Solar panel efficency
in [Design]
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From: Michael on 1 Jun 2010 11:54 On May 31, 3:16 pm, Tim Wescott <t...(a)seemywebsite.now> wrote: > On 05/30/2010 10:29 PM, Michael wrote: > > > > > On May 30, 9:03 pm, Robert Baer<robertb...(a)localnet.com> wrote: > >> Tim Wescott wrote: > >>> On 05/30/2010 03:16 PM, Spehro Pefhany wrote: > >>>> On Sun, 30 May 2010 14:20:26 -0700, the renowned Robert Baer > >>>> <robertb...(a)localnet.com> wrote: > > >>>>> I did a survey and this is the best i got. > >>>>> Makers: (1) BP Solar technology: Advanced multicrystalline& > >>>>> monocrystalline silicon nitride; (2) First Solar modules: Thin film > >>>>> cadmium telluride; (3) Nanosolar: Thin film CIGS (copper indium gallium > >>>>> selenium); (4) Sharp: Monocrystalline& polycrystalline (silicon?) (Thin > >>>>> film?); (5) Evergreen Solar: Silicon (Mono? Poly? not mentioned). > > >>>>> The questions in above are due to incompleteness of disclosure (on > >>>>> the web). > > >>>>> Of those technologies, which one is the MOST efficient in conversion > >>>>> of light / solar energy to electrical power (assume ideal load for given > >>>>> panel)? > >>>>> Is there another (commercially available) technology even more > >>>>> efficient? > > >>>> Oh, something like multijunction single-crystal GaAs or InS probably, > >>>> but unless you've got a NASA level budget you probably can't afford > >>>> them. > > >>>> The usual efficiency criteria for ground-based applications is $/peak > >>>> watt. > > >>> And I _still_ think that the criteria should be the net energy return > >>> over the whole lifetime of the product -- mean _after_ you take into > >>> consideration the entire extract/manufacture/install/dispose cycle of > >>> the panel into account, _including_ the trees you'll need to chop down > >>> to make room for them and some projections of the proportion of panels > >>> that will be retired early due to defects, obsolescence, vandalism, > >>> remodeling, and just plain accident. > > >>> Because I think that in principal the whole idea of renewable energy is > >>> a Really Good Thing, but it seems to be in the hands of a bunch of > >>> poly-anna ditzle-brains who turn off all thought processes when > >>> confronted by anything "green", and who are opposed by a bunch of > >>> mean-spirited ditzle-brains who let their thought processes get turned > >>> off by bibles long ago. > > >> Well, absolutely NO energy source is renewable; the sun is in a > >> downward nuclear fission / fusion path leading to iron. > >> What i looked for was an energy source that did not require energy > >> rich carbon sources (trees, oil); the other alternative would be foot > >> powered generators. > > > I've always been fond of the SEGS family of concentrating solar > > arrays, 30 to 80 MW each, in the California Mojave Desert. They focus > > sunlight onto a hydrocarbon heat transfer fluid, heating it to between > > 300 and 400 C, which then boils steam for a steam turbine. Apparently > > they can do it for a lower capital cost than the equivalent amount of > > solar cells would cost. > > > Is this for a third-world project? 100W, huh? No cost constraints? > > Remember, the most efficient technology won't come cheap. What's > > wrong with charcoal? Trees are plenty cheap. > > Somewhere in my brother's extensive collection of railroading books is a > picture of a valley in the American southwest that's been almost > entirely stripped bare of trees, for wood to run the railroad that > served the local mine. > > And there are plenty if citations that I've heard of places in 3rd world > countries where they've stripped their forests bare just for charcoal > for heating and cooking. > > Trees are only cheap for a very little while, then they are very dear > indeed. > > -- > Tim Wescott > Control system and signal processing consultingwww.wescottdesign.com I was thinking more along the lines of the charcoal remnants after California forest fires, the tree pruning services, and the folks hired to remove all the downed trees during our Sacramento winter storms. "Hey, we'll PAY you to take our fallen trees!" Plus the coconut shells that are so frequently wasted instead of being turned to charcoal in the Philippines... we pay something like $3/lb for activated coconut charcoal here in the US for wastewater treatment. And then there are the brilliant folks here, who convert unwanted trees into wood for artisans: http://www.na.fs.fed.us/spfo/pubs/misc/utilizingmunitrees/TreeServiceFirms.htm Convert a waste product into something useful. Of course, to chop down perfectly good forests for charcoal... that's more ludicrous than growing corn to make ethanol. Michael
From: Paul Keinanen on 1 Jun 2010 14:40 On Tue, 01 Jun 2010 09:15:00 +0100, Martin Brown <|||newspam|||@nezumi.demon.co.uk> wrote: > >But in more southerly climes where peak sun corresponds with a peak >demand for aircon it could make more sense to have PV arrays deployed. Or use absorbtion chillers for air conditioning and avoid the inefficient light to electricity conversion.
From: Bill Bowden on 1 Jun 2010 21:39 On May 31, 3:08 pm, Don Lancaster <d...(a)tinaja.com> wrote: > On 5/30/2010 2:20 PM, Robert Baer wrote: > > > I did a survey and this is the best i got. > > Makers: (1) BP Solar technology: Advanced multicrystalline & > > monocrystalline silicon nitride; (2) First Solar modules: Thin film > > cadmium telluride; (3) Nanosolar: Thin film CIGS (copper indium gallium > > selenium); (4) Sharp: Monocrystalline & polycrystalline (silicon?) (Thin > > film?); (5) Evergreen Solar: Silicon (Mono? Poly? not mentioned). > > > The questions in above are due to incompleteness of disclosure (on the > > web). > > > Of those technologies, which one is the MOST efficient in conversion of > > light / solar energy to electrical power (assume ideal load for given > > panel)? > > Is there another (commercially available) technology even more efficient? > > There is NO known pv solar panel technology that is capable of net energy.. > > All efficiencies are thus NEGATIVE. > > The belief that pv technology today is in any manner renewable, > sustainable, or green is an outright lie, > > Whithout exctption, ALL remain gasoline destroying net energy sinks. > > Seehttp://www.tinaja.com/glib/pvlect2.pdffor a detailed analysis > > -- > Many thanks, > > Don Lancaster voice phone: (928)428-4073 > Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552 > rss:http://www.tinaja.com/whtnu.xml email: d...(a)tinaja.com > > Please visit my GURU's LAIR web site athttp://www.tinaja.com Not true. There are many sources claiming net (solar panel) energy payback is far greater than the energy cost of production. And I know people in the business making a good living at it. And the customers are not stupid, even if they are subsidized a bit. http://www.csudh.edu/oliver/smt310-handouts/solarpan/pvpayback.htm "The 1983 book by Hu and White [1 ] summarises the results from a 1977 Solarex study [ 2] which found an energy payback time of 6.4 years for the manufacture of solar modules using silicon cells of 12.5 per cent efficiency." http://en.wikipedia.org/wiki/Solar_cell "Solar cells and energy payback Further information: Low-cost photovoltaic cell "In the 1990s, when silicon cells were twice as thick, efficiencies were much lower than today and lifetimes were shorter, it may well have cost more energy to make a cell than it could generate in a lifetime. In the meantime, the technology has progressed significantly, and the energy payback time, defined as the recovery time required for generating the energy spent for manufacturing of the respective technical energy systems, of a modern photovoltaic module is typically from 1 to 4 years[16][17] depending on the module type and location. Generally, thin-film technologies - despite having comparatively low conversion efficiencies - achieve significantly shorter energy payback times than conventional systems (often < 1 year).[18] With a typical lifetime of 20 to 30 years, this means that modern solar cells are net energy producers, i.e. they generate significantly more energy over their lifetime than the energy expended in producing them." -Bill
From: Sylvia Else on 2 Jun 2010 00:07 On 1/06/2010 5:05 AM, Winston wrote: > On 5/30/2010 5:21 PM, Tim Wescott wrote: > > (...) > >> And I _still_ think that the criteria should be the net energy return >> over the whole lifetime of the product -- mean _after_ you take into >> consideration the entire extract/manufacture/install/dispose cycle of >> the panel into account, _including_ the trees you'll need to chop down >> to make room for them and some projections of the proportion of panels >> that will be retired early due to defects, obsolescence, vandalism, >> remodeling, and just plain accident. > > If you were in the market for a generator set for an off grid home, > would you place any importance at all on the entire life cycle of > that device? Do manufacturers even make that information available? > You need to consider Tim's comment in the context in which it was made. Solar panels are being pushed as a green and renewable solution. The question is whether they are in fact such a solution. When the complete life cycle has passed, and for a given amount of energy yielded by the panels, are the Earth's resources actually depleted less than they would have been had some more conventional non-renewable solution been used? Sylvia.
From: Tim Wescott on 2 Jun 2010 01:01
On 05/31/2010 04:12 PM, Don Lancaster wrote: > >> Well, I don't _know_ that green energy is a net positive enterprise or >> not. > > > I do. > > It misses by a country mile and clearly remains a gasoline destroying > net energy sink. > > http://www.tinaja.com/glib/nrglect2.pdf Your presentation contains the huge logical fallacy that just because gasoline costs $3 a gallon, that a gallon of oil is automatically extracted from the ground every time someone pays $3 for something. For instance, if I go into the seedy part of town and pay $300* for a "special massage", I wouldn't expect that 100 gallons of oil would immediately teleport into the room with the 'lady' and me. If the transaction doesn't work in that circumstance I don't see that it necessarily applies to solar panels -- someone needs to dig, and do the energy budgets directly, not through convenient, simple, and probably wrong simplifications. It also contains the logical fallacy that just because a statement is wrong that the statement is a lie -- any statement can be wrong, it takes intent to make a lie. The digression into in-car electrolysis is extremely distracting -- I assume that it was topical at some point, but in the context of this discussion it is nothing short of zany. And I see absolutely no citations at all, which reduces its meaning from anything that may be useful to nothing more than your personal opinion -- thought provoking, yes, but not something that's going to make me light my torch and find my pitchfork. * Being a nerd I have no clue what the going rate is, nor would I know where to go to find the kind of lady who gives such massages, as opposed to the kind of lady who assists you to a paid visit to one of those hotels with the tacky concrete and steel decor. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com |