Tuesday, November 8, 2011

How Much Does it Cost to Charge an Electric Car?

With all the talk about electric cars lately, one thing that I keep hearing is people wondering how much electricity will an EV need? Are they simply ditching the gas pump only to pay just as much in their electric bill? I made a post on this subject last year and I think it's important enough to put it up again for anyone who hasn't seen it already. It's consistently one of the top questions I get when readers email me so I figure a re-post is in order...

One of the questions that people frequently ask me about the MINI-E is, "How much electricity does it use?" Sometimes they'll just say, "I love the car, but I wouldn't want to see your electric bill!"

When I tell them the car costs between $3.00 and $6.00 in electricity to go 100-120 miles they usually smile and say, "Wow, that's great." The reason the range is between $3.00 and $6.00 is because there is such a difference in electricity rates throughout the country. The MINI-E has a 35 kWh battery pack but only 80% of the pack is usable which means it has 28kWh of available power. That 28kWh can move the car between 90 and 120 miles depending on how efficiently you drive. It is less in the winter months because the heater uses a lot of energy, but for most of the year these numbers are correct as an average.

The national average cost for electricity is $.12 per kWh which means it would cost the average person $3.36 to fully charge a depleted battery on the MINI-E. However rates do vary. I pay $.11 per kWh at my restaurant in Montclair, lower than the national average, but it costs me $.18 per kWh at my home in Chester, only 30 miles from Montclair. So if I "fill up" at work it costs me $3.08 but at home it costs me $5.04! Obviously I take advantage of the lower rates and charge at work as much as possible. So basically for what it costs for a gallon of gas today, you can drive an electric car like the MINI-E or Nissan LEAF about 100 miles.

Since I have a solar PV array at my home, I sell the electricity back to the utility at the rate they sell it to me ($.18/kWh) so every kilowatt-hour that I charge at work saves me $.07. The average person drives about 15,000 miles per year. If they had a MINI-E they would need to use about 4,200kWh to drive 15,000 miles. If you use the national average, you would pay $504 for fuel for the entire year. If you use my rate at my restaurant, it's $462, at my home it's $756. So figure anywhere between a $40/month and $65/month increase in your electric bill if you had a MINI-E and drove it the average of 15,000 miles per year.

One of the great things about electric cars is that you can easily reduce your electric bill by $40 to $60 per month just by being more efficient and therefore completely eliminate your transportation fuel cost! You can't use less gasoline unless you drive less, but you can reduce your electricity usage at home and still drive as much as you always have. Simple measures like a programmable thermostat and the use of compact florescent light bulbs (and LEDs now) can make a big difference. In fact, five 100 watt light bulbs left on continuously for a year use the same amount of energy as it takes to power the MINI-E 15,000 miles! Here's how: five 100 watt light bulbs use 500 watts per hour. In 24 hours they use 12,000 watts or 12kWh. In 365 days they use 4,380kWh. What does the MINI-E use to go 15,000 miles? Remember above I calculated it to be 4,200kWh? So five 100 watt light bulbs use 180 more kWh than it takes to power 3,200lb MINI-E for 15,000 miles!

If you take a good look at your home electricity use, I'm sure you can reduce your usage enough to drastically offset the cost of electricity to power an electric car, if not completely eliminate it. Then, every penny of the money you would have spent on gasoline can go right into your pocket!

If you are considering an EV, you can basically figure that for every 100 miles you drive, you'll use about 25kWh of electricity. Today's EVs average about 4 miles of driving on every kWh of electricity used. Then look at your electricity bill and see what you are paying for a kWh of electricity. Then take the total miles you drive and divide it by 4, and multiply it by what you pay for a kWh of electricity and you'll know your annual fuel cost for an EV like a Nissan LEAF or a BMW ActiveE.

Let's say you drive 20,000 miles per year and pay .15 per kWh (which is higher than the national average). Your fuel cost would be about $750.00. Now if you drove those same miles in a car that gets 30mpg (much higher than the average car) and gas cost an average of $3.50/gallon (less than it has averaged the past year) your fuel costs would be $2,333.00! Now imagine if you had solar electric, or simply made your home more energy efficient and reduced your electric bill. You could probably cut $40 or $50 per month off your home's use pretty easily. That could add up to $500 to $600 per year of savings! With an annual fuel cost of only $750 to power an EV 20,000 miles, your transportation fuel expense would now be virtually eliminated! That's a savings of over $2,000 per year, and that's at today's gas prices. Unlike gasoline, electricity is regulated and the price is relatively stable. Gas prices are volatile and are constantly increasing drastically before slowly lowering only to suddenly jump back up again, and in the long run, always increase.


  1. Great post as usual Tom. This is helpful, mind if I repost it?

  2. "...and in the long run, always increase"

    You can argue that the savings don't outweigh the initial cost unless you're doing over 20,000 miles a year at least but who'd do that in an electric car?

    …Oh, wait.

  3. When you buy gasoline you are giving our money to people who do very bad things with your money. Like buy Congress.

    When you make your own electricity and or buy it, your money is being spent here in America and stays locally. Most of it stays in your pocket. So you have money to go to a restaurant and live it up!

    But you also have more money to back the politicians YOU, not lobbyist, want in office.

    Tom you are a great American,

    Jeff U'Ren

  4. Byrne: Sure you can repost anything from this blog

    Michael: How about over 30k?

    Jeff: Thank you. You are spot on with your energy dollars. 100% of the money you spend on electricity stays locally and at the worst, regoinally. that money is put back into our economy immediately and stimulates growth. When you buy oil, 65 to 70 cents of every dollar leaves America, and a lot of it ends up in radical Middle Eastern regimes that really hate us. We export over a billion dollars a day buying foreign oil. What do you think the long term effects of that are? That should be reason enough for every American to support electric cars.
    We have a lot of educating to do.

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