Tuesday, September 14, 2010

How Much Electricity Does the MINI-E Use?



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.

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 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 and still drive as much as you always have. Simple measures like a programmable thermostat and the use of compact florescent 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 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!

4 comments:

  1. Excellent -- and informative -- entry. It's really mind-boggling that five 100 watt bulbs running 24/7 for a whole year is essentially equivalent to powering a MINI E for 15,000 miles.

    Imagine if each of the approximately 115 million American households reduced its yearly electricity consumption by the equivalent of 1 (not 5) 100-watt bulb running 24/7 for 365 days (2.4 kWh per day, 876 kWh per year).

    115,000,000 households x 876 kWh = 100,740,000,000 kWh

    Assuming 4 miles per kWh, that's 402,960,000,000 miles of driving!

    divided by 15,000 miles per year = 2.7 million EVs driving the American annual average!

    I don't think many people think in these terms -- the fact that a light bulb turned off/not used by millions can = millions of miles of driving in a full-sized, highway capable automobile.

    But I think very soon, more and more people -- millions, actually -- will be thinking about how many auto miles turning off one 100-watt bulb x all of America can equal.

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  2. In Europe the numbers are quite different.

    In Spain oil cost 5,89$/galon (1,20€/l). The electricity price is nearly te same 0,18$/kwh but soon we will have at night a cheaper price (0,1$Kw/h?)

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  3. Christof: Yes, it is mind-boggling. You can definitely conserve(nega-watt!)enough electricity to offset the addition of an EV in your household. By doing so you can have a vehicle with no fuel cost!

    Obviously the best way to go is being conservative with your electricity usage and also installing a solar PV array as you and I promote, but for some that isn't possible.

    Also, you referenced 4 miles per kWh which is the accepted standard for EV's. If you look at my figures, I used 3.5 miles per kWh because the MINI-E isn't as efficient as most EV's are since it wasn't designed as an EV, just retrofitted and has more power (204hp) than most small EV's would.

    Most new EV's like the Leaf and the Volt are actually getting closer to 5 miles per kWh so they might only need four light bulbs to offset their usage. In a few years it will be three, and then two as these cars get more and more efficient.

    Bosqueslbericos:

    Yes, I know the price of gasoline in Europe is usually double what it is here in the states but I didn't know how your electricity costs compared. So you are basically saying they are about the same as here so that would mean driving an electric car would be even more beneficial to you in terms of fuel savings.

    Thanks for checking in!

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  4. I'm surprised how little electricity it takes to power the car. Only 5 light bulbs? I know you wouldn't typically have the lights on all day, every day, but it still seems like a small amount of electric to move an entire car 15,000 miles, very impressive.

    Electric cars have been getting a lot of attention lately, I can only imagine that they will become much more efficient as investment in improving the technology that drives them continues.

    I will probably not buy one of the first generation electric cars since I generally don't buy the first generation of anything, but I will definitely consider one in 5 or 6 years when the next generation of electric vehicles are available and improvements are made.

    Thank you for the information you post here. It is entertaining and educational.

    Sean Harsgrove

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