Hi nguyenner,
I bought a leaf last November and almost immediately signed up for the Plug-in Electric Vehicle rate (PEV). GA power came within a few days (maybe a couple?) to reconfigure the power meter so that it would track hourly use instead of daily use. I now see on my bill how many kWh I used on Peak, Off-Peak, and Super-off Peak hours. Unfortunately, the ability to view the daily usage history on your account on the GA Power website is lost (counter-intuitive, I know), so you can't track actual usage until you see your bill.
All of my electricity usage is charged at the same rate - meaning, after 11pm at night, all of my electricity usage - electric car charging, tv watching, lights, etc. are on the Super-off Peak tier. This also means that in the Summer time, if my AC runs in the afternoon from 2-7pm, it is in the Peak tier and charged at a base of 20 cents per kWh! (Plus taxes and fees, which bring it up to about 30 cents per kWh). That's a lot and can quickly negate the savings from the overnight rate! This only makes sense if you don't cool your house a lot during the Summer afternoons. Both of us work full-time, so no one is running the AC, lights or appliances until we get home in the evening. Because of this, based on my calculations we will have saved nearly $200 this year by switching to PEV (all for just being a little warm in the house when we get home until 7:00 pm
)
I would suggest you get a power meter to see how much electricity you use on average at different times of day. Then, you can easily calculate how much you would pay on the PEV rate and if you would have any savings. I personally got the Efergy E2 Wireless Electricity Monitor (I got mine on Amazon), installed it in less than 5 minutes and I can track my energy usage on an hourly basis. I got the monitor because I wanted to see my energy usage in real time and check individual appliances' effect on my electricity usage, but looking back I wish I had gotten the Hub (internet interface) because the monitor doesn't play nice with my computer and you have to hook it up to download the data. The process could be easier...
Lucky for you I've done all of the calculations on the latest GA Power pricing (as of July 2014). I'm in a city with 6% sales tax, so the franchise fee and sales tax apply and are included in my calculations:
Base charge: $13.57
Summer Standard rates: Base charge + (first 650 kWh)*$0.1143 + (651-1000 kWh)*$0.1617 + (kWh over 1000)*$0.1657
Winter Standard rates: Base charge + (first 650 kWh)*$0.1069 + (651-1000 kWh)*$0.0967 + (kWh over 1000)*$0.0956
PEV Summer: Base charge + (On peak kWh)*$0.3124 + (Off peak kWh)*$0.1251 + (Super off peak kWh)*$0.0603
PEV Winter: Base charge + (Off peak kWh)*$0.1177 + (Super off peak kWh)*$0.0529
I have a more detailed spreadsheet where you can put your own sales tax and usage if you want, let me know. You can also try the basic GA power calculator which will help break down the actual cost of each fee, but this only works for the Standard rate and not the PEV rate
http://www.psc.state.ga.us/calc/electric/gpcalc.asp . Since my calculations are with my sales tax and my city's franchise fee, it won't be as accurate for you but should be within a few dollars (less than $5, unless your usage is wayyyy high) of your actual costs.
I hope this helps!