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SunPower vs LG Quotes in North California

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  • #16
    Originally posted by J.P.M. View Post

    Since you seem to be asking:

    What makes you think Sunpower is worth any premium in the first place ? They are, in the opinion of many informed folks, no better and no more fit for purpose than other quality panels, and less so given the premium paid for Sunpower for no real benefit.

    Inverters are usually sized to the array. Learn that some clipping is probably acceptable from an economic standpoint, but oversizing an array relative to annual electrical load is not and usually hurts the economics.

    Your $$/your choice, but know that there's more than a small chance, depending on assumptions/guesses about the future used, that a less than 100 % offset of annual load will be more long term cost effective than a 100% or greater offset. In spite of what solar peddlers and the green media will imply as a given and done deal (those sneaky devils), more PV generation capacity is not necessarily better from a long term economic standpoint.

    On what you call overengineering: That's more like oversizing or building for excess generating capacity, not overengineering. Your money to spend, but if you're as concerned about cost effectiveness as you seem to write, why so much oversize ? Learn how your POCO rates are affected by usage (or lack of it via conservation) and something called LCOE or other life cycle costing method. Then learn how to optimize an array size for best (lowest) long term cost. Then find a system size and price/STC watt that minimizes that LCOE to meet the goal of supplying your long term electrical loads as you see fit.
    So you say that paying a little bit to the POCO for the extra power I need is much more cost effective than overbuilding and adding more panels. Our usage is probably just under 10kW but with a growing family that usage will increase as well. The cost of meeting that need more of the time is clipping mid-day. What can I say it's Massachusetts - we live on that green media (but don't discount the health benefits of positive thinking and feeling good about what you're doing and the choices you make!)

    re: Sunpower being the best - the installer showed me the panels and "explained" that they have better tech (something about connections, heat and front vs back of the panel) and he has Sunpower on his roof. I suppose the good ones are all about the same and indeed, I am skeptical of the degradation rates they quote. Comes down to money and the difference in cost isn't huge. As long as the system works and I can break even in year 5 I'll be happy.

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    • #17
      Originally posted by ay79 View Post

      So you say that paying a little bit to the POCO for the extra power I need is much more cost effective than overbuilding and adding more panels. Our usage is probably just under 10kW but with a growing family that usage will increase as well. The cost of meeting that need more of the time is clipping mid-day. What can I say it's Massachusetts - we live on that green media (but don't discount the health benefits of positive thinking and feeling good about what you're doing and the choices you make!)

      re: Sunpower being the best - the installer showed me the panels and "explained" that they have better tech (something about connections, heat and front vs back of the panel) and he has Sunpower on his roof. I suppose the good ones are all about the same and indeed, I am skeptical of the degradation rates they quote. Comes down to money and the difference in cost isn't huge. As long as the system works and I can break even in year 5 I'll be happy.
      No, that's not what I'm writing. I'm writing that the most cost effective way to meet long term electrical energy needs is not usually replacing 100% of annual residential electrical usage with PV, and the way to find out is to start by not assuming, or knee jerking because you've got a woody for the POCO, or get B.S.ed into it by some peddler who makes money putting PV on your property and not providing you with the most cost effective way to meet your long term electrical needs, that a 100+% offset makes the best sense. What I am writing is that if you're after the most long term cost effectiveness, it ain't that simple - not terribly more involved, but more than throwing simplistic and lazy thinking illogic at the situation.

      FWIW, the most long term cost effective way of supplying electrical needs to a residence is usually a mix of use reduction, conservation improvements, conventional POCO power, and finally alternate energy generation - and probably in something of that order in proportions that result in the lowest long term life cycle cost of supplying a current and future anticipated electrical load.

      As you wish on oversizing. NOMB. While I believe the way I've learned and studied such things makes flexible sense, it's probably more involved than most folks want to spend time on.

      As for your installer explaining things and perhaps hoping you'll infer that he'll be more believable or honest because he has a Sunpower system on his roof and thus perhaps a valid reason for you to perhaps believe him: I too have a Sunpower system on my roof. By my criteria, it's not cost effective for me but that's not why I have it.

      Nor do I have Sunpower because the quality is better - it is not, at least not for the premium paid. It's good quality, but no better or more fit for purpose than other equipment that's less expensive. Why I have Sunpower is a long, boring story and explained here in prior posts, but unrelated to (non)cost effectiveness.

      Opinions vary, and mine is but one. But, unlike your potential installer, I've got no skin in the game, and only more opinion or conjecture, I suspect I may have a working knowledge about some things related to alternate energy cost effectiveness (or, perhaps more correctly, the lack of cost effectiveness) than your potential installer may be aware of.

      Take what you want of the above. Scrap the rest.
      Last edited by J.P.M.; 11-01-2018, 09:02 PM. Reason: Spelling

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      • #18
        Originally posted by ay79 View Post
        So you say that paying a little bit to the POCO for the extra power I need is much more cost effective than overbuilding and adding more panels.
        Do the math and see if it is.

        If you are on a tiered rate, the first kwhrs you generate are worth a lot more than those extra kwhrs you generate. So your first (say) 6kW may do a lot to reduce your bill - the next 4kW not so much.

        Our usage is probably just under 10kW but with a growing family that usage will increase as well.
        That's a good thing to consider. If you determine your "ideal" power is 6kW, for example, you might want to increase that by some amount (say, 25%) to allow for growth. Future purchase of an EV may also affect that.

        re: Sunpower being the best - the installer showed me the panels and "explained" that they have better tech (something about connections, heat and front vs back of the panel) and he has Sunpower on his roof. I suppose the good ones are all about the same and indeed, I am skeptical of the degradation rates they quote. Comes down to money and the difference in cost isn't huge. As long as the system works and I can break even in year 5 I'll be happy.
        Sunpower makes good panels. But so do other manufacturers. Compare the panels on specs, not on salemanship. He may be referring to temperature coefficient, which gives you less power loss when it's hot. Fortunately that's readily available in the specs.

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