Going solar!

jetsam Posted By jetsam, Jun 8, 2019 at 2:15 PM

  1. jetsam

    jetsam
    Minister of Fire 2.
    NULL
    

    Dec 12, 2015
    4,055
    2,825
    Loc:
    Long Island, NY
    It's finally time for a new roof, so I'm going solar this year. I am tickled to see the advances in PV tech since last time I looked at it (microinverters/power optimizers, 20%+ efficiencies).

    I am getting in just in time to get 1:1 net metering, so no batteries for me. I have a generator for outages. I like the idea of onsite storage, but I don't like the idea of replacing batteries regularly.

    I am getting an oversized system with a view towards adding a split system, electric DHW, and hopefully electric vehicles at some point.

    The whole thing is adding up quickly ($13k roof, $23k for a 20 panel PV system, plus the house needs a new main lug and 200A service entry upgrade...).

    It'a still looking like a good deal after the tax credits right now. ROI at my old rate of power usage is about 8 years, and I plan to about double my usage (I currently heat with 100% wood and don't use AC, oil hot water heater), so you could argue that it's significantly lower.

    Anyone have any gotchas, tips, or things to consider before jumping in?
     
  2. EatenByLimestone

    EatenByLimestone
    Minister of Fire 2.
    NULL
    

    Jul 12, 2006
    6,730
    980
    Loc:
    Schenectady, NY
    I'll be watching. A new roof will be going on my house this year too. I'm interested in solar, but I'm not sure I'm ready to jump on that yet.

    I want to systematically tear out old insulation and closed cell foam my upstairs though. I really don't expect that to pay back in any reasonable time, but make the house much more comfortable.
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  3. begreen

    begreen
    Mooderator 2.
    NULL
    
    Staff Member

    Nov 18, 2005
    76,972
    12,410
    Loc:
    South Puget Sound, WA
    Get the basics figured out first, like solar exposure and roof capacity. Is there a substantial portion of the roof sloping to the south? Will the roof support the weight?
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  4. peakbagger

    peakbagger
    Minister of Fire 2.
    NULL
    

    Jul 11, 2008
    4,498
    1,332
    Loc:
    Northern NH
    Keep good records on the things like service entrance upgrades as they are covered by the 30% fed rebate.

    How is your shading and does your states electric code require Rapid Shutdown Devices (RSD) on the array?.The 2014 NEC requires that the array output has to drop below a low voltage sertpoint (Ithink 80 volts DC?) within so many seconds after a loss of grid power of when manually initiated. The 2019 is similar but requires it at the panel level. String Inverters can comply with the 2014 adding a remote shutdown relay in the local combiner box near the array. The relay is controlled remotely by low voltage signal run in a separate conduit. If you have shading issues, microinverters or panel optimizers meet the standards but add cost and complexity compared to a central string inverters for 2014 installations but for 2019 there is no option for conventional panels for just a string inverter, you either need a panel mounted optimizer or microinverter. Either option puts electronics on the back of each panel, its just the level of complexity. Microinverters (or so called AC modules) do not require a central inverter and are easier to configure since shading is less of an issue making them a favorite of some installers but the material cost is higher. The reliability of microinverters has been rocky, there have been multiple premature failures of multiple brands, the claim is that each generation is getting more reliable but they are in tough location for electronics. Optimizers also are panel level and deal with shading but the electronics are far less complex at the panels. They have not been 100% perfect on reliability but seem far better than microinverters. The trade off is you need one or more central string inverters located in hopefully in more optimum location.

    Pole mounts and ground mounts do not require RSD which offsets some of the extra cost for the mounts. The panel efficiency is slightly higher with a pole or ground mount as they run cooler which potentially extends component and panel life. I think a lot more folks are more comfortable doing a ground or pole mount compared to roof mount. I did both types by myself and came to the conclusion that each had its challenges but a factor for those who do not like working on roof.

    Factor in snow on the arrays, the snow does not magically disappear and contrary to the salesmens claims may not be gone the next day. If the snow does not stick its going to slide and anything below it will need to be protected. Frequently decks and porches are in the slide zone. You can get clips installed similar to those used on metal roofs but then your panels hold snow longer. Landscaping also can get wrecked.

    Run metal conduit through the interior of the house and have it terminated with a roof box that is installed when you have the roof done. Running conduit outside the house is a compromise and many installers cut corners. Keep it out of sight and avoid the hassle.

    Make sure there is a quality Surge Protection Device (SPD)between the main panel and the PV system.Nothing protects from a direct strike but the PV system is far more likely to be an entrance from a secondary surge. They work both ways, surges from the utility do happen on occasion. I had an inverter smoked by a utility surge several years ago. I also believe in a SPD on the roof at the junction box to keep surges from getting in the house. Note that there are cheap surge suppressors that may keep your house from burning down but will not protect the electronics.

    Consider buying some spare panels. Panel models change every 2 or 3 years and no one stocks old panels. Even if you have a great warranty and the company is still in business its unlikely they will have an exact spare. The installer buys them in bulk so a spare should not be expensive. Panels usually die quickly if defective so the spare is for physical damage like a golf ball, rock or a critter gnawing at the leads. Make sure you have good spot to store them.

    Unless you are a "tech geek" and atypical, the panels will rapidly become an appliance like a refrigerator or a washing machine. There are all sorts of very profitable options that the installer will gladly sell you. The reality is if configured correctly a typical person is not gong to look at all the bells and whistles after the first year. Odds are the cost of the options will exceed the electric output. I look at my 3 inverters when I walk by from about 5 feet away,one has no display except for a flashing LED and the other two have wattage readings. When I get my monthly power bill I note the credit and that is it for care and feeding of my panels. Summer rainstorms in my area wash them off. I do change panel angles on my wall mount and my pole mount quarterly but its quick and if I dont get around to it I do not stress over it.

    Factor in SRECs, some states have very profitable SREC programs and some installers keep the SREC revenue to themselves by hiding a clause in the contract assigning the SRECs to them. They just register the system in their firms name and the owner is none the wiser as the reporting goes through the same web ap that the owner uses to monitor the system. The web reporting is handy as its PITA for me to read my production meter every month and report it but the trade off is a lot of folks have issues with communications and usually the installer has to be the one that fixes them as it may require special software.The software gets upgraded on occasion ever years after the installation and on occasion the patch knocks the software out and the installer will need to reset it (usually at a call in fee). My theory is KISS (keep it simple stupid)

    Array bonding and grounding is a "black art" and even electricians and engineers seem to disagree on the proper approach.I have #4 cables running direct outside the house that terminate at the main house ground. My pole mounts ground goes to a local ground rod that ties into my main ground via a #4 run in the conduit trench to the main house ground. All the SPDs also tie into the main ground grid outside the house.
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
    jetsam, woodgeek, SpaceBus and 3 others like this.
  5. begreen

    begreen
    Mooderator 2.
    NULL
    
    Staff Member

    Nov 18, 2005
    76,972
    12,410
    Loc:
    South Puget Sound, WA
    Great advice as usual pb.
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  6. jetsam

    jetsam
    Minister of Fire 2.
    NULL
    

    Dec 12, 2015
    4,055
    2,825
    Loc:
    Long Island, NY
    Yeah, I'm going to sit down and pick through his reply in detail after work. Multiple things to research in there! I definitely hadn't thought about surge protection or spare panels.
     
  7. georgepds

    georgepds
    Minister of Fire 2.
    NULL
    

    Nov 25, 2012
    867
    247
    Re" 20%+ efficiencies"

    Remember the limit on most residential systems is 20% of the busbar amperage on the main panel. My understanding is most residential 100 amp services have 200 amp bus bars... so that's 40 amps,

    Might limit how many of those efficient panels you can put up
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  8. georgepds

    georgepds
    Minister of Fire 2.
    NULL
    

    Nov 25, 2012
    867
    247
    Re microinverter reliability... some anecdotal experience

    I've 18 enphase M215s for ~7 years, no problems yet
    I've another 10 enphase S280s for~ 3 years, no problems with those either
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...
  9. Where2

    Where2
    Feeling the Heat 2.
    NULL
    

    Feb 3, 2013
    335
    62
    Loc:
    South Florida
    Of my present 20 "operational" microinverters, I've lost one M215 in ~5.75 years, and they sent me an M250 as a replacement. (I have 41 more M215 units, they're just not installed yet...)

    As for PV prices, a week or two ago I got an email with panels + M215 microinverters for $0.44/W. My last freight shipping was ~$500 for a pallet of panels moved 3,000 miles...
     
    Stop hovering to collapse... Click to collapse... Hover to expand... Click to expand...

Share This Page