NJ newbie here! Saying hello!

[JSchnee21]

My array faces 175 degrees (almost due South -- very good) but my pitch is only 20 degrees (not good). Ideally it would be ~33.5 degrees. I haven't measured it, but the gap between my panels and the roof is also fairly small, probably 4 inches or so.

See this website:
www.solarpaneltilt.com/

Additionally I have shade on both sides of my house and across the street. And because I live in a raised ranch, my array is very wide and not very tall. As a result, I see a significant impact as the sun moves across the sky. Array is ~ 4 panels high (landscape) and 10 panels wide. Solar production is only optimal under full sun conditions when the angle of incidence is nearly orthogonal to the plane of panel.

GPE didn't do a lot of production estimates for me. I did most of them myself. My original GPE proposal was for a 12.775kW array with an estimated annual production of 15.3MWh. But this array size didn't fit on my roof. From my estimates of the array which ended up fitting (12.21kW 37x330W). I forecasted ~12 to 14 MWh. But, I know now that I failed to accurately estimate the how much shading I had, and how severely it would impact my production. I ended up with just under 12 MWh (11.8) last year.

If you look at the efficiency of arrays near you in NJ, you can get a rough impact of weather conditions in your local area and compare "efficiencies" of similar systems
pvoutput.org/ladder.jsp

E.g KWh (produced) per kW (DC):
Name Location Size Generation Efficiency Average Outputs Last Seen

For MacAddict
Mario' System - Sunnyside NJ United States 08833 8.960kW 19.251MWh 3.499kWh/kW 31.353kWh 614 days Today

For Me
Panasonic12kW_SolarEdge_GPE United States 08831 12.210kW 18.294MWh 2.477kWh/kW 30.239kWh 605 days Today

As you can see the productivity of MacAddict's system is much better than mine mainly due to the differences in our designs. I think MacAddict also gets more sun than I do (less clouds).

But a word of caution, no two installations are ever really the same. The efficiency parameter is an all encompassing comparator which is influenced by all system variable (equipment quality, installer quality, orientation, pitch, shade, age, soling, differences in micro-climate, etc.).

-Jonathan

[Ampster]

Yes, perhaps I was generalizing a bit too much. The HD series of inverters is not more "prone" to clipping, per se..............

All I'm saying is that installers should be more transparent about these types of choices and discuss the pros and cons.

I agree. In my case the difference between the 3800kW and the 5800kW was $150. If my installer had communicated to me that we were going to be at 150% I probably would have said let's go with a 6kW system instead of a 5.7kW. At 2.50 a Watt that would have been $750 more cost to me (and revenue to them) but their equipment costs would have increased maybe $500 and incremental labor and overhead very little.

[J.P.M.]

I received an updated estimate. This is with srecs at 175 and 10k down. I still think the yearly production sends too optimistic. How much do the estimates differ from real production?

SmartSelect_20190218-191250_Drive.jpg
Thanks

First, how much has been estimated for annual production in kWh? And by who ? What's your zip, your planned array size and array orientation (tilt and azimuth). Vendors commonly use models and often/commonly (at least the ones I've seen in CA) overestimate production by something like 10 % or more.


Run PV Watts and get your own unshaded estimate. Yearly unshaded output will vary by ~ +/- 10% or so, mostly due to weather. Can't be helped.

[flowing]

I received an updated estimate. This is with srecs at 175 and 10k down. I still think the yearly production sends too optimistic. How much do the estimates differ from real production?

SmartSelect_20190218-191250_Drive.jpg
Thanks

[flowing]

Are you guys south-facing?

[flowing]

@macaddict I see that yous install was done via GPE. How close was their estimate to the actual production you have been getting?

Thanks!

[JSchnee21]

Yes, perhaps I was generalizing a bit too much. The HD series of inverters is not more "prone" to clipping, per se. But there are two important differences which can lead to more clipping depending on the characteristics of individual installs:

1) Increase in supported DC to AC ratio. Yes, SE permits higher DC to AC ratios on the HD units without voiding the warranty. This has led some novice installers to "oversubscribe" more generously than they should be for some installs.

2) Name plate versus actual DC inverter capacity. Some models in the older A-series actually have a higher DC inverter capacity than their name plate suggests. In contrast, the new HD's series strictly curtails inverter capacity to match the nameplate.

See these comparison spec sheets. Most notably the 7600 which is one of the most popular sizes.

HD (7600VA for the 7600 A-Series)
https://www.solaredge.com/sites/defa...tasheet-na.pdf

A-Series (8350VA for the 7600 A-Series)
https://www.solaredge.com/sites/defa...-datasheet.pdf

While some minor clipping is generally acceptable -- in some cases even preferable to the added costs of replacing load centers, etc. if a line side tap is not permitted -- the reality is that the differential cost between models of the SE inverter line is pretty small. Usually only a few hundred dollars -- sometimes less. Which in the grand scheme of a $30k or $40k project is insignificant.

While upgrading inverters from ROI perspective may not always make fiscal sense, running electronics at 50-80% load versus 70-105% load, particularly passively cooled electronics, makes sense to me from a longevity perspective. But others may disagree.

Customers will complain when they see clipping, even if the amount of power lost is insignificant and not cost effective to remediate.

For example, the cost differential between the 7600HD and 10000HD on Alt-E for example is $429. ($1579 versus $1999)

https://www.altestore.com/store/inverters/grid-tie-inverters/solaredge-hd-wave-single-phase-grid-tie-inverters-p40704/#SEDSE7600H

And only $404 on Renvu (you need a log on to see pricing) $1,451.30 versus $1,855.02

https://www.renvu.com/Browse?website=solar#Solar-Products/Solar-Inverters/Optimizers-Maximizers

Similarly price differentials between the 6000 and 7600 and 10000 and 11400 are even less.

All I'm saying is that installers should be more transparent about these types of choices and discuss the pros and cons.

[bcroe]

Wow how big is that?

That is 2 of my 3KW strings, 12 each 250W panels. I could have set it straight up, but decided to try this
for a little more production. Another array, just outside the pic, has inches of snow on it. Bruce Roe

[flowing]

Wow how big is that?

[bcroe]

This is easy enough more me to say because I have be in the construction and real estate related industry
for 40 years. I have also added improvements to my homes based on function, utility or aesthetics.

Certainly building an array (in snow country) with easy summer/winter tilt change will take more resources.
Advantages here include far less snow removal efforts and improved sun angle production. Low maintenance
is a big deal to me, going out to change a few bolts in fall/spring sure beats pushing mountains of snow all
winter long. Just writing off winter production is almost certain with a roof mount, guessing some 20% of
system production. Bruce Roe

Sn4iE2.JPG

[Ampster]

Roof mount is certainly the quick and easy way to build it. But unless you are writing off snow season
production, there are some advantages to ground mount. You will not be able to tilt up roof mounted
panels for the low winter sun, or for better snow rejection. And cleaning them is usually impractical. I
have a list of 44 advantages of ground mounts. Bruce Roe

I agree based on the original posters desire to do a driveway cantilever design.
I have seen some very attractive driveway pergola designs that could enhance the value of a home. The problem that the original poster ran into is an installer whose expertise was limited to roof mount. If I was in that situation, and had the resources to spend on the aesthetics I would have a structure designed and engineered for solar panels. I would have the structure built by someone who has that expertise. I would
coordinate that design with an installer. There could be money saved on the installation portion because the installer would not have any roof leak warranty issues and the engineering work would already be done. I would also rationalize the structure as a value enhancing investment just like new landscaping, windows or many of the myriad other changes we make to our homes.

This is easy enough more me to say because I have be in the construction and real estate related industry for 40 years. I have also added improvements to my homes based on function, utility or aesthetics.

[Ampster]

....
..

Note that the newer HD version inverters are more prone to clipping that the older A-series (which I have). So depending on your panel layout, number of roof faces, angle, and orientation, you may want to consider 2x10k for example, if you're array is significantly over 15kW.

I don't think the HD Wave inverters are more prone to clipping. I think what is happening is the design of the inverter allows a higher DC to AC ratio so more systems are being designed with higher ratios, perhaps because of economics or other factors. The result is more people are seeing clipping with HD Wave inverters. I have two systems, both with Solaredge HD Wave inverters and the one with a 1.5 to 1 DC to AC ratio shows clipping. The other one has a DC to AC ratio of less than 1 to 1 and shows no clipping.

[J.P.M.]

Demand for SREC's is volatile and not guaranteed. In NJ as solar production has ramped faster than demand, the legislators have had to continually pass new legislation to accelerate demand to keep the prices up. While not 100% accurate, you can think of SREC's like "Cap and Trade." Legislation requires generators to be an increasing percentage "Green" each year. They need to buy the credits to offset dirty generation sources.

Last year there were some additional legislation changes which still haven't fully played out yet. Energy costs in NJ are low ($0.11 to $0.14 per kWh residential)and have actually slightly decreased in the 12 years I've lived here. Without SREC's the break even time horizon for solar is very long -- particularly with a purchase price > $3 / W.

That said, for the past several years, SREC's have been running around $200+ / MWh. Of course past performance is not a guarantee of future performance. So for a system that generates 20MWh / yr, that would be $4000 or more per year IFF things remain more or less the same.

Historical data here

https://www.flettexchange.com/markets/new-jersey/spot-data

If the OP can get a solar loan for 3.9% I'd say that's a pretty good deal. Paying a large chunk of it (bonus time) with cash would be better. Knocking down the price to $2.75 per Watt (not even sure if that is possible in NJ due to labor costs) would be outstanding.

One other important caveat to note for the OP:

While in theory homeowner owned solar (not leases, nor TPO's, nor PPA's) should increase the value of your home since it is a capital investment which lowers ongoing operating costs.. In practice, this is not really the case. Most people don't understand solar and this includes most real estate adjusters and lenders. It sounds like you love your home and plan to be there for the long haul. But if not, don't expect to recoup any of your investment when it comes time to sell your house. In fact, some buyers may be turned off. This is mostly due to misunderstandings about how solar works and the bad press that SunRun and others get. Even if you tell them you own it, they may not understand or trust you. A lot of people think they "own" their solar leases, too.
There are also concerns about long term maintenance and reliability, holes in your roof, and (largely unfounded) concerns about fire and firefighter response.

All that said, between your electricity offset and SREC's (assuming prices stay more or less the same) you should be able to break even in about 7 or 8 years. So assuming you plan to live in your home for more than 8 years, you should come out ahead. But, solar won't make you rich.

IMO, well stated, particularly the caveats about SREC volatility and effects PV may/may not have on home resale value or salability.

Seems to me those with money to make by overstating the goods and understating to the point of misrepresenting possible pitfalls and drawbacks are all to common. That $4K/yr. in SRECs looks particularly unreliable or at least uncertain and/or overly optimistic for use in long term planning. I'd knock that in half and see what it does to time to breakeven. If I went ahead w/ the project anyway and it turned out I was too pessimistic, I'd be pleasantly surprised rather than unpleasantly disappointed, particularly if I didn't plan on moving.

[flowing]

Thanks for the insight. I will inquire on a 5y option and see if I can put down more. This is requiring a lot of math 😊

[JSchnee21]

Your loan numbers look legit, but stretching it out over 10yrs (versus 5) is costing you an extra $6K in interest. You would do better to be cash flow neutral (or slightly negative) and be paid off in 5 yrs. Check with you're tax accountant, but a low interest home equity or HELOC loan might allow you to deduct the interest from your taxes. Though, I think, thanks to Trump's new tax plan, this is capped at $10k in interested deductions per year nowadays which is probably already spoken for by your mortgage.

This is one of the reasons I went with a 401k loan. All of the interest I paid (5% or so) is just an accelerated investment in my own retirement (yes, it is taxed twice (going in and coming out) -- but this is better than taxed once and given away to someone else). I've read all of the financial arguments against doing this and none of them really carry any weight. The only "real" concern is the risk of default if you lose your job. Well, that happened to me (got laid off 5 years ago), but Fidelity just let me keep making payments as if I was still employed. Worse case would have been a hardship withdrawal and 10% tax penalty. But IMHO this is a much better choice than defaulting on a real loan from a bank or bankruptcy -- both of which would negatively impact your credit.

But, to each his own.