Electric-Car Charging: Why Some Households Are Paying Too Much

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Owners of plug-in vehicles like the Nissan Leaf, Chevrolet Volt, and even the new Tesla Model S may be paying too much when they charge their car.

Why? Because they haven’t signed up with the right utility plan.

According to a recent survey from the California Center for Sustainable Energy (CCSE)—reported by the Union of Concerned Scientists—nearly one third of plug-in vehicle owners remain on their utility’s standard plan instead of a TOU (time of use) rate.

The idea of TOU billing options is nothing new, and it’s been tested for decades, but only in recent years has it become a widespread billing option for households, thanks to networked (and relatively inexpensive) ‘smart’ meters. In short, you pay only slightly more, typically, for electricity use during peak hours (typically afternoon into early evening) yet pay a deep-discounted rate for off-peak (overnight) use.

According to the CCSE survey (of those who’ve owned plug-in vehicles for six months or longer), most do already charge up at night, when the electricity supply is most abundant (and generation is most efficient). Meanwhile, 71 percent report access to public or workplace charging (or both), while 91 percent say that they’ve installed some kind of home charger and 56 percent received a free or subsidized Level 2 charger.

A difference of $400 a year

The Union of Concerned Scientists sums that the annual savings from switching to a TOU billing option could add up to $400—or as much as $1,000 for some who are really racking up all-electric miles.

The CCSE survey also found that, among plug-in owners, 85 percent were using their plug-in hybrid, electric vehicle, or extended-range electric vehicle as their primary vehicle—covering an average of 802 electric miles per month.

That figure is based on two California utilities—SCE and PG&E—but in Portland, Oregon, where two of us on the High Gear Media staff occasionally test plug-in vehicles, the public utility also offers a plan that could be favorable for EV owners.

“If adding an electric vehicle significantly changes your home electricity use, you may be able to save money by choosing our Time of Use rate plan rather than the Basic Service plan,” states Portland General Electric, advising that an electric vehicle driven 1,000 miles per month may use 250 kWh just for the vehicle.

Run the numbers for yourself

Prices per kWh vary greatly across the U.S., as a quick survey of our staff once indicated. Here in Portland, for instance, residential electricity costs about 13.3 cents per kWh on-peak, 7.5 cents mid-peak, or about 4.4 cents off-peak. That’s potentially a huge savings if you do most of your charging off-peak.

Portland General, like some other utilities, also offers a simple calculator to help determine if TOU billing is for you.

In any case, it helps you take note of how much you’re paying to charge your EV, and to the idea that electricity has different costs—monetary and environmental—depending on the time of day.

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Comments (12)
  1. Good article but do want to emphasize you need to do the math. For example, in Los Angeles Dept of Water & Power, one option is to go with a whole house TOU. You get $0.025 off 500 kWh/mo, but there is an $8/mo fee. If you do the math, you need to make sure you use at least 320 kWh/mo to break even (translates to driving about 15,000 miles/year).

  2. The Portland link shows saving more like $6/month.

  3. Those are really inexpensive rates. I am on TOU rates with Southern California Edison. Peak - $.50/KwH (10am-6pm) Super Off peak - $.15/KWh, (12am-6am) off peak $.25. But with my solar system I earn during peak(not home during the day) and use during off peak, charge during super off-peak so it actually works out really well. I use a lot more than I produce at no cost!

  4. UNION OF CONCERNED SCIENTISTs didn't really do math or really have NO FREAKING CLUE on how PG&E is scamming people.

    I wrote a long and detailed comment about how and why PG&E's E9-A and E9-B suck. For most EV owners it would be CHEAPER for them to stay on the E1-A than moving to E9s...

    Here is the brief description why:

    PG&E gives you great discount to charge your EV as low as $0.09/KWh in off peak rate. But it JACKS UP your peak rate (2pm-9pm) to $0.50/KWh or up to $0.55/KWh for tier-4.

    Now who does NOT use power during 6-9pm? Most household do.

    Also, E9A is assuming that additional EV load won't push the usage into high tiers. Typical EV such as Volt/Leaf double daily usage for average household. E9-B require $$$$K for 2nd mtr.

  5. "nearly one third of plug-in vehicle owners remain on their utility’s standard plan instead of a TOU (time of use) rate"

    B/c those EV owners did the math and found out that PG&E is full of CRAP and it is scamming people.

    The ONLY way to lower your bill is by installing solar.

    The "union of scientists" need to put their feet on the grounds sometimes and become "union of engineers"...

  6. PG&E TOU rates are currently pretty good for people with home SOLAR PV and EVs. BUT PG&E recently got a significant increase approved here in California.

    With home PV panels one can always stay out of the higher tiers and then use the E9A rate for off peak charging.

    With BOTH the Leaf AND the Volt in our garage getting topped off every night, we have an annual electricity "use" bill of......ZERO. That is ZERO total electricity charges for our 3000 square foot house and charging both cars! (We do pay a $13/month fee to be on the grid.)

  7. Yeah, PG&E's rate system is ONLY beneficial if you install large solar system on your roof.

    A typial 3,000 ft home in the PG&E area would use anywhere between 12 KWh/day to 22 KWh/day depending on A/C and other electric devices. A Volt and Leaf combined for 80 miles per day will require 24 KWh alone.

    Unless you have a 4KW or higher solar system, your electric bill will increase significantly...

  8. Makes me feel lucky to be in Canada. $0.06/KWh off-peak! If only I could afford the Tesla.

  9. Nick, only $.04/KWh off-peak in Michigan on an EV plan, but alas, I'm not able to afford the Tesla, either... Perhaps in about 2017 or so...?

  10. Not only do the power companies charge more for on peak power use when you switch, plus a monthly charge, plus the cost of installing the meter, here in Portland OR they also require you to opt out of their "Blue Sky" program (which uses wind, solar, biomass, etc) and automatically put you into their TOU mix: which is 62% COAL. We really need to pressure the utilities to offer us a plan for charging our cars on off hours without the current penalties.

  11. check out Viridian dot com. I joined them for a 6 month plan and they knocked off 1 penny per kWh. They generate their electricity without burning fossil fuels.

  12. I'm in NJ and pay 10.5 cents per kWh 24 hours a day. I used to pay 11.5 cents but I joined Viridian and that knocked off 1 penny. So I save around $16 a month.

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