PV in South Florida?

[Rodolfo Paiz]

Hello, everyone!

I'm starting to do a little research on PV for my home. The contractors I've spoken with are all pretty negative about the expected energy production and final ROI of the installation due to the frequent cloud cover... I'm generally being told that it isn't -- or isn't yet -- an excellent prospect to put significant PV onto a home in South Florida.

If any of y'all have a good-sized PV installation at your home, would you share a few details about your installation, the specs, the cost (if you like), the energy production, and the contractors involved? Any information at all is welcome and appreciated.

 

[Al Sherman]

I'm in the same boat (kind of) Rodolfo. I've been researching and getting quotes.The guy I like proposes 40 panels. Two rows of ten on each side of the main house roof.He estimates 13Kw for the Sunpower panels and 10 for the Mage panels. The Sunpower panels seem to be highly regarded but are more expensive. With micro inverters that add 10% to the cost he estimates 70 thousand installed. Not including 1 or 2 48volt batteries so that when the power is out we can run the geothermal heat.They are about 9k each.
I'm having trouble (I'm weak with numbers) figuring the actual Kwh production. The variable is hours of sunlight obviously. Seems as though people use 4 hours per day as a yearly average. The numbers just don't really seem to work for me as far as payback.
I really want to have solar though so I may just get it anyway.:smile:
I too would appreciate any and all advice.

 

[Larry Chanin]

This describes Nigel's last home.

Residential Solar System - PV to EV

Larry

 

[bollar]

FWIW, Solar City declined to bid on my PV installation. With electricity at $0.09/kWh and no utility incentives there was a negative ROI.

Other installers were much less expensive and had a 13-17 year payback.

@Al Sherman, if you want to calculate how much an array is expected to generate, use PVWatts: NREL: Renewable Resource Data Center - PVWatts

 

[Rodolfo Paiz]

My electric bill for the last 12 months was a little north of $6,000, and I don't really relish putting $120K on the roof when I just finished building my office and a guest room (1500 ft2 total) onto the house two months ago. I could use a bit of a breather between major projects. And... if the ROI and the energy production are as low as both Nigel's writeup and bollar's PVwatts resource indicate, then I'm definitely going to be better off waiting at least another year, maybe two, before installing PV. I'm pushing FPL on the issue of a time-of-use rate right now, and I'd rather settle that before committing to a PV install, too.

So the initial impression from what y'all are telling me is that I should not move on this... yet. Any and all discussion is always welcome, and thank you all for your input. I'm going to continue with my research and quotes, and as soon as I have something fairly definite I'll let you all know too.

 

[Al Sherman]

FWIW, Solar City declined to bid on my PV installation. With electricity at $0.09/kWh and no utility incentives there was a negative ROI.

Other installers were much less expensive and had a 13-17 year payback.

@Al Sherman, if you want to calculate how much an array is expected to generate, use PVWatts: NREL: Renewable Resource Data Center - PVWatts

Thanks for the link. I'm experiencing the same. 11 cents/kWh, no utility incentives, and no state incentives.

 

[Sans Gas]

How about a whole city run on solar - Babcock Ranch Florida

 

[bollar]

If you're looking for a way to "justify" solar, perhaps consider it part of your investment portfolio. I considered putting some of what I would have put into bonds into the array. The array's output is known and stable over 20 years. The variables are the cost/kWh for electricity (rising, we assume) and the risk of moving away from the house.

If you're going to be in the house for 7 years or so, IMO, you'd get your money out of the array through increased resale value and the kWh savings from the grid.

 

[Rodolfo Paiz]

Let me double-check some parameters here:

- Is $6/Watt of rated DC power a good benchmark for fully-installed cost?
- Is 1300 KWh/year a good benchmark for power production per rated KW of installed capacity?

If those are reasonable, then I'm looking at a 39 KW system if I want to get "net zero" (we go through about 50,000 KWh/year). That's roughly $240,000 with an ROI of 2.6% assuming no incentives. Those are not very attractive numbers, but like Al... I'll probably do it anyway, in one or two years. For now, I'll start making efficiency improvements (e.g. we're already starting to switch to LED lighting) to see if I can knock those 50,000 KWh down a little.

 

[stevezzzz]

...I've been researching and getting quotes.The guy I like proposes 40 panels. Two rows of ten on each side of the main house roof.He estimates 13Kw for the Sunpower panels and 10 for the Mage panels.
[snip]
I really want to have solar though so I may just get it anyway.:smile:
I too would appreciate any and all advice.

While it's hard to justify strictly on a ROI basis, there can be other justifications for solar PV. Depending on the state you live in, the carbon cost for the electricity you use varies widely; the numbers I've seen conclude that, in terms of carbon emissions due to driving, your Model S can range from the equivalent of a 30-plus mpg ICE (in states that get their electricity primarily by burning coal) to something well north of 100mpge (where electrical generation is primarily from greener sources). If you live in one of the former states (as I do), you may find it worthwhile to install PV panels just from an environmentalist POV.

By the way, I'm questioning that 13kW number from your contractor. I've got 30 Sunpower panels with a combined nominal rated output of 7.16kW, and my peak production in reality is just over 6kW around solar noon. I'm at 40 degrees N latitude. Does Sunpower now make a 325W panel?

 

[Rodolfo Paiz]

While it's hard to justify strictly on a ROI basis, there can be other justifications for solar PV. Depending on the state you live in, the carbon cost for the electricity you use varies widely [and] you may find it worthwhile to install PV panels just from an environmentalist POV.

Absolutely spot-on. And as I said, I'll eventually do it anyway. But the higher-than-anticipated sizing and cost also reminds me that the responsible approach is to start with conservation first. I don't know how many of those 50,000 KWh are spent heating the pool, for example... but I'm going to find out.

 

[stevezzzz]

Rodolfo, here in CO I have been averaging 1460kWh/year per kW of installed capacity (24 consecutive months sample). YMMV, of course: Colorado is a sunny place.

 

[Rodolfo Paiz]

Miami gets lots of sun, but also lots of rain and clouds, so MMMV indeed.

When I do this, I'll probably build out in stages... 10KW or so to start, maybe, with an eye toward future expansion. Nothing like cold hard data from a real install.

 

[fiksegts]

what about the solar reimbursement from the state of Florida? I think you apply each october, plus you get a 30% federal tax credit?

 

[Larry Chanin]

what about the solar reimbursement from the state of Florida? I think you apply each october, plus you get a 30% federal tax credit?

There is no solar reimbursement from the state of Florida. I think you are confusing a rebate provided by Florida Power & Light. There is a lottery in October to see if you can get the rebate. I think about half those applying are successful.

Larry

 

[Rodolfo Paiz]

The incentive you're talking about was provided by FPL, in the past: $2/watt if installed rated capacity, max 10KW. Note that one has to file a full application immediately when the window opens because the money goes very quickly... and you'd better be ready to execute, because if they approve your application you have 90 days to get the system installed and functioning. And we do not know for sure if that incentive program will be continued this year.

 

[Al Sherman]

By the way, I'm questioning that 13kW number from your contractor. I've got 30 Sunpower panels with a combined nominal rated output of 7.16kW, and my peak production in reality is just over 6kW around solar noon. I'm at 40 degrees N latitude. Does Sunpower now make a 325W panel?

I could be wrong, but I'm pretty sure he said 327W.

 

[ItsNotAboutTheMoney]

Given that they generally get better and cheaper, if you feel like waiting you can work on making your home more energy-efficient. Lots of ROI on energy efficiency, especially if you're going TOU and it helps lower your PV requirements.

 

[fiksegts]

yea, that was is it, funded by Florida Public Service Commission via FPL?

There is no solar reimbursement from the state of Florida. I think you are confusing a rebate provided by Florida Power & Light. There is a lottery in October to see if you can get the rebate. I think about half those applying are successful.

Larry

 

[tdelta1000]

In my research for a home system I came across this company: Solar Panels, PV Systems and Inverters Distributor

Sent from my SPH-L710 using Tapatalk 4 Beta