Dear EarthTalk: When the plug-in Prius is released, how much electricity will it use? Will my electric bill double if my Prius is plugged in each night? Or will the increase be minimal? Also, will all this recharging put a strain on the existing electricity grid?
—G. C. Marx, Colorado Springs, Colo.

It is difficult to pinpoint the answer to this question right now since Toyota has not yet released its much anticipated plug-in hybrid, but most analysts believe the increase in your electric bill from overnight charging will be minimal. According to the blog Futurewheels.com, electric cars and plug-in hybrids (those that have been converted by owners) currently average about two cents per mile to recharge (electric rates vary greatly by region), while gasoline-only cars average about 10 cents per mile to refuel.

Plug In America, a California based network of electric vehicle and (self-converted) plug-in hybrid owners, estimates the cost to charge a typical plug-in hybrid overnight to be less than a dollar. So while your electric bill might go up $30/month due to recharging, your gas bill will decrease by somewhere between 80 and 100 percent depending on your driving habits and what you were driving beforehand.

Of course, it’s important to keep in mind that regular hybrids cost between $2,000 and $10,000 more than their gas-only counterparts, and that plug-in hybrids will likely cost even more due to their larger, better batteries and other more advanced technologies. It would take years and years of gasoline-free driving to make up the sticker-price difference between a plug-in hybrid and an equivalent-sized gasoline-fueled car. So while plug-in hybrids will help the environment, they’re not so much about saving money—unless you drive thousands of miles a week, in which case you’ll recoup your costs in fuel savings in a few years.

As to strain on the existing electricity grid, most experts agree that plug-in hybrids and all-electric vehicles, even in the unlikely event that all of us switched over to them eventually, wouldn’t compromise the ability of utilities to provide power, given that they are already scaled up to handle peak loads during heat waves when everyone runs energy-hogging air conditioning.

Furthermore, most of us would charge our cars overnight—typically a slow period for utilities otherwise and during which they could generate much more power if customers wanted it. A 2007 study by the U.S. Department of Energy’s Pacific Northwest National Laboratory found that off-peak electricity capacity could fuel the daily commutes of nearly three-quarters of all cars, light trucks, SUVs and vans on American roads today if they were plug-in hybrids. Plug In America adds that many utilities are upgrading local electricity distribution systems to accommodate plug-in hybrids and electric vehicles “just as they do when residents add more air conditioners and TVs.”

So if you’re interested in taking the plug-in hybrid plunge when the cars become available, don’t worry about increased electric bills, as overall you’ll be saving gobs of cash at the pump. And given the popularity of the current hybrids on the road, enough of us might go for the plug-in versions so as to reduce the cost disparity with traditional cars—meaning we could “save green” in more ways than one.

CONTACTS: Future Wheels, www.futurewheels.com; Plug In America, www.pluginamerica.org;
Pacific Northwest National Laboratory, www.pnl.gov

EarthTalk is produced by E/The Environmental Magazine. GOT AN ENVIRONMENTAL QUESTION? Send it to: EarthTalk, c/o E/The Environmental Magazine, P.O. Box 5098, Westport, CT 06881; submit it at: www.emagazine.com/earthtalk/thisweek/, or e-mail: earthtalk@emagazine.com. Read past columns at: www.emagazine.com/earthtalk/archives.php

13 Comments

1. 1. mffoley 01:37 PM 4/27/10

   The analysis above overlooks at least one cost utilities will face and will pass along to consumers. Although there may be enough generating capacity to produce enough watts to power cars, the neighborhood infrastrucutre is generally not sufficient to handle the extra requirements for recharging vehicles. If a lot of people in a neighborhood decide to buy rechargeable vehicles, the utilities will have to upgrade local equipment to handle the demand.

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2. 2. RDH 01:59 PM 4/27/10

   This is good news to those that live in a highly populated state like California that never has to deal with high electricity demands by implementing such things a rolling blackouts after the day is over and workers all return home and plug in their cars.
   
   Or is it?
   
   http://news.cnet.com/Rolling-power-blackouts-darken-California/2100-1017_3-251091.html

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3. 3. niells 02:30 PM 4/27/10

   *Of course you can't drive thousands of miles per week at a 100 miles/charge.
   
   *Adding an energy demand peak at night pretty much guarantees that solar isn't the answer.
   
   *Lithium batteries used to power electric 25 inch long R/C helicopters offer about 10 minutes of run time after an hour of charging at power rates that make plugging two chargers into the same outlet dangerous. That is to say that charging your full size automobile overnight to run for 100 miles the next day will require using something like a 220V washing machine outlet. As much as 70 Amps accourding to GM:
   http://gm-volt.com/2009/04/16/plug-standard-needed-for-electric-car-charging-cord-interface-sae-j1772/

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4. 4. lamorpa in reply to mffoley 03:35 PM 4/27/10

   @mffoley: I suspect the utilities will use the infrastructure that is already there to handle the daytime load (since it is already handling the daytime load) Why would you think the infrastructure could not handle the same load at night? It's afraid of the dark?

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5. 5. JimfromSWON 03:38 PM 4/27/10

   An interesting ommision as to costing an electric is the cost of battery replacement. This has been seemingly kept quiet. The fact that any battery has a finite number of charge/recharge cycles, and then must be replaced. I have estimated the useful life to be 4-6 years at a cost of $4,000 to $8,000 USD. Gas or LNG or Propane seem to be dramatically cheaper!

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6. 6. sethdayal 05:37 PM 4/27/10

   Of course the utilities would still be dumping water from dams, burning coal, and natural gas to charge the batteries at night. No GHG savings there.
   
   Nuke plants cost nothing extra to run full blast 24/7 so we'll need a lot of those.
   
   CNG and NG derived methanol in flex fuel vehicles or conversions a lot cheaper until we get electric technology right.
   
   Utah sells CNG for a $1 a gallon equivalent and mass produced conversion and home fill kits would likely be under $2K installed in your average vehicle/home.

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7. 7. adaviel 06:03 PM 4/27/10

   The Prius Plugin has a range of only about 50km. As a commute vehicle, a pure electric like the Mitsubishi MiEV with a 160km range and a 30min fast recharge would be better. They say between 3x and 9x cheaper than gasoline

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8. 8. biks 09:29 PM 4/27/10

   I don't hear anyone including the current cost of tax on gasoline. That tax will somehow have to be added to the cost of electricty or miles driven. Once a tax always a tax. The average tax per gallon is currently 62 cents.
   For more info go to http://www.pennsylvaniagasprices.com/tax_info.aspx

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9. 9. biks 09:39 PM 4/27/10

   I don't hear anyone commenting on the current tax on gasoline ( federal, state, local ). The current tax will somehow have to be included either on the electricty or miles driven. The current tax would be more the the cost of the electricty. The average tax on gasoline is 62 cents per gallon.
   Once a tax always a tax.
   
   For more info go to:
   www.pennsylvaniagasprices.com/tax_info.aspx

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10. 10. JamesDavis 06:37 AM 4/28/10

    The big three is in no hurry to build or advance electric cars. If you go by their stats, and it seems like most of you are, electric cars will not be affordable for at least 50 years or more and their range will always be under a hundred miles...the big three will make sure of that because they do not want electric cars more affordable than their fossil fuel cars and most all American made electric cars are going to be shipped to China.
    
    Buy your electric car from a manufacturer outside the U.S.. Most of them -Japan made electric cars- can go further on one charge than fossil fuel cars can on one tank and their electric cars are a fraction of the cost to buy over a fossil fuel vehicle and they can be charged in under an hour and you can even use a solar panel to charge them, so you won't have to worry about overloading the grid.
    
    Germany has a beautiful electric car and their battery costs twice as much as a acid cell battery that you use in your current fossil fuel vehicle, so electric cars and their batteries are affordable and you can save a ton of money with them, but just not in the U.S..

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11. 11. sboschert 01:40 PM 4/28/10

    So many comments full of so many errors about plug-in cars -- I would have expected better of Scientific American readers. And I'm surprised that the article doesn't mention the govenment incentives that bring the cost of some new plug-in vehicles down BELOW the price of the gasoline-dependent Prius in some states. But never fear, Plug In America is here with the info you need to stay "current" (pun very much intended).
    
    See our "Top 12 Plug-in Electric Vehicle Myths" for a primer:
    http://www.pluginamerica.org/images/Top%20EV%20Myths.pdf
    
    To see what's available this year and get more detailed info on all things plug-in, get our new booklet, "Charged Up & Ready To Roll: The Definitive Guide To Plug-in Electric Vehicles" here:
    https://salsa.democracyinaction.org/o/2711/shop/item.jsp?storefront_KEY=553&t=&store_item_KEY=2724
    
    And see our list of incentives to buy plug-in vehicles (also contained in the book above):
    http://action.pluginamerica.org/t/5960/content.jsp?content_KEY=5545
    
    Sherry Boschert
    (Author, "Plug-in Hybrids: The Cars That Will Recharge America"
    
    

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12. 12. jack.123 06:15 PM 6/22/10

    I saw no where in the article or comments watts used and or watts per charge?If we knew what a gob was and converted that to gallons of gas or watts.Then we might be close to the answer for the original question.

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13. 13. bobguyjones in reply to JamesDavis 10:12 AM 5/28/11

    First of all I would like to see some of these cars you are bragging about. Second,I assume they don't go that fast and are way to small to be practical to people who don't live in the city. Small electric cars are great for inside the city but thats not what everyone needs. Some people really do need trucks and suv for they're daily lives. Also, I feel alot better (and it is safer, physics people it has a larger mass) going 75 miles an hour in my lincoln town car then a prius or something smart car sized. Yes, people do need to go that fast too with a total of three hours of travel time a day going slow would allow for no time at home. But really the problem with electric cars is storing the energy, even Li ion (which you want to call a german battery even though everyone nows about it) aren't that great if they can solve the over heating problem. Electric cars are cool technology but they just aren't practical. What America really needs to do is use our natural gas resources, its the cheapest option we have and can sustan use until we can figure out better and more practical technology.

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