# Does an electric car make economic sense?

Warning: Betteridge's Law Applies

I drive 8000 miles a year in a car with 45MPG actual fuel efficiency (2013 Prius). We paid somewhere around \$23000 for it. If I drive this car for 15 years, I'll buy around 2700 gallons of gas.

Compare this to the (discontinued) Prius Plugin Hybrid with MSRP of about \$30000. Imagine that I could have done all my driving in electric mode, and that its efficiency is ∞MPGe. I'd break even on the \$7000 higher initial price if the average gas price is \$2.56. Sounds plausible that I could save money that way, right?

But of course I couldn't go everywhere in "all-electric" / "charge depletion" mode, probably only about 2000 miles/year out of my 8000 miles/year would fall into this category (in-city driving 200 days a year at 10 miles/day). So now I'm only saving only about 670 gallons of gas *OVER THE COURSE OF OWNING THE CAR FOR 15 YEARS*. This is only break-even if gas is \$10/gallon.

But of course, the plug-in hybrid is not ∞MPGe, it's 110MPGe. MPGe is actually "miles per 33.7kWh". 33.7kWh of electricity costs \$3.17 in my local market at summer rates, or \$1.88 at winter rates, an average of \$2.31 (only 4 months are "summer"). So that's \$623 in electricity to operate the thing in electric mode for 30,000 miles. This pushes the break-even point higher, to around \$11/gal gasoline. (Note: a previous version of this page used incorrect math to arrive at a figure of \$19 as the break-even point)

Entry first conceived on 11 August 2016, 22:07 UTC, last modified on 23 February 2019, 17:30 UTC