Looking to go solar...everything looking good, am I missing something?

[HX_Guy]

Ok so here come the big dogs! I finally got a quote on SunPower panels and inverter, which everyone seems to agree are the best in the industry. They actually quoted me on the largest system yet, 11.2kW, to cover 100% of yearly electricity. I'm waiting to receive the month-by-month production number so I can plug them in and see if it's worth going with a system that big.

11.2kW system producing 21,300 kWh per year
35 x SunPower SPR-320NW-WHT-D 320W panels
1 x SunPower SPR-11401f-i UNI inverter
$43,904 pre-tax credits ($3.92/watt) - $29,732.80 after tax credits ($2.65/watt)

You do get a better "bang for your buck" on these more expensive systems because you get a lot more back tax credit wise. So for example a $44,000 system will end up being $30,000 net, while a $31,000 system would be $21,000 net...so you get $14,000 for $9,000 basically.

One thing I've learned, which I wasn't told of until today, is that these 2.99% financing deals seem to only be available on the higher priced panels (SunPower, SunEdison). The lower priced (Canadian Solar, Hanwha) have a rate of 7.99% so you're getting a lot less for your money, combined with less tax credit, doesn't really seem to make a lot of sense.

[JohnInSoCal]

holy cow why is solar so cheap in AZ ? $2.85 a watt ? But in CA I can only get around $4 a watt (not using discontinued panels or anything like that)

[Ian S]

Quote #1: 10.06kW system producing 16,564 kWh per year
42 x Hanwha HXL60P6-PA-0-240TB 240W panels
1 x Fronius USA IG+ A 10.0-240 inverter
$28,576 pre-tax credits ($2.85/watt) - $19,003 after tax credits ($1.90/watt)

Quote #2: 10.92kW system producing 18,121 kWh per year
42 x LG LG260S1C-G3 260W panels
1 x Fronius USA IG+ A 10.0-240 inverter
$32,552.85 pre-tax credits ($2.98/watt) - $21,787.00 after tax credits ($2.00/watt)

Feedback on either of those? Thanks.

For some reason, the annual production for the LG system is somewhat higher than expected compared to that expected from the Hanwha system. The nameplate power of the Hanwha system is 42 X 240 = 10.08 kW; that for the LG system is 42 X 260 = 10.92 kW.
(10.92/10.08) X 16564 = 17944 which is 177 kWh less than the 18121 given. Since it was the same guy doing the estimating, I wonder why that is. Maybe the LG panels have less deterioration or just better performance wrt nameplate? Dunno.

[HX_Guy]

Received updated quotes from the guy that stopped by earlier today. Very impressed with their thoroughness and professionalism and their prices seem pretty good I think, but hopefully I can get some more input on that. He has been the only to to actually go up on the roof and do measurements plus used some sort of device to calculate if there will be any shade in the winter months because our south neighbor has a 2 story house. Doing that, he actually figured that there would be some shade on the lower part of the roof and laid out the panels in a different configuration.



He gave me two quotes on bigger systems, one using the same Hanwha panels and the other using LG panels. The LG panels have better specs and I have to assume are better reliability wise, just by the brand recognition? He gave me two quotes on bigger systems, one using the same Hanwha panels and the other using LG panels. The LG panels have better specs and I have to assume are better reliability wise, just by the brand recognition? Both panels have a 25 year warranty, though I thinking theres a much higher chance that LG will still be around 25 years from now

Quote #1: 10.06kW system producing 16,564 kWh per year
42 x Hanwha HXL60P6-PA-0-240TB 240W panels
1 x Fronius USA IG+ A 10.0-240 inverter
$28,576 pre-tax credits ($2.85/watt) - $19,003 after tax credits ($1.90/watt)

Quote #2: 10.92kW system producing 18,121 kWh per year
42 x LG LG260S1C-G3 260W panels
1 x Fronius USA IG+ A 10.0-240 inverter
$32,552.85 pre-tax credits ($2.98/watt) - $21,787.00 after tax credits ($2.00/watt)

Feedback on either of those? Thanks.

[HX_Guy]

Received a second estimate, the guy is actually still here on the roof but he did an estimate before he came out. The system is smaller at 8.64kW but the price per watt is actually cheaper than the bigger system which impressed me. He said if we wanted a bigger system (and he's up on the roof measuring for how big of a system we could have), the price should come down (per watt).

This is what I was quoted...

Hanwha HSL60P6-PA-0-240TB panels and Fronius USA IG+ A 7.5 240 Inverter total system cost of $25,574.80 or $2.85/watt. After tax credits, it would be $16,202.36 or $1.88 per watt. Price seems pretty good, but I have no idea if the panels are any good.

Input?

[HX_Guy]

That's a lot of panels! I don't think we can fit that many...or we could, but I don't want any facing west or north as then we'd see them from the street coming home and I don't want that. Good to hear that the system produces more than they estimates, seems that's the trend with everyone.

[josefaz]

Ay! There's definitely a lot of things to consider.

I did see some numbers on another site from someone in Phoenix who was on the noon-7pm TOU and you're completely right, they had a bunch of excess kWh on-peak and no enough off-peak, but with off-peak being 1/4 of the cost of on-peak power, it still worked out better in their opinion. Then someone else chimed in and said they are on the standard rate plan and they found that it worked best for them.

I guess it goes without saying that it will depend from person to person. We are currently on the noon-7pm TOU already and we use quite a bit on-peak since we are home all day and keep the A/C at 77º even during the day, and have a 5 ton and a 1.5 ton A/C system.

Is there really a way to accurately calculate? I mean I know how much we use on-peak vs off-peak, but how do you figure how much the system will produce between the different hours? How big is your system Ian and which way do the panels face? What is your production like if you don't mind sharing?

Another Phoenician here... I signed up with Solar City back in Jun 2012 and had the 11.5 KW system installed in mid Nov 2012. Back then I had options of what type of inverters and panels to install. Check if you have that option as well and research the available panels/inverters they have. I'm with APS and before installation I'm on the TOU as well but changed to standard in the beginning of 2013. If I remember, I think the rule of thumb was if your overall monthly usage is less than 1 Kwh, the standard rate will cost you less vs the TOU.

Just to give you an idea since the system you have in mind is almost the same size. In 2013, my system produced about 19200 KWh and an excess of 3400 Kwh at the end of the year. Solar City's estimate was 16500. Your south facing panels may produce more. Half my 48 panels face east and the other half west.

[J.P.M.]

Whoa that's awesome! I love stuff like that (graphcs/tracking/etc), will definitely look at it more in depth in a bit here.

Your yearly usage sounds close to ours, we're a bit higher but not much more at about 20,000 kWh. So even with a somewhat smaller system like that, you're still over producing peak power? Have you calculated what it would mean for your bills if you went with the standard rate? Let me know if you need a spreadsheet with all the APS formulas already inputed, you would just need to plug in your kWh used per month.

FWIW, Further to local system output and some SWAG check as to potential output as an adjunct/check on PVWatts or other tools - check out PVOutlet.org., go to "teams", "United States", then map to your area. It appears Phoenix has 4 systems. I'd only caution to keep in mind individual local results will be different because of different tilt and azimuth as well as shading and other conditions. If you find two systems w/ similar tilt/az. it's interesting to note the usual close agreement in output per D.C. Watt irrespective of panel make.

[HX_Guy]

Yeah, I would be interested in that spreadsheet. I made one way back before solar but it's a mess and not really well-suited to comparing the standard with TOU rates.

Check your messages, I sent you a link to the Google Docs spreadsheet.

[HX_Guy]

Ian, thanks again for the link to your numbers, very helpful.

I took the numbers of your 6.9kW system and applied them to a 10.5kW (assuming it's linear) and got a yearly production of 18,621 which is close to the 18,020 I was quoted today. I then used a 1.52 multiplier and applied it to the past 12 months and compared the production to our usage. Now of course this is a total estimate but I'm hoping it's close to +/-10%.



This is based off the standard rate plan, not the TOU. Figuring the TOU would be a lot more difficult, I may do it if I get super bored.
According to this, I could see a potential savings right off the bat of ~$300/year. After the solar system is paid off, then the savings would be $2,400 per year. Does that seem about right?

[Ian S]

Your yearly usage sounds close to ours, we're a bit higher but not much more at about 20,000 kWh. So even with a somewhat smaller system like that, you're still over producing peak power? Have you calculated what it would mean for your bills if you went with the standard rate? Let me know if you need a spreadsheet with all the APS formulas already inputed, you would just need to plug in your kWh used per month.

Yeah the over production is an annoyance - would love to have it offset off peak instead. However, when my system was installed in 2012, the true-up rate was about $0.06/kWh which in effect made it close to offsetting off-peak usage. But in 2013, APS changed the rate to $0.029/ kWh and I wouldn't be surprised if they reduced it further. I did look in a quick and dirty way at how the standard rate would have worked and unfortunately, it would be deadly in the summer and wind up costing some hundreds more overall. That said, I'll soon be in the market for a new HVAC system with higher efficiency so that might make the standard rate more appealing. Yeah, I would be interested in that spreadsheet. I made one way back before solar but it's a mess and not really well-suited to comparing the standard with TOU rates.

[silversaver]

I have Bosch 255W panels install since Dec 2103. I don't think they are any different as other brand name (discontinued) and I got them at $2.84 per Watt DC before incentives. I have lots friends looking for the same deal and wish they can get my deal, but no more.

I don't think you can get Bosch through Solar City or other leasing company, because the bank will not use discontinued brand name panels.

[HX_Guy]

Whoa that's awesome! I love stuff like that (graphcs/tracking/etc), will definitely look at it more in depth in a bit here.

Your yearly usage sounds close to ours, we're a bit higher but not much more at about 20,000 kWh. So even with a somewhat smaller system like that, you're still over producing peak power? Have you calculated what it would mean for your bills if you went with the standard rate? Let me know if you need a spreadsheet with all the APS formulas already inputed, you would just need to plug in your kWh used per month.

[Ian S]

Ay! There's definitely a lot of things to consider.

I did see some numbers on another site from someone in Phoenix who was on the noon-7pm TOU and you're completely right, they had a bunch of excess kWh on-peak and no enough off-peak, but with off-peak being 1/4 of the cost of on-peak power, it still worked out better in their opinion. Then someone else chimed in and said they are on the standard rate plan and they found that it worked best for them.

I guess it goes without saying that it will depend from person to person. We are currently on the noon-7pm TOU already and we use quite a bit on-peak since we are home all day and keep the A/C at 77º even during the day, and have a 5 ton and a 1.5 ton A/C system.

Is there really a way to accurately calculate? I mean I know how much we use on-peak vs off-peak, but how do you figure how much the system will produce between the different hours? How big is your system Ian and which way do the panels face? What is your production like if you don't mind sharing?

We're like you - home during the day. Home is old (1969) all on one level with a 5 ton gaspack. I haven't checked in awhile but last time I calculated the on vs off peak production, I think on peak/off peak ratio was about 55/45. That's for a southern exposure and would obviously be different for other orientations. My system is a 6.9 kW Sunpower system, 15 deg panel slope and produces about 12,400 kWh annually in central Phoenix. Pre-solar, we used about 18,750 kWh annually. We're saving about $1500/year. Here's a link to see my actual production data. You could probably check to see what the ratio is between on and off peak production.

[HX_Guy]

Depends on who you talk to. If the panels have Bosh name on them, I think they're discontinued. Ask another CA poster w/the handle "Silversaver". He got a great deal on some discontinued Bosch - <$3.00/W and his performance seems up to snuff. I've got a Rebadged PVI 5000. It's only been in service about 6-7 months and seems OK. Runs quiet as a church mouse, but clips at 5035 W, which is mostly OK under clear skies around here, as max. array clear sky output will be ~~ 4,800 W, +/- some. The clipping occurs when transient irradiance behavior under pt. cloudy skies cause reflections from clouds and enhances irradiance by about 10 - 20% momentarily and intermittently. Based on my experience, On a 10.7 kW sys., I wouldn't go smaller than 2 X 5kW Power One's.

Thanks for the input. I actually just wrapped up my first on-site estimate from a local company. Unfortunately their salesman wasn't very good and I don't even know if I can trust his information but he gave me two quotes with panels/inverters that I've never heard of, though I have no experience with this so that doesn't mean much.

The first was a 10.6kW system using 40 Sun Edison panels and a Fronius inverter. The price was $43,000 (before credits) and he said it included an electrical panel change which will be necessary according to him. We have a 200 AMP panel and he said we'll need a 400 AMP panel, does that sound correct?

The second was a 10.5kW system using 42 Canadian Solar panels and also a Fornius inverter. Price was $33,000 (before credits) and also included the upgraded panel change. Obviously much better price, but he didn't know the model numbers of the panels or inverters [Edit: Found on the quote that the inverter is a Fronius USA, Model: IG Plus A 10.0-240.]

Any input on those?