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  • Paradigm shift needed in how we view solar panel cost vs performance?

    As you can tell by my post count I'm clearly a solar subject matter expert (NOT lol)!

    I have been doing quite a bit of research and to make a long story short the subject scenario is what I really do want the "true" subject matter experts to weigh in on! First, here are a couple of quotes from Energysage that are likely irrefutable:

    10 years ago, in 2009, the cost of a solar panel installation was $8.50 per watt. The solar industry today looks very different: in addition to solar panel efficiency increasing dramatically, solar panel producers have significantly improved their manufacturing processes. Solar installers, too, can deploy solar PV across the United States more efficiently now than they could ten years ago. The result: the price of solar has fallen by over 60 percent, to just $3.05/watt.

    The price decreases over the past ten years are a major reason why homeowners are increasingly interested in installing solar panels. For a standard 6 kW home solar system, the average gross cost has fallen from $51,000 to just $18,300 in about the past decade. Subtract the 30 percent federal tax credit for solar, and you're looking at $12,810....

    So let me set the stage one step further...if I told you that today's "premium" top tier high technology cell phone, laptop or UHD TV today came with a 10 to 25 year product/performance warranty are you likely to keep it and use it for 10 to 25 years? Why not? Simple, technology will make it obsolete long before 10-25 years!

    Ok you say...oh but solar panels are different, they can produce for not only the 25 years, there are panels made decades ago that still produce. Of course this is true but at what relative cost then and inefficiency compared to "today's" current products?

    So here is the crux of where I want to hear the pro's vs. the cons.....If TODAY I buy a ~30Kw solar system with "good" (e.g. REC/Peimar) but not top tier performance panels (LG/Panasonic/Sunpower) that can be had at close to half the price (e.g. REC N-Peak REC320NP 320w Mono Solar Panel for ~$176/panel vs Panasonic VBHN330SA16 330w Mono Solar Panel @ ~$342/panel) the "today's" cost of just panel's is about $15,488 vs. $30,096, close to a $15K price difference!!! For discussion purposes let's assume that the rest of the system is top notch by using the best inverter's available today, etc. And by the way, my estimated annual energy consumption is in the 75Kw range so even with a rated 30Kw system I will only be supplying about 2/3 of my requirements. I live in the Phoenix AZ area and yes I realize that I should be very focused on Panel temperature performance based on my location, hence my point for this whole discussion!

    Set aside issues like inflation, current tax incentives, etc. to keep the analysis simple for a minute because one thing we all can agree on is that the relative cost/watt of ALL solar panels will continue to decrease over time.....so am I money ahead just flat out banking the ~ $15K price difference today and in 10-12 years when we see another "significant" step function change in panel cost reduction AND more importantly performance increases..... just flat replace today's "good" panels with "good" new future panels because I absolutely positively guarantee that a relative "good" panel in a decade will make todays "premium" panels look totally inefficient compared to what WILL be available then and enjoy the savings of a "good" system today and a killer system (relative to today) in 10-12 years rather than one which will clearly be mediocre by future standards that just continues to deteriorate and can't perform relative to what will be available?

  • #2
    There is no "super panel" lurking in the sidelines. There are cheap panels that need acres to harvest, but you likely won't have enough roof.

    My feeling is the tax benefits are going away, and as mfg's fall out of the market, the remaining panels will start to increase in price over then next few years.
    Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister

    Comment


    • #3
      Assuming reputable companies with quality product, highly efficient panels versus less efficient panel have mainly four benefits.


      A better number of Watts per square feet:
      • This is mostly valuable to you if you have limited space for the array, If you have enough unshaded space to reach your array power with panels that have a lower W/sqft, it is irrelevant
      • A marginal benefit is also that less panels require less labor and rack mount. You can compute the saving in labor and rack and see if it is larger than the saving in panel cost.
      They usually have a better production warranty overtime.
      For example, a 280W Mitsubishi panel will have an 80% performance warranty at 25 years, versus a 90% warranty for a Panasonic panel
      By running your Return On Investment calculations, you can decide if the savings down the line are worth the expense upfront.

      They usually have a better temperature coefficient.
      This is mostly valuable if you live in a place with extreme temperature.

      They often have a longer product workmanship warranty like 10 years versus 25 years
      Depending on the panel price difference that can be a wash. If you pay $190 for a panel that has 10 year warranty versus $350 for a panel with 25 years, you can afford to replace 84% of the cheap panels over the 25 year period for the same price. And probably even more as the $/W will keep going down.

      So the reality is that in many cases, going for highly efficient panel is not necessary, and offers marginal benefits.
      But the actual benefit depends on your particular situation.
      Last edited by scrambler; 04-01-2019, 08:20 PM.

      Comment


      • #4
        Originally posted by Mike90250 View Post
        There is no "super panel" lurking in the sidelines. There are cheap panels that need acres to harvest, but you likely won't have enough roof.

        My feeling is the tax benefits are going away, and as mfg's fall out of the market, the remaining panels will start to increase in price over then next few years.
        Thanks for the reply and I should have qualified...I am going ground mount...I have 3 acres!

        Comment


        • #5
          Originally posted by Mike90250 View Post
          ...and as mfg's fall out of the market, the remaining panels will start to increase in price over then next few years.
          I respectfully disagree! I do agree that tax incentives are going away so without incentives available, the cost of solar would become prohibitive so if the price doesn't continue to come down....they'll price themselves out of business, plain and simple!

          Comment


          • #6
            Originally posted by Bzzy56 View Post
            .... just flat replace today's "good" panels with "good" new future panels because I absolutely positively guarantee that a relative "good" panel in a decade will make todays "premium" panels look totally inefficient compared to what WILL be available then and enjoy the savings of a "good" system today and a killer system...
            To what end? Do you understand that a properly sized net-metered system gains little from excess production?

            Comment


            • #7
              Originally posted by Bzzy56 View Post

              Thanks for the reply and I should have qualified...I am going ground mount...I have 3 acres!
              Then all I can add is what I saw in Denmark. Mount them high enough so you can hire sheep to keep the grass from growing tall enough to shade the panels. Oh, wait, you are in the desert.LOL
              9 kW solar, 42kWh LFP storage. EV owner since 2012

              Comment


              • #8
                Originally posted by sdold View Post
                To what end? Do you understand that a properly sized net-metered system gains little from excess production?
                sdold, my proposed system size today only covers approximately 2/3 of the projected consumption. My Utility only pays 0.028 cents for any "excess" that I generate and with today's system I am still at a significant shortfall to cover demand so I'm not following you....if I generate in the neighborhood of 50Kw annually today and consume 75Kw annually I still have a significant shortfall and I don't have a fat enough wallet to buy a larger system today.

                Comment


                • #9

                  The quotes you cite are generally accurate or at least in the ballpark, but far from irrefutable.
                  You'll find that residential systems are more commonly priced in terms of $/STC W w/that price including panels, inverters, racking, wiring labor, etc. Also, using panel only prices from online retailers can be misleading unless you're considering DIY. You'll still have a lot of other stuff to buy.

                  Your estimated energy consumption that you quote makes no sense. 75Kw (sic) is a rate of energy use or energy production, not an energy use rate.

                  FWIW, a 30 kW system in Phoenix, with a decent array orientation and min. shading, produce ~ 50,000-55,000 kWh/yr. of electrical energy. It'll probably set you back something like $75K+ or more unless DIY. If DIY, and some diligence, you might get away for maybe $1.25/STC W.

                  If your annual electrical energy usage is (I'm guessing here from the "75Kw" (sic) statement) 75,000 kWh/yr, aa 30 kW system will indeed offset ~ 2/3 of your load.

                  But, at that level of annual energy use, you're a candidate for an energy audit and a very serious energy conservation intervention. You'll save more $$ with conservation than PV, at least initially. Not bragging here, but if your usage is that high, it's more than an order of magnitude higher than mine. I appreciate Phoenix and heat, but damn !

                  I agree that costs will continue to drop, but I'd suggest probably not at the same rate as they've dropped in the last 10-12 years. PV tech., in spite of the marketing hype that's always with us, is at sort of a plateau just now and w/the decline of NEM which will have a large influence on residential PV cost effectiveness, there won't be as much of an increase in demand - another reason prices will drop (some), lower margins will make it hard(er) to pay for the R & D for real advances .

                  The gutting of NEM will be biggest contributor to further PV system price declines. It's called selling to the market. We'll see.

                  As others have commented, don't pay for gold plated panels. Beyond some basic (good) quality level, equal electrical sized systems in the same location (including Phoenix), orientation and duty will produce about the same annual output for about as long as you'll own a system. Don't believe me ? Check out a site called PVOutlet.org. Look for systems near you with similar orientations and shading.

                  If you're worried about high temp. performance rolloff, you'll have fewer problems w/ a ground mount. As for a lower temp. coeff. on the panels, to the extent the above comment about annual output being about the same irrespective of panel is correct, the temp. coeff. of performance doesn't matter as much as you might think. I monitor about a dozen arrays in my HOA and the annual oytput/installed STC kW is about the same for all of them once adjusted for orientation. I think lower temp. coeff. have little effect on annual output.

                  BTW, you'll pay more for a ground mount system (how much ???), but in some opinions (mine included) it'll be worth it. But it'll still be more cost effective to first reduce your usage. You'll save twice. A lower bill and a smaller system for less money to meet the smaller load.

                  Welcome to the neighborhood.

                  Comment


                  • #10
                    Originally posted by Bzzy56 View Post

                    ...... ..
                    I don't have a fat enough wallet to buy a larger system today.
                    Then buy a less expensive system. That way you will get closer to covering your consumption than a more expensive system that is smaller. Simple economics. The alternative is paralysis by analysis. I can say that because I have to fight that temptation most of the time.
                    9 kW solar, 42kWh LFP storage. EV owner since 2012

                    Comment


                    • #11
                      Originally posted by Bzzy56 View Post

                      sdold, my proposed system size today only covers approximately 2/3 of the projected consumption. My Utility only pays 0.028 cents for any "excess" that I generate and with today's system I am still at a significant shortfall to cover demand so I'm not following you....if I generate in the neighborhood of 50Kw annually today and consume 75Kw annually I still have a significant shortfall and I don't have a fat enough wallet to buy a larger system today.
                      If you generate 50MWh and consume 75MWh (note the h is important here) annually then maybe what would work better is to get a less expensive system that generates 45MWh annually, spend the savings on better insulation and other efficiency improvements to reduce your consumption from 75MWh to 60MWh
                      Now you have a difference of 15MWh vs 25MWh
                      put all your savings from year one into a savings account and get yourself a new heat pump changinge your 15MWh shortfall to a 5MWh overage.
                      Last edited by ButchDeal; 04-02-2019, 01:22 PM.
                      OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

                      Comment


                      • #12
                        Thanks for the input guys and yes J.P.M., I dumbed up, it's 75,000 Kw annual consumption, MY BAD!!! And I also realize that the cost of the system is not just panels....even for a DIY the system I am looking at is about $42K before incentives and no labor with the REC panels.

                        And here's the problem on the consumption side that I am working with the Utility to try and narrow down....I am a General Contractor and just built our home and we moved into it in November last year. It is top of the line from an Energy Efficient standpoint....all energy star appliances, ~R-40 spray foam insulation at the roof truss-line, 2x6 walls with foam, Anderson top of the line composite frame Low E SmartSun* Glass with U value of 0.27 and SHGC of 0.22. We're consuming around 3500Kw in the Winter months with no heat or AC going and I haven't added a pool with heat pump yet. I suspect that our two 80 gallon HW tanks with recirculation pump are the big energy pigs because my neighbor had just one of the exact same models and switched his HW to propane fired and reduced his electrical consumption from ~3000Kw/month to ~1200Kw/month so I am having the local Utility come over and run an audit on each breaker to determine what the issue at our home is because we never see below about 3Kw usage per hour 24/7!

                        I also have the ~3700 SF house set up with 3 heat pumps, a 2 ton for the guest suites, a 5 ton for the main part of the house and a 2 ton in the Master Wing where we only cool the Master to 72 at night versus cooling the whole house. These are also the latest generation heat pumps with 2 stage compressors for maximum efficiency!
                        Last edited by Bzzy56; 04-02-2019, 11:41 AM. Reason: Added info

                        Comment


                        • #13
                          Originally posted by Bzzy56 View Post
                          Thanks for the input guys and yes J.P.M., I dumbed up, it's 75,000 Kw annual consumption, MY BAD!!! And I also realize that the cost of the system is not just panels....even for a DIY the system I am looking at is about $42K before incentives and no labor with the REC panels.

                          And here's the problem on the consumption side that I am working with the Utility to try and narrow down....I am a General Contractor and just built our home and we moved into it in November last year. It is top of the line from an Energy Efficient standpoint....all energy star appliances, ~R-40 spray foam insulation at the roof truss-line, 2x6 walls with foam, Anderson top of the line composite frame Low E SmartSun* Glass with U value of 0.27 and SHGC of 0.22. We're consuming around 3500Kw in the Winter months with no heat or AC going and I haven't added a pool with heat pump yet. I suspect that our two 80 gallon HW tanks with recirculation pump are the big energy pigs because my neighbor had just one of the exact same models and switched his HW to propane fired and reduced his electrical consumption from ~3000Kw/month to ~1200Kw/month so I am having the local Utility come over and run an audit on each breaker to determine what the issue at our home is because we never see below about 3Kw usage per hour 24/7!
                          Still your bad. That's 75,000 kilowatt hours per year (75,000 kWh/yr.), not 75,000 kilowatts/year. If you used energy at a rate of 75,000 kW/yr. you would be consuming (75,000 kW * 8,760 hrs./yr.) = 6,562,500,000 kWh/yr. Folks around here may seem to get porky about units but doing so avoids a lot of confusion and mistakes. It's also and often a tell on how (un)knowledgeable a poster is.

                          Also, and not a snide knock, but your very high usage and all the high tech/low use/energy conservation stuff you've got doesn't speak well for the value or the stuff, at least not on the surface of it. Just sayin'.

                          A heat pump (water heater ?) for a pool water heater ? Have you considered getting a motorized cover and supply the heat with solar thermal collectors when the time comes ? You'll go broke doing it with a heat pump, or at least the cost of running it and providing heat to a pool that way will sure be a wake up call.

                          On your DHW recirc, system:

                          1.) For many/most situations, there are more economical ways to heat water than resistance electric. Doing so is akin to cutting butter with a chain saw. For most applications even propane is a better and less expensive alternative. A gal. of propane burned at 70 % eff. will provide ~ the same amount of heat as ~ 18.3 kWh of electricity used at 100% efficiency (electric resistance.) Check prices and run some numbers if you haven't already. A heat pump water heater may be an option, but they have been known to have some glitches/problems and drawbacks, at least at this time.

                          2.) A bigger/biggest energy use consideration you have is that hot water recirculation system. Such systems are energy hogs. I ran some #'s once and as a rough rule of thumb, every 100 ft. of uninsulated 3/4" line running at +60 F above ambient wastes very ~ 0.7kWh/hr. (or gets added to the dwelling and so the A/C load in cooling season, or as an uncontrolled heat gain in heating season such as one exists in Phoenix ) for every hour it runs. I bet that's part of your 3 kWh/hr., maybe quite a bit. So 24 hrs. ~ 15 - 20 kWh., or ~ 500 kWh/month, or ~ 6,000 kWh/yr. per 100 ft. of line. for 24/7 circulation. More rough approx./modifiers.:
                          - Half that loss for a line w/decent or std. line insulation
                          - Multiply for multiple's of 100 ft. of line (how much DHW line do you have both out and back from the tanks ?).
                          - Divide the hrs./day the rcecirc. runs by 24 for partial operation use figures on a daily basis.

                          Some think that's a lot of energy cost for semi instantaneous hot water convenience at the taps. My experience is that most owners of such systems are clueless of the energy use and cost associated with such systems. If they were, my semi-educated guess is there would be a lot fewer such systems around. The few measurements I've done on residences in my HOA seem to bear out the rough calcs. I bet some measurable portion of that 3,500 kWh/month your write of, and also a fair amount of the 3,000 kWh/yr. your neighbor used before changeover to propane (and now a lot of the propane used) is from the DHW recirc. heat load.

                          Comment


                          • #14
                            I played the heat loss vs water usage with my recirc pump, and went with the recirc pump. I know it eats propane, but a replacement tank of water costs 3x delivered, and my limited water is more expensive than propane. Yes, we could collect the ambient water in a jug to water plants with, and we don't want to be moving jugs around .

                            I strongly recommend a series pair of 30 gal gas heaters. Set the first for 90F and the 2nd for 120F Neither gets thermal shock and you still have 2 burners going if you HAVE to fill the hot tub. Circ pump only on the 120 tank. I ran this in my old house for 15 years, really low gas bills too
                            Last edited by Mike90250; 04-02-2019, 11:51 PM.
                            Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                            || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                            || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

                            solar: http://tinyurl.com/LMR-Solar
                            gen: http://tinyurl.com/LMR-Lister

                            Comment


                            • #15
                              Originally posted by J.P.M. View Post

                              Still your bad. That's 75,000 kilowatt hours per year (75,000 kWh/yr.), not 75,000 kilowatts/year. If you used energy at a rate of 75,000 kW/yr. you would be consuming (75,000 kW * 8,760 hrs./yr.) = 6,562,500,000 kWh/yr. Folks around here may seem to get porky about units but doing so avoids a lot of confusion and mistakes. It's also and often a tell on how (un)knowledgeable a poster is.
                              Dang....bitch-slap accepted lol but you'll find that I am a quick study! No more Kw Captain...ONLY Kwh from now on!!!

                              Originally posted by J.P.M. View Post
                              Also, and not a snide knock, but your very high usage and all the high tech/low use/energy conservation stuff you've got doesn't speak well for the value or the stuff, at least not on the surface of it. Just sayin'.
                              I tend to disagree a bit here and again, this is why I intuitively without facts and data have suspected the DWH recirculation system as a chief contributor (until I see what you have now provided, THANKS!) rather than thinking that the energy conservation isn't of a decent quality or working......this Winter we recorded outside our windows a record low of 23F early in the AM so needless to say we've had a bit of an unseasonably cold AZ Winter. For that fact, the Estrella Mountains which are next to us even received a generous amount of snow during one week! This is nearly unheard of for decades around here but my point for bringing this up is our house temperature never got below 70 degrees ALL Winter long. I have our garage, MH stall and 40x40 shop insulated as well and these area's never dipped below the low 60's all Winter so I think there is some good here.

                              Nonetheless, to specifically answer your comments regarding the DWH recirculation system, I likely have several hundred feet of uninsulated hot water pipe in the attic space that I have planned on insulating after viewing these energy consumption bills. For example, there is one dedicated 3/4" line running specifically from the HW tank to the Jacuzzi tub in the master bath that is 80' long just in the attic space not to mention 80' back to the HW tank! This doesn't account for the other HW lines nor the line going out to my shop or outdoor BBQ.

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