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Solar at Home


The trials, tribulations and rewards of going solar
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Solar panels for the rest of us

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Editor’s Note: Scientific American‘s George Musser will be chronicling his experiences installing solar panels in Solar at Home (formerly 60-Second Solar). Read his introduction here and see all posts here.

Just last week, I blogged about how the future would bring solar panels with built-in electrical inverters, greatly simplifying the design and installation of solar arrays. Well, the future is here already. Two days after my post, California installer Akeena Solar announced that Lowes’s California stores would begin selling Andalay solar panels that, because they incorporate an inverter, output AC power rather than DC. “AC modules will be one of those technologies that change things,” says Andrew McCalla, CEO of Meridian Solar, the leading installer in Texas.

Most solar installations today consist of a string of solar panels wired in electrical series to a centralized inverter. Cables carry DC power from the roof down to the basement, where the inverter converts the current to AC and feeds it into the service panel. But as I discussed in an earlier post, this setup is very restrictive: to avoid an electrical mismatch, the panels must all have the same orientation with respect to the sun. The situation is analogous to old-style holiday lights wired in series. Either all of them light up, or none.

In my case, I can fit put 15 panels on my roof in such a way that they have the same orientation, even though there is room for another six at a different orientation. You might think that I could wire those six to a separate inverter, but six panels would not produce a high enough voltage for a centralized inverter to convert to household current.

The solution is to give each panel its own inverter, known as a microinverter. The Andalay panels produce 208 or 240 volts AC (depending on the model) and you wire them together in electrical parallel, which lessens their sensitivity to one another’s output. Each inverter optimizes the power output of its panel. "These microinverters are great because they allow you to max-power-track by the module," says Chris Anderson of Borrego Solar, a large commercial installer.

You can stick each panel on at whatever orientation you want. You can have an array of one panel or as many as 21. Not only does this let you fill out your roof, it allows you to install panels incrementally as your budget permits and as technology improves. Because precision alignment is less important, advanced DIYers could install panels on their own. Loosely speaking, AC panels are to DC panels what window air-conditioners are to central a/c.

To be sure, there are risks, too. Good design is still crucial to ensuring the best performance, and most people should still leave it to the pros. Anderson says that a pilot project in Mill Valley found that microinverters had a higher failure rate than centralized inverters. For a large commercial installation, their maintenance costs could outweigh the benefits. But homeowners should investigate these new devices, whether by Akeena or another company. I plan to use them myself in a few years to expand my system.

Andalay AC panels on a Habitat for Humanity installation, courtesy of Akeena Solar

 





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  1. 1. toomyw 4:16 pm 12/15/2009

    I really like the idea of the micro-inverter. As I’ve seen, many stand-alone inverters usually have a 10 year warranty (though they’ll likely last longer),

    These micro-inverters offer a 15 year warranty. That’s great, but it can be problematic being one of the first testers to ensure that they last that long. If there’s a problem, is the homeowner responsible for the change out costs? It could be tough changing out 10-20 inverters since they’re all behind the panels which are on the roof.

    Having said that, I like that they’re pushing things forward.

    Link to this
  2. 2. lamorpa 4:24 pm 12/15/2009

    @lakota2012:
    Seriously. You live off the grid and deal with all the issues of personal energy production and responsibility. Good for you. No one can fault you or tell you about ‘correct’ and ‘incorrect’ energy use (I mean it). You live it.

    I am just worried about the casual suburbanites playing with their toy PV installations and then losing interest – completely wasting valuable resources. It happened with solar hot water, it will happen with PV. (Maybe there will be a cheap aftermarket in used PV panels!)

    If someone cannot be bothered to start and sustain energy conservation this month, they are not going to go to the trouble of maintaining a PV installation for 20 or 30 years.

    I saw a Chevrolet Tahoe Hybrid the other day. The waste put into the big chromed ‘hybrid’ plaques on all sides of it alone will offset any gas savings the hybrid drive will produce. These SUVs sell very well.

    ‘Weekend’ greeners are just another form of gratuitous consumers. Better to let them feed from the general energy trough than to have them install more showoff toys that will be cast aside as soon as the next cool trend appears.

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  3. 3. Deepwalker 4:32 pm 12/15/2009

    Someone name the products that use AC power in a modern home…
    1. Fridge (motor)
    2. Freezer (motor)
    3. ummm…
    Whats (pun intended) the wastage globally of conversion to AC power for local sources.
    AC power is used to transfer energy over long distance AT HIGH voltage. How much energy is wasted converting your DV micro voltage into Grid AC power? Get a battery. If that doesnt help.. ask a neighbour if he wants one. wooo personal

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  4. 4. lakota2012 6:03 pm 12/15/2009

    lamorpa:
    "Should I apologize for not blindly believing that PV is a pure green savior?"
    ————-

    Nah….but you look foolish ranting against solar hot water, PV and even 50-year roofing material, since they all work great.

    There is no single "savior" for our future, since it is a combination of many different technologies and ideas for our solution to solve our energy problem, and those that have a need to fight every one of them like you, just show their political color and do not help in solving our many problems.

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  5. 5. lakota2012 6:15 pm 12/15/2009

    lamorpa:
    "I brought up the net energy issue to start debate. At this point, I do believe PVs are net producers…"
    —————-

    Of course they are, and they last much longer than you first wrongly stated, just because you hate RENEWABLE ENERGY.

    Starting a debate with LIES and absolutely no facts like you did, only puts that foot further into your mouth!

    Nobody said anything about ZERO maintenance, but neither is any other system of producing power — I just said the source is clean, green and free, and produces no emissions!

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  6. 6. lakota2012 6:25 pm 12/15/2009

    lamorpa:
    "Seriously. You live off the grid and deal with all the issues of personal energy production and responsibility. Good for you. No one can fault you or tell you about ‘correct’ and ‘incorrect’ energy use (I mean it). You live it."
    ——————

    Thank you, and if anyone knows about energy consumption, it would be people like me producing all their own power, and knowing what energy efficiency actually is and exactly how much power every device in my home draws.

    As far as maintaining any home or property, adding renewable energy just adds equity and shouldn’t be referred to as "toy PV installations," since there are no moving parts and should last for decades with little or no mainenance!

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  7. 7. lakota2012 7:14 pm 12/15/2009

    lamorpa:
    "The waste put into the big chromed ‘hybrid’ plaques on all sides of it alone will offset any gas savings the hybrid drive will produce."
    ————–

    I sincerely doubt it very much, and just proves my point, that some of us are DOERS and some like you are COMPLAINERS.

    Whether you want to admit it or not, thrift was once an American virtue and will, of necessity, be so again. Our contemporary civilization was designed around $10-a-barrel OIL, but that’s long gone. Higher gasoline price, courtesy of a coming collapse in Mexican petroleum exports due to a crashing Cantarell and booming car markets in Asia, will further reduce U.S. OIL imports and kick-start hybrid-electric and all-electric vehicles. In years to come, U.S. motorists who pull into a service station will be bidding against millions of first-time drivers in "Chindia." Our 25% use of the total daily worldwide production of OIL has been slowly eroding since 2007, although our 3% of the worldwide OIL reserves has not increased!

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  8. 8. rockjohny 9:17 pm 12/15/2009

    I would be concerned that laying those panels right on the roof would prevent the shingles from drying out after rain or heavy dew. Just having tree branches close to a roof keeps wind flow and the sun from drying out the roof and the underlayment will rot even though the shingles look fine. You have to have free air flow to prevent a roof from rotting.

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  9. 9. Michael Hanlon 10:19 pm 12/15/2009

    This debate has gone beyond the issues and is on the verge of ICBM launching. Please, everybody back down a bit. Thank you.
    One side seems to want any form of Solar at whatever the cost while the other side is saying there is a cost and don’t let it get out of hand. And, there are people who jump on the band wagon. I tried to point out an article or two ago that some people who become producers end their participation in conservation (Check Mr. Cronshaw and his bill. He went from a pre panel consumption of 10 KW/day to post panel consumption of 17 KW/day. That is close to the issue that lampora airs. And there historically has been a messiah attitude to those who actively practice green. Admit it and we can move on.
    This article, so well researched and presented to us by Mr. Musser, is about the difference between series and parallel problems of panel incorporation into either a stand alone or grid connected system. Can we perchance get to some idea of a consensus on that topic?
    Okay, I’ll weigh in first. My electronics background reminds me that there is a compromise method of redundancy in connection with power supplies. That is, a series/parallel configuration. It gives the benefit of both while eliminating the failings of both. Win-win.

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  10. 10. ormondotvos 11:34 pm 12/15/2009

    Iamorpa, you are a genius at presenting good ideas in such a fashion as to totally repel the reader. Yes, negawatts are the best, and grid connections are a good thing for emergencies, and we should all get serious about global warming and kiss our kids more. What’s the point of saying it so violently? You think it improves reception? I’m angry and frustrated at the inability of humans to adapt to their niche as fast as they change it, but one of the biggest problems is how poorly the leading thinkers about it communicate it to the poor schmucks who are told by their exploiters to spend their way out of recessions and make the economy hum again. Maybe the economy is humming "It’s all over now, Baby Blue."

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  11. 11. quist9 11:56 am 12/16/2009

    The article promoted interconnecting (paralleling) several of these panels. But there was no mention of how to get the phase of the individual AC panel outputs matched. Does somebody know something I don’t?

    Link to this
  12. 12. lamorpa 11:59 am 12/16/2009

    I’ve never been against solar generation (or 50-year roofing for that matter). I never said I was. I am against gratuitous consumption by uncommitted, uninformed people. In the wrong hands/applications, when used for short periods and cast aside, these technologies have the potential to be a greater waste than just consuming current methods.

    Again, when someone cannot make a commitment to lower their consumption next month, why supply them with big environmentally loading equipment (it’s manufacture) to play with and waste with a few short years.

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  13. 13. lamorpa 2:44 pm 12/16/2009

    @lakota2012:
    "some of us are DOERS and some like you are COMPLAINERS."

    Again your anger. The viciousness with which you attack any information about renewable energy that is not purely positive invalidates anything you say. I am sorry if there are some cons along with the pros for renewable energy. I sincerely doubt you will improve the technology through hatred of those bringing up these issues.

    What is funny is that you espouse precisely what one of the problems is: doers (I don’t have to shout it), in the case of blind trend followers, is another word for ‘gratuitous consumers’ (like the people who think they are saving the environment by recycling all of their single use containers and tin foil).

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  14. 14. Michael Hanlon 2:00 am 12/17/2009

    One way to possibly "synchronize" the phase outputs of individual mini-inverters is to put a bell in the systsem. If ringing is introduced to the (excuse me for stealing this term from computerdom) Local Area Network, it is quite possible that the output transformers will get in beat with each other. This happens with broadcast sine waves (Take a radio station frequency and set a local generator to that frequency and the two will beat, cancelling the radio signal). Of course this is another component that could add to the ‘mean time to failure’ figure. But we won’t know until someone tries. And then the local signal needs to be blocked from influencing neighbors bells.

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  15. 15. gmusser 11:16 am 12/17/2009

    Microinverters, like whole-array inverters, lock to the AC phase of the grid current.

    Link to this
  16. 16. Michael Hanlon 7:35 pm 12/17/2009

    Well, might not the system be off grid at times? How then to synchronize? The ringing should work. One more definite way is to tie all the output transformers cores together. That way the energy passes from inverter side to the output side as if all the transformers were expanding and collapsing fields around the same core hunk of iron. ONLY in-phase signals can pass that barrier. Yup, common cored output transformers on all the mini- or micro- inverters Please don’t introduce trade names or pet nomenclactures used by individual manufacturers into the discussion. Thank you..

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  17. 17. Michael Hanlon 7:52 pm 12/17/2009

    Back to a small issue mentioned in the article about needing to array the panels in sreies. I understand that as they are, a parallel connection could cause high output from one in the sun to feed against the lower current coming from one in the shade. If a simple Varactor or current limiting diode (which by definition is current directional) was in the output circuits, that problem goes away. Batteries also act in a crude, unreliable manner of current directing too. When incorporated with the diode devices, they definitely work to direct flow (they sometimes are depicted as modified capacitors in some circuits). Then an array of series parallel can be established. And then they can feed Inverters which have been configured in parallel.

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  18. 18. jnrowell 9:51 pm 12/17/2009

    Each microinverter can sense the line voltage and keep in step. The power from the solar array can be disconnected at the breaker panel.

    Link to this
  19. 19. jnrowell 9:53 pm 12/17/2009

    These panels aren’t intended for battery based systems – they’re designed for net metering, where any excess power is sent back to the grid and is credited to them by running the meter backwards. The grid acts as a battery so there is no battery.

    Link to this
  20. 20. Michael Hanlon 4:06 am 12/18/2009

    Yes, they only work to produce for the POCOs. In the event of a power failure, say mid summer brown out or winter ice-downed lines, even though you spent $10,000 on power generators, you’re shit out of luck ’cause they’ll shut down if the grid is down. If I had to sit shivering in the dark because the POCOs wanted complete control of all electrons. I’d be pretty pissed off.
    Better if the system installed is diversified, giving some to the POCOs to earn some income and the rest to supply your own needs.. That way many of your energy requiring home activities can stand alone lights, entertainment, PCs, etc. and during the brown times, only need you worry about your motor using appliances i.e., fridge, A/C, Furnace, Range and water heater…
    So, you see, I’m not condemning your approach, I’m trying to paint a broader, more inclusive and hopefully, a more successful way to enjoy modern technologies.

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  21. 21. bertwindon 1:29 pm 12/18/2009

    Yes, I have pondered the point that you – I hope – overstate here. Just how many kW-hrs does a "pv panel" need to supply to enable us to make the next ?. I know only "Wind" facts for sure, in this respect.
    Viz
    The cost of facing any given area of wind is a necklace-shaped function of (log) Size of the "TADs" deployed, because Turbines and Alternators exhibit opposite "economy of Size". There are a couple of other reasons which account for why current (80m high) "technology" returns only about 1/50 of the percentage of its cost, annually, as can be obtained from very well designed TAD of about the size where the T costs about the same as the A, i.e. about 1 metre diameter. Just under this a gearbox is no longer required.
    I continue to point this out to all and sundry – including Lord Hunt, who, it appears, is about to advocate another "Drop" of several hundred million GBP -worth of CO2 into the oceans – quite literally. Well, the North, and Irish sea, but let’s not split-hairs at a a time like this. Also to the "FoE" who prefer to keep their blinkers on it seems. I guess it just doesn’t fit in well with their adgenda either. Who needs arithmetic anyway – apart from chancellors and weathermen, of course !

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  22. 22. auhunter04 4:45 pm 12/18/2009

    I have been trying to learn about practical solar power generation off and on for years. I learned more from this single small article that from all the reading pondering and head scratching I have ever done.
    Where can I find book(s) on the practical realife requirements of solar panel instillation and use for home and small industrial settings? This is an off the grid (way off) location
    can someone guide me please. There is so much DIY stuff out there is that is basically useless that I have practically given up. For example this article gives the reality that panels are like old fashiioned christmas tree lights, if one dont work they all dont work. After it was said ya duh, but where can I learn these little things. help please
    Butch
    auhunter04@yahoo.com

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  23. 23. auhunter04 4:51 pm 12/18/2009

    I find the german reference highly interesting, leades me to think my off the grid small mine using solar supplimental power is not as unreasonable as I thought. Thank you

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  24. 24. auhunter04 4:58 pm 12/18/2009

    watch for falling lampora B.S. it could splatter all over your systems and cause a fire by shorting things out ( Bull____ burns)

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  25. 25. Professor Ferret 7:30 pm 12/20/2009

    Hello …..With individual inverters, you would have to have zero-cross switching and phase synchronization circuits for each inverter. Not only would this be a costly method to pump power backwards into the grid but also inefficient. Way back in the 50′s this guy invented a thing called a diode. It dissipates very little heat and works great for balancing varied outputs. The DC can be paralleled and then fed to an inverter. From the inverter the power can enter a zero-cross switch and capacitor bank for phase synchronization. As far as the chemicals go read the recent news on the CGIS solar cells, which are 99% recyclable, and have a life expectancy of about 15 years at 90% design output.

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  26. 26. Professor Ferret 7:30 pm 12/20/2009

    Hello …..With individual inverters, you would have to have zero-cross switching and phase synchronization circuits for each inverter. Not only would this be a costly method to pump power backwards into the grid but also inefficient. Way back in the 50′s this guy invented a thing called a diode. It dissipates very little heat and works great for balancing varied outputs. The DC can be paralleled and then fed to an inverter. From the inverter the power can enter a zero-cross switch and capacitor bank for phase synchronization. As far as the chemicals go read the recent news on the CGIS solar cells, which are 90% recyclable, and have a life expectancy of about 15 years at 90% design output.

    Link to this
  27. 27. Michael Hanlon 10:43 pm 12/20/2009

    CLARIFICATION:
    The rectification properties of certain chemical crystals was discovered in 1873 by Guthrie (Check wikipedia entry at "diodes"). The vacuum tube diode was in wide labratory use by the start of the 20th century. It was through the use of a diode to investigate some quantum phenomenna that the CRT was developed in the 30′s. To say ‘Some guy invented diodes in the 50′s could be considered either 3/4 of a century or half a century in error. I just hate it when people think electronics began with the invention of the transistor at Bell Labs in the 50′s. (See the first article in this series for that one)

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  28. 28. FCPHIL 12:27 pm 12/22/2009

    Your article does not get into panel orientation, Effect on present roofing materials. How to sell power generated to the Power Sompany. A more complete analysis of cost and payback. How other have approached the local estetic regulations. Just for starters.

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  29. 29. calmlyuselogic 11:29 pm 12/22/2009

    Interesting discussion regarding some of the issues even thoughw e could have spared some energy and time in repetitive no constructive arguments.

    I have been struggling with the idea to install or not. Here is why:

    I am looking at two aspects:

    1. Return on energy: I think it is important that we consider the total energy balance sheet over the lifetime of the panels. Otherwise we commit the same idiocy as we have started with Bio Ethanol. There must be some numbers for modern 200 watt panels which retail for about $ 650 in terms of energy balance and waste materials produced. Who has that data for individual technologies and manufacturers? In CT we calculate an average of 4 hours of sun per day – at a generation charge of about 10 cents per Kwh. Therefore in pure cost the panel has to return 6500 Kwh to cover its cost or run for approx 8125 days = 22.25 years. Lets make an assumption (totally uninformed I admit) that about half of the cost is attributed to energy consumption from raw material to finished panel (mining, transport, manufacturing, administration etc.) – this is still more than 10+ years for energy return. Does not sound environmentally sound to me – can someopne who really knows answer the question?

    2. The policdy side of the wholde proposal. In CT you only get a subsidy (which in the end has no impact on the environmental impact and balance) if the system is installed by a state approved installer (nice racket – installers, lobbying well done!) however I can install for the same price as the the professional install less subsidy. not taking the tax money seems to make sense. Does anyone have any experience with circumventing the system and still getting approval and subsidy after proving how many PV’s you have put back into the system (that should be the ultimate criteria – no?) I hope one of our honorable state legislators reads this. It still may make sense to have a renewable source regardless of the cost longterm. But only after having answered question one – because if the energy balance is not very positive (or help us negative) we should avoid subsidizing it in the first place.

    On solar hot water systems – I find more agreement here about the efficiency and the maintenance of such systems all depends on the layout and the components and materials used.

    I also believe that when it comes to energy considerations in residential applications the gold is found in heating and cooling –> geothermal -(which could make good use of electrons)

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  30. 30. Tree 2:16 am 12/23/2009

    I dont know whether the production electrical power pollutes our air or not, this system finds its place in market in the near future

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  31. 31. Michael Hanlon 11:58 am 12/23/2009

    To calmlyuselogic:
    kindlyusemath: 6500 KWhr payback divided by 4 hr/day = 1625 days not 8,000+ days! 1625 days = 4.5 yrs.
    And, isn’t your statement of using 4 hrs a little bit of a mis-statement? Surely that figure applies to peak production and a curve tail dropoff to either side (AM & PM) gives you more juice per day than, well just how much are you figuring, just the single 200W panel you mentioned?
    This all points to a lack of standards in this industry. Type of panel, nonstandard. Amount of electrons moved, nonstandard, nomenclature for amount of electrons moved, nonstandard. Base production period, nonstandard.methods of deployment, nonstandard.connection to grid, nonstandard, agreement with POCO, nonstandard, involvement of governments, nonstandardmethods of determining ‘payback’, nonstandard, methods of determining manufacturing cost versus payback costs, nonstandard. Isn’t that enough to send the IEEE to sit , conference and establish those standards?
    Merry Christmas.

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  32. 32. lakota2012 3:13 pm 12/23/2009

    calmlyuselogic:
    "Lets make an assumption (totally uninformed I admit) that about half of the cost is attributed to energy consumption from raw material to finished panel (mining, transport, manufacturing, administration etc.) – this is still more than 10+ years for energy return."
    —————–

    Instead of trying to ass-u-me or guess the EROI of PV, why not read the NREL’s energy payback for PV publication? Several researchers are mentioned, and the general consensus was between 2 to 4 years in 2004, and 1 to 2 years by 2014. Most recent estimates I’ve see about thin-film PV modules, projects a cost of only $1/watt and a payback of only one year very soon.

    PV FAQs: What is the Energy Payback for PV?
    “energy payback” captures this idea. How long does a PV system have …
    http://www.nrel.gov/docs/fy05osti/37322.pdf

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  33. 33. lakota2012 3:37 pm 12/23/2009

    calmlyuselogic:
    "because if the energy balance is not very positive (or help us negative) we should avoid subsidizing it in the first place."
    ———————

    With conventional PV manufacturers, the net energy return for PV systems is between 6 and 15 times the energy required to manufacture them, and even more in the not to distant future with thin-film PV.

    Using renewable energy sources in manufacturing and transportation would further drop carbon emissions. BP Solar owns two factories built by Solarex (one in Maryland, the other in Virginia) in which all of the energy used to manufacture solar panels is produced by solar panels. My personal BP-150′s came from the Maryland facility.

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  34. 34. calmlyuselogic 8:17 pm 12/23/2009

    To Michael: Lets kindly use math: if you have a 200 watt panel and the sun is active for an average of 4 hours a day you generate 0.8kwh per day – Thus dividing 6500 by 0.8 gives you 8125. Am I missing something here?

    The 4 hours of sun as an average are used by the state and the installers to calculate the output of your system. A friend of mine put a large 40kw system on the roof of his factory nearby and the results so far (active since May) seem to verify this factor pretty well. We are certainly not more than 20% off either way.

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  35. 35. calmlyuselogic 8:29 pm 12/23/2009

    To Lakota:

    Liked your second take better – this is not about money – it is about return on energy. So you say currently this return is 6-15 times and the fact that Solarex uses all PV energy to make PV panels is a good indicator. However – I am not totally satisfied by this answer. And believe me – I want this to work (but – it must make sense)

    The reason I do not feel satisfactorily informed is that I do not know the manufacturing depth of the Solarex plants. If it is strictly assembly your statement actually would reflect on poor energy efficiency by Solarex. If they produce everything from raw materials it would be much better. This still would not nclude the mining of the raw materials and the transportation.

    What I am saying here is this: we seem to be pretty emotional about this solution instead of looking at its real efficiencies and the development necessary to make it environmentally sound to distribute to the masses. If thin film PV’s reduce manufacturing energy input great, especially if it is a proportional gain relative to the longevity of those panels – speaking they last as long as the conventional ones. My current number is 20 to 25 years from what manufacturers have told me.

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  36. 36. lakota2012 10:07 am 12/24/2009

    calmlyuselogic:
    "To Michael: Lets kindly use math: if you have a 200 watt panel and the sun is active for an average of 4 hours a day you generate 0.8kwh per day"
    ————————–

    Ah….but that’s in a perfect world, so I’d be willing to go along with the plus/minus 20%. Actually, as the panels heat-up (even in winter) due to their dark color, they produce less. High clouds will reduce output some, and fully cloudy days will sometimes produce up to 25-50% of the rated output. The other day while it was snowing here, I was producing a "whopping" 100 watts from an 1,800 watt array.

    My 24 vdc panels are rated at 150 watts, and I’ve seen up to 160 watts out of them mainly due to my FlexMax80 MPPT controller, but for the 4 hours you talk about, it’s probably closer to 100-120 watts average. That correlates to about 0.5 KwH each per day, for about 6+ KwH for the array on a good solar day. I’d be willing to bet those hypothetical 200 watt (MAX) panels would be closer to about 0.65 KwH per day in the real world.

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  37. 37. lakota2012 10:48 am 12/24/2009

    calmlyuselogic:
    "If thin film PV’s reduce manufacturing energy input great, especially if it is a proportional gain relative to the longevity of those panels – speaking they last as long as the conventional ones. My current number is 20 to 25 years from what manufacturers have told me."
    ———————-

    Without a doubt, thin-film PV will definitely cut manufacturing costs quite considerably since they are frameless and use very little semiconductor material. The major energy costs for maufacturing are the substrate on which the thin films are deposited, the film-deposition process, and facility operation. It has been estimated to take 120 KwH/m2 to make near-future, frameless, amorphous-silicon PV modules.

    Now, nobody knows the lifespan or durability of thin-film PV since it is so new, but I’ve seen typical PV panels from a desert test facility after 25 years, and 10 years down the road are still putting out 95% of their rated power. This leads me to believe that typical multicrystalline PV panels, guaranteed for 25 years from the manufacturer, will probably last in excess of 50 years with little deterioration of output.

    http://www.solarbuzz.com/solarindex/cellmanufacturers.htm

    Solar Energy Industry Solar Photovoltaic PV Cell ManufacturersWorld wide listing of solar cell manufacturers. …. BP Solar, 630 Solarex Court Frederick, Maryland 21703, USA, Tel: 1 301 698 4200. Fax: 1 410 981 0278 …. E Mail: contact@solar-cells.net, Amorphous silicon thin film …

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  38. 38. calmlyuselogic 5:23 pm 12/24/2009

    To Lakota: Is it a good assumption that 1 square meter thin film PV puts out about 200 w max?

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  39. 39. Michael Hanlon 2:45 am 12/25/2009

    Yes there was something missing not in your response but in your first run through. It isn’t until your respnse that we find the figure you used::: 0.8KW/day.
    My main point you don’t comment on? The need for standardization both in manufacturing and use but also terminology-wise?

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  40. 40. calmlyuselogic 8:12 pm 12/26/2009

    Michael: What about a 200 Watt panel for $ 650 and an average of 4 sun hours per day was there not to understand?

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  41. 41. Michael Hanlon 5:25 am 12/28/2009

    Well, you fit in a $0.10 /KW to confuse things. Look, I agree with your math now that a little more conversation has transpired.
    So,
    Again,
    What of the more important issue I raised regarding the need for standards?
    Happy New Year and I hope this one brings you resolution to your questions of whether to invest at this time.
    My only hinderance to a yes response would be if finances prevented it. In other words, if you have the greens go green. No second thoughts allowed.

    Link to this
  42. 42. Michael Hanlon 1:58 am 12/29/2009

    Let me ask:
    Who in their right minds out there believes that the payback time for a solar electric generator is 22.5 years?

    Link to this
  43. 43. NewEnergyPortal 4:31 am 02/17/2010

    I agree

    Link to this
  44. 44. quoc52lieu 4:39 pm 03/28/2010

    Hi, I have a few questions, based on several of your articles.

    The batteries and grid-system shows a controller comes before the inverter. With the built-in microinverter system, are there controller and batteries that can be installed after the inverter?

    Are there a solar power system that combine the PV and water heating?

    Thank you.

    Link to this
  45. 45. online solar training 8:34 pm 03/31/2010

    Any word of when Lowe’s will start selling solar panels?

    Link to this
  46. 46. online solar training 8:35 pm 03/31/2010

    Any word when Lowes will sell solar panels?

    Link to this
  47. 47. Edward Davis 1:33 am 05/12/2010

    Having home solar panels installed your home can give you a lot of benefits. First, you can really save a lot of money. Since the energy from the sun is free, you will only spend for the device and installation. Second, it has low or no maintenance fee. Because it is a stand-alone device you can just leave it as it is. Third, it can give you electric independence. No need to tie-up with your utility company to give you electricity because the panels produce the energy you need. Lastly, it is environment-friendly. It doesnt have any emissions plus it reduces the harmful greenhouse gasses as well.

    Link to this
  48. 48. diysolarpv 3:55 pm 08/22/2010

    In my humble opinion, homeowners will be slow to buy panels that can’t be upgraded as new technology comes along…thereby increasing their efficiency. Are the built-in inverters serviceable? Can they be easily replaced? I doubt it, but you’re our main man in the field.

    Link to this
  49. 49. diysolarpv 3:57 pm 08/22/2010

    It reads right to me, but then I fix the dang things.

    Link to this
  50. 50. diysolarpv 4:38 pm 08/22/2010

    The same could be said for computers 20 years ago. But I guess "when it’s raining in GA, it’s raining all over the world."

    Link to this

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