Thursday, June 6, 2013

How Much Will It Cost To Fuel The i3?

The concept i3 coupe parked with a BMW i branded level 2 wall charger
I get asked all the time "How much does it cost to drive an electric car?" I've also had a fair share of people say " I like the car, but I wouldn't want to see your electric bill". Like gas cars, some electric cars are more efficient than others. The BMW i3 has been purpose built to not only offer the dynamic driving experience BMW customers have come to expect, but to also be a highly efficient car. But what is efficient for an electric car? Everybody understands MPG for gas cars but few really understand how electric cars are measured for efficiency, let alone how that will translate into the cost to operate it.

The ActiveE Monroney sticker
First off lets discuss how the EPA calculates the miles per gallon equivalent(MPGe) for electric cars. Gas cars have the official EPA miles per gallon listed on the window(Monroney) sticker and electric cars have a rating called MPGe. Since one gallon of gasoline creates the same energy as 33.7 kilowatt hours of electricity, electric cars are tested to see how far they can go on 33.7kWh's and that is the official MPGe which is listed on the window sticker of every new EV. The BMW ActiveE I drive has a rating of 107 MPGe. Not bad for a heavy converted gas car, but not especially good as far as electric vehicles go. The Chevy Spark EV, recently was rated at 119 MPGe making it the most efficient EV rated so far as it barely beat out the Honda Fit EV's 118 MPGe rating.

Neither The Fit EV or the Spark EV were purpose built as electric vehicles. They are converted gas cars like the ActiveE. Being purpose built as an EV with a lightweight CFRP body and aluminum frame, the i3 should easily top the Spark's 119 MPGe rating. I'm guessing the i3 may have an MPGe rating as high as 130, which will give it the "most efficient EV" crown, one that it may hold for quite some time as there is really no other EV coming out anytime soon that will challenge it in my opinion.

So lets say the i3 gets a 130MPGe rating for arguments sake. That means it will go 3.86 miles for every kilowatt hour of electricity you use to charge it or need about 26kWh's to drive 100 miles. The average price of electricity in the US is 11 cents per kWh, however that varies greatly from state to state. I pay 18 cents per kWh so for me it would cost $4.68 to drive an i3 100 miles. If I were to drive 15,000 miles per year my annual fuel cost would only be $702! How far can you currently drive on $702 in gas? If your car gets 25 miles per gallon and you pay on average $3.50 per gallon(which is lower than what we have averaged the past year) it would cost you $2,100 in gas to drive the same 15,000 miles! Plus, we all know gas prices will only climb over time. Electricity rates do go up occasionally but historically they are much more stable than gas prices. Plus, many people do have the option of installing a solar array which will guarantee a free supply of electricity for the next 25 to 30 years. There is nothing the gas and oil industry can offer to compete with solar, as the customer supplies, and has control over their own energy.

BMW will offer solar canopies to i3 customers

So whip out your electric bill and find out how much you pay per kWh for your electricity. Then divide the number of miles you drive per year by 3.86 and multiply that by your electricity rate and you'll know how much it would cost you to fuel an i3 for a year. I'm sure you already know how much you dump into the gas pump so calculating your savings won't be too hard. Of course if you want to save even more you can install a solar array at your home like I did and start making your own electricity. Sure there's an initial outlay of cash for the solar system and not everybody can afford it, but if you can it's a fantastic set up and you'll have it paid off in a few years of savings from driving your i3 on sunshine!

5 comments:

  1. Regarding the initial cash outlay for solar, the power purchase agreements are getting much more reasonable, allowing people to get in on the solar game for zero dollars, and pay less than they pay the utility today. Sure, it's not the best long-term investment option, but it costs nothing. Can't beat that.

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    1. Yes, you are 100% correct PPA's can allow you to go solar with no money out of pocket. Your electric won't be free but you'll be getting it at a substantial savings with no cost to you. With a PPA the $702 per year may drop down to about $500/ year compared to over $2,000 for gas. Plus that's with today's gas prices. You will be locked into the cheap electricity cost for many years with the PPA and gas will continue to rise. At $5 per gallon the gas cost for the above mentioned example goes up to $3,000! It's a huge savings!

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  2. Here in the Atlanta area, our biggest electric utility Georgia Power offers a time-of-use plan that drops the overnight electrical cost to about 7 cents per kWh. Scaling your 15,000 mile example, the annual fuel cost would be around $270. Personally I drive about 7000-8000 miles per year (relatively short commute) and my electric bill went up only about FIVE DOLLARS PER MONTH.

    For this reason, when talking to locals here in Atlanta about EVs, I answer that "how much does the electricity cost" question with this: IT'S A TRIVIAL AMOUNT OF MONEY. It is literally a negligible amount, and thus my driving is effectively free. In my personal case it's $5/month, but even if you drive more miles than me and don't have the utility's TOU rate plan, it's like $20/month.

    Seriously, twenty dollars a month is negligible.

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    1. Excellent Chris. I could also add that with such a small amount of energy needed to drive 8,000 miles per year you could probably reduce the cost down to zero simply by replacing your light bulbs(if you haven't already) with LED's and by just being a little more efficient around the house.
      That's another cool thing about EV's you can really eliminate your fuel expense by just being more efficient at home. With gas, you can't really use much less unless you drive less, but there are many ways to use less electricity at home and thus offset the additional kWh's you 'll use to charge your car.

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