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**Alisobob** · 12-11-2014, 12:49 PM

Originally posted by sensij

Aesthetics are important to me, so that will be one of the criteria by which the success of the installation will ultimately be judged. Some neighbors put up black framed panels with a clear anodized rack, and that convinced me the black racking would be better. Black everything may cost some generation because of thermal effects, but I'm thinking that it is a price I'm willing to pay.

Same thoughts here...

sw10.JPG sw9.JPG sw7.JPG

Also one of the reasons I went with Micro-Inverters.... they make such a clean install. This single piece of conduit (and a few stickers )is the only visible piece that was added to the house.

solar f2 (1).jpg solar f (1).jpg

Good luck on the install.. Smart doing the roof as part of the install. I did the same and its supposed to pour rain on Friday... It will be a great test to see if I get any leaks!!!

Bob

**J.P.M.** · 12-11-2014, 12:55 PM

Originally posted by sensij

Nothing like blatant plagiarism to title a thread. The first payment was yesterday, so I'm finally moving forward. Shopping began in earnest in August, and now 4 months later I think I'm getting a system I want at a price I can be happy with. Finding the installer took some time, and the installer I have contracted with is discussed in this thread. Feel free to contact me with questions about them, if you have any.

Panels: 12 x Canadian Solar CS6P-260P-BLK
Inverter: SolarEdge SE3000A-US w/ P300 Nema 6 enclosed optimizers
Racking: Iron Ridge, black

Aesthetics are important to me, so that will be one of the criteria by which the success of the installation will ultimately be judged. Some neighbors put up black framed panels with a clear anodized rack, and that convinced me the black racking would be better. Black everything may cost some generation because of thermal effects, but I'm thinking that it is a price I'm willing to pay. The system is slightly oversized for my needs, but the price per watt for smaller arrays increases in a way that convinced me a 3000 W inverter with a matched array was best for my situation.

The new roof will start to go up on 12/18, with Certainteed Solaris shingles. Paying for the high reflectivity of the shingles might not prove to be cost effective, but in a house without A/C, reflecting more of the sun away seems like a good thing to me. I haven't determined if the reflective shingles will affect the PV generation at all, if the net thermal affect will be positive or negative. I am treating it as a non-contributor. The roofer will, at a minimum, reinspect the roof after the quickmounts are installed, and then again when the system is complete. Between the shingles, improved venting, and new insulation in the attic, I am hoping that the annual temptation to install A/C when the Santa Ana's hit can continue to be resisted.

The proposal was for $3.30 / W, cash, for a system cost of $10296. Assumption used in the financial calculations:
1) Annual electric consumption stays constant + 600 kWh for a new (large) fridge we just installed.
2) SDG&E rates (coastal, standard service) through 2018 are bracketed by my understanding of ORA's Sept. 15 testimony and SDG&E's Oct 17 response, mostly Chapter 4. Since the system may produce more than what I will use, whether the $10 / mo comes in as a fixed charge or a minimum charge won't matter a whole lot.
3) Rates after 2018 increase at 2.1% annually.
4) 4.25% discount rate, corresponding to some loans I carry.

With these assumptions, I estimate the system would break even at something close to 10 years. I have defined break even in this case as the point at which the NPV of difference in cash flow with and without solar is 0. It is a little bit longer than I hoped for going into this, but I hope the assumptions are skewed conservatively and the errors in them will tend to push the break even point sooner.

Edit: Forgot to mention the array installation will be in a single row along the south-facing eve, portrait orientation at 179 deg azimuth and 18.5 deg tilt (4/12 roof pitch). A SunEye report by the installer suggests solar access of 97-98% due to some distant tree shading and local topography, with a TSRF of 95%, which should account for non-optimal tilt and azimuth. The installer uses Buildertrend.com as a cloud based project management / communication tool, which is kind of cool.

In spite of the usual verbal joisting we usually get into, FWIW, I think, my opinion only, your logic and choices are sound. What is est. annual usage and est. output ?

Meant in a not unfriendly way, I'd respectfully suggest, if you have an interest, you consider a weather station and mount it near the array. More raw data than you will know what to do with. It'll cost about $1K or so, but if you want a decent way to monitor performance, that's probably, IMO only, the best practical method to get close to reliable data. In addition, besides performance monitoring, a little creativity can yield a lot of information you seem to be interested in. More FWIW, the Davis instruments I have seem to perform as advertised.

**SunEagle** · 12-11-2014, 02:05 PM

Originally posted by sensij

Nothing like blatant plagiarism to title a thread. The first payment was yesterday, so I'm finally moving forward. Shopping began in earnest in August, and now 4 months later I think I'm getting a system I want at a price I can be happy with. Finding the installer took some time, and the installer I have contracted with is discussed in this thread. Feel free to contact me with questions about them, if you have any.

Panels: 12 x Canadian Solar CS6P-260P-BLK
Inverter: SolarEdge SE3000A-US w/ P300 Nema 6 enclosed optimizers
Racking: Iron Ridge, black

Aesthetics are important to me, so that will be one of the criteria by which the success of the installation will ultimately be judged. Some neighbors put up black framed panels with a clear anodized rack, and that convinced me the black racking would be better. Black everything may cost some generation because of thermal effects, but I'm thinking that it is a price I'm willing to pay. The system is slightly oversized for my needs, but the price per watt for smaller arrays increases in a way that convinced me a 3000 W inverter with a matched array was best for my situation.

The new roof will start to go up on 12/18, with Certainteed Solaris shingles. Paying for the high reflectivity of the shingles might not prove to be cost effective, but in a house without A/C, reflecting more of the sun away seems like a good thing to me. I haven't determined if the reflective shingles will affect the PV generation at all, if the net thermal affect will be positive or negative. I am treating it as a non-contributor. The roofer will, at a minimum, reinspect the roof after the quickmounts are installed, and then again when the system is complete. Between the shingles, improved venting, and new insulation in the attic, I am hoping that the annual temptation to install A/C when the Santa Ana's hit can continue to be resisted.

The proposal was for $3.30 / W, cash, for a system cost of $10296. Assumption used in the financial calculations:
1) Annual electric consumption stays constant + 600 kWh for a new (large) fridge we just installed.
2) SDG&E rates (coastal, standard service) through 2018 are bracketed by my understanding of ORA's Sept. 15 testimony and SDG&E's Oct 17 response, mostly Chapter 4. Since the system may produce more than what I will use, whether the $10 / mo comes in as a fixed charge or a minimum charge won't matter a whole lot.
3) Rates after 2018 increase at 2.1% annually.
4) 4.25% discount rate, corresponding to some loans I carry.

With these assumptions, I estimate the system would break even at something close to 10 years. I have defined break even in this case as the point at which the NPV of difference in cash flow with and without solar is 0. It is a little bit longer than I hoped for going into this, but I hope the assumptions are skewed conservatively and the errors in them will tend to push the break even point sooner.

Edit: Forgot to mention the array installation will be in a single row along the south-facing eve, portrait orientation at 179 deg azimuth and 18.5 deg tilt (4/12 roof pitch). A SunEye report by the installer suggests solar access of 97-98% due to some distant tree shading and local topography, with a TSRF of 94%-95%, which is the fraction relative to a system with optimal fixed tilt, azimuth, and no shade. The installer uses Buildertrend.com as a cloud based project management / communication tool, which is kind of cool.

Looks like you did a lot of homework and calculations before pulling the trigger. My hats off to you for going down this path instead of jumping in before you know how deep the puddle is.

Thanks for the update and keep us informed on the install.

**sensij** · 12-11-2014, 02:15 PM

Annual consumption has been between 4000-4100 kWh the last couple years, mostly tier 1/2 with a few dips into tier 3 when it is very hot (aside... my education about electric rates came the year I had been running an electric space heater in winter, when I could have just used the gas furnace. dumb, dumb, dumb). I've been projecting ~4600 kWh with the 2nd fridge. I'm using something around 5000 kWh as year 1 PV system output. Zip code is 92111, I've used the Montgomery Field station for most of the estimates, although with it being further inland, that might be slightly optimistic. In practice, I try to treat my assumptions as ranges to understand the sensitivity of the analysis to each. Because the system is oversized, I know it isn't as cost-effective as it could be. The oversized system does meet my (loosened) bar for acceptability, but if $ / W was constant and equipment options were infinite, I would probably have targeted a system around 2.5 kW.

I didn't comment on expandability, but meant to. For the sake of completeness, the panel is 100 A endfed, with no reason to believe the busbar is rated higher. The poor labeling might be a problem with the AHJ, we'll see. 20 A is the max breaker allowed by 2011 NEC / current CA code, so for this system, a panel upgrade should not be required.

10% increase allowed by current CPUC ruling on AB327: 312 W

If expansion >10% under the new tariff is cost-effective (and my understanding is that *all* grandfathering is lost, not just the new piece)

Maximum increase supported by existing inverter: 630 W
Maximum increase on this panel by switching to a SE3800A inverter: 1630 W
Alternative if 2014 NEC is adopted by CA: 4 panels with M250 microinverters, end feeding through a new breaker.

@J.P.M I really like the idea of the weather station. If I do put one up, I hope you won't mind some questions about ways to try to get at the diffuse fraction from the non-solar data it reports. For the sake of others reading the thread, installing one falls for me strictly in the hobby territory, I would not ever expect to use its feedback in a way that cost effectively identifies a problem with the PV system. I don't know if I am meticulous or committed enough to perform fouling measurements alluded to by J.P.M. in other threads, but I do very much enjoy the subject matter.

I really appreciate what I've learned on this forum, and the people who share their knowledge, even though I am not always in perfect agreement with some of the opinions that come along with that (free) education.

Edit: One other point... where I live, houses are very close together, and my neighbor will have a very excellent view of the panels. She is home all day and might object to that, so I did talk with her first so that she knows it is coming. Fortunately, I was able to allay her fears that it will be an eyesore, and I hope that I will not be proven wrong in that.

**SoCalsolar** · 12-11-2014, 03:37 PM

The last time I read this rate case I thought it

Originally posted by sensij

The proposal was for $3.30 / W, cash, for a system cost of $10296. Assumptions used in the financial calculations:
1) Annual electric consumption stays constant + 600 kWh for a new (large) fridge we just installed.
2) SDG&E rates (coastal, standard service) through 2018 are bracketed by my understanding of ORA's Sept. 15 testimony and SDG&E's Oct 17 response, mostly Chapter 4. Since the system may produce more than what I will use, whether the $10 / mo comes in as a fixed charge or a minimum charge won't matter a whole lot.
3) Rates after 2018 increase at 2.1% annually.
4) 4.25% discount rate, corresponding to some loans I carry.

The last time I read this rate case I thought it referred to minimum increase plus the an increase tied to the CPI (consumer price index)?

Below is the language about increases being tied to the CPI or inflation. Hope we don't hit an inflationary period in the near future. Where did you get the 2.1% increase? Historical inflation number?

" To increase the minimum bill charge for master metered customers beginning in 2015,
with no changes for CARE customers with the exception of an annual CPI adjustment
that will be implemented beginning in 2016 for both non-CARE and CARE master
metered customers. "

Congrats on the new system. Did you spend more on the roof or more on the solar?

**sensij** · 12-11-2014, 05:49 PM

Originally posted by SoCalsolar

The last time I read this rate case I thought it referred to minimum increase plus the an increase tied to the CPI (consumer price index)?

Below is the language about increases being tied to the CPI or inflation. Hope we don't hit an inflationary period in the near future. Where did you get the 2.1% increase? Historical inflation number?

" To increase the minimum bill charge for master metered customers beginning in 2015,
with no changes for CARE customers with the exception of an annual CPI adjustment
that will be implemented beginning in 2016 for both non-CARE and CARE master
metered customers. "

Congrats on the new system. Did you spend more on the roof or more on the solar?

In the ORA testimony (if the link doesn't work soon, I'll replace it with a dropbox version of the file), Chapter 5 is focused on SDG&E. ORA's proposal starts on page 5-3, and presents most of its data in the context of a 2.1% system revenue increase. By this rate design, that translates to a 2.25% RAR (residential average rate) increase. They also present a plan based on 2.2% RAR, and then contrast it with a 5% RAR to (I think) show the rate shock that would occur in that environment.

In Chapter 4 of the Oct. 17 SDG&E testimony, on page CF-47 they present a revenue neutral plan for restructuring the rates, and then also a 2.1% CPI adjusted plan. No plans with rate increases higher than that are presented.

Every time I read through these documents, a small but increasing percentage of the content sinks in. I certainly do not grasp all of the nuance in the discussion. My best guess, somewhat consistent with historical rate increases, is that rates will follow inflation. 2.1% feels like the lower bound, and is what I wanted to model with, but I would not argue much with someone who prefers predictions closer to 3%. Over a 10 year time frame, the impact of that range is not much. Higher than 3% starts to require speculation that I find harder to support, and 4% was the upper bound that I spent any time modeling.

The re-roofing and requested modifications will be $10,900, slightly more than the solar.

**J.P.M.** · 12-11-2014, 06:04 PM

On the diffuse fraction, start as usual with Duffie & Beckman. NREL also has some stuff, but unless you have at least a pair of Eppley instruments @ ~ $5K-$10k ea. + a careful handling and maint., the HDKR, or Perez methods will get you in the ballpark as well as most anything. Even with the instruments, diffuse fraction is a usually an approximation and close is usually the best you can hope for. Fortunately, that's often good enough given all the other uncertainties involved. It's mostly back to the basics. A guy by the name of Christian Gueymard has done/published some interesting stuff, the early work being perhaps a bit easier to program. There are lots of others. Check the Journal "Solar Energy" for some of his work and that of others.

**J.P.M.** · 12-11-2014, 06:22 PM

Originally posted by sensij

In the ORA testimony (if the link doesn't work soon, I'll replace it with a dropbox version of the file), Chapter 5 is focused on SDG&E. ORA's proposal starts on page 5-3, and presents most of its data in the context of a 2.1% system revenue increase. By this rate design, that translates to a 2.25% RAR (residential average rate) increase. They also present a plan based on 2.2% RAR, and then contrast it with a 5% RAR to (I think) show the rate shock that would occur in that environment.

In Chapter 4 of the Oct. 17 SDG&E testimony, on page CF-47 they present a revenue neutral plan for restructuring the rates, and then also a 2.1% CPI adjusted plan. No plans with rate increases higher than that are presented.

Every time I read through these documents, a small but increasing percentage of the content sinks in. I certainly do not grasp all of the nuance in the discussion. My best guess, somewhat consistent with historical rate increases, is that rates will follow inflation. 2.1% feels like the lower bound, and is what I wanted to model with, but I would not argue much with someone who prefers estimates closer to 3%. Over a 10 year time frame, the impact of that range is not much. Higher than 3% starts to require speculation that I find harder to support, and 4% was the upper bound that I spent any time modeling.

The re-roofing and requested modifications will be $10,900, slightly more than the solar.

Rate structure information and guessing sure is fun, ain't it ? Given that all the details are not final on rate structures yet, and will probably be fluid for the near future, I'd offer an opinion that 2-3 % is probably as good a stab as any. I often use 3.2% for no other reason than it's close to the prior 10 yr. ave. CPI + .75%, but I'd not dispute that's probably a B.S. method.

**sensij** · 12-19-2014, 03:36 PM

Roofing work is underway. The panels will go in one row along the south facing eve.

chimney.jpg south roof.jpg

**sensij** · 02-03-2015, 05:08 PM

There were some delays in the roofing work and some delays by the installer that have added a few weeks to the installation time, but I didn't really expect things to move quickly during the holidays. The permit application was submitted to the city last week and is expected to be approved by 2/12.

Roof.jpg

Ridge vents were eventually installed; they will be in the pictures I take once the panels start to go up. At that time, the roofer will return to verify the integrity of the roof, and make sure the penetrations are reliably flashed and sealed.

**sensij** · 03-20-2015, 12:05 PM

The permit application was approved after a resubmitting with more detail on the system fire rating, you can see my posts at the end of this thread for more information.

Shipping confirmation on the equipment has been received, with an installation date on Wednesday next week. The installer is including a TED5000 and an ANSI approved production meter, so along with the SolarEdge inverter's own data and the net data from my SDG&E meter (provided by the Eagle device), I should be able to get a good idea of what the system is producing (and equally, if not more important, continue to track my consumption).

I'm looking forward to posting more next week!

**HX_Guy** · 03-20-2015, 12:58 PM

Exciting stuff! Looking forward to the install.

**sensij** · 03-26-2015, 03:26 PM

The installers are hard at work and what they've done so far looks fantastic. I've checked in the attic, and cannot find evidence that any of the 16 lag bolts missed their intended rafter.

Rails
20150326_115642.jpg

Chalk Lines for alignment.
20150326_115704.jpg

Properly flashed and sealed.
20150326_115713.jpg

**MikeInRialto** · 03-26-2015, 06:37 PM

: ) liking like things will start to move very quick now

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