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Thursday, May 24, 2012

How Much Electric Does An EV Use?



With all of 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 did a post on this subject on my MINI-E blog last year and I think it's important enough to put it up again here for anyone who hadn't seen it already.

One of the questions that people frequently ask me about my electric car is, "How much electricity does it use?" Sometimes they'll just say, "I love it, but I wouldn't want to see your electric bill!" When I tell them it costs between $3.00 and $6.00 in electricity to go about 100 miles they usually smile and say, "Really? 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 and the amount of energy the car uses is dictated by how efficiently you drive. The ActiveE has a 32 kWh battery pack but only 28kWh of it is available for use. That 28kWh can move the car between 80 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 ActiveE. However rates do vary. In New Jersey, we have much higher than average electricity rates and I pay about 18 cents per kWh. Therefore it would cost me about $5.00 to fully charge a depleted battery. So basically for only a little more than what it costs for one gallon of gas today, you can drive an electric car like the ActiveE or Nissan LEAF about 100 miles.

EV + PV is a fantastic combination!
Since I have a solar PV array at my home, I generate most of the electricity my home and car uses and I pay very little for my electric. Many months my electric bill is even zero and I drive much more than the average person, about 35,000 miles per year. The average person drives about 15,000 miles per year. If they had an ActiveE they would need to use about 4,200kWh of electricity to drive 15,000 miles. If you use the national average, you would pay about $504 for fuel for the entire year. If you use my rate at my house, and forgot about the solar array, you’d pay $756 to power the car all year. Therefore, figure anywhere between a $40/month and $70/month increase in your electric bill if you had an electric car like the ActiveE 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 $70 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 or LED light bulbs 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 ActiveE 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 ActiveE 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 the 4,000lb ActiveE 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 to 35kWh of electricity. Today's EVs average about 3.5 to 4 miles of driving on every kWh of electricity used. However very soon there will be even more efficient EVs like the BMW i3 which will probably exceed 5 miles per kWh used. So 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.

Gas prices will only go up in the long run
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 drastically increasing before slowly lowering only to suddenly jump back up again, and, in the long run, always increase.

11 comments:

  1. Great information. The cost is very low, and then adding in solar makes it a zero sum game. Thank you for the breakdown.

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  2. Thanks for this Tom. This is the kind of useful information I come here for. It's too bad BMW and the other car makers don't explain this like you do. Your mini-e blog and now this one have been great resources! Thank you!

    Donnie

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  3. About a year ago, I started a major push to reduce my electric bill. I notice now the entire electric cost of an Active E can be offset by swapping out incandescent lightbulbs and buying a more efficient fridge.

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    1. Exactly Doug! I've been saying this for two years now but rarely hear it anywhere else. I think this needs to be more prominently advertised. You can EASILY offset the additional electric use of an electric vehicle by being more energy efficient at home. Then your personal transportation fuel expense effectively becomes ZERO. You can never do that with gas!

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  4. Hi! I just have seen that the RSS of this website is functioning without any failures, did you complete all the properties on your own or you turned to the default settings of this widget?

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  5. So, unless a person can afford PV, it would take about two tons of coal to generate 4200kWh.

    That isn't green.

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    1. I suppose if you are using coal exclusively to make your electricity then no that's not very good - still better than using gasoline, but not very good indeed.

      To say that unless you have a solar array you will burn 2 tons of coal is not very accurate though. There are a few places that still use coal for most of their electricity generation, but they are indeed rare. In fact, here in the US there are very few places that do so. Coal is used for less than 40% of our overall electricity generation and that percentage is dropping every year as more and more renewable are introduced.

      The US DOE has a website where you can see how driving an electric car where you live compares to driving a gas or a hybrid car, based on where you live and what the electricity generation mix is there. In every instance, even when coal is the exclusive fuel for electricity, an EV emits less emissions than a gas car would.

      So, while burning coal isn't green, it still is better for the air quality than burning gasoline.

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