Moon because there is no rain/moisture, though ilmenite is an oxide of iron-titanium, and about a month ago the Hubble telescope was turned toward to moon to look for ilmenite deposits, because it's pretty much the only lunar material we can successfully/efficiently process for now.
*The Earth has quite a bit of coal still, that, according to some estimates, at the current rate of consumption would last a few hundred years even, and can be processed into oil/gasoline type fuels at $35/barrel longterm. However this just means even more greenhouse gases, unless we find suitable carbon dioxide sinks to sequester it, to keep it out of the atmosphere. There are a few methods, such as liquefying and pumping deep under the ocean, pumping it into used up but empty natural gas and oil well underground  caverns, or binding it chemically, into things such as calcium carbonate. Finding a way to economically process silicates (such as anorthite to obtain the silicon, instead of just plain quartz) may yield their calcium in the form of quicklime as a byproduct, which is the perfect chemical binding agent for carbon dioxide. Quicklime has a lot of industrial uses, including construction raw materials such as mortar, that set by binding atmospheric carbon dioxide. Quicklime is currently obtained by calcining limestone (calcium carbonate), and releasing the carbon dioxide into the atmosphere, each ton of quicklime generating 0.79 ton of carbon dioxide byproduct (56 g CaO releasing 44 g CO2.) So to shoot two or more birds with one stone, if suitable technology is developed to process silicate minerals, we could ban and abstain from calcining calcium carbonate throughout the world, and instead use silicates as the lime source, and thus instead of emitting .78 ton CO2/ton lime, we'd be absorbing the equivalent amount, and all this happening as a side effect during the useful process of building construction. (Actually it's not a full doubling of effect, because some of the carbon dioxide released during calcining is reabsorbed when mortar sets.) Of course building construction raw material usage does not keep up with the amount of coal we'd like to burn, but any little bit helps. Also, obtaining quicklime this way as the sole purpose may be very uneconomical, but if silicate processing is done for other things such as extracting uranium and thorium from otherwise uneconomical, non-ore-grade concentration rocks, adding up all these little benefits - using the byproduct silicon, magnesium, titanium, aluminum, using the byproduct quicklime, etc. - might tip the balance toward that rock being considered ore-grade, and profitable. By the way, just like we currently have a "looming energy crisis," sooner or later we'll have a similar "ore crisis", when all the cheaply extractable ores are used up, and we will ultimately have to resort to dealing with the harder to extract ores, most of the Earth's mantle and also the Moon's and Mars' mantle being made up of silicates, that we can't profitably touch for now.
* There is an off-the-wall idea of using silicon as the basic energy carrier, since it's energy dense, safe, and there is so much of it around (75% of the Earth's crust is silicon dioxide). In the desert energy could be stored into metallic silicon, that's stable, and could be shipped to anywhere in the world. However this idea remains off the wall, unless a high efficiency method of converting silicon back and forth from the oxide is somehow found, also allowing easy harnessing of the available energy. Since neither silicon nor the oxide are fluid or gaseous, it seems unlikely that they will ever make a good fuel. Even coal can easily be gasified to CO + H2 with water, but silicon dioxide is solid, plugging any kind of fuel conduit. The only thing silicon dioxide reacts easily with is fluoride, but the fluoride ion is a very toxic and dangerous thing in small scale devices, compared to other fuel methodologies, such as liquid ammonia, magnesium metal, etc.
Sillybilly 02:44, 23 November 2005 (UTC)
thread_title:  Comment 

message: In "Theory and Construction", does AU mean Atomic units? Diotti 02:13, 26 December 2005 (UTC)
replies: text:  I don't know for sure.. but I just followed the AU link and none made any sense relating to solar panels, so I made an edit/fixup to the article. But then, reading further down in the article I saw more AU's where they seem to mean "astronomical units", as in Jupiter being 5.25 AU from the Sun, and I assume Earth is 1 AU away, as an average distance. By the way, ratiation intensity drops with the square of the distance. Sillybilly 06:45, 26 December 2005 (UTC)
thread_title:  AU 

message: Anyone know enough about Wikipedia formatting to fix this page?  All the pictures seem to be messing up the first several "edit" buttons, which, instead of appearing by their respective sections, are clumped together by one of the later sections.  --Allen 02:41, 4 January 2006 (UTC)
thread_title:  Formatting problems, help? 

message: I am trying to clarify the writing in the current development section.  I want to note that:
*I am making no effort to verify the facts here, but this needs to be done.  The economics of solar panels are controversial enough that I think in-line references would be appropriate here.
*I may have misunderstood the intent of some of the original writing.  If so, please correct me.
*The writing could still be clearer.
--Allen 03:05, 4 January 2006 (UTC)
thread_title:  Clarifying "current development" section 

message: See Talk:Solar cell#Merging Solar panel into Solar cell. —MESSEDROCKER (talk) 04:47, 2 April 2006 (UTC)
replies: text: Solar Cell IS NOT the same as Solar Panel and discussion resulted in the decision not to merge. I'm taking the merge notice from the page. --Sunpower 14:09, 26 April 2006 (UTC)
thread_title:  Merge discussion 

message: The first few paragraphs present POV which is not referenced. And with the constantly changing technology it makes little sense to pose arguments based on limitations/details of recent technology. I think the introduction should be much shorter and concise and just state what a solar panel is and does without going into details.  Details can be in the sub-sections. --Sunpower 09:23, 27 April 2006 (UTC)
thread_title:  Introduction 

message: Two links in external sites point to pages on http://www.oja-services.nl/ , they probably need to be combined. --Benplaut 05:37, 5 May 2006 (UTC)
thread_title:  Duplicate Links 

message: 66.213.148.48 tells us that the average installed cost has gone up from $3-4 per watt in 2005 (where did that figure come from, though?) to $4.50 to $6.00 already this year.  Are these figures just made up?  Surely these are classic examples of cases where citations are essential.  If no-one can come up with any sources for these figures, I will assume they really are made-up nonsense and delete them both in a few days.  --Nigelj 21:48, 12 May 2006 (UTC)
replies: text: I completely agree with Nigelj and support deletion of uncited data in the Solar Panel wiki (in particular economic claims that could easily have been taken out of context). Go for it. Nanomech 12:07, 15 May 2006 (UTC)
thread_title:  50 - 100% average cost increase in a year? 

message: This paragraph:
On a bright day, the sun delivers about 1 kW/m² to the Earth's surface. Typical solar panels have an average efficiency of 12%, with the best commercially available panels at 20%, and recent prototype panels at around 30%. This would result in 200 W/m². However, not all days have bright sunlight, and therefore not enough solar energy can be captured.
1: please use the same unit all over, it makes it much easier to read. (1 kW/m² and 200 W/m²)
2: Where is this 1 kW/m²? When the sun is directly overhead? At which angle?
If i'm not mistaken the formula for the flux
Q = (integral over some area "sigma") flux_vector DOT PRODUCT area_normal_vector dSigma - which transforms to
W/m² = "ideal W/m²" * cos(lattitude)
where "ideal W/m²" is the flux trough a 1m² surface oriented normal to the flux (normal vector pointing straight towards the sun)
So are this 1 kW/m² this "ideal flux"?
--- kyrsjo
EDIT: Erm, it isn't "cos(lattitude)" - the angle is also modifyed by earth axis tilt and therefore also seasons - and of course time of day.
:I replaced that whole section. linas 22:30, 22 July 2006 (UTC)
thread_title:  Strange paragraph