New system config in Bay Area

[DanKegel]

For me even at $2/watt would take me more than 10 years to maybe break even.

Ouch. What's your cost of electricity?

Default settings at http://www.tampaelectric.com/company...larcalculator/ say 7 years payback time for $2/watt in their area...

[SunEagle]

Ouch. What's your cost of electricity?

Default settings at http://www.tampaelectric.com/company...larcalculator/ say 7 years payback time for $2/watt in their area...

Well maybe you can do the math.

But based on PV watts a 6000 watt system all facing South (I actually might only be able to put 1/2 facing South & 1/2 facing West) would save me ~ 8200 kWh or ~$1000 per year using $0.12/kWh.

So at $2/watt that comes to $12000 or 12 years. Now if my price was that $12000 minus the 30% Fed Tax rebate it would come to $8400 or about 8.5 years. But my electric rate is now at $0.095/kWh for the first 1000kWh so if I save 8200 kWh that would come to ~ $780/yr saving or a little over 10 year payback. ($8400 / $780/yr = 10.8 yrs.

Now if I use a higher DC to AC derating factor from 0.77 to say .85 I would get a shorter payback but it still depends on how my panels are facing and what type of weather I can get.

So with my plans to retire and move out within 5 years only a Free solar pv system would make economical sense.

[fraser]

After much deliberation and back and forth and 16-18 configs/quotes later I think I have made up my mind

I am going with 18 LG320 panels and SE P300 power optimizers and SE7600 inverter.

Total system power would be 5.76kW and price would be $19,465 => $3.38/Watt.

After rebate cost ~ $13,625.

I am also doing my panel upgrade from 100A to 200A as part of this project.

Had some questions about that:

1. What panel should I be putting? I dont want the best in class but I want best bang for the buck and good saftey rating.
2. I will be putting 1 240V outlet for charging my car at home. Anything special I need to keep in mind when the circuit is wired?

Thanks for all the feedback and help guys.
Appreciate it!

-AM

Sorry to chime in late, but have you considered using APSystems Yc500a microinverters? They connect to 2 panels instead of 1. Couple of sites have them at near or less than $200, so less than $100/panel with an upper limit of 305w per panel. Personally, I like the microinverters as you can easily increase the system size later without many changes. Enphase even has an AC compatible battery coming out. Also, for a 6kw system, how much are those panels each? Should be at around $0.80 per watt for the panels, $.60 if you go with lesser known panels. I've priced the panels and microinverters and if you look around you can find them for less than $6k total, before the 30% federal tax break. Plenty of 305w panels at $200 each, some less. So 20 of those is $4k, plus$2k for the microinverters. Then you just need the BOS and installation. Should be able to be all in at less than $10k on a 6kw system ($7k after taxes), if you are buying the materials yourself and having someone do the install.

Ok, maybe another $600-700 for 60 cell panels. Still....

[ButchDeal]

OP is looking for 60 cell high efficiency modules not 72 cell.

[ButchDeal]

likely more than that for 60 cell high performance. Also need some racking, and flashing.
Then you have all the permits, inspections and labor. You will have at least one electrician onsite for the install (they are not cheap), probably two days considering the MSP upgrade.
Also generally pricing is calculated BEFORE incentives including tax incentive.
OP has hashed out micros vs optimizers already (this is post #78 in the thread) and has a rather decent price. Did you read the thread?

[activemind]

What about roof mounts? I can keep on pointing things like this till your system is complete. Better look at the components of a prebuilt solar kit online and then see where you can save costs rather than thinking that there is just panel and inverter involved!

And yes, I DID look at APS YC500 microinverters and infact even have a quote for a system with them. The price difference for a similar size system between Enphase and YC500 is around 2K. I feel that if I wanted to go microinverter I would pick Enphase rather than APS. Personal preference!

[activemind]

What about misc cost...breaker considerations...permits... pge interconnect...

[ButchDeal]

What about misc cost...breaker considerations...permits... pge interconnect...

Racking, flashing, wires, conduit, combiner, breakers, disconnect,

[fraser]

Great, how would each cost you break out assuming you were looking to keep costs low? I don't think we get to $4k in total, which is what i suggested. If it is more than 4k, then clear
Y there is opportunity for simplification and cost cutting. We should be aiming for $1.50 -$175 installed cost with the installer still making $1-2k for a day's work. It may take longer to actually complete but that' why you parallel path certain aspects of different projects.

[NYHeel]

Most good installers aren't going to take $1-2k for a day's work. First of all with all the inspections it's not going to be a day's work. Second, installers need to spend a lot of money and time creating the permits and dealing with the project management of the process.

Now I agree that pre-incentive costs are kept high because of the government subsidies. If all subsidies went away pricing would probably come down a lot, though not to the current post-subsidy pricing levels. But I just don't see how you're getting this work done for $1-2k

[NYHeel]

The only other thing I can think of is that PVWatts only provides weather data from a few locations so the weather data used in my PVWatts model is the closest location to me but it's far away enough that actual weather can be quite different since the Bay Area has many micro-climates.

PVWatts can provide local SolarAnywhere® data. You just need to check the box to enable it and then double click on the map by your house.

[Willaby]

After much deliberation and back and forth and 16-18 configs/quotes later I think I have made up my mind

I am going with 18 LG320 panels and SE P300 power optimizers and SE7600 inverter.

Total system power would be 5.76kW and price would be $19,465 => $3.38/Watt.

After rebate cost ~ $13,625.

I am also doing my panel upgrade from 100A to 200A as part of this project.

Had some questions about that:

1. What panel should I be putting? I dont want the best in class but I want best bang for the buck and good saftey rating.
2. I will be putting 1 240V outlet for charging my car at home. Anything special I need to keep in mind when the circuit is wired?

Thanks for all the feedback and help guys.
Appreciate it!

-AM

From me, It sounds like you've done your homework. My system is 4.5kw 16 LG280's with SE P400 optimizers and SE5000 inverter.

1) Like you, I upsized the inverter a little just in case. It was only ~$40 more from an SE3800. Small price to pay incase you decide to add a couple panels later.
2) I had a choice of LG280 or LG300 panels. At that time the LG280's had dropped in price and were $60 less each than the LG300. So I went with 16 280w panels instead of 15 300 and it saved me ~$800. You might find a similar savings between the 320w and 300w.
3) My cost was $3.45/w almost a year ago. Still probably a pretty good deal on a tile roof today.

I can't help you on the panel as mine was fine (barely), but for the EV charging, I was able to convert my existing 3-prong dryer outlet myself to a modern 4-prong 30amp compatible with my Clipper Creek charger. My Volt charges at the rate of adding 10 miles per hour and even if I had a Tesla I likely wouldn't upgrade because they have so much range. I could always supercharge if needed too. Since you are getting the panel anyway, you might as well have them put in a higher capacity circuit.

[activemind]

Looks like our requirements and chosen config are very similar.

I will talk to the electrician when installing about the cost differnce between 50A vs higher. I thinm i will be fine with 50A...based on my driving patterns and overnight charging.

I was offered 310 and 320. The price differnce was not much and specially if you look at the life of this project. So i just chose to go with 320s to get the max power i could.

My inverter is SE7600 so i should have a lot of spare capacity if i wanted to add more panels later. Though i doubt it unless our consumption increases by a factor.

I took a long time to decide between microinverter vs solaredge.... i like the features microinverter specially enphase offERS but i am really concerned about all those electronics on the roof exposed to elements. Hence decided to go with solaredge solution.

I am basically looking for a set it and forget it type of system. Lets see how it perfoms.

-AM

[ltbighorn]

Some detailed discussion of the next generation of PG&E's TOU plans was filed here:

https://www.pge.com/nots/rates/tarif...LEC_4764-E.pdf

The TOU pilot structures they are experimenting with create a nice window through which we can see what direction they would like to go.

See also the following, which shows how the E-6 plan will evolve in 2021.

https://www.pge.com/nots/rates/tarif...LEC_4769-E.pdf

I generally recommend sizing a system such that there is a reasonable probability of it paying for itself within the first 10 years. Beyond that, no matter what rates do, your system should be a net benefit. If you size so large that it takes longer than that to recover the installation costs (for example, by buying Sunpower), the exposure to rate uncertainty is even higher and it is hard to know if the system will ever actually get into the black.

Thanks for the links sensij. I'm most of the way through reading them. In the broader sense I was already familiar with their overall plans but the details and reasoning behind them is always interesting. What I don't have a good sense of is how badly it'll affect the effective TOU NEM credit multiplier, which obviously is affected heavily by individual usage patterns. Unfortunately my spreadsheet-fu is weak, but at least I now have almost a year of usage data, which should help if I can figure out how to calculate the impact of TOU changes.

Right now I'm trying to size for 100% kWh offset today (probably >100% bill offset), but I'll start charging my EV at home (currently charge elsewhere) in 18 months, which should bring me down to about 80% kWh offset and probably closer to 100% bill offset later. Payoff should be in 8-9 years under current conditions (would be 7-8 if I wasn't paying extra for the roofers to seal all the penetrations as part of reroofing). Since there's a $10/month min charge, slightly less than 100% bill offset long term is ideal, but between panel degradation and TOU multiplier reduction (possibly going negative), it leads to some uncertainty. I imagine many others are having to take the same factors into consideration.

[r8rs4lf]

After much deliberation and back and forth and 16-18 configs/quotes later I think I have made up my mind

I am going with 18 LG320 panels and SE P300 power optimizers and SE7600 inverter.

Total system power would be 5.76kW and price would be $19,465 => $3.38/Watt.

After rebate cost ~ $13,625.

I am also doing my panel upgrade from 100A to 200A as part of this project.

Had some questions about that:

1. What panel should I be putting? I dont want the best in class but I want best bang for the buck and good saftey rating.
2. I will be putting 1 240V outlet for charging my car at home. Anything special I need to keep in mind when the circuit is wired?

Thanks for all the feedback and help guys.
Appreciate it!

-AM

I'm interested to know your reason for not going with the enphase micro inverters. I'm in the same boat trying to decide which way to go.

[activemind]

I liked everything about enphase but we just dont have enough data on how all those electronic will do up on the roof exposed to all the elements over a period of 25 yrs!

I just went with "safer" inverter with power optimizers config. This way at least I can place the inverter in a shaded area.

The jury is still out and while I do believe that microinverters ARE the future, I am just not sure how well they will do on the roof with today's stuff.

-AM