Help. Should I apply for EV-TOU2 rate with SDGE?

I live in a condo and could not get the second meter installed. My last months usage 533.

kWh used 313 baseline (@ 0.138) 94 (1-30% @ 0.16) 124 (31-100% @ 0.29)

313 x .138 = 43.19
94 x .16 = 15.04
124 x .29 = 36.54

Total = 94.77

I charge about 10 kWh per day with the leaf so my estimated full month increase is 300 kWh for a total of 833kWh so instead of 124 @ 0.29, it'll be 217 @ 0.29 and 224 @ 0.31

313 x .138 = 43.19
94 x .16 = 15.04
217 x .29 = 62.93
224 x .31 = 69.44

Total = 190.60

If I switch to EV-TOU2, assuming my non EV usage doesn't change (533 broken down per rate period).

Super Off Peak
533 x (5/24) x .145 = 16.10

Off Peak
533 x (7/24) x .167 = 25.96

Peak
533 x (6/24) x .258 = 34.38

Off Peak
533 x (6/24) x .167 = 22.25

Total = 98.69

Additional 300 kWh

100% Super Off Peak
300 x .145 = 43.50

80% Super off Peak 20% off peak
300 x .145 x .8 + 300 x .167 x .2 = 44.82

50% Super off Peak 50% off peak
300 x .145 x .5 + 300 x .167 x .5 = 46.80

100% Peak
300 x .258 = 77.40

Best Case EV-TOU2
98.69 + 43.50 = 142.19

Worst Case EV-TOU2
98.69 + 77.40 = 176.09

If all my math is correct, my worst case with EV-TOU2 is still better than Schedule DR. Can someone look over my math and assumptions before I submit my application for EV-TOU2? According to SDGE, you can't change for 12 months after a rate switch.

THANKS!

Basically, even the Peak TOU is 26¢, and the tier 4 rate is higher, at 31¢.

You have assumed that your initial whole-house usage of 533 is evenly spread over the 24 hours. If that is not true, and you run A/C during the afternoon, the TOU treatment of the 533 kWh might be noticably different.

Garygid brings up the critical point that your usage over time is the primary determinant of which will be cheaper.

Go sign up for Google PowerMeter http://www.google.com/powermeter/about/ -- with it, you can see your energy usage over the day, and run the numbers in a valid comparison.

I'd do that too, if SDG&E/PowerMeter worked with net metering (e.g., houses with PV systems); it'd give me a better idea if DR-SES is a better rate for me than plain old DR.

My wife and I are away from the house from roughly 7AM to 5:30PM for work. I have a home server that's on 24 hours a day which probably accounts for about half my monthly electrical usage. My assumption is that most of my extra usage would be during Off Peak times (when we get ready for work in the morning and when we are at home in the evenings.
I did sign up for Google Powermeter last night but data the hasn't been populated yet.

BTW, do EV-TOU2 rates apply 7 days a week or only weekdays? I'm sure I use more at Peak during the weekends since I'm actually home.

The infamous X rate takes away much of the benefit of the second meter. The X rate costs double the super off peak rate compared to the other two rates

supernoman said:

BTW, do EV-TOU2 rates apply 7 days a week or only weekdays? I'm sure I use more at Peak during the weekends since I'm actually home.

Click to expand...

7 days a week. There is no special weekend rate

We have grid tied solar. After 3 months of TOU (SCE) - we find TOU billing to be a hideous nightmare. It has cost us 60% of the solar surplus that we have averaged over the past 2 years of solar generation (100's of dollars)... even though we've switched collateral power usage to after 6pm and prior to 10am. Even the utility company can not explain how to read ... or make sense of the different screen readouts (screen 01 ...07 ... 71 ... 02 etc) nor the meaning of the little corner dial that only flashes between 1 and 2 ... though it's numbered through 4 ... nor whether it's supposed to relate to weekends ... time of day ... or seasons ... because as of now ... it follows NO discernable pattern. We were promised an audit ... that somehow no one remembers talking to us about. We told edison to get this meter OUT of here ... and they can't enen manage to do THAT. No ... don't even get me started on our TOU experience .

sorry for the rant

Is this with a second meter or single meter? My situation is about single meter SDGE EV-TOU2 rate.

hill said:

We have grid tied solar. After 3 months of TOU (SCE) - we find TOU billing to be a hideous nightmare. It has cost us 60% of the solar surplus that we have averaged over the past 2 years of solar generation (100's of dollars)... even though we've switched collateral power usage to after 6pm and prior to 10am. Even the utility company can not explain how to read ... or make sense of the different screen readouts (screen 01 ...07 ... 71 ... 02 etc) nor the meaning of the little corner dial that only flashes between 1 and 2 ... though it's numbered through 4 ... nor whether it's supposed to relate to weekends ... time of day ... or seasons ... because as of now ... it follows NO discernable pattern. We were promised an audit ... that somehow no one remembers talking to us about. We told edison to get this meter OUT of here ... and they can't enen manage to do THAT. No ... don't even get me started on our TOU experience .

sorry for the rant

Click to expand...

hill said:

We have grid tied solar. After 3 months of TOU (SCE) - we find TOU billing to be a hideous nightmare. It has cost us 60% of the solar surplus that we have averaged over the past 2 years of solar generation (100's of dollars)... even though we've switched collateral power usage to after 6pm and prior to 10am. Even the utility company can not explain how to read ... or make sense of the different screen readouts (screen 01 ...07 ... 71 ... 02 etc) nor the meaning of the little corner dial that only flashes between 1 and 2 ... though it's numbered through 4 ... nor whether it's supposed to relate to weekends ... time of day ... or seasons ... because as of now ... it follows NO discernable pattern. We were promised an audit ... that somehow no one remembers talking to us about. We told edison to get this meter OUT of here ... and they can't enen manage to do THAT. No ... don't even get me started on our TOU experience .

sorry for the rant

Click to expand...

For what it's worth, this sounds like exactly the reason I dropped out of the TOU plan as well.

It was completely impossible for me to predict or confirm my own power bill, even with the head of SDG&E Billing on the phone. They finally conceded that there are "important factors" that are not shown on the bill which play into the rates and totals shown.

It was totally inscrutable. AND I had the actual data from the meter, using the same software SDG&E uses to read the meter. I had very accurate numbers, and still couldn't compute my own power bill to within 20%.

I went back to flat-rate DR and let them know that TOU was too confusing, and too expensive. This was three years ago, and I know SDG&E has revised the billing statements since. I don't know if the TOU situation has improved.

Even with simple Net-Metering for a Solar PV system, there are numbers (usually "credits" for overgeneration) that just "appear" on the SDG&E bill, with no "calculation" of where they came from.

So, even without TOU, the SDG&E billing can be obtuse if you have PV over-generation.

Hmmm...these replies have me scared. I don't have a PV system so it *should* be a pretty simple setup to calcluate.

We just went through a very thorough analysis of this here: The REAL Charging Cost per SDG&E and "Equivalent ICE mpg"

Bottom line is that the TOU rates are only useful if you use a lot of energy. Otherwise you are better off with the second meter and the tiered rate schedule. This is even true if you get the "X" rate - which is the one I got :evil:

I actually started with the TOU and switched to the EV second meter after discussions with SDG&E and reviewing tables that are available on their web site. Oh, there is another thing confirmed in the "Real Charging Cost" discussion - if you are on the "experimental rate" either X,Y or Z, which by the way expires in Nov. 2012, that is an "all in" rate, whereas their other rates have adders for transmission cost, generation cost, bond issues, etc. that double the kWH rate shown on your bill. Read the fine print below the rate table, then work the numbers and you will see your real kWH rate. Also note that the "generation rate" changes in summer/winter seasons.