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**albert436** · 08-12-2015, 12:46 PM

Where in San Diego are you ?

Which direction does your roof face ?

What kind of angle is it ?

**thejq** · 08-12-2015, 12:58 PM

Depending on the orientation and tilt, ~5KW is a common size (not that small) in SD area. Sunpower is a premium brand with the best warranty in the industry but with premium pricing as well. Personally I wouldn't pay more than 10% extra (eg. than LGs) for that. Both LGs and Solarworld are good panels, but LG is definitely more bankable, as Solarworld almost went BK twice. Other good choices are Canadian solar, Trina and Sunedison. If you don't have shading and want the highest reliability, I'd go with SMA and save a little money too. But if you want the best performance with panel level monitoring/debugging capability, go with Solaredge. Enphase is fine if you plan to pair with lower wattage panels, but will likely clip with the ones on your list. If you have a normal roof (tile or shingle), QuickMount system is tried and proven and trusted. As expensive as fixing the roof can be, I won't save a few bucks by using cheap mounting HW.

As for your price, $3.5-$3.75 seems to be the norm in SD without special installation requirements. Check your PM.

**jakepv** · 08-12-2015, 01:27 PM

Originally posted by albert436

Where in San Diego are you ?

Which direction does your roof face ?

What kind of angle is it ?

Carlsbad, SE and 20*

**J.P.M.** · 08-12-2015, 01:39 PM

Originally posted by jakepv

Carlsbad, SE and 20*

1.) I missed the post about what your annual approx. annual electrical usage is. .................2.) Have you run PVWatts on your own yet ? If not, suggest you try it and use a 8 -10% system derate instead of the 14 % default rate, and the Carlsbab airport data.................... 3.) Sometimes, depending on use PATTERNS, using a T.O.U. pricing tariff can allow for a smaller system size to have the end result of the same $$ reduction in an annual electric bill as when on tiered rates, thus lowering initial costs even more.

**thejq** · 08-12-2015, 01:48 PM

Originally posted by jakepv

Carlsbad, SE and 20*

SE is definitely not ideal in Carlsbad (92008 and 92011 are the worst) when most of the time the marine layer doesn't disappear until late morning. Anyway you can put it on a SW roof or even partially? Like JPM said, get a good estimation on your system size with http://pvwatts.nrel.gov/ .

**jakepv** · 08-12-2015, 02:33 PM

Originally posted by J.P.M.

1.) I missed the post about what your annual approx. annual electrical usage is. .................2.) Have you run PVWatts on your own yet ? If not, suggest you try it and use a 8 -10% system derate instead of the 14 % default rate, and the Carlsbab airport data.................... 3.) Sometimes, depending on use PATTERNS, using a T.O.U. pricing tariff can allow for a smaller system size to have the end result of the same $$ reduction in an annual electric bill as when on tiered rates, thus lowering initial costs even more.

1) 8,400 kWh
2) 8,472 kWh
3) TOU seems to be a bit of a gamble to me since my understanding is that you can only opt in/out once a year. An installer told me that TOU is recommended for folks with electric cars (which is not me). I work from home during the day and my wife is a stay at home mom so I don't think TOU makes sense for us, would you agree?

**J.P.M.** · 08-12-2015, 03:16 PM

Originally posted by jakepv

1) 8,400 kWh
2) 8,472 kWh
3) TOU seems to be a bit of a gamble to me since my understanding is that you can only opt in/out once a year. An installer told me that TOU is recommended for folks with electric cars (which is not me). I work from home during the day and my wife is a stay at home mom so I don't think TOU makes sense for us, would you agree?

Thank you. On #3, T.O.U. may or may not make economic sense for everyone. That's why it takes a bit of analysis. ONE consideration that usually tips the balance to T.O.U. is the ability to charge an EV at super off peak rates. It is not the only consideration.........................If you want to do the homework, and can get a fairly decent guess on your usage PATTERN, you may find (or maybe find to the contrary) that energy generated under a T.O.U. tariff is, on average, worth more/kWh than the cost paid per average kWh of energy used, allowing a smaller system to produce as much revenue as a larger system. That's were and how the initial increase in savings under T.O.U. can occur.

**thejq** · 08-12-2015, 04:17 PM

With SDG&E, you can download the per-hour usage data from their website. If you're good with spread sheet, you can superimpose that with different TOU plans and see if it makes sense. Even without EV, if you can shift bulk of your usage (eg. electric dryer, AC etc) to the cheapest hours, it might still work. Also the orientation of the panels becomes more important with TOU as well.

**J.P.M.** · 08-12-2015, 05:08 PM

Originally posted by thejq

With SDG&E, you can download the per-hour usage data from their website. If you're good with spread sheet, you can superimpose that with different TOU plans and see if it makes sense. Even without EV, if you can shift bulk of your usage (eg. electric dryer, AC etc) to the cheapest hours, it might still work. Also the orientation of the panels becomes more important with TOU as well.

Lots of fun but doable. Just keep in mind that use patterns are just that - and not locked in...........................On the array orientation: The optimum orientation shift to max out system REVENUE is a function of the T.O.U. pricing and time schedule rather than usage. A certain orientation will produce a value of the revenue independent of a usage pattern. Around here, that optimum is somewhere around 195 - 205 deg. az. and about 30 deg. tilt. That's mostly an academic exercise, because most arrays are parallel to a roof fixed surface. Basically, for T.O.U. array sizing optimization, run PVWatts for all the orientations you have and, for any array size, pick the one that maximizes REVENUE, not necessarily PRODUCTION.

**jakepv** · 08-12-2015, 05:37 PM

Looks like the ideal TOU pattern would be to limit or have no consumption during on-peak hours and shift major consumption to off or super off-peak hours per the chart linked below:

Page not found | San Diego Gas & Electric

http://www.sdge.com/clean-energy/ev-rates

This is good stuff!

**J.P.M.** · 08-12-2015, 10:40 PM

Originally posted by jakepv

Looks like the ideal TOU pattern would be to limit or have no consumption during on-peak hours and shift major consumption to off or super off-peak hours per the chart linked below:

Page not found | San Diego Gas & Electric

http://www.sdge.com/clean-energy/ev-rates

This is good stuff!

Pretty much. As something of a limiting example (only), if ALL use is at super off peak, at say $0.18/kWh, and all generation were at peak times only, with a blended summer/winter rate of say $0.36/kWh on average, then a system that generated, say 8,000 kWh/yr. would produce (8,000 kWh/yr) X ( $0.36/kWh) = $2,880/yr. Meanwhile, that would completely offset ($2,880/yr)/($0.18/kWh) = 16,000 kWh/yr. in usage. So, for this impractical example, the system can be sized to produce half the electricity needed, and offset the entire bill. Again, a limiting example and probably VERY impractical from a use standpoint. However, it does point out that generating when costs/revenues are high(er) while shifting as much of the use/load to times when costs/revenues are low(er) can result in system size reductions and lower initial system costs. The downside, besides doing laundry @ 2 A.M., is that a fair amount of cooperation is required among family members. Check out the SDG & E tariff DR-SES. Also, note that tariff rates and hours are subject to change and probably will.

**albert436** · 08-14-2015, 12:47 PM

Originally posted by J.P.M.

Lots of fun but doable. Just keep in mind that use patterns are just that - and not locked in...........................On the array orientation: The optimum orientation shift to max out system REVENUE is a function of the T.O.U. pricing and time schedule rather than usage. A certain orientation will produce a value of the revenue independent of a usage pattern. Around here, that optimum is somewhere around 195 - 205 deg. az. and about 30 deg. tilt. That's mostly an academic exercise, because most arrays are parallel to a roof fixed surface. Basically, for T.O.U. array sizing optimization, run PVWatts for all the orientations you have and, for any array size, pick the one that maximizes REVENUE, not necessarily PRODUCTION.

Great stuff, thanks.

**jakepv** · 08-16-2015, 05:00 AM

I'm down to two proposals, LG vs SunPower. The SunPower proposal is about 10% higher than the LG. In my layman's mind, the premium is mostly for the SP 25 year warranty compared to 12 for LG.

As for the inverters, I understand the argument(s) for Solar Edge vs SMA but just learned that the SE inverter is warrantied for only 12 years, so even though the sales message is 25 years that really just applies to the optimizers. I think I can consider this contest a draw, no?

So the question is, would you pay a 10% premium for SP over LG?

Thanks again to everyone for the sage advice!

**truav8r** · 08-16-2015, 10:13 AM

Originally posted by jakepv

So the question is, would you pay a 10% premium for SP over LG?

FWIW, I just paid a 15% premium for my SP/SMA system compared to an LG quote and 16% over a Solar World quote. Everyone's value perception is going to be different. Chevy's are perfect grocery haulers, but BMW is in no danger of going out of business either.

I totally understand and agree with not overpaying. But taken to the extreme, an argument could be made that driving anything newer than a 1990 Yugo is "overpaying" for transportation.

My reasons for going with SP equipment include both aesthetics (everything on the roof is black, including the InvisiMount racks and even the flashing, which was important to me since the system is on the front of the house) and the quality of the modules. YMMV

So bottom line Jake... I support you either way

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~5 kW System in San Diego

~5 kW System in San Diego

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