CSI EPBB Calculator Question

[J.P.M.]

JPM please can you post a link?

Thanks.

A link For what ?

[albert436]

The rant.

[silversaver]

$43K - nice. Capitalism at work. Know this: The salesperson's job is to leave your home with an order for goods and services - not help you because you're a nice person, not reduce your electric bill, not save the planet - all nice sentiments that perhaps will come to pass, but in the end coincidental to the mission - sell equipment as profitably as possible. That's not evil - it's just business. Caveat Emptor. Several quotes help. Bet your glad you found this forum , huh ? You must have missed my epistle some months back when/where I think I described my request for quote/bid selection process. In fairness to sales folks in general, most don't have the time for what I very briefly described, and right now probably don't have time to bend over and scratch. All the more reason to get and be informed before you get (several) quotes - part of my rant about trying to know the answers before you ask the questions.

I'm definitely glad I have found this forum, and I don't think many people here getting what I got for $2.84 per Watt DC before incentive. I have referral the same solar company to my neighbor and he is about to sign a 8.5kW system install on his NE 70 roof. and SE160 roof. Majority of panels will be on NE facing roof. We all know that is not the best place for them, but he doesn't want the solar panels to be seen in front of the house. Estimate 11,000kWh for a 8.5kW system seem to be little, but that's what he prefered.

[J.P.M.]

The rant.

Oh. OK. I'm not sure where it is in my past 360 + posts and I'm not any more inclined to look for it than anyone else. It may be on a different forum now that I'm thinking about it. I'll do it again and P.M. you.

[J.P.M.]

I'm definitely glad I have found this forum, and I don't think many people here getting what I got for $2.84 per Watt DC before incentive. I have referral the same solar company to my neighbor and he is about to sign a 8.5kW system install on his NE 70 roof. and SE160 roof. Majority of panels will be on NE facing roof. We all know that is not the best place for them, but he doesn't want the solar panels to be seen in front of the house. Estimate 11,000kWh for a 8.5kW system seem to be little, but that's what he prefered.

It's a free country and it's just business. SE 160 is actually pretty good. Lets all hope the panel el. angle is relatively low on the NE70 portion. What panel mfg ?

[silversaver]

It's a free country and it's just business. SE 160 is actually pretty good. Lets all hope the panel el. angle is relatively low on the NE70 portion. What panel mfg ?

about 20 tilt. Kyocera 35 X 245W panels. 24 panels on NE roof.

[J.P.M.]

about 20 tilt. Kyocera 35 X 245W panels. 24 panels on NE roof.

Thank you. a similar sys. in my neighborhood that I'm more familiar with than most seems to be producing about 10-15% more than predicted by the vendor. Tilt 20 deg., Az. 77., 18 - 245 Watt. FWIW

[silversaver]

Thank you. a similar sys. in my neighborhood that I'm more familiar with than most seems to be producing about 10-15% more than predicted by the vendor. Tilt 20 deg., Az. 77., 18 - 245 Watt. FWIW

My neighbor would love to heard that. In general, I think most of new install seems to getting those "surplus" mainly due to the nice weather we got here. My Jan 2014 expected production were 535kWh and I'm getiing 633.47kWh. What's your?

[J.P.M.]

My neighbor would love to heard that. In general, I think most of new install seems to getting those "surplus" mainly due to the nice weather we got here. My Jan 2014 expected production were 535kWh and I'm getiing 633.47kWh. What's your?

I should have been more specific. That system's performance is something like 10-15 % greater than the vendor's data would have predicted for the same actual weather data we experienced for Dec. & Jan. The vendor used that probably overly conservative .77 from the CSI incentive calculator (which BTW, as Russ alluded to is not a design/sizing tool). I'd suggest .82-.85 would have been a more appropriate using PV Watts.
What happened here is another example and pretty typical of how vendors can and all to often do use customers ignorance to sell more product. Customers, in their ignorance are usually happy because their system is producing more than they were told it would, thinking they got a deal, but are clueless that they may have been misled by an overly conservative estimate into buying more and thus paying more than is actually necessary for what they were told they would need. This can often result in oversized systems that are almost always less cost effective, which is fine if that's the customer's choice. Usually however, they don't know a thing and get screwed. Give the customer straight information, don't take advantage of their ignorance and let them make their choice on honest, more realistic information. The possible deception as I describe is what I have a lot of trouble with. I apologize to any ethical vendors who may take exception to my opinion(s).

Caveat Emptor.

[J.P.M.]

I should have been more specific. That system's performance is something like 10-15 % greater than the vendor's data would have predicted for the same actual weather data we experienced for Dec. & Jan. The vendor used that probably overly conservative .77 from the CSI incentive calculator (which BTW, as Russ alluded to is not a design/sizing tool). I'd suggest .82-.85 would have been a more appropriate using PV Watts.
What happened here is another example and pretty typical of how vendors can and all to often do use customers ignorance to sell more product. Customers, in their ignorance are usually happy because their system is producing more than they were told it would, thinking they got a deal, but are clueless that they may have been misled by an overly conservative estimate into buying more and thus paying more than is actually necessary for what they were told they would need. This can often result in oversized systems that are almost always less cost effective, which is fine if that's the customer's choice. Usually however, they don't know a thing and get screwed. Give the customer straight information, don't take advantage of their ignorance and let them make their choice on honest, more realistic information. The possible deception as I describe is what I have a lot of trouble with. I apologize to any ethical vendors who may take exception to my opinion(s).

Caveat Emptor.

To your question of my Jan. production:

1.) Production as reported by the monitor was 629.95 kWhrs, 01/01 - 01/31 inclusive.
2.) If Jan. weather was identical to a typical TMY 3 Jan. for Miramar MCAS and slightly irradiance adjusted for zip 92026, using my methods, my production would have been 610 kWhrs. Using SAM and TMY 3 data for Miramar MCAS, the output estimate was 620 kWhrs. for Jan. Thus, the data would suggest Jan. was about 1 to 2% or so better than a Jan. that had TMY 3 weather and irradiance.
3.) My weather station horiz. irradiance for Jan. was about 102,647 Watts/m^2 w/ some shading after about 1430-1500 hrs. or so. I'm guessing I might add 1-2 % to that total to account for the afternoon shade. TMY 3 is about 102,881 W/m^2.
4.) My SWAG for Jan. at my house, based on the above is that it was a pretty typical Jan., maybe a few % more sunshine in spite of what I, and most others thought was a pretty sunny month. I try to be careful about data gathering and interpretation. This data seems to make sense and hold together even I it does seem to go against what I think happened last month. We'll see what Feb. brings.

System : 5.232 kW, Az. 195 deg., Tilt 18.5 deg., lat. 33.21 N, long. 117.096 W., El. 1380 ft. above M.S.L.

Without knowing any more about your system, I guess that your larger size and perhaps less ideal azimuths than my sys. would tend to make our outputs somewhat similar, which your 633 kWhr. output might suggest.

It may be interesting to note that your estimate of 535 kWhrs. is about 15 % less than what you achieved in what may have been, based on the above an only slightly better than normal month. Did that 535 kWhr. figure come from the vendor or the CSI incentive calculator or PV Watts or somewhere else ? While not a smoking gun for overselling by underestimating, it looks like it might fit the pattern.

[silversaver]

To your question of my Jan. production:

1.) Production as reported by the monitor was 629.95 kWhrs, 01/01 - 01/31 inclusive.
2.) If Jan. weather was identical to a typical TMY 3 Jan. for Miramar MCAS and slightly irradiance adjusted for zip 92026, using my methods, my production would have been 610 kWhrs. Using SAM and TMY 3 data for Miramar MCAS, the output estimate was 620 kWhrs. for Jan. Thus, the data would suggest Jan. was about 1 to 2% or so better than a Jan. that had TMY 3 weather and irradiance.
3.) My weather station horiz. irradiance for Jan. was about 102,647 Watts/m^2 w/ some shading after about 1430-1500 hrs. or so. I'm guessing I might add 1-2 % to that total to account for the afternoon shade. TMY 3 is about 102,881 W/m^2.
4.) My SWAG for Jan. at my house, based on the above is that it was a pretty typical Jan., maybe a few % more sunshine in spite of what I, and most others thought was a pretty sunny month. I try to be careful about data gathering and interpretation. This data seems to make sense and hold together even I it does seem to go against what I think happened last month. We'll see what Feb. brings.

System : 5.232 kW, Az. 195 deg., Tilt 18.5 deg., lat. 33.21 N, long. 117.096 W., El. 1380 ft. above M.S.L.

Without knowing any more about your system, I guess that your larger size and perhaps less ideal azimuths than my sys. would tend to make our outputs somewhat similar, which your 633 kWhr. output might suggest.

It may be interesting to note that your estimate of 535 kWhrs. is about 15 % less than what you achieved in what may have been, based on the above an only slightly better than normal month. Did that 535 kWhr. figure come from the vendor or the CSI incentive calculator or PV Watts or somewhere else ? While not a smoking gun for overselling by underestimating, it looks like it might fit the pattern.

The estimate is based on CSI calculator, which not much different from PVWatt when I plug in the number. I'm pro oversizing, so I wish I can go larger if SCE allows me to. I know I will be using more electricity in the feature. I actually ask for larger system but vendor says no. I have been conserved the last 2 years, and it make no sense to me to live in the same style even with solar installed.

System : 6.63 kW, Az. 245 deg Tilt 23 deg

[J.P.M.]

The estimate is based on CSI calculator, which not much different from PVWatt when I plug in the number. I'm pro oversizing, so I wish I can go larger if SCE allows me to. I know I will be using more electricity in the feature. I actually ask for larger system but vendor says no. I have been conserved the last 2 years, and it make no sense to me to live in the same style even with solar installed.

System : 6.63 kW, Az. 245 deg Tilt 23 deg

I thought the purpose of the CSI calculator was to calculate the CSI incentive, not size systems or estimate performance necessarily. Using it as a sizing tool seems like a possible misapplication. The CSI calculator uses PV Watts w/ the default adjustment factor of .77. I'm suggesting that .77 may be too low a number. PV Watts used by itself will allow less conservative and perhaps more appropriate adjustments that may lead to more accurate and realistic estimates and thus more cost effective (less oversized) systems. Using the CSI calculator as a sizing tool will likely lead to oversizing which may seem wonderful because it leads to more production, which will feel great until you think about it and come to the conclusion that your paying more money for a larger system that in all likihood will replace electricity in the lower tiers (cheaper), or even overproduce past 100%, and thus be less cost effective. Too small a system may not be the greatest, but too big a system is, IMO, much worse. You're paying for more than is cost effective, or what you may need and may not know it. In the end , it's a free country.

[silversaver]

I thought the purpose of the CSI calculator was to calculate the CSI incentive, not size systems or estimate performance necessarily. Using it as a sizing tool seems like a possible misapplication. The CSI calculator uses PV Watts w/ the default adjustment factor of .77. I'm suggesting that .77 may be too low a number. PV Watts used by itself will allow less conservative and perhaps more appropriate adjustments that may lead to more accurate and realistic estimates and thus more cost effective (less oversized) systems. Using the CSI calculator as a sizing tool will likely lead to oversizing which may seem wonderful because it leads to more production, which will feel great until you think about it and come to the conclusion that your paying more money for a larger system that in all likihood will replace electricity in the lower tiers (cheaper), or even overproduce past 100%, and thus be less cost effective. Too small a system may not be the greatest, but too big a system is, IMO, much worse. You're paying for more than is cost effective, or what you may need and may not know it. In the end , it's a free country.

Like I said, I prefer larger system because I know I will NEED it. EV car will take about 4800kWh for 15k miles per year. In reality, my system is too small for my demand.

[J.P.M.]

Like I said, I prefer larger system because I know I will NEED it. EV car will take about 4800kWh for 15k miles per year. In reality, my system is too small for my demand.

Mine will be about right once the EV come along, probably ~~2-4 yrs, SWAG.

Regards.

[bando]

My neighbor would love to heard that. In general, I think most of new install seems to getting those "surplus" mainly due to the nice weather we got here. My Jan 2014 expected production were 535kWh and I'm getiing 633.47kWh. What's your?

silver, mine was 1,027 expected per Locus and Jan 2014 production was 1,342