Solar panel efficency
in [Design]
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From: JosephKK on 9 Jun 2010 05:50 On Sat, 05 Jun 2010 12:11:32 +1000, Sylvia Else <sylvia(a)not.here.invalid> wrote: >On 5/06/2010 10:41 AM, Bill Bowden wrote: >> On Jun 3, 8:16 pm, John Larkin >> <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >>> On Thu, 3 Jun 2010 20:00:24 -0700 (PDT), Bill Bowden >>> >>> >>> >>> <wrongaddr...(a)att.net> wrote: >>>> On Jun 2, 11:55 pm, Martin Brown<|||newspam...(a)nezumi.demon.co.uk> >>>> wrote: >>>>> 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.xmlemail: 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 >>> >>>> Interesting article. Also found this article about a 250MW solar >>>> project by a SCE in the southern California area. Must have some value >>>> if SCE wants to build it. >>> >>> California utilities are required to get a portion of their power from >>> renewables. They might not if the decision were purely economic. >>> >>> John >> >> How about hydro-electric which qualifies as renewable. Why waste time >> with solar if economics are better with hydro? Or is this a dumb >> question? >> >> -Bill > >The economics of hydro are good, if there's a suitably place to build >one. Suitable means that the topography and rainfall have to be >appropriate, and it's mustn't be too far from the place where the power >will be used. > >Sylvia. The distance to usage point is no where as significant as you think. They ship hydropower electric from Washington state to LA and San Diego, over 1000 miles with recently built infrastructure.
From: Martin Brown on 9 Jun 2010 06:04 On 05/06/2010 03:11, Sylvia Else wrote: > On 5/06/2010 10:41 AM, Bill Bowden wrote: >> On Jun 3, 8:16 pm, John Larkin >> <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >>> On Thu, 3 Jun 2010 20:00:24 -0700 (PDT), Bill Bowden >>> <wrongaddr...(a)att.net> wrote: >>>> On Jun 2, 11:55 pm, Martin Brown<|||newspam...(a)nezumi.demon.co.uk> >>>> wrote: >>>>> 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 >>> >>>> Interesting article. Also found this article about a 250MW solar >>>> project by a SCE in the southern California area. Must have some value >>>> if SCE wants to build it. >>> >>> California utilities are required to get a portion of their power from >>> renewables. They might not if the decision were purely economic. I suspect that is true, but it may not hold for too much longer if screen or inkjet printable semiconductors become stable enough to be worth using in this application. Or some other thin film PV trick. Again being seen to do something may get brownie points even if it isn't particularly effective. Be interesting to see the numbers. >> How about hydro-electric which qualifies as renewable. Why waste time >> with solar if economics are better with hydro? Or is this a dumb >> question? > > The economics of hydro are good, if there's a suitably place to build > one. Suitable means that the topography and rainfall have to be > appropriate, and it's mustn't be too far from the place where the power > will be used. Or you can be clever and use hydro pumped storage at two different levels to supply fast peak demand and then run it backwards at night when generation for base load is more than demand. The overall efficiency is not that great, but the very fast start capability is worthwhile for key aspects of load balancing. Dinorwig hydro in Wales is still I think the flagship for this technology in Europe. http://www.fhc.co.uk/dinorwig.htm Regards, Martin Brown
From: Dirk Bruere at NeoPax on 9 Jun 2010 06:21 On 09/06/2010 11:04, Martin Brown wrote: > On 05/06/2010 03:11, Sylvia Else wrote: >> On 5/06/2010 10:41 AM, Bill Bowden wrote: >>> On Jun 3, 8:16 pm, John Larkin >>> <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >>>> On Thu, 3 Jun 2010 20:00:24 -0700 (PDT), Bill Bowden >>>> <wrongaddr...(a)att.net> wrote: >>>>> On Jun 2, 11:55 pm, Martin Brown<|||newspam...(a)nezumi.demon.co.uk> >>>>> wrote: > >>>>>> 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 >>>> >>>>> Interesting article. Also found this article about a 250MW solar >>>>> project by a SCE in the southern California area. Must have some value >>>>> if SCE wants to build it. >>>> >>>> California utilities are required to get a portion of their power from >>>> renewables. They might not if the decision were purely economic. > > I suspect that is true, but it may not hold for too much longer if > screen or inkjet printable semiconductors become stable enough to be > worth using in this application. Or some other thin film PV trick. Since Nanosolar claim that they can now manufacture PV for $0.70 per peak watt, and it's currently selling at around $2, it gives an indication of the scope for prices falling when supply finally exceeds demand by a large margin. The key being economy of scale. -- Dirk http://www.transcendence.me.uk/ - Transcendence UK http://www.blogtalkradio.com/onetribe - Occult Talk Show
From: Paul Keinanen on 9 Jun 2010 15:54 On Wed, 09 Jun 2010 11:04:45 +0100, Martin Brown <|||newspam|||@nezumi.demon.co.uk> wrote: >On 05/06/2010 03:11, Sylvia Else wrote: >> On 5/06/2010 10:41 AM, Bill Bowden wrote: >>> How about hydro-electric which qualifies as renewable. Why waste time >>> with solar if economics are better with hydro? Or is this a dumb >>> question? >> >> The economics of hydro are good, if there's a suitably place to build >> one. Suitable means that the topography and rainfall have to be >> appropriate, and it's mustn't be too far from the place where the power >> will be used. > >Or you can be clever and use hydro pumped storage at two different >levels to supply fast peak demand and then run it backwards at night >when generation for base load is more than demand. The overall >efficiency is not that great, but the very fast start capability is >worthwhile for key aspects of load balancing. You must be really desperate, if you start thinking about pumping storage :-). At low latitudes in which the annual peak load is in the summer, due to air conditioning, it is economically sensible to build solar (PV or solar thermal) plants with a total power as large as the day/night consumption difference. Building more than that will require desperate measures as pumping storage or accumulators. Check your local day/night consumption figures. At higher latitudes (Central and Northern Europe), the peak consumption is during the winter months, with minimal solar production. During the summer months, when the solar production is high, the consumption is low (and nuclear power plants are shut down for annual maintenance during the summer) and hence the price that you can get from the solar electricity is quite low.
From: Martin Brown on 9 Jun 2010 16:29
On 09/06/2010 20:54, Paul Keinanen wrote: > On Wed, 09 Jun 2010 11:04:45 +0100, Martin Brown > <|||newspam|||@nezumi.demon.co.uk> wrote: > >> On 05/06/2010 03:11, Sylvia Else wrote: >>> On 5/06/2010 10:41 AM, Bill Bowden wrote: > >>>> How about hydro-electric which qualifies as renewable. Why waste time >>>> with solar if economics are better with hydro? Or is this a dumb >>>> question? >>> >>> The economics of hydro are good, if there's a suitably place to build >>> one. Suitable means that the topography and rainfall have to be >>> appropriate, and it's mustn't be too far from the place where the power >>> will be used. >> >> Or you can be clever and use hydro pumped storage at two different >> levels to supply fast peak demand and then run it backwards at night >> when generation for base load is more than demand. The overall >> efficiency is not that great, but the very fast start capability is >> worthwhile for key aspects of load balancing. > > You must be really desperate, if you start thinking about pumping > storage :-). It is faintly useful for transient load balancing - quick to come onstream with full power and synchronisation in 12s from standby. And it is probably better to use some pumped storage than smelt a bit more iron, aluminium or make sodium and chlorine which are the ultimate load balancing energy dumps on lowest rate very interuptable tariff. > > At low latitudes in which the annual peak load is in the summer, due > to air conditioning, it is economically sensible to build solar (PV > or solar thermal) plants with a total power as large as the day/night > consumption difference. Building more than that will require desperate > measures as pumping storage or accumulators. Check your local > day/night consumption figures. And/or put them on the roof so that some solar power goes into PV cells and the roof itself is not heated by direct sunlight. > > At higher latitudes (Central and Northern Europe), the peak > consumption is during the winter months, with minimal solar > production. During the summer months, when the solar production is > high, the consumption is low (and nuclear power plants are shut down > for annual maintenance during the summer) and hence the price that you > can get from the solar electricity is quite low. I agree. PV is a dead loss at our latitude since it hardly generates anything at all in the dull grey winters. To my amazement though in the bleak midwinter on the few sunny days with blue skies my friends 2kW PV array generates about 800W despite the low midday solar elevation of just 26 degrees. The cold improves the overall efficiency somewhat - and conversely a hot panel derates its output with extra losses. The combined water heating and PV designs look like a smart idea if the reliability can be improved. Regards, Martin Brown |