Monday, March 21, 2011

Electric Cars Are Coming — And I Am Certainly Ready!

As I've reported before, Dominion Virginia Power is proposing 2 new Electric Vehicle rates.  But a recent article by Cory Nealson considers whether the Commonwealth of Virginia is ready for 86,000 new Electric Vehicles on the road by 2020.  The article makes some good points, but it's sometimes interesting to see what comments are generated on an EV piece like this.

Of course, I'm not one to let EV misinformation propagate through these informal discussions and so I've composed my share of replies to some of the comments appended to this article and I though it might be instructive to collect them here as well:

How much does it cost to charge an electric car to go 40 miles, as compared to filling up a gas vehicle to go 400 miles? (Hampton Handyman)

Hampton, to answer your question, we need to make some assumptions.

  1. What is the cost of fuel; let's say an even $3, which is what I paid about a fortnight ago; it is going to go up though, but for your argument, let's say it doesn't.

  2. How much does Electricity Cost?  Well, I happen to have Dominion Virginia Power's filing right here and so let's see…

    The base rate for the 2-meter EV-only setup (I'll stick with that as it's simpler) is 0.684¢kWh from 01:00 - 05:00; but that's just the base rate for Distribution and Supply.  There's also a $2.90 per month cost, then a bunch of riders and taxes and in the end you come up with basically 4.632¢kWh + $2.90 per month.  So for the monthly cost, let's assume a 30 day month, which adds about 10¢day or basically per charge.  There are a bit of other complexities, such as county tax and potentially lower tax rates with additional usage, but overall, this is a good ballpark for what you would be paying to charge your car overnight.

  3. Gasoline Car Efficiency; let's be positive and go with the Prius's astoundingly high value of 50 mpg.

  4. And for our Electric Vehicle, we'll go with a conservative 3⅓ miles per kWh.

The math is simple…

…Person A fills up his Prius.  To go 400 mi, he buys 8 gallons (400 mi ÷ 50 mpg) which at $3gal comes to $24.

Person B charges her EV over night, each night, going 40 miles per day.  In this case, she needs 12 kWh each night (40 mi ÷ 3⅓ mpg), which at 4.632¢kWh or $0.04632kWh comes to about 56¢.  Add in the 10¢ per day and we come to 66¢ or $0.66 for 40 miles.

Now, after 10 days, Person B has gone 400 mi too (40 mi × 10) but she's paid only $6.60.  It's not much, but $6.60 is still better than $8 and do you really get 50 mpg?  I didn't think so!  So, you can try to hate on EVs all you want Hampton, but the truth is, as far as cost per mile, EVs already have your best hybrids and gasoline engine cars beat!  And you can take that to the bank!

Note: Whoever voted me down on that commentary clearly can't handle the truth!

DVP's installation of charging stations at rest stops makes no sense. (MarcLee)

Well said, Marc, but the thing is, you have a Volt.  The Volt and the Focus Electric don't have the ability to fast charge, but the Nissan LEAF does through its CHAdeMo connection.  It doesn't make sense to install chargers at rest areas if all they can do is Level 2, which for the LEAF and Volt means 3.3kW charging (8 hr / 4 hr, respectively), for the Focus it means 6.7kW (4 hr).  But L3 / DC / Quick-Charging does make sense once the U.S. standardizes on a connector and protocol.  As I said, the LEAF uses CHAdeMO and it's a risk that we'll use that Japanese standard over a European standard.

But, given the LEAF, CHAdeMO may become the de facto standard in the U.S.  And with CHAdeMO's up to 500VDC × 125A capacity, this means about 62.5kW charging, which on the LEAF means 80% in about 18 minutes.  Sure, 18 minutes is still a pain to wait when filling a tank is about half that, and that fill up is only getting you 80 more miles, but it does serve a purpose.  I just would never suggest someone try to make it up to Maine from Florida stopping every 90 minutes for a 20 minute break.  It's not plesant for the driver and that amount of quick charging isn't good for the battery either.  Nissan recommends no more than 1 Quick-Charge per day to keep your battery fresh and capacious.

The Volt uses 12kw for a full recharge… The Leaf and Focus Electric would require roughly 3 times that amount… There is a 4 hour window under which you can save 6 cents/kwh and a 17 hour window during which you are penalized 6 cents/kwh. (MarcLee)

As far as the rates are concerned, I've done the calculations on 95% battery capacity of a LEAF per weekday, or 22.8kW, and half that (11.4kWh) each weekend day (the LEAF, BTW, has a battery exactly 2 times larger than the Volt and takes twice as long to charge; the Focus has one slightly less than twice, at 23kWh, but has the 6.7kW charger so also takes about 4 hours).

Anyway, the short answer is you save about $200 a year under this scenario under the Schedule EV rider vs. the base Schedule 1 rate.  And under the Household 1EV rate, you save an additional $25yr.  Sure, that's only about $18.75 a month in savings, but in this economy every dollar counts IMHO.

The problem comes if you need a Monday Touch-up, as I find I may need occasionally.  Then, the year is divided in half, with 6 months at $0.77 and 6 at $0.28 for a 2 hour touch-up.  I don't intend to do these kind of touch-ups very often, so maybe I spend $3 on them in a given month, but that's still much less than $18.75 for the household rate.

Or, let's consider the Schedule EV rider instead: now we're saving only $16.67 per month, and our touch-up goes for $0.86 per 2 hour touch-up, year-round.  Not quite as good as the household Schedule 1EV rate, but still you come out ahead even with a few touch-ups.

Also, I should point out that I was the main guy who pushed DVP to add this rate when I couldn't get Schedule 1T.


  1. Hi Jeff. I'm a fellow LEAF lover, blogger, MNLer, and now owner, since March 30, of my new Blue Ocean LEAF. One comment. When you're calculating efuel costs, be sure to include a charging efficiency factor. I'm reliably getting about 3.0 miles per kWh from the Wall. My LEAF is showing an average of 3.6 miles/kWh from the battery. So I think I'm getting about 3.0/3.6 = 83% charging efficiency.

  2. Hi, Phil! Thanks for the real-world data! I love getting these from folks like you on the forum. As it is, I assume a 3 ⅓ mi/kWh efficiency in my internal calculations for the cost to drive, which is suppose to incorporate charger and EVSE efficiency. This is partly because I intend to use a lot of ECO Mode during my commute. I came up with that expected efficiency from reading about experiences on the My Nissan LEAF forum and from other electric vehicles from my fellow EVA/DC members. I admit though that I may be off when I calculate that in Virginia I might be spending $425 - $450 per year on electricity to go about 23,792.94 miles per year under the new Dominion Virginia Power EV rates. Compare this to about $2500 to go that same distance in my current car. But like I said, I could be wrong.

    Also, please vote for me in the Electric Drive competition: