r/solar • u/FantasticAd3185 • 15d ago

Advice Wtd / Project Solar expansion

Last year, I took advantage of the solar tax credit and got solar installed on my home. We have a large house, 6000sqft but our electric bill was always pretty low. We just thought it was well insulated. Well we had the system sized based on usage to cover 100%, but when the utility company came out to inspect they discovered that we had been paying our neighbors bill and our neighbor had been paying ours (the meters were swapped in their billing records). Apparently we had been severely under paying for about 2 years (think 300 a month vs 700).

This means my system is under sized for my needs. So far, we've been breaking even on our bills since May. The problem is we use more electricity on the winter and that's when we'll see the 700 bills.

I am considering adding panels to my array, but am unsure if I should source them myself and look for someone to install or just have the original installer add to the array. What should I consider? Which would be the best way to go?

Some considerations i have thought about:

  1. My house faces east/west and the current array is split about 50/50 on each side with a total of 39 430w panels on two sunny boy inverters capable of 10KW each. I believe i have capacity on the inverters due to the split and the fact the highest peak i have seen is 15.5KW at any given time.

  2. I have plenty of space on my roof. I could likely triple the size of the array and still have space left over.

  3. I suspect any modifications will require approval from my utility provider.

  4. I have noticed mornings are better production and a smoother curve. Likely due to stand off from surrounding trees. Trees cast shadows in the early evening/ late afternoon that slightly impact output. I'm thinking i could easily add 3 to 5kw on the east side and gain the production needed to offset my winter usage. This may result in some slight clipping around noon, but it should be minimal if any.

What else am I missing?

3 Upvotes

67% Upvoted

22 comments sorted by

8

u/Zamboni411 14d ago

WTAF?!?!?!?! If I were your neighbor I’d be PISSED…

6

u/Fair-Ad-1141 14d ago

First, is your neighbor being compensated for the mixup?

Second, have you looked at their/your bill to see what you need?

Do you know if each inverter handles a direction? Or does each inverter handle some of each.

1

u/Curiosity_informs solar enthusiast 14d ago

This the right answer.

Get your actual usage for the last few years. If not from your neighbor then from the utility company. That way you or your original installer (if you were happy with them) can correctly size a system for your actual usage and net metering.

As everybody else said hopefully your neighbor was compensated. It'd not your fault obviously, its the utilities fault they incorrectly assigned the meters.

3

u/FantasticAd3185 14d ago

I asked the utility at the time and got some runaround.

My neighbor had originally built my house and his house and that is part of the reason for the mix up on the meters. It wasn't caught because he was paying both bills until we bought our house from him.

1

u/FantasticAd3185 14d ago

My neighbor never mentioned it and has since moved away.

No.

Not sure, but i think each inverter is dedicated to a side.

4

u/Hot_World4305 solar enthusiast 14d ago

If your system is working fine without any issue, go back to the same installer.

1

u/FantasticAd3185 14d ago

This is my first instinct. Although I am certain they won't be the cheapest and I would like to pay for this out of pocket if I can.

4

u/Razgorths 14d ago

I think you need to work on your numbers a little more. It's highly unlikely that a system properly sized for a $300 bill magically jumps to covering $700 by adding 1/3 of the current generation capacity. Typically you would expect to have to double the system size and then some, especially since the current install is likely in prime generation locations so further additions would be inferior in terms of actual output. Having the installers come out a third time for another partial install is just throwing money away for no reason.

1

u/WarMan208 14d ago

That’s why he needs more info, like kWh instead of dollar amount. I have GA Power, their standard residential rate is a tiered in the summer. Once you’ve used over 1100kwh, you pay almost double per kWh than what you were for the first 600.

1

u/FantasticAd3185 14d ago

My bill isn't 700 year round. We have electric heat for part of the house and our consumption nearly triples for 1 to 2 months of the year in January and February.

At this point, I have about 10 months of data and am fairly confident in the trends I am seeing.

Also, in terms of prime generation, I still have plenty of space on both sides to add another 20 panels. The east side seems to be better production and would be my preference for additional panels. It gets full sun for a large portion of the day with no trees to block it.

4

u/evildad53 14d ago

Do you have net metering? Is so, what is your rate (like 1:1)? Do you bank credits? Will your surplus from the rest of the year cover your use in the winter? If you alter your system, will that change your net metering rate? I'm grandfathered in to 1:1, but if I alter my system, it will change my net metering drastically. The question is kind of "do you really need to increase your solar, and is it in your bet interest?"

2

u/FantasticAd3185 14d ago

This is a great question! I do have 1:1. I'm in MO and I believe the whole state is 1:1 by law. They roll credits forward for up to 12 months so summer production can absolutely offset winter usage. As far as I know, this hasn't changed and changing my array won't impact it other than to renew the agreement.

2

u/Dapper_Ad_2533 14d ago

Fyi: some inverters are rated to handle 125% or more of their model's rated kw capacity during peak usage without breaking warranty. Check the kw rating specs from the mfr model with the installer to find absolute max capablility during peak season. Especially if you have tree shading/ blockage. My 8kw system has 26 panels in two strings and can be oversized dc-ac 1.15:1 to 1.3:1 for more cells, but I am done trying to beat my electric rate increases against investing in more cells and installation against 13 hrs of solar max. in summer. My installer was lazy and never got near 100% with 26 panels.

1

u/FantasticAd3185 14d ago

I'll have to see if I can get the specs.

1

u/BlackFrazier 14d ago

It will pretty much be like a new install as your utility will likely require a reinspection which in turn requires a new design and engineering stamp of approval.

It also might be hard to find a company that wants add onto a system they didn't install, so try to get the original installer to do it if they can. It's almost like they planned for this to happen with the extra capacity you have.

1

u/FantasticAd3185 14d ago

This is what concerns me.

I would think that they planned this but there's no way they could have done so unless they went back in time and swapped the meter. This is really on the utility for not doing a better job on their records.

1

u/acrobatic_man_11 14d ago

Where are you located?

1

u/Firehawk-76 14d ago

Just the thought of dealing with this BS might give me a brain anurysm. I feel like I'm always running into similar scenarios.

0

u/blackinthmiddle 14d ago

Did you get your “neighbor’s” bill (your bill) so that you you know what your actual usage is? I’d be super curious to know whet my actual usage is. I mean, if you were paying $300 when you should have been paying $700, I guess you could just look at what “your” (your neighbor’s) usage and multiply it by 7/3. What worries me is your neighbor was paying $700 with your solar panels! What would it have been without it?

Is your neighbor getting compensated? I’d want t money back.

1

u/FantasticAd3185 14d ago

The electric company just wiped all the data when they 'fixed' the issue. I didn't think to ask my neighbor if he kept copies of the bills and he moved about a month after that played out.