Best Grid Friendly Charging Schedule

[ClarksonCote]

I wanted to find out what the best time would be for EV's to charge their vehicles, that would minimize their strain on the electrical grid. In theory, these are times where base load power plants may also not be operating at their nameplate capacity (and therefore not at their peak efficiency). This conclusion seems to agree studies done in the past, and the implication should be that charging during these times also makes the grid power generation more efficient.

In any case, I looked at the NY ISO grid data over the last 8 months, and compiled many graphs (some shown below). I also looked at a report that had a graph showing notional demand across the country (also shown below). The results are similar, with some time skewing.

In short, for New York state, the lowest point of demand is centered around 4:00am. What does this mean? Here's some examples of settings that would charge your vehicle to minimize the amount of strain on the grid and help with load balancing in New York State:
- Example 1, Fully Discharged Volt, Level 2 (240V) Charger: Set to Delayed charging, with a finish time of 6:00am.
- Example 2, Fully Discharged Volt, Level 1 (120V) Charger: Set to Delayed charging, with a finish time of 9:00am.
- Example 3, Fully Discharged Leaf, Level 2 (240V) Charger: Set to Delayed charging, with a finish time of 8:00am.
- Example 4, Half Discharged Volt, Level 2 (240V) Charger: Set to Delayed charging, with a finish time of 5:00am.

You get the idea... For my specific use, I usually am about half to 3/4 discharged on my Volt, so I've decided to set my default schedule to delayed charging with an end time of 5:30am.

NY Time of Day Electricity Demand Detail.jpg
NY Time of Day Electricity Demand.jpg
US Time of Day Electricity Demand.jpg

[Selling Volts At Sundance]

Thank you- ClarksonCote for all that you contribute here. Your spirited technical posts have helped many to get a better understanding of our amazing machine.

I have posted this before and here it is again. Senator Lemar Alexander (R) Kentucky, a Nissan Leaf owner, we missed that one, commenting on the Us Senate floor, May 19, 2011.

"A conservative estimate is that we have an amount of electricity unused at night that’s equal to the output of 65 to 70 nuclear power plants between 6 p.m. and 6 a.m.
[...]
“I suspect that’s probably our greatest unused resource in the United States. If we were to use that to plug in cars and trucks at night, we could electrify 43 percent of our cars and trucks without building one new power plant.”

http://www.torquenews.com/397/senato...ional-resource


Best!

Thomas J. Thias

[Noel Park]

@ Clarkson Cote,

I'm in the Southern California Edison service area with a TOD meter. The "Super Off Peak" billing period is 10:00 PM to 6:00 AM. I have my Volt set to finish charging at 5:00 AM, which tracks pretty well with what you're doing.

[ClarksonCote]

ClarksonCote,

Any idea of what the economic impact (benefit) of upgrading the Volt's onboard charger and standard EVSE to 240V 7KW would be for the nation?

If all the Volts, say 1M vehicles, could recharge in a two hour period from 1am - 3am rather than over a 10 hour period.

Well, the Level 1 has a 10 hour time, but the existing 3.3kW Level 2/240 V charger is a 4 hour recharge time, which fits nicely into the trough of the demand curve. A 7kW charger could let you hit just the lowest of the demand trough, but I don't know how to quantify any benefit. I'm guessing it's more likely that these would be worse for the grid, sine there are always times when people will use these chargers during peak times as well.

[ClarksonCote]

@ Clarkson Cote,

I'm in the Southern California Edison service area with a TOD meter. The "Super Off Peak" billing period is 10:00 PM to 6:00 AM. I have my Volt set to finish charging at 5:00 AM, which tracks pretty well with what you're doing.

Nice. I'm guessing their lowest demand point is right in the center of that time window too, so your charging end time is pretty good. I wish we had off peak EV charging rates here. Our only option is a TOU meter that is only cost effective if your house is an energy hog. They increase the base charge by 100% with TOU here, making it hard to recoup that cost unless you use a lot of energy.

[Dithermaster]

I set mine to start at 9 pm, which is when our local off-peak rates start (practicing for when I'm on time-of-use metering). Yes, you could set it later if you want to fill the bottom end of the usage curve.

By the time we have a significant number of EVs on the road they will communicate with the grid and self balance usage dynamically. Also, they'll provide power output during peak hours and fill back up before you need it.