planet4ever said:
Sorry, but I think you must have a bug in your spreadsheet somewhere. I have been on E-6 for nearly five years, and I, too, have a spreadsheet. I have to admit I haven't kept it up to date recently, and they keep changing the rates every few months, but when I was keeping it up I was always within a few cents of the cost PG&E calculated. The final statement in the document you pointed to says, "Note that the top tier is the same for all TOU periods."
You can't get into tier 4 or 5 for off-peak without also getting into the same tier for the other two time periods. That is the whole point of the dynamic (by month) reallocation of percentages of baseline to the various time periods. And that is why I said in my previous post, "this is going to shift the ratio of peak to part-peak to off-peak usage." The more you charge your LEAF the more baseline you will get off-peak, and so the more of your charge will fall in the sweet spot below 130% of baseline.
My spreadsheet calculates the E-6 bill within a few cents of the actual bill. I think it's off less than $1 for the total of all the bills the last 2 years. It calculates hypothetical E-1 too to see how much benefit I get from TOU . I also have my actual bills with E-1 prior to going to E-6 and the total was within one cent.
And I keep up with all the rates, as one of the columns is a the name of another sheet, which itself contains the PG&E rate-of-the-month. This field then gets used with an INDIRECT reference. So it is very easy for me to add any the new PG&E rate going forward. New rates seem to take effect on average every 3 months for the last 2 years.
I think you are correct that I can't get into tier 4 or 5 for off-peak without it being so for the other TOU periods. However, the other TOU periods in the summertime are negative so it's actually a good thing to be in tier 4 or 5 for them.
Here is an example with the actual data ending 8/19 :
peak usage -238 kWh
part peak -9 kWh
off peak +764 kWh
net kWh is 517 kWh . This period has 30 days, so that's 17 kWh per day.
Baseline is 11 kWh per day. So I already hit tier 3 (above 130% of usage).
If I was on E-1 , the bill would be $87.37 . Ie. $0.16899 per kWh average.
On E-6 according to my calculations, it is :
+$12.67 for meter charges/taxes
-$73.96 for peak
-$1.82 for part peak
+$99.11 for off peak
total $36.00 calculated. The actual E-6 bill was $36.15.
Note that $36 divided by 517 is is 0.069 per kWh . That's my average cost per kWh for my grid usage in august. Funny how that's lower than any of the rates on the E-6 or E-1 rate schedules, but this is actually correct. That's what solar PV and having negative peak usage does.
Let's add 12 kWh per day to off-peak for EV charging . There are 30 days, so that's 360 kWh per day . Let's assume this charging is 100% in off-peak .
off peak usage changed to +1124 kWh.
The total net kWh for the month jumps from 512 to 877, an increase of 71% in usage.
That's 29.23 kWh per day vs baseline of 11 . I am now in tier 4, above 200% of baseline . Which is the same price as tier 5.
According to my spreadsheet, the hypothetical E-1 bill jumps from to $208.64, whereas it would be $87.37 without the EV charging .
The bill went up 138% .
That means the net cost of charging for the month on E-1 is $121.27 . Divided by 360 kWh, it's 0.3368 per kWh .
Tier 3 is 0.29561 per kWh and tier 4 is 0.33561 . So that sounds high.
Until you realize there are also 5% utility user's tax, 0.3% of San Jose franchise tax, and a 0.00022 per kWh CEC tax.
Those are all accounted for in the spreadsheet too.
The $208.64 bill is broken down between $197.96 of energy charges, and $10.68 of CEC kwH and San Jose franchise tax.
So, in summary, adding daily EV charging if I was on E-1 would cost me $121 .
Let's recompute with E-6 .
My spreadsheet says the total cost would be $140.26 .
This breaks down as :
-$89.58 for peak
-$2.41 for part peak
+$219.58 for off-peak
+$12.67 for meter charges/taxes
The E-6 bill was $36.00 without EV charging. Going to $140.26, that's a jump of $104.26 for EV charging. The bill actually went up 289% ! Ie. it nearly quadruples for that month if I charge at home.
$104.26 divided by the 360 additional kWh means the extra kWh for EV charged were charged at a rate of 0.28961 per kWh.
Feel free to double and triple check the calculations if you want
But sadly, I believe they are correct.
Edit: you can PM and I will share the spreadsheet with you if you like...
I agree with your estimate of 4500kWh/year for the way you intend to use the LEAF. But that means, as I said, about 12.3kWh/day. If you are in territory X as I am and use natural gas for heating, that is an additional load just a bit over baseline. If you are currently below baseline, that can't take you much beyond 200%, meaning just at the edge of tier 4. Yes, due to seasonal variations in solar output and air conditioning, the percentages will vary by month, so you will have some tier 4 usage. If you go hog-wild with December lighting you might hit tier 5 that month (when solar is at its minimum).
Ray
I am in territory X. But at 17 kWh/day net grid usage, I am not in baseline, even with plain E-1. I am actually in low tier 3.
Adding 12 kWh per day increases net grid usage 71% and pushes me to high tier 4.
The net result is a very large electric bill increase.
On an annual basis, with E-6, the bill goes roughly from $800 to $1900 .
With E-1, it goes from $1100 to $2400 .
That is, charging 12 kWh/day at home costs an extra $1100 a year to $1300 a year depending on which rate I choose.
Of course, I choose the E-6 rate which is lower for me due to the PV.
This increase is almost exactly what it costs me in gasoline annually with my much longer range Prius.
