Announcement

Collapse
No announcement yet.

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

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #31
    Originally posted by foo1bar View Post

    It may (or may not) need to be multiplied by 40.
    But it certainly is not because of your 400A main service panel.
    A "400A panel" is like saying how big of a pipe you have - it isn't measuring how much water is flowing through.
    The POCO use the same meter whether you have a 400A panel or a 200A panel or an old 60A panel. And no matter what size panel it's hooked up to if you have a 4kW hot water heater drawing power it should (and will) give the exact same measurement.

    If it were me I'd do something to determine what the right multiplier is - if any. I'd borrow a "kill-a-watt" - your library may have them - the POCO may have them for loaning out. I'd use that to measure something that uses significant power (like a hairdryer, which is often ~1kW) Then I'd check that when I turn on/off the appliance the meter readings go up/down by that amount. (Or determine how much they go up/down by so that I can determine what multiplier is correct)
    Why do you believe that this is not the correct multiplier? I didn't say "because it is a 400 amp panel"....I said "for my" 400 amp panel, BIG difference! When the Tech who installed it says that the meter head is unable to register direct measurement because of the size of the panel and he showed me the device inside the panel that is the multiplier and how it is wired to the meter head. He then whipped out his pocket calculator to show me how to calculate the instant usage readout by multiplying by 40. When he says the multiplier is 40, it's 40....trust me, there is absolutely positively no other answer for FOR THIS panel other than 40 as the multiplier....he's from the Utility Company that installs, tests, maintains and services them, who else would know this better than them???? CASE CLOSED lol!!!Panel.jpg
    Last edited by Bzzy56; 04-05-2019, 12:13 PM. Reason: Added pic

    Comment


    • #32
      Originally posted by foo1bar View Post

      It may (or may not) need to be multiplied by 40.
      But it certainly is not because of your 400A main service panel.
      A "400A panel" is like saying how big of a pipe you have - it isn't measuring how much water is flowing through.
      The POCO use the same meter whether you have a 400A panel or a 200A panel or an old 60A panel. And no matter what size panel it's hooked up to if you have a 4kW hot water heater drawing power it should (and will) give the exact same measurement.

      If it were me I'd do something to determine what the right multiplier is - if any. I'd borrow a "kill-a-watt" - your library may have them - the POCO may have them for loaning out. I'd use that to measure something that uses significant power (like a hairdryer, which is often ~1kW) Then I'd check that when I turn on/off the appliance the meter readings go up/down by that amount. (Or determine how much they go up/down by so that I can determine what multiplier is correct)
      That'll work for 110 V applications, and a $25 kill-a-watt meter ios always a good investment, but I wouldn't use the method for motor type loads tec. that may have a significant P.F. reductions. Also 240 V applications will need another method as there is not a 240 V usable kill-a-watt meter.

      Comment


      • #33
        Originally posted by Bzzy56 View Post
        Why do you believe that this is not the correct multiplier? I didn't say "because it is a 400 amp panel"....I said "for my" 400 amp panel, BIG difference!
        you said: "which needs to be multipled by 40 (for my 400 Amp panel)"

        That is IMO strongly implying that there is a 40x multiplier because it's a 400A panel.

        When he says the multiplier is 40, it's 40....trust me, there is absolutely positively no other answer for FOR THIS panel other than 40 as the multiplier....he's from the Utility Company that installs, tests, maintains and services them, who else would know this better than them???? CASE CLOSED lol!!!
        Maybe it is 40, But if it were me, I would verify it independently myself. (if you saw a 200:5 label on the equipment inside it - I'd say that's verification.)

        Comment


        • #34
          Originally posted by Bzzy56 View Post
          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?
          I sort of agree but I view it all a bit differently!!! When making a choice between the various panels in today's market it is clear that the best value proposition is the lowest cost producer of the most advanced technology, clearly the REC N-Peak family. The next step is choose the most efficient offering to minimize racking/mounting cost. The efficiency of the REC N Peak is right up with the very expensive stuff. The N channel technology degrades over time as slowly as the most expensive despite the warranty differences. The temperature characteristics aren't the very best but you'll get over 95% of the total power out at half the cost. I'm hoping I can get the all black version in a few months.

          Comment


          • #35
            Originally posted by Jerry Liebler View Post
            I sort of agree but I view it all a bit differently!!! When making a choice between the various panels in today's market it is clear that the best value proposition is the lowest cost producer of the most advanced technology, clearly the REC N-Peak family.
            That's not clear to me.

            It looks like those panels are ~$215 for 320W module.
            That's ~$0.67/W

            I see that I can get a Mission Solar MSE305SQ5K (305W) for $168.
            Or a Canadian Solar 300W for $167.

            So I could spend $4300 for 20 of the 320W modules. (6400W)
            Or $4200 for 25 of the 305W modules (7625W)

            IOW - spend a little less - but get 19% more power.
            And that means even if you expect that REC has less degradation over time you're still going to come out ahead.

            Now there may be other good arguments for going with a 320W module - like it works out better for a situation where you have limited footprint.
            But looking at the numbers, I don't agree that REC is clearly the best choice.

            FWIW I looked at >10 different options for my DIY installation. I looked at different efficiency panels - and when I looked I found that my situation I was better off not going with the lowest $/W modules. Limited roof space played into it, as well as rebates.

            Comment


            • #36
              Solaris is selling the REK N-Peak 320W for $185 so $4300 gets you 23 or 7360W.

              Comment


              • #37
                Hello all, just thought I would provide an update on my quest to understand consumption before I buy or those DYING with curiosity like me lol. Knowing that the HW tanks were the culprit for a significant energy consumption courtesy of the recirc pump I placed the recirc pump on a timer May 1st so that it only comes on for 3 hours in the AM and 2 hours at Bedtime (basically the windows that we shower in the AM and my wife washes off her make-up at night) rather than running 24/7 and my base load dropped from an average of around 3Kwh to just about 1Kwh!!! You can see on the graph below how that reflects for the daily usage. Please disregard the erroneous data points 4 days prior to this because I also determined that I had a heating element out in one HW tank, hence the lower overall usage!

                The good news for me now is that even at outdoor temps of 112/113, I am only seeing consumption in the low 100Kwh range (actually 105-110) and with daily temps in the low 100's (100-105) I am only seeing usage in the mid 90-ish Kwh range/day so I will be able to size the system from 30Kw to ~15Kw!!!image_12478.jpg
                Last edited by Bzzy56; 06-21-2019, 07:51 PM.

                Comment


                • #38
                  Originally posted by Bzzy56 View Post
                  Hello all, just thought I would provide an update on my quest to understand consumption before I buy or those DYING with curiosity like me lol. Knowing that the HW tanks were the culprit for a significant energy consumption courtesy of the recirc pump I placed the recirc pump on a timer May 1st so that it only comes on for 3 hours in the AM and 2 hours at Bedtime (basically the windows that we shower in the AM and my wife washes off her make-up at night) rather than running 24/7 and my base load dropped from an average of around 3Kwh to just about 1Kwh!!! You can see on the graph below how that reflects for the daily usage. Please disregard the erroneous data points 4 days prior to this because I also determined that I had a heating element out in one HW tank, hence the lower overall usage!

                  The good news for me now is that even at outdoor temps of 112/113
                  Thank you. as I wrote in the last sentence of my 04/04/19 post, I appreciate word on results. Without agreeing with most of your other points, your experience with the DHW recirculation hog, anecdotal as it may seem or be, agrees with the statements and posts I've been making around here for years with respect to those systems. You want to save more energy, rip the whole damn recirc. system out.
                  Last edited by J.P.M.; 06-21-2019, 04:36 PM.

                  Comment


                  • #39
                    Originally posted by J.P.M. View Post
                    Thank you. as I wrote in the last sentence of my 04/04/19 post, I appreciate word on results. Without agreeing with most of your other points, your experience with the DHW recirculation hog, anecdotal as it may seem or be, agrees with the statements and posts I've been making around here for years with respect to those systems. You want to save more energy, rip the whole damn recirc. system out.
                    You're welcome and thanks again for your insights!

                    Comment


                    • #40
                      I've got my recirculation on a timer, only runs select hours. Water is more precious here than propane, and can't be shuffling jugs of water around waiting for tap to get hot
                      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


                      • #41
                        Originally posted by J.P.M.
                        a $25 kill-a-watt meter ios always a good investment, but I wouldn't use the method for motor type loads tec. that may have a significant P.F. reductions. Also 240 V applications will need another method as there is not a 240 V usable kill-a-watt meter.
                        This is my answer to 240 V energy use. The $20 meter does not show power factor or
                        instantaneous values, but will measure KWH for the biggest wires you can connect.

                        I checked, and the Kill-A-Watt does keep real and reactive power separate. Bruce Roe

                        ENEmeter.png
                        Last edited by bcroe; 06-21-2019, 10:24 PM.

                        Comment


                        • #42
                          Originally posted by bcroe View Post

                          This is my answer to 240 V energy use. The $20 meter does not show power factor or
                          instantaneous values, but will measure KWH for the biggest wires you can connect.

                          I checked, and the Kill-A-Watt does keep real and reactive power separate. Bruce Roe

                          ENEmeter.png
                          Yea, the Whr. meters utilities used, and may still be using are one of the other methods I had in mind. My newer kill-a-watt meters have a P.F. option. The older, but not oldest ones had a V*A option.

                          Comment


                          • #43
                            Originally posted by Mike90250 View Post
                            I've got my recirculation on a timer, only runs select hours. Water is more precious here than propane, and can't be shuffling jugs of water around waiting for tap to get hot
                            That is an important trade off. In California water is a scarce resource. In one home I made the recirc happen by pushing a button which only ran the recirc pump for enough time to get the water hot at the farthest tap, which was the shower.
                            9 kW solar, 42kWh LFP storage. EV owner since 2012

                            Comment


                            • #44
                              Originally posted by Ampster
                              That is an important trade off. In California water is a scarce resource. In one home
                              I made the recirc happen by pushing a button which only ran the recirc pump for enough time to get the
                              water hot at the farthest tap, which was the shower.
                              I think that would be about 10 minutes here, there is a 5W pump and a gauge to read out the temp at
                              both ends. No water shortage, end of my block looks something like this. Bruce Roe

                              IL19Spring.png

                              Comment


                              • #45
                                Have you considered small and/or instant water heaters at the sinks and dump the 2nd water heater and recirc pump? The ambient water temp in AZ should be high enough that instant water heaters should be adequate.

                                Comment

                                Working...
                                X