Quote for SunPower system - Good Price

[Volusiano]

If you have time of day (TOD) pricing you can net zero your bill while not zeroing your consumption as long as you use a good fraction of your consumption during off-peak hours. The solar contribution will be mostly during the higher priced on-peak times.
A west of south orientation can increase this effect, by moving your production more into the afternoon and early evening times instead of before noon when the rates are lower.

Since you mentioned that your house is south facing but you're putting the panels on the west roof, I assume that you have east/west roofs maybe? Otherwise, south facing roof would be the most ideal location in general.

If you're on a TOU plan with the on-peak time in the afternoon, then panels on the west roof is probably best.

But if you're NOT on a TOU plan, and you have an east facing roof as well, it may make more sense to put the panels on the east facing roof because your panels will run cooler in the morning and give better production in the cooler temperature. But this is only if you're NOT on TOU and only have 1 energy bucket to bank your solar credits.

I'm on TOU and my on-peak time is 1-8pm in the summer time, so I put all my panels on the west roof even though I have just as much room on the east roof. I'm looking to maximize the production value of my solar by lining it up with the on-peak time where it costs $0.21/kwh. My off-peak cost is only $0.07/kwh so I don't mind paying POCO this rate for off-peak usage, as long as I don't pay POCO $0.21 for on-peak usage.

[gbp1s]

Yes, I have both an East and West roof. I believe the expectation is that I will be on a TOU plan.

Since you mentioned that your house is south facing but you're putting the panels on the west roof, I assume that you have east/west roofs maybe? Otherwise, south facing roof would be the most ideal location in general.

If you're on a TOU plan with the on-peak time in the afternoon, then panels on the west roof is probably best.

But if you're NOT on a TOU plan, and you have an east facing roof as well, it may make more sense to put the panels on the east facing roof because your panels will run cooler in the morning and give better production in the cooler temperature. But this is only if you're NOT on TOU and only have 1 energy bucket to bank your solar credits.

I'm on TOU and my on-peak time is 1-8pm in the summer time, so I put all my panels on the west roof even though I have just as much room on the east roof. I'm looking to maximize the production value of my solar by lining it up with the on-peak time where it costs $0.21/kwh. My off-peak cost is only $0.07/kwh so I don't mind paying POCO this rate for off-peak usage, as long as I don't pay POCO $0.21 for on-peak usage.

[J.P.M.]

Hi everyone,

Newbie here from Los Angeles, CA and am looking for some help on a system purchase. I have a quote for 18 x E20s with 1 x SPR650-1F-240, producing 5.89kW (DC), 5.10kw (AC). Estimated 1st year production is 8586kwh for a cost of $27K (after $3K SunPower family/friend discount but before state/fed rebates). My monthly usage averages about 900kwh and I am being told that this system will just about cover 98% of electrical bill. I have no shade issues since I live in a newer track housing community. My house faces south and the panels will point towards the direction of the west.


My questions

- Is the quote competitive?
- Will the system generate enough to cover me 100% in real world settings or too optimistic?

Thanks,
Kevin

Competitive: $4.59/watt D.C. may not be too bad for Sunpower. I think you may do a bit better on price if you really want Sunpower- <$4.50/Watt. However, the bigger question may be: Competitive compared to what ? There are those of us (by no means everyone BTW) who believe buying Sunpower stuff is like buying a Mercedes when a Ford may be fit for purpose. Unless you have area (size) limitations, other stuff from reputable manufacturers will likely get you pretty close to the same yearly output per installed D.C. Watt as Sunpower for a fair amount less money and will probably last as long or longer than you'll own the property. I've seen well made and installed systems using reputable, non Sunpower manufacturers and installers for about $3.40-$3.70/D.C. Watt. Sunpower's very good stuff, but it's still an appliance - not a lifestyle. Also, most conservation efforts made before adding solar are usually more cost effective than throwing expensive solar panels at a bloated energy use. Finally, even though it may seem like a no brainer and counterintuitive, replacing 100% of your annual electric load may not be the most cost effective way to go. Think of the cost of money and potential return over 5/10/20 yrs, etc.
Potential output: Depending on orientation and tilt, 10,000 to 11,000 kWhrs. per year (~98% of 10800 hWhrs/yr. What's up w/8586 Kwhrs. = 80% not 98% ?) for a 6kW system seems a bit optimistic, but possible for a new system with no shade, and optimum tilt and azimuth. Almost all systems' output decreases by some fraction of 1% per year, how much is a matter of some variation, speculation and discussion.

I'd suggest more quotes, research, including threads on this forum, and a lot to thought about what you want to accomplish and why. Be deliberate, take your time and don't be rushed. Ask a lot of questions. Do your homework.

[Volusiano]

Yes, I have both an East and West roof. I believe the expectation is that I will be on a TOU plan.

OK, you should research your POCO's TOU offerings and understanding it very well first, because whichever TOU plan you select will greatly influence where you place your panels.

Also, consider this. If you truly want to have net zero metering that will cover 100% of your usage, then you actually DON'T want to be on a TOU plan. That's because if you don't buy energy from your POCO, why do you care how much it costs anyway? It can be $0.10/kwh or $10/kwh and it's still irrelevant to you, because you'll be getting 100% of your energy from your solar production anyway. You only want to be on TOU only if you want to take advantage of their lower rate(s) during their off-peak time, which assumes that you'll need to buy from them, but you don't with net zero metering.

The problem with TOU when it comes to net metering is that you usually have to bank your solar credits in 2 different buckets -> an on-peak bucket and an off-peak bucket. You cannot take credits from the on-peak bucket for off-peak use, and vice-versa. So it's not very conducive to sharing banked credits. But if you're just on the basic plan, there's only 1 buckets to store and share all credits.

So if you plan on sizing your system for net zero metering (solar covers 100% of your demand), you don't want to be on TOU. You want to be on the basic plan. Which means you'll probably want to place your panels on the east roof to get the most production in the morning while the panels are still nice and cool.

[silversaver]

So if you plan on sizing your system for net zero metering (solar covers 100% of your demand), you don't want to be on TOU. You want to be on the basic plan. Which means you'll probably want to place your panels on the east roof to get the most production in the morning while the panels are still nice and cool.

Yes, he is right about that. I plan my solar system to cover 100% usage, so I rather stay in basic net metering plan. For some, they think to bank on peak and buy it back during off peak which is a great idea, but that is really for families that don't use electricity during day time because no one home. If you don't plan your calculation right, you might end up paying more money because the calculation is more complex. Standard Net Metering plan is much simple for me.

[Volusiano]

For some, they think to bank on peak and buy it back during off peak which is a great idea...

That was what I used to assume how it works, which would have been great if you can bank the VALUE (not the actual kwh energy) into one single bucket. So that way, when you withdraw the banked energy during off-peak, you only withdraw a much smaller VALUE. If it works this way, and on-peak is 3 times off-peak cost, every kwh banked during on-peak will effectively yield 3 kwh credit during off-peak.

Unfortunately this is too good to be true and usually it doesn't work like that. The reality is that you have 2 separate buckets, one for on-peak and one for off-peak. Whatever you bank for on-peak can only be withdrawn during on-peak hours, and vice-versa. There's no sharing and you can't withdraw from the on-peak bucket for off-peak use and vice-versa. So you'll have to manage your usage of the 2 buckets separately. If you have excess on-peak credits you want to use up and are short of off-peak credits, the only way to do this is to shift usage that can be shifted (laundry, pool pump, etc) to on-peak time to use up the on-peak credits.

Talk to Ian S on this forum and he'll tell you he had excess on-peak credits at the end of the year that he had to sell to the POCO for a song. But there's still value with TOU if you're not quite at net zero metering and want your solar credits to count for the most value.

[J.P.M.]

Yes quoted for SP327W panels. I do have more available real estate space on the roof. ROI is important but I am also looking for reliability. I have a second quote for

30 x Premium 7.500 KW (DC) Canadian Solar system with Fronius USA Inverters with Estimated first year electrity production: 10433 kWh. Price is $28,125.

My understanding is that the SunPowerP panels are more efficient so there is a inclination to go with SunPower but I have yet to make up my mind.

Price sounds more in line. You could do worse than Canadian Solar. As others suggest, try PV Watts w/a derate > .77. My experience is also that around .87 for new system is more accurate +/- just a bit. I've found SAM from NREL to be good/better for specific performance estimates - Kind of like PV Watts on steroids, less so w/respect to accuracy of utility rates, but you can plug in your own. SAM's kind of a PITA, but may be worth for the flexibility and specifics it gives. Opinions vary.
S.P. 's efficiency refers to area , not cost effectiveness necessarily.

[inetdog]

That was what I used to assume how it works, which would have been great if you can bank the VALUE (not the actual kwh energy) into one single bucket. So that way, when you withdraw the banked energy during off-peak, you only withdraw a much smaller VALUE. If it works this way, and on-peak is 3 times off-peak cost, every kwh banked during on-peak will effectively yield 3 kwh credit during off-peak.

Unfortunately this is too good to be true and usually it doesn't work like that. The reality is that you have 2 separate buckets, one for on-peak and one for off-peak. Whatever you bank for on-peak can only be withdrawn during on-peak hours, and vice-versa. There's no sharing and you can't withdraw from the on-peak bucket for off-peak use and vice-versa. So you'll have to manage your usage of the 2 buckets separately. If you have excess on-peak credits you want to use up and are short of off-peak credits, the only way to do this is to shift usage that can be shifted (laundry, pool pump, etc) to on-peak time to use up the on-peak credits.

Talk to Ian S on this forum and he'll tell you he had excess on-peak credits at the end of the year that he had to sell to the POCO for a song. But there's still value with TOU if you're not quite at net zero metering and want your solar credits to count for the most value.

Here in CA PG&E keeps separate buckets, but because of the way CA's net metering law works they do have to credit the value for each bucket. The only non-refundable amount occurs when you have an excess at the end of the year after adding both bucket values together.

[Volusiano]

Here in CA PG&E keeps separate buckets, but because of the way CA's net metering law works they do have to credit the value for each bucket. The only non-refundable amount occurs when you have an excess at the end of the year after adding both bucket values together.

For SRP and APS in AZ, excess credits in each bucket every month do get rolled over to the next month. And at the end of the 12 month period (end of calendar year for APS and end of April for SRP), they pay you WHOLESALE (much cheaper than what they charge you) for any unused excess in each bucket and reset your account back to 0 for the next 12 months.

[silversaver]

So what's the calendar date for SCE in SoCal?

[gbp1s]

Competitive: $4.59/watt D.C. may not be too bad for Sunpower. I think you may do a bit better on price if you really want Sunpower- <$4.50/Watt. However, the bigger question may be: Competitive compared to what ? There are those of us (by no means everyone BTW) who believe buying Sunpower stuff is like buying a Mercedes when a Ford may be fit for purpose. Unless you have area (size) limitations, other stuff from reputable manufacturers will likely get you pretty close to the same yearly output per installed D.C. Watt as Sunpower for a fair amount less money and will probably last as long or longer than you'll own the property. I've seen well made and installed systems using reputable, non Sunpower manufacturers and installers for about $3.40-$3.70/D.C. Watt. Sunpower's very good stuff, but it's still an appliance - not a lifestyle. Also, most conservation efforts made before adding solar are usually more cost effective than throwing expensive solar panels at a bloated energy use. Finally, even though it may seem like a no brainer and counterintuitive, replacing 100% of your annual electric load may not be the most cost effective way to go. Think of the cost of money and potential return over 5/10/20 yrs, etc.
Potential output: Depending on orientation and tilt, 10,000 to 11,000 kWhrs. per year (~98% of 10800 hWhrs/yr. What's up w/8586 Kwhrs. = 80% not 98% ?) for a 6kW system seems a bit optimistic, but possible for a new system with no shade, and optimum tilt and azimuth. Almost all systems' output decreases by some fraction of 1% per year, how much is a matter of some variation, speculation and discussion.

I'd suggest more quotes, research, including threads on this forum, and a lot to thought about what you want to accomplish and why. Be deliberate, take your time and don't be rushed. Ask a lot of questions. Do your homework.

Thank you for the reply. This is helpful. I spoke to my SunPower rep again and he clarified that the quote is based on zeroing out with bill averaging $200/month via a TOU plan. If I wanted to match my electrical usage to a system, I would need closer to 21 E20/327 panels which is would be a 6.87kw (DC) system for price of $31,335. (Not sure if it matters, but the monitoring system is included with the install.)

The long term expectation is that we're not moving and but if a move happens, then home becomes a rental. As for as conservation, we've pretty much maximized this area. We have enough saved to purchase the system outright and in looking at the long term value, it seems logical to purchase a PV system. After fed rebates, I assume that a system could run $21K. Divided by 20 yrs or 240 months, I basically prepay electricity for about $88.00 per month vs the $200 average I pay today (not factoring in SCE rate hikes)

I'm more inclined with SunPower over Canadian Solar panels given the fact that SunPower is guaranteeing 87% after 25 years vs the 80% from Canadian Solar. I see this is the 'premium' for going SunPower. However, I came to this board to give myself a more objective perspective from other owners.

[gbp1s]

That was what I used to assume how it works, which would have been great if you can bank the VALUE (not the actual kwh energy) into one single bucket. So that way, when you withdraw the banked energy during off-peak, you only withdraw a much smaller VALUE. If it works this way, and on-peak is 3 times off-peak cost, every kwh banked during on-peak will effectively yield 3 kwh credit during off-peak.

Unfortunately this is too good to be true and usually it doesn't work like that. The reality is that you have 2 separate buckets, one for on-peak and one for off-peak. Whatever you bank for on-peak can only be withdrawn during on-peak hours, and vice-versa. There's no sharing and you can't withdraw from the on-peak bucket for off-peak use and vice-versa. So you'll have to manage your usage of the 2 buckets separately. If you have excess on-peak credits you want to use up and are short of off-peak credits, the only way to do this is to shift usage that can be shifted (laundry, pool pump, etc) to on-peak time to use up the on-peak credits.

Talk to Ian S on this forum and he'll tell you he had excess on-peak credits at the end of the year that he had to sell to the POCO for a song. But there's still value with TOU if you're not quite at net zero metering and want your solar credits to count for the most value.

I guess TOU is still a bit foreign to me. Our demand is pretty consistent all day (.80kwh-1kwh) during the hours of 10pm-5pm. From 5pm-10pm, it ranges from 1.15kwh to 1.3kwh. Does this make me a good candidate for TOU?

[gbp1s]

So what's the calendar date for SCE in SoCal?

Hopefully, this is what you are asking about.....From my initial search, TOU for SCE 10am-6pm for peak.

[Volusiano]

I guess TOU is still a bit foreign to me. Our demand is pretty consistent all day (.80kwh-1kwh) during the hours of 10pm-5pm. From 5pm-10pm, it ranges from 1.15kwh to 1.3kwh. Does this make me a good candidate for TOU?

Nobody can answer this question unless you know what the on-peak time is for TOU. For some POCO, the on-peak time is the same year round, for others, it's different between the summer and winter. On top of that, there may be multiple TOU plans available, with different on-peak times among themselves. So you really need to go online to your POCO and find out what's being offered and determine which one is most suitable for you.

Since you seem to know pretty well your demand throughout the day, you can plug all the numbers into a spreadsheet to figure out how things will work out for you and which TOU plan is the best (if there are multiple). Just run the numbers through multiple worksheets, one for the basic plan, one for TOU plan A, one for TOU plan B, etc. Plug in your 24 hour usage pattern against the various rates of the different peak times to see what the final dollars cost turn out to be for each plan.

[Volusiano]

Hopefully, this is what you are asking about.....From my initial search, TOU for SCE 10am-6pm for peak.

I think what he's asking for is actually not when on-peak time is for SCE, but what is the annual 12 month reset date for SCE if you're on net metering? Usually you get to roll over your solar credits month to month until the 12th month, at which time you have to sell any excess back to the POCO at whole sale rate and start out the 12 month cycle again a 0 credit. For some company it's the end of the calendar year. For others it may be the end of a different month.