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New PV System Finally Running

Post in 'The Green Room' started by Vic99, Oct 28, 2012.

  1. Vic99

    Vic99 Minister of Fire

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    Had a 6.375kW system installed on my roof. Twenty five American made Suniva 255W panels with Enphase microinverters. Microinverters allow each panel to operate independently of the others to partly counteract shading.

    I expect shading to increase as winter approaches. I predict this will affect the panels lower on the roof more, but the price jump to put those 3 extra panels was not really significant in the big picture. Almost added another row even lower, but I think that would have crossed the point where it would not really be cost effective, particularly when you look at the long term.

    The system is bigger than I need both because I want to get a plug-in hybrid in the future and because MA pays out SRECs for each MW generated. SREC market is at the floor right now, but it is still cost effective, I think.

    Company was very professional and overall did a great job. There were a few delays and set back, but that is to be expected with such a large, complex project, particularly where multiple permits, rebates and other incentives are involved.

    I expect the break even point to be around 7-8 years.

    Attached Files:

    jharkin, milleo and PapaDave like this.

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  2. begreen

    begreen Mooderator Staff Member

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    Nice going. Keep us posted on how it performs over the seasons and how well the Enphase units stand up.
    PapaDave likes this.
  3. Vic99

    Vic99 Minister of Fire

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    Thanks.

    I failed to mention it is grid-tied. Yesterday and today were overcast, so not much power production yet. Nice to see the meter running backwards at times, though.
    daveswoodhauler likes this.
  4. daveswoodhauler

    daveswoodhauler Minister of Fire

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    Nice system Vic. Neat set up and I will also be curious to see how the micro inverters work with the different pitches on your roof....looks like it will work well in all conditions...some peak output in the summer with the less angled panel on your dormer and good year round output with the steeper pitch arrays.

    I may send you a PM to ask some details and perhaps cost as I am only a little west of you.

    Please keep us posted on how it performs.
  5. Vic99

    Vic99 Minister of Fire

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    We went through several design schemes before settling on the final. My roof pitches are acceptable, but far from ideal. They just about face true south, though, which is perfect. Shade analysis got me at 82% of full sun. The state wants 80%+ to qualify for a rebate.

    Started looking into solar seriously in March. Got 3 companies to come out and take a look. Only went live late Friday.

    PM if you get serious.
  6. macmaine

    macmaine New Member

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    Congrats Vic
    Looks Sweet!!!!!!!!!!
    That is a great accomplishment.
    No moving parts, should last 25-30 years, means you MAKE money after your 7-8 years are up?
    BTW I would suggest Chevy Volt for your EV
    Lease payments now at 199-299 close to 1/2 what I spent on gas on Highlander fill ups_g
  7. peakbagger

    peakbagger Minister of Fire

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    Looks good, plan on buying a roof rake. The enphases help with partial shading caused by snow sliding down and blocking the base of the panel but sometimes the snow is just right where the panels are covered and it can take days for the snow to melt off. A plastic roof rake usually speeds things up quickly to get back in production.

    BTW, most plans figure in inverter replacements every 10 years. As the inverter change so often who know how long newer designs will last.
  8. Vic99

    Vic99 Minister of Fire

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    Thanks all Peak, Enphase warranties the micoinverters for 25 yrs.
  9. Slow1

    Slow1 Minister of Fire

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    Looks great! Yes the SREC market in MA is in the tanks, but still better than some states. Perhaps it will recover though.

    I'm just about to hit the 1 year mark on our install and am very happy that we did it, I imagine you will be too.
  10. Vic99

    Vic99 Minister of Fire

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    Although the floor for the SRECs is $300/MW, the hope is that after MA hits its goal, the market will close to newer installations. Hopefully the demand goes back up as the "need" for credits from the power companies goes up with a finite # of producers. Would be nice if that happened ~5 years from now.
  11. osagebow

    osagebow Minister of Fire

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    Very nice. I think VA is still lagging behind on this stuff, unfortunately. Don't think our companies are required to credit our input to the grid if we're over producing. Makes it hard to pull the trigger on a system.
  12. glenc0322

    glenc0322 Minister of Fire

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    nice job does your system have a battery back up incase of power failure?
  13. Vic99

    Vic99 Minister of Fire

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    Thanks.

    No. Proper off-grid battery storage doubles the cost. My research points to batteries lasting 5-6 years, 9-10 if you really baby them and pay attention to their charge levels. Like I have time for that with a wife, two kids and a wood stove.

    Even a small battery set up didn't seem practical both cost and maintenance-wise. The grid is already right here, so excess power gets sold back to the grid at what they charge to sell it to me. Even now The Man owes me ~35kWh of power for the month of November. Last November I used 245 kWh for the month. Year before was 250kWh.

    In the 9 years I've been here I've lost power only three times for 4+ hours. Worst was 1.5 days. I like the idea of a propane generator that can run on a grill tank, but I don't lose power enough to justify the cost. I realize I might have just been lucky, but 9 years is a long time.
  14. pdf27

    pdf27 Member

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    Might be worth looking at something like a Sunny Island unit - lets you run the house off the PV panels directly with no batteries if the grid goes down, but doesn't work at night. Quite steep too, but comparable with a permanently installed generator and should be maintenence free.
  15. velvetfoot

    velvetfoot Minister of Fire

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    That's great! We're getting someone out to check out our place next Monday.
    I was thinking of oversizing the PV surface area too; I'll maybe install some mini-split heat pumps. Although, that'll probably increase my summer consumption - the A/C will be too tempting!

    Seems like a shame not to realize some kind of emergency backup out of the deal though.
  16. peakbagger

    peakbagger Minister of Fire

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    The japanese apparently require some minimal backup capacity for systems that qualify for a new very lucrative subsidy for solar. SMA (sunny boy) has a proposed model that has a 120 volt 8 amp backup only when the sun is shining (no batteries) and I expect other companies will also offer something.

    In the short term the Outback Radian system has a battery bank using sealed batteries that dont require maintenance (but do require routine replacement at some point.) WIth a Radian system, you can use a generator if the sun isnt shining to charge the batteries. The fed rebate still applies to this system but the up front cost is higher as the system cabling has to be bigger and potentially more complex plus the inverter and batteries will add in six to seven thousand (thats a real swag and is highly dependent upon how many batteries you use). The grid tie installers are less familiar with this type of system and will require more upfront design experience and time. I dont think there are any leasing companies that would be interested in this design. Another option is the Schneider XW high voltage charger controller. It can plug directly into a typical grid tie configuration but you then need a bunch of other expensive components, like a large AC inverter with export capabilities and a battery bank to be able to grid tie and "island" the system when needed.

    Unfortunately the numbers just dont work out to have battery backup compared to a generator. If you have a critical load like medical equipment that has to run 24/7 , you may be able to justify it but for the typical homeowner, buy a generator and keep your homeowners insurance paid up.
  17. velvetfoot

    velvetfoot Minister of Fire

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    Thanks for the great info!

    I know it's simplistic thinking, but if the power being supplied back to the grid is high quality 120v. AC., it would seem that you could configure things so that a couple of manual switches/interlocks could be thrown and you could feed house panel. Not approved, or anything, but possible?
  18. peakbagger

    peakbagger Minister of Fire

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    Your question is one of the most asked ones on the various solar forums, sort of like "why doesnt my stove burn right with wet wood" on this site. It has been answered numerous times by folks far smarter about power electronics and me and the answer is always "not that simple" Wish it was.

    My backup plan is that I do have an old charge controler sitting around and some older 12 volt panels and an inverter. If I really had to I could set something up to charge a car battery and then run my inverter off the battery (and hope I dont trash the battery before the power comes back on)
  19. velvetfoot

    velvetfoot Minister of Fire

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    Thanks.
  20. pdf27

    pdf27 Member

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    To protect linesmen in the case of a power cut, the standard inverters rely on the grid to set the frequency and timing of the alternating current. If the grid goes down, they cut off automatically - and the same is true if you throw the breakers and isolate the system.

    What the Sunny Island and similar systems do is automate the breakers so that in the event of a power cut they isolate the house from the grid, and then it generates a synthetic AC signal to trick the inverter into thinking there is a grid signal and producing power. IIRC it can also throttle the inverter so the current it produces is matched to the loads, but I'm not sure how it would do this.

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