Running the numbers on electric car fuel savings

A neighbor recently asked me for my opinion on the potential cost savings of a fully electric car. I looked around on the Internet but wasn’t totally satisfied with what I found.

What I found was missing from popular media articles is the effective cost of electricity. In California we have tiered pricing, and so once you go over a certain level of electricity use (130% of a defined baseline that is currently 335 kWh) then you end up paying much more: 30 cents per kWh as opposed to 15 cents per kWh. Charging a car uses a lot of electricity, and so I wondered “what happens to your energy savings if you get pushed into the next pricing tier?”

Also I have a natural disdain for breathless hype, and lazy reports, especially when the math needed to put together real numbers is something that enthusiastic elementary school kids can readily do. So I busted out my grade school arithmetic and put together  this nifty spreadsheet:

XLS: Costs to run a gasoline vs. electric car in San Mateo

I decided to only compare fuel costs, and disregard differences in upfront purchase cost, maintenance costs, battery replacement costs and so on and just looked at what it costs to make the thing move. I *did* put in real numbers based on a variety of user reports, energy costs, and so on.

Here’s a summary of what I found:

If you commute 29 miles each way, 5 days a week, in a 2012 Chevy Volt, then your costs per mile come out as follows:

  • Chevy Volt on gasoline (at $4 a gallon): 10.8 cents per mile
  • Chevy Volt on battery, Heavy electrical use household: 6.8 cents per mile
  • Chevy Volt on battery, Efficient electrical use household: 3.6 cents per mile

So at least on the basis of fuel costs, it looks like there are decent savings to be had. Furthermore if you think that gasoline prices will continue marching upwards, faster than electricity costs, then those savings will grow over time.

Of course if you really want to “change the game” then move to a bike-able,  transit friendly community and drive much, much less. I’m not there yet, but I’m working on it.

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