Question:

With today’s economics,Solar Panel Inverter design  the longer you run a system installed fully burdened solar cell, the more it costs you.

Maybe with your screwball economics, but not any sensible economics. Use a definition of “dollar” as “personal use and control of the amount of energy in three quarts of gasoline”, and it all falls in place.

Except that such a definition is not stable over time.  The price of gasoline varies. Solar Panel Inverter design

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Heard that Spectrolab, a div of Hughes electronics, has developed solar cell with efficiency reaching 32 percent with further potential to elevate this figure to 40 percent. From their web page Solar Panel Inverter design

Notice the keyword “space” in “space solar cell efficiency”. Maybe for use on the space shuttle?  Is there something more recent. Maybe Don Lancaster has something to say related about exergy on this or has a PDF file for it (he does on everything else!Solar Panel Inverter design

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Heard that Spectrolab, a div of Hughes electronics, has developed solar cell with efficiency reaching 32 percent with further potential to elevate this figure to 40 percent. Can anyone here confirm this news report and if so, what is the present status regarding mass production and sale of this solar cell.

Solar Panel Inverter design  a div of Hughes electronics, has developed solar cell with efficiency reaching 32 percent with further potential to elevate this figure to 40 percent. Can anyone here confirm this news report and if so, what is the present status regarding mass production and sale of this solar cell. The impression I had was that at over 23 percent efficiency solar cells becomes technically and commercially viable. The maximum efficieny reportedly attained so far for a solar cell  was about 18 percent in a Swedish University research lab. Rgds John

You can (fairly) easily build PV solar cells with efficiencies as high as 43%. The secret is to use multiple junctions having different work functions.. Unfortunately, no multiple junction solar cell to date comes even remotely near returning the energy needed for its manufacture. Which leaves them largely useless for terrestral apps. Dandy for deep space, though. — Many thanks, Don Lancaster Synergetics   3860 West First Street  Box 809  Thatcher, AZ 85552 Please visit my GURU’s LAIR web site at Solar Panel Inverter design

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Heard that Spectrolab, a div of Hughes electronics, has developed solar cell with efficiency reaching 32 percent with further potential to elevate this figure to 40 percent. Can anyone here confirm this news report and if so, what is the present status regarding mass production and sale of this solar cell. The impression I had was that at over 23 percent efficiency solar cells becomes technically and commercially viable. The maximum efficieny reportedly attained so far for a solar cell  was about 18 percent in a Swedish University research lab. Solar Panel Inverter design

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Solar Panel Inverter design a div of Hughes electronics, has developed solar cell with efficiency reaching 32 percent with further potential to elevate this figure to 40 percent. Can anyone here confirm this news report and if so, what is the present status regarding mass production and sale of this solar cell. The impression I had was that at over 23 percent efficiency solar cells becomes technically and commercially viable. The maximum efficieny reportedly attained so far for a solar cell  was about 18 percent in a Swedish University research lab.

Well, I normally get my science news from the InquirerSolar Panel Inverter design. The secret is to use multiple junctions having different work functions.. Unfortunately, no multiple junction solar cell to date comes even remotely near returning the energy needed for its manufacture. Which leaves them largely useless for terrestral apps. This seems counter-intuitive.  I have a hard time imagining that that much energy is required to build semiconductors, especially since a solar cell could run for decades (if given a location with regularly scheduled sunlight).  Granted, the way solar cells are constructed at present is rather inefficient, given that wafers have to sawn out of semiconductor ingots and processed more-or-less one at a time. Could you go into more detail?Solar Panel Inverter design

With today’s economics, the longer you run a system installed fully burdened solar cell, the more it costs you. Use a definition of “dollar” as “personal use and control of the amount of energy in three quarts of gasoline”, and it all falls in place. You voted for this definition last week when you made a withdrawal from the ATM pump at your local Texaco bank. A single PV cell over its lifetime generates total electricity of very low value. It does not take much cost and amortiztion to override this. Solar cells become interesting at something under fifty cents per peak watt. Multiple work function cells are unlikely to even remotely approach this goal in the next few decades.Solar Panel Inverter design

You can (fairly) easily build PV solar cells with efficiencies as high as 43%. The secret is to use multiple junctions having different work functions.. Unfortunately, no multiple junction solar cell to date comes even remotely near returning the energy needed for its manufacture. Which leaves them largely useless for terrestral apps.

This seems counter-intuitive.  I have a hard time imagining that that much energy is required to build semiconductors, especially since a solar cell could run for decades (if given a location with regularly scheduled sunlight).  Granted, the way solar cells are constructed at present is rather inefficient, given that wafers have to sawn out of semiconductor ingots and processed more-or-less one at a time.  Last I remember hearing, ‘ribbon’ processing of semiconductor materials still isn’t a reality. Could you go into more detail? Dandy for deep space,Solar Panel Inverter design  a div of Hughes electronics, has developed solar cell with efficiency reaching 32 percent with further potential to elevate this figure to 40 percent. Can anyone here confirm this news report and if so, what is the present status regarding mass production and sale of this solar cell. The impression I had was that at over 23 percent efficiency solar cells becomes technically and commercially viable. The maximum efficieny reportedly attained so far for a solar cell  was about 18 percent in a Swedish University research lab. Well, I normally get my science news from the Inquirer (<: but I’m assuming they got their numbers for solar conditions equivalent to outer space, not at the bottom of the atmosphere. Also, they probably managed to stack several different energy band layers together to absorb more of the total spectrum – easy to say, but hard to do in a transparent way. Probably costly as the dickens right now, but if there’s a terrestrial potential, this could be the start of something (unlike the previous 2 or 3 announcements of “super-efficient” cells that are still stuck in the lab).Solar Panel Inverter design

– If you get the time please do check the web site of ENN – Enviornmental News Network: There is a detailed article with pictures etc. The article clearly states that the solar cell developed by the scientists of Hughes Electronics and Dept of Energy and National Renewable Energy Laboratory is Terrestial solar cell. Not space based. It is called – triple-junction gallium-indium-phosphide on gallium arsenide on germanium concentrator solar cell. — So what gives. That article says that the cell was developed in more than an year ago. Have they progressed from 32.8 percent to 40 percent ? If all this is true, will the quest for Hydrogen based energy ( and Wind power ) soon take the back seat ? Approx 1 KW of sunlight falls on 1 Sq Meter. With even 30 percent efficiency, that would be 300 watts of electrical power. An acre of land under sunlight will yield 500 x 300 = 150, 000 watts. – I hope all that news is true..and we could see the real stuff on a commercial scale.

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With today’s economics, the longer you run a system installed fully burdened solar cell, the more it costs you. Maybe with your screwball economics, but not any sensible economics.

According to information on the National Renewable Energy Laboratory’s website (www.nrel.gov), the cost of installing and operating a solar photovoltaic electric production system, amortized over the lifetime of the system, is $0.25-$0.50 / kWh.  This compares to an average cost of grid electricity in the US of about $0.10 / kWh (in Colorado where I live, I think it’s about $0.075).  Since fuel for a PV system is free (sunlight), I’m not sure why Don says it costs you more the longer you run it, since the costs are almost entirely paid for up front. I note that NREL says that PV is an economical means of power generation in the US if your home is more than 1/4 mile from the nearest power line.  The costs of building power lines add up rapidly, apparently.Solar Panel Inverter design

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With today’s economics, the longer you run a system installed fully burdened solar cell, the more it costs you. According to information on the National Renewable Energy Laboratory’s website (www.nrel.gov), the cost of installing and operating a solar photovoltaic electric production system, amortized over the lifetime of the system, is $0.25-$0.50 / kWh.Solar Panel Inverter design

Their statement is prima facie absurd. There ~must~ be some hidden gotchas and weasel words in their analysis. Or you are misinterpreting what they said. It certainly could not include storage and conversion to useful voltage levels. If this was the case, utility power would be used only sparingly for leveling and backup. If this was the case, solar panels would account for the overwhelming majority of electrical energy consumed in the US. Overall, all costs and energies considered, not one net watt of solar PV electricity has ~ever~ been produced. Such breakeven will probably take place something like eight years after the fully burdened and fully amortized cost of usefully delivered 110 volt 60 Hertz solar energy drops under eight cents per kilowatt hour.Solar Panel Inverter design  With today’s economics, the longer you run a system installed fully burdened solar cell, the more it costs you. Maybe with your screwball economics, but not any sensible economics. According to information on the National Renewable Energy Laboratory’s website (www.nrel.gov), the cost of installing and operating a solar photovoltaic electric production system, amortized over the lifetime of the system, is $0.25-$0.50 / kWh.  This compares to an average cost of grid electricity in the US of about $0.10 / kWh (in Colorado where I live, I think it’s about $0.075).  Since fuel for a PV system is free (sunlight), I’m not sure why Don says it costs you more the longer you run it, since the costs are almost entirely paid for up front.

Unless there is a hidden subsidy (such as pole charges), twenty-five cent per kwh electricity is a net consumer of existing energy. And thus an energy sink. Not one net watt of system wide fully burdened solar PV electricity has ever been produced. Breakeven will probably take place eight years after the fully burdened costs drop under eight cents per kilowatt hour. Until then, solar PV users are simply destroying gasoline.Solar Panel Inverter design

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According to information on the National Renewable Energy Laboratory’s website (www.nrel.gov), the cost of installing and operating a solar photovoltaic electric production system, amortized over the lifetime of the system, is $0.25-$0.50 / kWh. — Greg Wimpey

Their statement is prima facie absurd. There ~must~ be some hidden gotchas and weasel words in their analysis.

Not really, no.  There *is* a “gotcha” of sorts though: silicon PV cells today are made from “reject” silicon that has already been purified for the chip industry.  There is a limited supply of such silicon, and in fact, as the cost of solar PV production has come down, demand has gone up to the point where at least one currently-profitable solar-PV company has made a deal with another company to supply large quantities of “solar-grade” silicon, instead of small quantities of “reject chip-grade” stuff. Or you are misinterpreting what they said. It certainly could not include storage and conversion to useful voltage levels.

Solar panels (not cells) currently go for about $7/peak watt [1]. A 2500 watt inverter costs about $2500 [2, 3].  Combined, this costs about $19500 retail [1, w/ "buydown" added back in].  Such a system will produce about 280 kWh/mo on average around here (you get more in the south and less in the north), and is warranted for 25 years, or about 84000 kWh of production.  That comes to 23.2 cents per kWh. (Economies of scale can bring the cost down, but see the first paragraph above — there is just not enough “reject” silicon available.)Solar Panel Inverter design.  The solar power equipment will remain in use as long as the cost to keep it in service is less than the cost of maintaining and financing its replacement.

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The solar power equipment will remain in use as long as the cost to keep it in service is less than the cost of maintaining and financing its replacement.

Solar differs tremendously from traditional sources of power in that it requires an enormous amount of space.  That space has substantial value, so the “cost to keep it in service” includes a large rent (or imputed rent).  When there are more efficient cells available, people will want to rip out the old ones so the space can be used more efficiently.  25 years is a long time.  I wouldn’t want to bet on wanting to use today’s solar technology in more than 10 years.

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The solar power equipment will remain in use as long as the cost to keep it in service is less than the cost of maintaining and financing its replacement.

The good thing about rooftop home PV is that the maintenance cost is effectively zero (the inverters tend to fail more often than the panels so that part may be nonzero, but the panels fail at about the same rate as the roof itself does). In warmer climates, the solar PV rooftop panels actually have a side benefit of reduced air conditioning load.  (You could get the same thing by having a second layer of roof, with air circulation underneath, covering the same area as the panels.  That would cost less than the PV panels, and have the same lifetime, but would not generate any electricity.) (This benefit is rather marginal, admittedly, but when the marginal cost of each kWh today is so close to the marginal PV cost-savings of each kWh today, that marginal benefit may tip the balance to PV.) Solar differs tremendously from traditional sources of power in that it requires an enormous amount of space.  That space has substantial value, so the “cost to keep it in service” includes a large rent (or imputed rent).  When there are more efficient cells available, people will want to rip out the old ones so the space can be used more efficiently.

One could make the same argument for replacing one’s asphalt shingles every five of ten years.  In practice, homewners wait the full 30 years until they fail. Certainly “utility scale” (as opposed to home-hobbyist-type) solar has to take this into account, though. — In-Real-Life: Chris Torek, Berkeley Software Design Inc Note:Solar Panel Inverter design

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Solar differs tremendously from traditional sources of power in that it requires an enormous amount of space.  That space has substantial value, so the “cost to keep it in service” includes a large rent (or imputed rent).  When there are more efficient cells available, people will want to rip out the old ones so the space can be used more efficiently. One could make the same argument for replacing one’s asphalt shingles every five of ten years.

No, new shingles don’t work any better than the old (but still working) ones. Certainly “utility scale” (as opposed to home-hobbyist-type) solar has to take this into account, though.

Hobbyists can do whatever the hell they want.  Hobbies don’t have to make sense economically, because they also yield enjoyment and satisfaction.  If solar becomes successful on a wider scale, most people adopting it — even at the home rooftop level, but certainly at the office rooftop level — are going to be motivated by monetary savings, not hobby interest.

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One could make the same argument for replacing one’s asphalt shingles every five of ten years.

No, new shingles don’t work any better than the old (but still working) ones.

Oh but they do!  You have not been following the asphalt shingle industry? (Seriously, you can now get all kinds of interesting decorative etc.  shingles with new features.  There has been a mini materials renaissance in the last decade.) Hobbyists can do whatever the hell they want.  Hobbies don’t have to make sense economically, because they also yield enjoyment and satisfaction.  If solar becomes successful on a wider scale, most people adopting it — even at the home rooftop level, but certainly at the office rooftop level — are going to be motivated by monetary savings, not hobby interest.

Well, the Santa Rita jail over near (in?) Dublin just contracted for the largest rooftop PV in the bay area, or maybe the world.  They believe their system will save them money.Solar Panel Inverter design

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Well, the Santa Rita jail over near (in?) Dublin just contracted for the largest rooftop PV in the bay area, or maybe the world.  They believe their system will save them money.

Maybe.  Politicians do things not only because they save money but also because they look good, because a contractor has political connections, etc..  When private landlords start doing this on a large scale, that will be better indication that the economics make sense.   In this case, they claim it will generate 650,000 kWh/year.  At $0.10/kWh (commercial customers like a county can almost certainly get a 25-year contract at that price, or lower), that’s only $65,000/year. They don’t say how much the system will cost, but we can probably assume it will be at least $5, if not more, after the cost of installation, or $2.5 million.  Pretty bad rate of return.

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They don’t say how much the system will cost, but we can probably assume it will be at least $5, if not more, after the cost of installation, or $2.5 million.

This should have read “at least $5/W, if not more.”  (The press release describes the system as being 500 kW.)

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(BTW, I should add that I believe that the $7/watt price from sixriverssolar includes all wiring, standoffs, etc.  This is why there is the big step up from the base ~$4/watt panel-only price.) Well, the Santa Rita jail over near (in?) Dublin just contracted for the largest rooftop PV in the bay area, or maybe the world.  They believe their system will save them money.

Maybe.  Politicians do things not only because they save money but also because they look good, because a contractor has political connections, etc..  When private landlords start doing this on a large scale, that will be better indication that the economics make sense.

True enough.  There is a sort of “inertia”, though: when something only just barely makes economic sense, many people will refrain from doing it until many other people are doing it. In this case, they claim it will generate 650,000 kWh/year.  At $0.10/kWh (commercial customers like a county can almost certainly get a 25-year contract at that price, or lower), that’s only $65,000/year.

They claim an avoided cost of $190k/yr:     We estimate that Alameda County will save an average of $190,000     in electricity costs per year as a result of deploying solar     power … Some of that is directly-avoided costs, by self-generation; other is indirectly-avoided costs, partly through superior roof insulation achieved by the solar tiles, leading to reduced air conditioning load, and partly through an upgraded physical plant (presumably new higher-efficiency air conditioning units).  They break out the two:     The project … will result in the annual generation of 650,000     kilowatt-hours of clean energy, and save an additional 890,000     kilowatt-hours. The total here is 1 540 000 kWh/yr; for this to represent $190 000, they have to be paying $.123/kWh.  They believe it will have a 30-year lifetime (5.5M$/190k$). They don’t say how much the system will cost, but we can probably assume it will be at least $5, if not more, after the cost of installation, or $2.5 million.  Pretty bad rate of return.

(I am not sure what you mean above with the $5 figure.) I found a county agenda item on google Solar Panel Inverter design     Approve energy services contract with PowerLight Corporation     (Principal: Thomas Dinwoodie; Location: Berkeley) to design,     manufacture, and install a maximum 500 kilowatt integrated     rooftop photovoltaic system, and design and install energy-efficiency     measures at Santa Rita Jail ($2,968,696); approve related budget     adjustments and authorize the Director to apply for energy     efficiency grants – CAO Recommends:  Approve – (4/5 Vote) So the whole system costs about $3M, including design, materials, and labor for PV tiles, insulation, and central plant; these costs are not broken down.  The $3M expenditure is expected to save $5.5M over 30 years.  The $3M itself costs an unknown amount over those 30 years — assuming 7% return and 4% inflation, the $3M costs $7.5M, but perhaps the roof and air conditioning need replacing today anyway, and perhaps that would cost $1M anyway, in which case the $2.5M “extra” expense costs $5.0M over 30 years, for a net savings of $0.5M. — In-Real-Life: Chris Torek, Berkeley Software Design Inc Note: PacBell news service is rotten

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In this case, they claim it will generate 650,000 kWh/year.  At $0.10/kWh (commercial customers like a county can almost certainly get a 25-year contract at that price, or lower), that’s only $65,000/year. They claim an avoided cost of $190k/yr: … and partly through an upgraded physical plant (presumably new higher-efficiency air conditioning units).

Right, which is why I bypassed that number and went straight to the energy generated per year: The total here is 1 540 000 kWh/yr; for this to represent $190 000, they have to be paying $.123/kWh.

OK, fair enough.  So that’s $81,250 worth of electricity produced. They don’t say how much the system will cost, but we can probably assume it will be at least $5, if not more, after the cost of installation, or $2.5 million.  Pretty bad rate of return. (I am not sure what you mean above with the $5 figure.Solar Panel Inverter design

As I clarified in a follow up, I was estimating the cost of the PV component of the project at $5/W, or $2.5 million, which we must do to back out the effects of a new air conditioning system, etc.[*] $81,250/year savings with a 25 year life (which, as I suggested earlier, I think is too long, but we’ll ignore that for now) doesn’t even pay for the $2.5 million up front invesment, much less generate any savings. There are probably some subsidizes available, but overall this does not look like a very good deal.  (Probably a good deal for the contractor though.) [*] I don’t believe the additional insulation to be worth very much. Solar Panel Inverter design

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