TOU (Time of Use) rates with electric co

kinabalu · Jan 28, 2016

So I called my electric co and had it changed from a tiered rate plan, to the Time of Use plan. Which at their rates is $0.12 / kWh from the hours of 10pm to 8am. Have to wait till the end of Feb before the new rate plan will kick in though.

Wondering if those who are using TOU rate plans found it beneficial? My bill because of tiered rate was $165 when previous months it had never eeked past $65. I am getting a JuiceBox installed within the next week, so I'll have better ability to schedule in the off hours to take advantage.

How much electricity would you guys say on average each month you're using to charge the car at night? I think last month I just passed 700 but considering I may have more once the JuiceBox gets installed and I can drink from the hose a lot faster.

vin · Jan 28, 2016

Based on the super-off-peak period and rate you specified, I'm guessing that you're with So Cal Edison. So am I, and when I switched from their residential tiered rate to TOU a couple of years ago, it came to about a 27% savings for the one month that I sampled. That was when the super-off-peak period was 12am-6am. Now that the period has been extended by 4 hours, I'm pretty sure I'm saving even more. My initial write-up on the subject is here:

http://ev-vin.blogspot.com/2014/11/choosing-rate-plan.html

I also have a write-up on SCE's current TOU rate structures (which one to choose), which seems to be getting more hits lately - wondering if SCE put out some kind of mailer about TOU to folks with usage patterns that might benefit:

http://ev-vin.blogspot.com/2015/02/new-sce-time-of-use-rate-structure.html

I'm currently on TOU-D-B, since we use more than 700 KWh/month. Using waaay more electricity than two years ago (~30%), and our bill is still much less than the same month in 2014. Hope this helps!

As far as how much charging I do at night - on any given night there are two cars charging at L1 from 10pm to 8am, so that's

10 hours * 12 amps * 120 volts * 2 cars = 28.8 KWh per night. Multiply that by 30 days, that's 864 KWh/month.

lindner · Feb 4, 2016

When I switch to ToU I saved 30% compared to the previous month, so yes it's likely that you can pay for the cost of the Juicebox in a few months.

And this is with PG&E - which has really stupid "Peaks" including weekends from 3-7pm.

ColinM · Feb 23, 2016

lindner said:
When I switch to ToU I saved 30% compared to the previous month, so yes it's likely that you can pay for the cost of the Juicebox in a few months.

And this is with PG&E - which has really stupid "Peaks" including weekends from 3-7pm.

Looks like the 3-7pm is on the "EV" plan, not the "E6" ToU plan. I'm looking at all the plans/numbers now, had to dig through a lot of crap to actually get all the hard numbers. Made a spreadsheet so it was easier to compare (though the "E6" plan is getting replaced on Mar 1 2016 with two new plans and the tiers are getting squished again (not sure if that's happening at the same time or not, but it says "2016" for moving to 3 tiers).

Here it is (open for comment): https://goo.gl/HHNyBe

Just a rough start to flip between sheets to see differences in plans.

Stretch2727 · Feb 28, 2016

I am on TOU rate with 2 Electric cars. I live in NJ.

Off Peak Rate = $0.09
On Peak Rate = $0.19

Peak is M-F 8am-9pm.

With the cars charging at night I never use more than 20% peak Kwh. 80% of my Kwh is off peak.

So my blended rate is $0.11 = 0.09*0.8+0.19*0.2

My old non tiered rate was about $0.18. So I save about $0.07 per Kwh. I use on average about 800 Kwh per month so I save about $56 a month.

Actually this is about $46 per month as the service fee for the TOU meter is $10 per month.

I just went on TOU in Sept 2015. So far I am seeing the savings. June-August I don't expect to save to much as they raise the peak rate to $0.26. My calculations show I should be neutral during these months. So I will save the $46 for 9 months a year..approx $400.

jphollywood · Mar 1, 2016

We have a TOU meter from LA-DWP (City of Los Angeles). We have not had it long enough to really qualify it (DWP bills bi-monthly) but it appears to have reduce our billing significantly. We expect to have more billing information in another month and be really able to see the difference. Based on just visual stops by the meter, we are running over 75% of our usage in base (lowest) rate (8PM to 10AM).