Going solar!

[jetsam]

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?

 

[EatenByLimestone]

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.

 

[begreen]

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?

 

[peakbagger]

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.

 

[begreen]

Great advice as usual pb.

 

[jetsam]

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.

 

[georgepds]

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

 

[georgepds]

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

 

[Where2]

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

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...

 

[maple1]

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...).

How many watts is that? Guessing maybe around 6000? Which would be pushing $4/watt - and sounds a bit pricey? I might be off base a bit.

This is still in the back of my head, and I should really stop in to see the (new) local solar guys and ask some questions.

One main thing I really have reservations about is the snow aspect. If panels went on the roof, there is no way I would be cleaning them off (two stories). And not sure I would want them dumping snow where it would be heading. And not sure we have the yard space/location for ground mount - and really not sure I could sell my other half on that kind of setup. There is a new incentive program here, put in place the past winter. But they only have a limited pot and not sure how much uptake they've gotten - I really need to poo or get off the pot.

 

[georgepds]

Re snow

I never clean my panels of snow, and it snows a lot on the ocean in NE MA

Generally the snow sticks a day or two, with it sticking to the panel bottom at the end. I think that's because the panel is exposed to cold air underneath. I never have the snow fall off in a big lump. I think it mostly blows away as a powder, melting is another possibility.

 

[peakbagger]

Mine usually slides off in sheets from the second story. It would damage people and landscaping.

 

[georgepds]

Hmm, I wonder what accounts for the difference, maybe roof pitch

Mine is 5/13

 

[Rob711]

Im strongly looking into solar as well. Had a guy come out from a company that 4 co workers used. He called about hr before he was to arrive to say he’s on way but we have a few strikes. 45 degree pitch, east west roof and shading from neighbors trees.
We’ve extensively remodeled this house, and only have been in it since mid June so it’s hard to get a accurate usage as far as kWh.
The salesman calculated using 12000 kWh a year. Said that’s average for family of 5. Central air, electric dryer. After rebates it would be close to 30k which I’d have to finance at this point. 15 yr loan. 267 a month for 18 months. Then 222 for the remainder. Last bill was 175 but we weren’t living in the house at least half that billing cycle. I’d be good even if it was a bill swap. I’m told this would cover all our electricity.
Jetsam I believe we pay same rates. I’ll be curious how it goes.

 

[jetsam]

I wound up going for a 7kw grid-tied system. I started out wanting a battery bank, but then I found out that the local power company offers 1:1 generation credits- so from a money point of view, they are a 100% efficient battery that never needs replacing.

I am looking at paying $3.06/w installed, with the 21% LG 360w panels and the newest enphase IQ 7+ microinverters.

The system is going to end up costing about $12k after tax credits.

The whole project (which includes a new roof, 200A service entry/meter pan, and a main panel upgrade) is about $40k up front, since labor for everything is through the roof around here. The solar is actually less than the infrastructure (though it was time for a roof anyway, which is why we are doing the solar now.)

I told my wife that I could get Chuck In A Truck to do the roof for half the price of her Angie's List guys, and she wasn't having any....

After that I think I'll put in a split system- and have AC in the summer, and be a "supplemental heat" wood burner in the winter! (We heat with 100% wood wood now, but why split all that wood to save on free solar power?)

Not sure if I'll light one fire in the fall and just burn 24/7 but on low, or light bigger fires as needed. Guess we'll see!

I would say that greatly reduced wood consumption will be nice, but I will miss poking at the fire. Right now I get to play with it 3x a day in the cold parts of the winter... after solar, it'll be on low burns and 24 hour loads.... if I even burn 24/7.... horrors!

 

[maple1]

Im strongly looking into solar as well. Had a guy come out from a company that 4 co workers used. He called about hr before he was to arrive to say he’s on way but we have a few strikes. 45 degree pitch, east west roof and shading from neighbors trees.
We’ve extensively remodeled this house, and only have been in it since mid June so it’s hard to get a accurate usage as far as kWh.
The salesman calculated using 12000 kWh a year. Said that’s average for family of 5. Central air, electric dryer. After rebates it would be close to 30k which I’d have to finance at this point. 15 yr loan. 267 a month for 18 months. Then 222 for the remainder. Last bill was 175 but we weren’t living in the house at least half that billing cycle. I’d be good even if it was a bill swap. I’m told this would cover all our electricity.
Jetsam I believe we pay same rates. I’ll be curious how it goes.

What is the system size? Sounds pricey for an after incentive number?

 

[Rob711]

42 lg panels. About 15kw system but will produce 12 due to roof and shade. Salesman said the grade systems. I’m a D!

 

[Rob711]

 

[Rob711]

I think I can get a separate bill from contractor for the cost of roof and 200 amp upgrade that was done. So if I understand I could get 30% of that back at tax time. What’s a roof and panel upgrade go for??

 

[jetsam]

I think I can get a separate bill from contractor for the cost of roof and 200 amp upgrade that was done. So if I understand I could get 30% of that back at tax time. What’s a roof and panel upgrade go for??

How are you getting a tax break on your roof and service entry?

Roofing is really, really variable. Shingles are around a hundred bucks a square and the price difference between cheap ones and good ones isn't much at all. Almost all of your price is labor.

 

[peakbagger]

Taking the tax break on the roof and service upgrade is one of these talk to your tax accountant issues. That said some folks like to roll the dice and push it and hope they don't get audited. One of the reported tricks of the trade by the leasing firms is they push the outer limit on the front end cost by adding in a lot of overhead on their installs to boost the rebate. The reality is the company really only cares about the next quarter so if the write offs get disqualified three or four years down the road they will worry about it when it happens.

That said, if the service panel needs to be upgraded due to the 20% rule or not enough space for a dual pole breaker many folks do write off the service upgrade even if they are getting additional benefits like the panel was ancient or undersized for other reasons. Of course one can argue that in that situation a line side tap may be the more economical option.

The roof replacement IMHO is another story. Sure folks claim to write off the entire roof and deal with totally unrelated repairs but they also can under report their income and a whole host of other illegal or questionable acts. If the solar panels cover all the exposures of the roof (highly unlikely) then IMO charge the entire cost of the roof. On the other hand, if the panels are on the south exposure (which is far more typical) then IMO either do just half the roof or write off half the charge. Sure some may argue that they need to do the whole roof because the color will not match and some may be comfortable sitting across the table from an IRS auditor trying to sell it.

 

[jetsam]

They put the panels on the roof today. System was making 150 watts when we first turned it on. Looks like it'll be possibly even less all day tomorrow, but the panels will get a good rinse anyway.

I got 20 of the new LG 370s with enphase inverters. If the sun ever comes out, it'll be good for my electric bill!

Next project is to swap out the oil fired DHW for an electric heater! Should break even on the equipment there, as I'll have a $1500 oil fired one in good condition to sell.

 

[Rob711]

Nice! Almost a month ago I got 42 of the same panels, should cover 102% of my electric, of course oct nov dec are bad producing months. Now volcanoes are erupting so expect dusty hazy skies. My neighbor bought a new snow blower so at least we won’t get any substantial snow this yr

 

[peakbagger]

Great, you even got the system in before the deadline for the 30% fed rebate. Have fun learning the characteristics of the system. It definitely puts most folks more in tune with the local weather conditions affecting the sun.

 

[jetsam]

Great, you even got the system in before the deadline for the 30% fed rebate. Have fun learning the characteristics of the system. It definitely puts most folks more in tune with the local weather conditions affecting the sun.

The blue line is cloud cover for today!

Making ~800w at the moment.