Sanity check for a new system (San Diego)

[AMCSquared]

Couple updates. I started getting quotes for a slightly bigger system due to the Prius Plug-In. 4kW system would have given me a little breathing room during the Winter months.

Company "M"
3.9kW
13 x LG300W
13 x M250 w/ monitoring
$15,405 (or $3.95 / watt)

Company "B"
3kW
11 x LG275W (?)
Either Power One or SMA
Around $13,000 (or ~$4.33 / watt).
Note: This company was pleasant to speak to. However, they were upfront that they couldn't meet or beat the $4 threshold. So I didn't get an exact quote since I don't want to waste their time.

I also made an Excel sheet to see if DR-SES rate structure (Time of Use for Solar System) would save me money. As expected, DR-SES doesn't make sense for winter month when compared with the regular DR tier rate. It would cost somewhere between $5 to $10 more w/ DR-SES than just plain DR.

However, summer month not only reverses the trend (as expected), but by a large margin! Instead of SDG&E owing me $10 dollar for say July on DR, DR-SES calculation says July should be negative $75! I guess SDG&E's $0.45 / kWh summer peak rate makes a huge difference. The extra credit during summer could potentially offset overall winter costs. So instead of being short of 1000kWh per year, the total cost could be a net zero.

The cynic in me says SDG&E would alleviate this disparity quickly.

[J.P.M.]

Yeah, we can not predict what SDG&E will do in the future. Heck, just look at how many drastic changes they made in the past year on DR and TOU rates. You can bet that anyone that installed their PV system just last year can throw away any calculation they did to justify the purchase/lease. With talk of making PV owner paying their "fair share" of infrastructure and potential changes to lower the Tier 3/4 but raise Tier 1/2 cost, we simply can not make any long term prediction.

The are simply too many variables and many of them are beyond our control. I guess the best we could do is an educated guess.

To that: Agreed. However, for anyone who doesn't know or hasn't internalized the idea that the future is always a crap shoot devoid of promises:

1.) In the past, now or in the future neither SDG & E or any POCO, or their customers are capable of predicting the future or their response to what will happen. In that sense, some things never change.

2.) IMO, SDG & E rate changes so far for the last 12 mo. are not that much more mercurial than in the more distant past - 10 yrs. back or so. The reasons may be slightly different, but that's about it. Depending on how AB 327 mandated rate reform influences things, rates/rate changes may calm down a bit, maybe not. I'd guess next couple of yrs. will have a surprise or two but may calm down some after that. MAYBE.

3.) Most plans as related to long term cost effectiveness are like orders of battle : Obsolete on step off.

4.) An educated guess was all we could ever and will ever be able to do. That too has not and is unlikely to change.

5.) Even so, financial planning is still worthwhile if only as a platform on which to set scenarios. With reasonable information, if you bat .500 on decisions/guesses, you'll probably come out ahead of the great unwashed masses. Worth it ? Your money/time/choice.

6.) As an aside, all this obvious uncertainty about the future makes me wonder about the judgment of many people who seem to swallow unquestioningly the claims of astronomical future utility rates/rate increases made by many peddlers. Looks to me that the peddlers take advantage of general ignorance with no logical behind them, but only fear mongering, half truths and gross distortions as if they have some special, magic lock on predicting the future.

[AMCSquared]

However, since that final cost # is very sensitive to assumptions about the future, and our ability to predict the future is notoriously bad, lifecycle costing is mostly a crap shoot limited by our ability to make reasonable guesses about the future. Still, depending on one's confidence in the assumptions, and since this is still a free country, the information can be useful, or ignored, but it may be food for thought and may lead to a more cost effective outcome.

FWIW on the tree issue, CA solar access laws may be of some help. Take photos NOW, before any install, and at the solstices and at each equinox at around (solar) noon and put the date in the photo. BROADLY, If you have clear sky between 10 and 2 when the array goes up and you can document it, you get to keep that clear sky and the obstruction loses. The law's a bit slippery, but the stated intent is a workable compromise with solar access in mind.

Yeah, we can not predict what SDG&E will do in the future. Heck, just look at how many drastic changes they made in the past year on DR and TOU rates. You can bet that anyone that installed their PV system just last year can throw away any calculation they did to justify the purchase/lease. With talk of making PV owner paying their "fair share" of infrastructure and potential changes to lower the Tier 3/4 but raise Tier 1/2 cost, we simply can not make any long term prediction.

The are simply too many variables and many of them are beyond our control. I guess the best we could do is an educated guess.

[J.P.M.]

Thanks for the offer to take a closer look at my bills. I think the online rate analyzer gives me a pretty good "rough" guide on the potential saving. It doesn't really matter if they are off by couple cents per kWh. The variance of +/- $50 a year really won't affect my decisions that much.

The only major decision is micro-inverter vs. string. Currently there is no shading issues. However, my neighbor's tree is already a tad taller than my 2nd floor roofline. I am not sure how much taller the trees will be, and if they go another 10 or 15 feet, it will definitely create shading issues. I am leaning towards micro-inverter for this eventuality. Plus due to the new fire code, I may have to place my panels at more than 2 orientations. This would push the design towards micro-inverter.

You're welcome. As you wish.

I only bring up the inadequacies of the rate analyzer because in life cycle cost terms, or present worth of the sum of future electrical costs, depending on particulars, a seemingly small change - a fraction of a cent/kWhr.diff., $50/yr., inaccurate billing schedules, etc. - can make a big difference in the future cost of electricity. $50/yr. difference can often translate to $500 or more in terms of present worth which may garner more attention than the fraction of a cent/kWhr. difference that induced that $500 change in present worth. It may make a system costing $500 more or less than some other system justifiable or unjustifiable from a cost perspective. Just another piece in the decision making puzzle.

However, since that final cost # is very sensitive to assumptions about the future, and our ability to predict the future is notoriously bad, lifecycle costing is mostly a crap shoot limited by our ability to make reasonable guesses about the future. Still, depending on one's confidence in the assumptions, and since this is still a free country, the information can be useful, or ignored, but it may be food for thought and may lead to a more cost effective outcome.

I'd only suggest the rate analyzer is not as accurate as one may think and to not take it as absolute for reasons already stated.

FWIW on the tree issue, CA solar access laws may be of some help. Take photos NOW, before any install, and at the solstices and at each equinox at around (solar) noon and put the date in the photo. BROADLY, If you have clear sky between 10 and 2 when the array goes up and you can document it, you get to keep that clear sky and the obstruction loses. The law's a bit slippery, but the stated intent is a workable compromise with solar access in mind.

[AMCSquared]

4.) FWIW, given your stated usage, I'd guess your annual bill using 05/01/2014 rates for Coastal, non all elec., but still using calendar days for billing will be closer to about $1,480. If you want, holler back w/ your billing cycle # (P.2 of your bill to the left of the meter #) and I'll nail it a bit harder.

Thanks for the offer to take a closer look at my bills. I think the online rate analyzer gives me a pretty good "rough" guide on the potential saving. It doesn't really matter if they are off by couple cents per kWh. The variance of +/- $50 a year really won't affect my decisions that much.

The only major decision is micro-inverter vs. string. Currently there is no shading issues. However, my neighbor's tree is already a tad taller than my 2nd floor roofline. I am not sure how much taller the trees will be, and if they go another 10 or 15 feet, it will definitely create shading issues. I am leaning towards micro-inverter for this eventuality. Plus due to the new fire code, I may have to place my panels at more than 2 orientations. This would push the design towards micro-inverter.

[J.P.M.]

I have been looking at getting PV system to replace my SDG&E Tier 3 and 4 usage for the past couple years. I think the current PV pricing ($3.5 to $3.75 per watt before federal credit) plus the outrageous Tier 4 pricing of $0.38 / kWh (!) has finally pushed the ROI into a more realistic 7 years or so. Here is my past 12 month usage history

• Apr - 540
• Mar - 549
• Feb - 452
• Jan - 540
• Dec - 528
• Nov - 604
• Oct - 527
• Sep - 432
• Aug - 810 (unusually hot)
• Jul - 491
• Jun - 586
• May - 550

This is a total about 6600 kWh per year or $1400 a year. I already plugged my usage number into this handy online calculator (which is VERY useful for SDG&E folks).

I am aiming for about a 3kWh system and I already started getting quotes from local installers. 2kWh is probably enough for my intended scenario (i.e eliminate Tier 3 and 4 usage). However, to "muddle" the water a bit, I recently got a Prius Plug-In and I would like to be able to charge that (about additional 100 kWh per month) while staying at Tier 1 & 2.

Due to my house roofline and orientation (mainly splitting between East and West), PVWatts says that my 3kW system should produce about 4200kWh. Plugging that into the online calculator (using 2.4kW AC as the input), I should be saving about $1100 a year.

Now I started getting quotes from local installers already. I have to say, this experience is WORSE than dealing with car salesman. With couple exceptions, getting any sort of quote is like pulling teeth. I probably will end up using Enphase M250 micro inverter due to the split system layout. I also could use something like PowerOne with two MPPT. Here are 3 quotes I got so far (all pre 30% tax credit).

Company "M"
3kW System
10 x LG 300W
10 x Enphase M250
$11,900 (or $3.97 / watt)

3kW System
10 x LG 300W
1 x PowerOne PVI 3.0
$11,750 (or $3.92 / watt)

Company "R"
3.38kW System
13 x REC 260W
1 x PowerOne PVI 4.2
$13,825 (or $4.09 / watt)

Company "S"
3.3kW System
12 x LG 275W
12 x Enphase M250
$16,476 (or $4.99 / watt)

3kW System
10 x LG 300W
10 x M250
$16,230 (or $5.41 / watt !!!)

You gotta love Company "S" for quoting the exact same LG+M250 system for over 35% more! When I pointed that out, the salesperson basically played dumb and said that their pricing is very "competitive" (NOT!). The worse part is that Company "S" is a good referral where they installed a SunPower system at $4.7 per watt and a non-SP at $3.5 / watt for family friends.

I am still waiting for more quotes (once again, one of the most painful "shopping" experience). However, company "M" is the quickest to respond and appears to be most willing to work with me. BTW, I got company "M" from a mention within this forum.

$3.90 / watt is still a tad on the high side and that would increase the ROI by another year or so. I am not exactly thrilled with the quote, but that is only about 4 or 5% away from $3.75.

Any comments are welcome!

From what I've gleaned, company "S", if it's who I suspect, seems to run hot/cold on attitude w/ customers. I couldn't comes to terms w/it, maybe they didn't like me based on my situation of reviewing jobs they sell in my HOA. Their work seems adequate (if it's who I think it is).

Given the system size, the pricing may be reasonable.

A 3 kW system will certainly get you out of tiers 3 & 4 and probably more.

FWIW, if no shade problems, I'd go w/ the power one over the micros.

Agreeing w/ Ian, I'd run PVWatts w/a .84 derate and see what pops up. Depending on how far inland you are use Lindberg data if close to the coast, use Miramar data if > ~15 miles inland.

Almost forgot I.): Check the CSI database to see what else these vendors have done. Lots of good info.

Almost forgot 2.): Be careful of the rate analyzer.

1.) I think the rates are for 01/01/2014. Things change a lot. 05/01/2014 rates are lower in the upper tiers and higher in the lower tiers. I think it may have something to do w/ AB 327 rate restructure and jockeying.
2.) The billing days the rate analyzer uses are calendar days/month. The actual # of billing days SDG & E uses usually does not agree w/ calendar days. This screws up the rate analyzer's basic allowance and thus all the rest of it.
3.) Hard to tell but I think the rate analyzer leaves some small taxes and the DWR bond charge out.
4.) FWIW, given your stated usage, I'd guess your annual bill using 05/01/2014 rates for Coastal, non all elec., but still using calendar days for billing will be closer to about $1,480. If you want, holler back w/ your billing cycle # (P.2 of your bill to the left of the meter #) and I'll nail it a bit harder.

I was pissed when I saw that CSI copied my rate calc method until I figured out the logic was a no brainer, and anyway, they had no idea what I was doing or had done. Then I found out my stuff was more inclusive of billing variations and usually more current.

[kmm]

I have been looking at getting PV system to replace my SDG&E Tier 3 and 4 usage for the past couple years. I think the current PV pricing ($3.5 to $3.75 per watt before federal credit) plus the outrageous Tier 4 pricing of $0.38 / kWh (!) has finally pushed the ROI into a more realistic 7 years or so. Here is my past 12 month usage history

• Apr - 540
• Mar - 549
• Feb - 452
• Jan - 540
• Dec - 528
• Nov - 604
• Oct - 527
• Sep - 432
• Aug - 810 (unusually hot)
• Jul - 491
• Jun - 586
• May - 550

Company "M"
3kW System
10 x LG 300W
10 x Enphase M250
$11,900 (or $3.97 / watt)

3kW System
10 x LG 300W
1 x PowerOne PVI 3.0
$11,750 (or $3.92 / watt)

Company "R"
3.38kW System
13 x REC 260W
1 x PowerOne PVI 4.2
$13,825 (or $4.09 / watt)

Company "S"
3.3kW System
12 x LG 275W
12 x Enphase M250
$16,476 (or $4.99 / watt)

3kW System
10 x LG 300W
10 x M250
$16,230 (or $5.41 / watt !!!)

You gotta love Company "S" for quoting the exact same LG+M250 system for over 35% more! When I pointed that out, the salesperson basically played dumb and said that their pricing is very "competitive" (NOT!). The worse part is that Company "S" is a good referral where they installed a SunPower system at $4.7 per watt and a non-SP at $3.5 / watt for family friends.

I am still waiting for more quotes (once again, one of the most painful "shopping" experience). However, company "M" is the quickest to respond and appears to be most willing to work with me. BTW, I got company "M" from a mention within this forum.

$3.90 / watt is still a tad on the high side and that would increase the ROI by another year or so. I am not exactly thrilled with the quote, but that is only about 4 or 5% away from $3.75.

Any comments are welcome!

I live in an unincorporated area of San Diego and my energy use is similar to yours-just a little more.

The Mrs. has a Prius but it is a 2008 so there is nowhere to plug it in.

Like the cost of solar for the house once was, the Prius did not make financial sense when it first came out but once Hybrid battery prices came WAY down, the car made sense. BTW, I caught a Prius taxi in Las Vegas and I asked the driver how many miles on the vehicle. It was over 200K miles and he was still on the original hybrid battery. You just can't beat a car that consistently gets 46+ MPG.

I think I know who company "M" might be (also suggested by a poster here) but am waiting to finish up my quote with company "B" before I do some comparison shopping. Interestingly enough, company B's website suggests that anyone considering solar get 2 bids. Also, 3 of my immediate neighbors have used company B and rave about them.

I am looking forward to following your shopping experience. Personally, I do not like the look of solar panels. The company that I am working with is suggesting a hybrid roof mount/pole mount system (to reduce visual blight), so we will see what their final proposal looks like.

Good luck won't your shopping and subsequent installation. Looking forward to seeing how the final numbers shake out.

[AMCSquared]

3kW is a fairly small system so that may make the per kW cost a little higher. If you used the default 0.77 derate factor in PVWatts, your numbers will be a bit low. Try 0.84 instead. Unless you have shading issues, I'm not sure the micros offer any advantage. Check out warranties on all the equipment, workmanship and output (if any). Also see what kind of monitoring is provided for each system. Also, see how the payments are structured: the less you have to pay upfront, the better for you.

Agreed that 3kW system is a relatively small system. That is why $3.9 quote may be fair when compared to $3.5 at 7kW+. I actually used 0.83 derate factor with 18 degree tilt and 97 degree orientation. I am close to the coast, so I do get the San Diego May gray / June gloom (marine layer which doesn't burn off until later in the day). I have taken a look at the hourly stats from PVWatts and it does appear that they do account for that.

[Ian S]

3kW is a fairly small system so that may make the per kW cost a little higher. If you used the default 0.77 derate factor in PVWatts, your numbers will be a bit low. Try 0.84 instead. Unless you have shading issues, I'm not sure the micros offer any advantage. Check out warranties on all the equipment, workmanship and output (if any). Also see what kind of monitoring is provided for each system. Also, see how the payments are structured: the less you have to pay upfront, the better for you.

[AMCSquared]

I have been looking at getting PV system to replace my SDG&E Tier 3 and 4 usage for the past couple years. I think the current PV pricing ($3.5 to $3.75 per watt before federal credit) plus the outrageous Tier 4 pricing of $0.38 / kWh (!) has finally pushed the ROI into a more realistic 7 years or so. Here is my past 12 month usage history

• Apr - 540
• Mar - 549
• Feb - 452
• Jan - 540
• Dec - 528
• Nov - 604
• Oct - 527
• Sep - 432
• Aug - 810 (unusually hot)
• Jul - 491
• Jun - 586
• May - 550

This is a total about 6600 kWh per year or $1400 a year. I already plugged my usage number into this handy online calculator (which is VERY useful for SDG&E folks).

I am aiming for about a 3kWh system and I already started getting quotes from local installers. 2kWh is probably enough for my intended scenario (i.e eliminate Tier 3 and 4 usage). However, to "muddle" the water a bit, I recently got a Prius Plug-In and I would like to be able to charge that (about additional 100 kWh per month) while staying at Tier 1 & 2.

Due to my house roofline and orientation (mainly splitting between East and West), PVWatts says that my 3kW system should produce about 4200kWh. Plugging that into the online calculator (using 2.4kW AC as the input), I should be saving about $1100 a year.

Now I started getting quotes from local installers already. I have to say, this experience is WORSE than dealing with car salesman. With couple exceptions, getting any sort of quote is like pulling teeth. I probably will end up using Enphase M250 micro inverter due to the split system layout. I also could use something like PowerOne with two MPPT. Here are 3 quotes I got so far (all pre 30% tax credit).

Company "M"
3kW System
10 x LG 300W
10 x Enphase M250
$11,900 (or $3.97 / watt)

3kW System
10 x LG 300W
1 x PowerOne PVI 3.0
$11,750 (or $3.92 / watt)

Company "R"
3.38kW System
13 x REC 260W
1 x PowerOne PVI 4.2
$13,825 (or $4.09 / watt)

Company "S"
3.3kW System
12 x LG 275W
12 x Enphase M250
$16,476 (or $4.99 / watt)

3kW System
10 x LG 300W
10 x M250
$16,230 (or $5.41 / watt !!!)

You gotta love Company "S" for quoting the exact same LG+M250 system for over 35% more! When I pointed that out, the salesperson basically played dumb and said that their pricing is very "competitive" (NOT!). The worse part is that Company "S" is a good referral where they installed a SunPower system at $4.7 per watt and a non-SP at $3.5 / watt for family friends.

I am still waiting for more quotes (once again, one of the most painful "shopping" experience). However, company "M" is the quickest to respond and appears to be most willing to work with me. BTW, I got company "M" from a mention within this forum.

$3.90 / watt is still a tad on the high side and that would increase the ROI by another year or so. I am not exactly thrilled with the quote, but that is only about 4 or 5% away from $3.75.

Any comments are welcome!