Solar panel efficency
in [Design]
|
From: Sylvia Else on 2 Jun 2010 22:10 On 3/06/2010 1:37 AM, Don Lancaster wrote: > On 6/1/2010 9:07 PM, Sylvia Else wrote: >> 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. > > > Its not even remotely close. > Not by a country mile. > > Present costs are $3.50 per peak panel watt. > 0.25 per peak panel watt is required for net energy displacing > renewibility or sustainability. > > At present, not one net watthour of pv energy has EVER been produced. > The panels remain gasoline destroying net energy sinks. > > Absolute proof of this is that not one utility anyplace anytime is > routinely using pv for peaking that is completely independent of > subsidies, tax breaks, R&D effort, or other money grubbing scams. I don't really see the link. Certainly PV cells are an uneconomic source of electricity. They also produce power when it suits them (daytime, sunlight) rather than when it's required, which makes then unsuitable for peaking (or much else, indeed, without expensive resource consuming batteries). But that does not in itself mean that they're necessarily energy sinks, though I'm not arguing that they're not. Sylvia.
From: AZ Nomad on 2 Jun 2010 22:42 On Thu, 03 Jun 2010 12:10:11 +1000, Sylvia Else <sylvia(a)not.here.invalid> wrote: >I don't really see the link. Certainly PV cells are an uneconomic source >of electricity. They also produce power when it suits them (daytime, >sunlight) rather than when it's required, which makes then unsuitable >for peaking (or much else, indeed, without expensive resource consuming >batteries). >But that does not in itself mean that they're necessarily energy sinks, >though I'm not arguing that they're not. If you compare the upfront cost with their lifetime energy reception, you'd probably find that they never break even. Good for some portable applications or remote locations, but not much else.
From: Sylvia Else on 3 Jun 2010 01:22 On 3/06/2010 12:42 PM, AZ Nomad wrote: > On Thu, 03 Jun 2010 12:10:11 +1000, Sylvia Else<sylvia(a)not.here.invalid> wrote: > >> I don't really see the link. Certainly PV cells are an uneconomic source >> of electricity. They also produce power when it suits them (daytime, >> sunlight) rather than when it's required, which makes then unsuitable >> for peaking (or much else, indeed, without expensive resource consuming >> batteries). > >> But that does not in itself mean that they're necessarily energy sinks, >> though I'm not arguing that they're not. > > If you compare the upfront cost with their lifetime energy reception, > you'd probably find that they never break even. Good for some portable > applications or remote locations, but not much else. You really need to be careful in your choice of terminology when discussing this. In place where grid power is available, PV cells never repay the financial cost of their manufacture. That is, absent subsidies, you cannot sell the energy they generate for enough money to justify the expenditure of the money invested in them. Whether they return all the energy used to make them is a different question. Sylvia.
From: Martin Brown on 3 Jun 2010 02:55 On 03/06/2010 00:39, Bill Bowden wrote: > On Jun 2, 8:45 am, Don Lancaster<d...(a)tinaja.com> wrote: >>> There are many sources claiming net (solar panel) energy >>> payback is far greater than the energy cost of production. >> >> These claims are utterly bogus as they treat subsidies as assets, rather >> than as much larger "iceberg" liabilities. The key issue is addressed at >> <http://www.tinaja.com/whtnu10.asp#d05-31-10> >> >>> And I know people in the business making a good living at it. >> >> So do I. Including the few remaining honest pioneers that have all the >> arrows in their backs. And when you get them drunk enough or stoned >> enough, they freely admit they are stealing federal and state dollars >> just like everybody else does. >> >> <http://www.tinaja.com/blig/nrglect2.pdf> >> >> -- >> 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 Junk science. > > Well that's nice. Now if you can just give me a couple other > references, not written by you, I will be a believer. That isn't going to happen. Although the myth that solar panels never pay back their energy investment is widespread. They may never pay back the cost to make, install and use them over their lifetime, but that is an entirely different matter. And the economics is shifting as someone demonstrated there appear to be panels on the market now at $2/W. > > Here's another one you don't want to read. > > http://en.wikipedia.org/wiki/Photovoltaics > > "Energy payback time and energy returned on energy invested > > The energy payback time is the time required to produce an amount of > energy as great as what was consumed during production. The energy > payback time is determined from a life cycle analysis of energy. The > energy needed to produce solar panels is paid back in the first few > years of use.[79] > > Another key indicator of environmental performance, tightly related to > the energy payback time, is the ratio of electricity generated divided > by the energy required to build and maintain the equipment. This ratio > is called the energy returned on energy invested (EROEI). This should > not be confused with the economic return on investment, which varies > according to local energy prices, subsidies available and metering > techniques. > > Life-cycle analyses show that the energy intensity of typical solar > photovoltaic technologies is rapidly evolving. In 2000 the energy > payback time was estimated as 8 to 11 years,[80] but more recent > studies suggest that technological progress has reduced this to 1.5 to > 3.5 years for crystalline silicon PV systems.[74] > > Thin film technologies now have energy pay-back times in the range of > 1-1.5 years (S.Europe).[74] With lifetimes of such systems of at least > 30 years[citation needed], the EROEI is in the range of 10 to 30. They > thus generate enough energy over their lifetimes to reproduce > themselves many times (6-31 reproductions, the EROEI is a bit lower) > depending on what type of material, balance of system (or BOS), and > the geographic location of the system.[81] " You can't always trust Wiki but there is also stuff in the peer reviewed literature that refute his bogus claim (which to be fair might once have been true decades ago when solar cells were *much* thicker). See Richards & Watt (2007) http://www.inference.phy.cam.ac.uk/sustainable/refs/solar/Myth.pdf Regards, Martin Brown
From: Dirk Bruere at NeoPax on 3 Jun 2010 08:38
On 03/06/2010 06:22, Sylvia Else wrote: > On 3/06/2010 12:42 PM, AZ Nomad wrote: >> On Thu, 03 Jun 2010 12:10:11 +1000, Sylvia >> Else<sylvia(a)not.here.invalid> wrote: >> >>> I don't really see the link. Certainly PV cells are an uneconomic source >>> of electricity. They also produce power when it suits them (daytime, >>> sunlight) rather than when it's required, which makes then unsuitable >>> for peaking (or much else, indeed, without expensive resource consuming >>> batteries). >> >>> But that does not in itself mean that they're necessarily energy sinks, >>> though I'm not arguing that they're not. >> >> If you compare the upfront cost with their lifetime energy reception, >> you'd probably find that they never break even. Good for some portable >> applications or remote locations, but not much else. > > You really need to be careful in your choice of terminology when > discussing this. > > In place where grid power is available, PV cells never repay the > financial cost of their manufacture. That is, absent subsidies, you > cannot sell the energy they generate for enough money to justify the > expenditure of the money invested in them. Depends if you want to sell the energy. In S Europe, without subsidies, domestic PV electricity is already comparable to domestic grid cost. -- Dirk http://www.transcendence.me.uk/ - Transcendence UK http://www.blogtalkradio.com/onetribe - Occult Talk Show |