Solar Roof order August 19, 2020

[Cyber_Dav]

I placed an order earlier but canceled when I found my utility restricts me to a max 5kw system. Have gotten over it (mostly) and placed a new order today.

Tesla is recommending a 23kw system! It's kind of nuts they don't let you specify a size.

My service entrance / main panel is at the top left (in this google view) of the detached garage. Will they be willing to mount the active tiles on the garage? It would definitely simplify the electrical. They can put anything they want inside the garage, just inches or feet from the main panel.

 

[BrettS]

Unfortunately I don’t think that tesla will install a 5kW solar roof on a house that could support a 23kW system. I suspect that if you really are limited to 5kW then tesla will probably cancel the order at some point. From what we’ve seen in the past they pick and choose their installs to some extent and installing nearly an entire roof of inactive tiles is not likely an install that they would want to do.

 

[wjgjr]

Unfortunately I don’t think that tesla will install a 5kW solar roof on a house that could support a 23kW system. I suspect that if you really are limited to 5kW then tesla will probably cancel the order at some point. From what we’ve seen in the past they pick and choose their installs to some extent and installing nearly an entire roof of inactive tiles is not likely an install that they would want to do.

I agree it is unlikely they would perform such a solar roof install because of the number of inactive tiles. We have a much smaller solar roof (maxed out, ~8.2 kW DC system) and they would not have gone for a smaller install (we inquired about options/pricing to include and exclude the north-facing roof since it will produce only a little more than half that of the south-facing roof.)

The more interesting question, out of curiosity, is why the 5 kW limit? We've seen other utilities that offer less favorable terms for exported power, either based on current usage or some size cutoff, but a hard limit of 5 kW seems really harsh (and oddly out of place in CA, when they now have rules requiring solar for new construction, among other things.)

 

[jjrandorin]

Most of the utilities out here will want you to size the solar to no more than about 110-120% of prior years usage. They usually have some sort of document you can file that says you expect your electrical usage to change because you are installing a pool / buying an EV etc, or that you have not been in the home for 12 months so the prior 12 months usage doesnt apply to you.

I suspect OPs "5k limit" is coming from previous usage, but should be able to be upsized some if OP states they expect higher usage as above. With that being said, I doubt they are going to let OP size that much above current usage, and I also doubt tesla will do a 5k solar roof on the property in that picture. You would be looking at solar panels, not a solar roof, imo.

If OP has usage that is somewhat near that size solar though, he can likely get it through the utility, by showing a months usage that would justify that size solar.

 

[wjgjr]

Most of the utilities out here will want you to size the solar to no more than about 110-120% of prior years usage. They usually have some sort of document you can file that says you expect your electrical usage to change because you are installing a pool / buying an EV etc, or that you have not been in the home for 12 months so the prior 12 months usage doesnt apply to you.

I suspect OPs "5k limit" is coming from previous usage, but should be able to be upsized some if OP states they expect higher usage as above. With that being said, I doubt they are going to let OP size that much above current usage, and I also doubt tesla will do a 5k solar roof on the property in that picture. You would be looking at solar panels, not a solar roof, imo.

If OP has usage that is somewhat near that size solar though, he can likely get it through the utility, by showing a months usage that would justify that size solar.

That makes sense, though it does seem like 5 kW is surprisingly low for a structure with a roof that can support 23 kW of solar roof, but I do not know the full story.

Even then, what I was also trying to figure out is what those limits mean. Our utility's rules are more generous in that you can size up to 200% usage, but they are clear that limit is applicable only if you want to take advantage of net metering. If you install larger, my reading is you can still do so and connect to the grid, but excess usage would (I believe) be paid out at a wholesale rate other generators get. So I was trying to figure out whether 5 kW is a hard limit (either based on usage or just a flat rule) or a limit to take advantage of better net metering or other terms. If it is the latter, a larger system might still be worthwhile if it is sized properly, including use of PWs, to try to be as close to self-sufficient as possible.

 

[GHTech]

Hi!

When I was originally considering a solar roof (couple of months ago), they said that they had a minimum of 2.5 w per sq. ft. of roof. At that time, my minimum was 8.5 kW system. Now they seem to be allowing me to get a 7 kW system. But, I already reroofed and getting am getting PV and 2 PW on the 1st of Sep.

Regards,

GHTech

 

[Cyber_Dav]

1) Previous solar roof quote from Tesla was 5.1kW. Their online estimator is simply screwed up. 23kW for this house (2,300 sq ft) would be insane.

2) My utility (Anza Electric Cooperative) is very small, about 4,000 customers. They have 1 'solar guy', Don Downing. Here is what he wrote me: "Also the size of the system is limited to a 5 Kw system or consumers historic use whichever is less.". Draconian? Yes. Flexible? No.

My only question is, will they install on a detached garage?

Note: in reference to original quote: I wanted 8 to 11 kW system. When I found out about my utility's limit I canceled the order. I have since decided 5 is better than nothing.

 

[dsss]

My only question is, will they install on a detached garage?

Yes, it can be done. They quoted me an add-on for our attached garage but it wasn't cost or energy efficient so we passed. We are putting the powerwalls inside our garage however, so they quoted me some custom trenchwork to make that happen.

 

[wjgjr]

1) Previous solar roof quote from Tesla was 5.1kW. Their online estimator is simply screwed up. 23kW for this house (2,300 sq ft) would be insane.

2) My utility (Anza Electric Cooperative) is very small, about 4,000 customers. They have 1 'solar guy', Don Downing. Here is what he wrote me: "Also the size of the system is limited to a 5 Kw system or consumers historic use whichever is less.". Draconian? Yes. Flexible? No.

My only question is, will they install on a detached garage?

Note: in reference to original quote: I wanted 8 to 11 kW system. When I found out about my utility's limit I canceled the order. I have since decided 5 is better than nothing.

@dsss answered for a PV-producing system. For non-PV (and with a 5 kW limit, not sure if you just planned it all on the house,) the answer should also be yes, but @GHTech mentioned the possible limits for Tesla on non-PV compared to PV. Our solar roof has PV on our main, 2-story roof. However, we have a small, one-story room (sort of a small patio that was enclosed) and Tesla re-roofed that entirely with non-PV material since the small size and lower elevation meant PV would not work. Don't see why a garage, attached or not, would be any different for a non-PV isnstall.

 

[jjrandorin]

1) Previous solar roof quote from Tesla was 5.1kW. Their online estimator is simply screwed up. 23kW for this house (2,300 sq ft) would be insane.

2) My utility (Anza Electric Cooperative) is very small, about 4,000 customers. They have 1 'solar guy', Don Downing. Here is what he wrote me: "Also the size of the system is limited to a 5 Kw system or consumers historic use whichever is less.". Draconian? Yes. Flexible? No.

My only question is, will they install on a detached garage?

Note: in reference to original quote: I wanted 8 to 11 kW system. When I found out about my utility's limit I canceled the order. I have since decided 5 is better than nothing.

I took a quick peek (since I know roughly where anza is, because I live in temecula), and even the net metering they offer is different. Maybe ask them how big of an array you can get if they dont net meter it, that is, if you plan to get something that has PV and batteries that would let you keep "most" of your energy.

Thats pretty draconian out there... I didnt know that Anza had its own electricity co-op

 

[Cyber_Dav]

I took a quick peek (since I know roughly where anza is, because I live in temecula), and even the net metering they offer is different. Maybe ask them how big of an array you can get if they dont net meter it, that is, if you plan to get something that has PV and batteries that would let you keep "most" of your energy.

Hey neighbor!

What I figure is the co-op has nothing to say regarding off-grid solar. So I'll get the 5kW grid-tied system now, and if I need more add some off-grid.

 

[BrettS]

Hey neighbor!

What I figure is the co-op has nothing to say regarding off-grid solar. So I'll get the 5kW grid-tied system now, and if I need more add some off-grid.

If you are serious about adding an off grid system later you might want to take some time to think about exactly what that would look like and how that would work for you. It likely won’t be possible add more active tiles to your solar roof once it is installed, especially if you want it to be part of a separate off grid system. So you’d be looking at adding panels for this other system, and since you couldn’t mount the panels over your solar roof you’d be looking at a ground mount system.

Additionally keep in mind that an off grid system would have to be something totally separate. You can’t use an off grid system to supplement the power going to your house. You might be able to use it for a work shed that doesn’t have a grid connection or maybe even a car charger (although that starts to get complicated because a car can draw so much power that a small off grid system is unlikely to be able to provide enough power and/or power at the time that you actually want to charge your car)

What @jjrandorin was suggesting was a no export or limited export system. You can have a grid tied system that is configured not to export any excess power to the grid. So that way (assuming your utility is OK with it) you could have a system that was large enough to cover all or most of your power demand, but at the times there was excess solar power it would simply limit the inverter power output rather than sending the excess power to the grid. If could also be configured to send no more than x kW back to the grid. However, you are still grid tied, so if there are days when you don’t generate enough solar power you can still pull power from the grid. If the utility is concerned about a significant amount of power being fed back into the grid, then this might be a good compromise.

 

[jboy210]

1) Previous solar roof quote from Tesla was 5.1kW. Their online estimator is simply screwed up. 23kW for this house (2,300 sq ft) would be insane.

2) My utility (Anza Electric Cooperative) is very small, about 4,000 customers. They have 1 'solar guy', Don Downing. Here is what he wrote me: "Also the size of the system is limited to a 5 Kw system or consumers historic use whichever is less.". Draconian? Yes. Flexible? No.

My only question is, will they install on a detached garage?

Note: in reference to original quote: I wanted 8 to 11 kW system. When I found out about my utility's limit I canceled the order. I have since decided 5 is better than nothing.

Do you have options for another power provider? Same wiring, just different sources and more importantly rules on solar.

But, given your rural setting is a solar roof or any rooftop solar necessary? I can't tell where the property lines are, but it looks like you have the space for ground-based panel installation. That could be at optimum angles and orientation for solar production.

 

[jjrandorin]

Hey neighbor!

What I figure is the co-op has nothing to say regarding off-grid solar. So I'll get the 5kW grid-tied system now, and if I need more add some off-grid.

I am guessing you likely have some land you could put a ground mounted system on, if you wanted to. Even if thats not the case, As someone else mentioned, if you are even thinking about a true off grid system, you want to plan that now, because i am not sure if a grid tied and non grid tied system will integrate at all (my guess is, no they wont).

@BrettS captured what I was thinking very well (thanks!), thats what i would likely look at if I was out there. I also wouldnt get a solar roof if I was out there, I would either get regular solar panels ontop of my existing roof, or replace the roof if it needed it and get regular solar panels on top. fairly easy to expand with more solar panels on a regular roof. Impossible to expand solar on a solar roof without re roofing, which you are not going to do.

Tesla likely wouldnt do a solar roof that small anyway, but would likely have no issue doing a panel install that small as it would be relatively quick and painless.

All depends on your goals and your power usage (both now and planned in the future) though.

 

[njhtran]

would completely off grid scenario be out of the picture? Where you get the large capacity with powerwalls only and detach from utility?

 

[BrettS]

would completely off grid scenario be out of the picture? Where you get the large capacity with powerwalls only and detach from utility?

Technically such a system is possible, but usually it doesn’t really make financial sense. You need to make sure that the solar portion of the system is large enough to get you through the lowest production times in the winter and make sure the powerwalls are big enough to carry you through several cloudy/rainy days in a row. This will wind up being a much larger and much more expensive system than you would need for a grid tied system since a grid tied system can always draw some power from the grid if necessary.

It also means that a lot of power will be wasted because a system that will be big enough to get you through the winter off grid will be way oversized for the summer and will produce much more power than you need or can use during the summer. It doesn’t really make financial sense to buy that much more capacity that you don’t need for most of the year.

There also may be regulations to deal with. In florida, at least, it’s not legal to go completely off grid. Even if you have a system that’s big enough to generate 100% of your power 100% of the time you still need to stay connected to the grid. But I think that’s a uniquely Florida thing.

 

[njhtran]

You need to make sure that the solar portion of the system is large enough to get you through the lowest production times in the winter and make sure the powerwalls are big enough to carry you through several cloudy/rainy days in a row.

agreed however in socal we dont really have a winter

 

[BrettS]

agreed however in socal we dont really have a winter

This is true, but due to the sun’s position in the sky and the shorter days there is still much lower production during the winter months. Just for fun I plugged in a random San Diego address into PVWatts. I put in a 15kW system with a due south orientation and it’s showing nearly 1000kWh less per month over the the winter months than the summer months.

 

[njhtran]

Yes San Diego is near the coast but from what I can tell OP is in the desert

 

[jjrandorin]

Yes San Diego is near the coast but from what I can tell OP is in the desert

We still have significantly less production in winter than summer due to sun angles etc. The way solar is sold is based on yearly production but it waxes and wanes through the months.

Peak production for me here in temecula with my 8.7kW system is March -June, maxing out at about 52kWh daily production. Same system in december, maxes out at around 22 kWh daily production (both on clear sunny days).

22 kWh isnt enough to run my house during the winter, while 52 kWh is more than I need to run my home during the summer. Thats what @BrettS is talking about... and it effects everyone, even those of us with mostly sunny days