Considering solar panels, looking for sizing/financing advice

[steve3]

You might be right about the tsunami. I was able to place my order, but now when I go to add the details in my Tesla account the page crashes

Even after a cache/cookie clear. Have you been able to get in to manage your order?

EDIT: Only way I've found to get into the Home Assessment is through a mobile phone.

I finished the home assessment photo uploads yesterday, using a laptop because that’s where I had started the process, and had no clue how many pics would be required! It looks like you were able to complete it on your phone, right? So no more crashing in your account page? At this point, I guess we just wait to hear back from Tesla for the next steps.

Good luck with your project!

 

[willow_hiller]

Got my layout, but I can't view it because the URL does not resolve. They're still using Solar City servers, and it appears they're struggling a little with the traffic right now:

 

[Zaxxon]

Well that's got to be frustrating.

 

[Motorbeans]

Got my layout, but I can't view it because the URL does not resolve. They're still using Solar City servers, and it appears they're struggling a little with the traffic right now:

View attachment 555488

I'm in the exact same boat. I was excited that it seemed to be moving quickly...ugh.

 

[willow_hiller]

It's working this morning!

14,249 kW divided by 36 panels would imply 395 watt each

Also, does the Est. Annual Production seem a bit low? Even if I assume 340 watt per panel, PVWatts says for my address:

• 12 panels SW should generate 5,067 to 5,506 kWh per year
• 10 panels SE should generate 4,267 to 4,636 kWh per year
• 10 panels NW should generate 3,217 to 3,495 kWh per year
• 4 panels NE should generate 1,305 to 1,418 kWh per year

So a range from 13,856 kWh to 15,055 kWh annually?

 

[BrettS]

It's working this morning!
14,249 kW divided by 36 panels would imply 395 watt each

That’s really odd. I’m not sure what to make of that. In my case I got a 15120w system with 48 315w panels and the math works out perfectly.

Also, does the Est. Annual Production seem a bit low?

From my experience I believe that Tesla is pretty conservative on the annual estimate. My system was just installed yesterday, so obviously I don’t know what I’m actually going to get, but comparing quotes from a number of other companies and Tesla it seemed that Tesla was 10-15% lower than other compatible systems. I asked one of the energy advisors about it and they said that they do tend to estimate on the low side just to make sure no one gets any bad surprises.

 

[Zaxxon]

The nameplate kW capacity of my system design also matched my panel count divided by W/panel (in my case, 315 W last year) perfectly. And yes, their annual estimate looks to have been conservative for me, as well (though I'm not yet a full year in, so we'll see). My best guess is that I'll overproduce their estimate by 5-10%.

 

[willow_hiller]

@Motorbeans I'm interested in your system kW capacity when your design document loads. I wonder if this is something unique to QCell G6+ panels.

 

[BrettS]

@Motorbeans I'm interested in your system kW capacity when your design document loads. I wonder if this is something unique to QCell G6+ panels.

I feel like it must be a mistake of some sort. Someone else posted the other day because they had requested 3 powerwalls, but their design docs gave them the specs for a 9 powerwall system. They called and apparently something screwed up the numbers on Tesla’s side.

I’d suggest calling 877-571-7652 to talk to one of the energy advisors. They should be able to either explain why it’s showing those numbers or get it corrected if it’s a mistake.

 

[willow_hiller]

I’d suggest calling 877-571-7652 to talk to one of the energy advisors. They should be able to either explain why it’s showing those numbers or get it corrected if it’s a mistake.

It's a typo. The advisor said he would correct it, it should show 12,240 kW.

At first he started explaining to me the difference between size and production, and then was really confused when I told him I wasn't asking about production I was asking about size

 

[Motorbeans]

The layout docs still are not loading for me. Agh!!!

 

[Motorbeans]

Well that was easy. I called them up and the guy was able to move the document to the completed section that allowed me to download it. Works out to 340 watts per panel for the size and about 447 watts in annual generation per panel.

 

[BrettS]

Well that was easy. I called them up and the guy was able to move the document to the completed section that allowed me to download it.

I tried to view the document and it didn’t load for me, so you might need to repost it. However, before you do, the layout document usually has your name and address, so you might just want to take a screenshot of the doc and edit it to remove your personal information before you post it.

 

[Motorbeans]

I tried to view the document and it didn’t load for me, so you might need to repost it. However, before you do, the layout document usually has your name and address, so you might just want to take a screenshot of the doc and edit it to remove your personal information before you post it.

My bad, I meant to just load the pic as opposed to the pdf. Fixed!

 

[Zaxxon]

Well that was easy. I called them up and the guy was able to move the document to the completed section that allowed me to download it. Works out to 340 watts per panel for the size and about 447 watts in annual generation per panel. View attachment 555712

Friendly correction, as you're joining the PV club and everyone has trouble with units at first. 'watts of annual generation' isn't a thing--watts are a measure of power (instantaneous). Wh, or watt-hours, are a measure of energy (over time).

Your system is 24 340W panels, and thus the max *power* output is 8,160 watts. The estimated *energy* output is 10,731 kWh/year, or 447 kWh/panel/year (447,000 watt-hours/year/panel). In short, if you're measuring how much a system is using *right now*, you're talking watts, and if you're measuring production over time, you're talking watt-hours.

I'm glad they got your layout documents fixed!

@Motorbeans, out of curiosity, is this system estimated to cover 100% of your annual production? If not, have you considered moving to the 'large' system class? Your roof appears to have the space and to not be in an orientation that's problematic, assuming the layout is representative.

 

[Motorbeans]

Friendly correction, as you're joining the PV club and everyone has trouble with units at first. 'watts of annual generation' isn't a thing--watts are a measure of power (instantaneous). Wh, or watt-hours, are a measure of energy (over time).

Your system is 24 340W panels, and thus the max *power* output is 8,160 watts. The estimated *energy* output is 10,731 kWh/year, or 447 kWh/panel/year (447,000 watt-hours/year/panel). In short, if you're measuring how much a system is using *right now*, you're talking watts, and if you're measuring production over time, you're talking watt-hours.

I'm glad they got your layout documents fixed!

@Motorbeans, out of curiosity, is this system estimated to cover 100% of your annual production? If not, have you considered moving to the 'large' system class? Your roof appears to have the space and to not be in an orientation that's problematic, assuming the layout is representative.

Thank you! Yes, I realize I am using the terms interchangeably and it is not correct. Thank you for the quick and easy clarification.

This size should cover about 105% of our annual use. We have a net metering program in Utah that pays a bit less than what we are charged for (about $0.09 per kWh) vs .$0.10-$0.14 per kWh and then they have an annual true-up. I have thought a little bit about the larger system but I'm having a difficult time justifying with our usage and the fact we will have net metering at this rate for roughly the next 10 years before we are kicked off to the wholesale rate. That's what the utility is claiming at least and what has been negotiated with the state.

What are your thoughts on over-sizing in scenario like mine?

 

[steve3]

I’d suggest calling 877-571-7652 to talk to one of the energy advisors.

Thanks for providing this number, it was very helpful. I was able to speak to an energy advisor & submitted a panel layout tweak I’d like to see, & I let them know I’m going ahead with both breaker panel & service upgrades before the solar install, so all my photos will change. The advisor was great.

 

[Zaxxon]

[Edit - Directed at Motorbeans]

If that will cover all your current (and expected) usage, awesome. My general thought is that it's better to oversize when installing if you think there's any chance you may want more later, as it's a lot less of a PITA than going through the whole process again later. Exacerbated in my case because my first system wasn't with Tesla, so I have 2 completely independent systems on my roof. It works out just fine, but was definitely more work and pain going my route.

Also, in my case, I initially sized the first system based in part on what I wanted to spend vs what I really needed (mistake!), and I also wasn't counting on eventually becoming a 2 EV household, migrating half my home heating to electric, etc.

Do you have a Tesla car? If not, do you see yourself getting one (or two, or any other EVs) in the future? If so, that will add a considerable amount of electrical usage (a rough calculation for a Model 3 is 250 kWh/year per 1,000 miles driven).

 

[BrettS]

Thank you! Yes, I realize I am using the terms interchangeably and it is not correct. Thank you for the quick and easy clarification.

This size should cover about 105% of our annual use. We have a net metering program in Utah that pays a bit less than what we are charged for (about $0.09 per kWh) vs .$0.10-$0.14 per kWh and then they have an annual true-up. I have thought a little bit about the larger system but I'm having a difficult time justifying with our usage and the fact we will have net metering at this rate for roughly the next 10 years before we are kicked off to the wholesale rate. That's what the utility is claiming at least and what has been negotiated with the state.

What are your thoughts on over-sizing in scenario like mine?

I think oversizing by 5% is not a problem at all. It seems like energy demand only goes up over time and you may wind up with an electric car or something that will take more power. Additionally the panel production will go down over time, so at the end of their lives they may be producing less power.

I wouldn’t go overboard and get a system that produces 150% of your power demand unless you knew that you were going to be getting something like an electric car that would use it. But 105% seems totally reasonable.

 

[Motorbeans]

[Edit - Directed at Motorbeans]

If that will cover all your current (and expected) usage, awesome. My general thought is that it's better to oversize when installing if you think there's any chance you may want more later, as it's a lot less of a PITA than going through the whole process again later. Exacerbated in my case because my first system wasn't with Tesla, so I have 2 completely independent systems on my roof. It works out just fine, but was definitely more work and pain going my route.

Also, in my case, I initially sized the first system based in part on what I wanted to spend vs what I really needed (mistake!), and I also wasn't counting on eventually becoming a 2 EV household, migrating half my home heating to electric, etc.

Do you have a Tesla car? If not, do you see yourself getting one (or two, or any other EVs) in the future? If so, that will add a considerable amount of electrical usage (a rough calculation for a Model 3 is 250 kWh/year per 1,000 miles driven).

So we have a Model 3 and a Chevy Volt (had the Volt for years so our usage definitely accounts for the Volt) but our energy usage over the last several months is all out of wack because of the pandemic and I only got the M3 around October of last year so it's not very easy to figure out my real usage because on top of it.... when I drove to work I almost exclusively charged there for free. Now that I'm working remote I am barely driving at all... But, I am also at a point where in the future I would prefer to replace my gas water heater to electric and then even further in the future try to get more electric heating in place. If I need to get more panels 10 years from now I suspect that pricing will be much cheaper considering the trend of the pricing but then like you said... PITA to actually do that. Decisions are hard.