I've looked at the Chevy Bolt, since that is the cheapest decent EV (after current incentives) in my state. Here's what they say about the Bolt:

> If a driver owns a Nissan Versa, Hyundai Elantra, or Kia Forte, it's set to cost them about $9.78 in gas for every 100 miles.

> But switch to a Nissan Leaf or Chevrolet Bolt, and that increases to about $12.55 in home-charging expenses

The highest mpg ICE car of the three they list gets 39 mpg highway, so 100 miles would use 2.56 gallons.

Bolt level 1 charges at 4 miles/hour. Typical home 120 V circuits are 15 A max, so lets assume that is how many amps it charges at. For 100 miles that would be 25 hours @ 4 miles/hour. That would use 25 hours x 120 V x 15 A = 45 kWh of electricity.

We pay about $0.12/kWh here which would put 45 kWh at $5.40. The Bolt wins unless I can get gas for under $2.11/gallon. It's over $5/gallon here right now, so the Bolt wins big.

Furthermore, Google tells me the Bolt actually only charges at 8 A at 120 V. If that is what the 4 miles/hour charge rate is based on then the Bolt would actually win unless gas was below $1.13/gallon. Google also tells me that there is a manual override that raises it to 12 A. If that's what the 4 miles/hour was based on gas would need to be under $1.69/gallon for the Bolt to lose.

Looking at this from the other direction, the state with the cheapest gas right now is Mississippi at around $3.30/gallon, which would be $8.45 for 100 miles in a Kia Forte.

Using 4 miles/hour charge @ 120 V, 12 A for the Bolt gives 36 kWh for 100 miles of charge. That would beat a Kia Forte on Mississippi gas anyplace where electricity is under $0.23/kWh. That's every state except Alaska, Rhode Island, Massachusetts, Maine, California, New Hampshire, Connecticut, and Hawaii.

In general, the Bolt wins when charged at level 1 at home given electricity at $E/kWh and gas at $G/gallon if:

  14.1 < G/E

Here is G, E, and G/E for US states and DC:

   G     E    G/E  State
  $4.72 $0.42 11.2 Hawaii
  $3.65 $0.31 11.9 New Hampshire
  $3.79 $0.31 12.1 Connecticut
  $3.71 $0.29 12.8 Massachusetts
  $3.78 $0.29 12.9 Maine
  $3.70 $0.27 13.8 Rhode Island
  ----- Bolt wins below this line -----
  $5.03 $0.30 16.9 California
  $4.37 $0.25 17.6 Alaska
  $3.76 $0.21 17.9 Vermont
  $3.87 $0.20 18.9 New York
  $3.66 $0.19 19.7 Michigan
  $3.59 $0.17 20.7 Wisconsin
  $3.87 $0.18 21.2 Pennsylvania
  $3.72 $0.17 21.7 New Jersey
  $3.66 $0.17 22.0 Delaware
  $3.48 $0.15 22.5 Ohio
  $4.02 $0.18 22.5 Illinois
  $3.94 $0.17 23.1 District of Columbia
  $3.31 $0.14 23.5 Mississippi
  $3.78 $0.16 23.5 Maryland
  $3.44 $0.15 23.7 Alabama
  $3.64 $0.15 23.9 Virginia
  $3.48 $0.14 24.0 Texas
  $3.67 $0.15 24.3 Indiana
  $3.56 $0.15 24.3 West Virginia
  $3.53 $0.14 24.5 South Carolina
  $4.32 $0.17 24.8 Nevada
  $3.80 $0.15 25.0 Minnesota
  $3.82 $0.15 25.1 Florida
  $3.57 $0.14 25.3 Kansas
  $3.63 $0.14 25.9 Georgia
  $3.77 $0.14 26.6 Iowa
  $3.86 $0.14 27.0 Arizona
  $3.59 $0.13 27.1 North Carolina
  $3.46 $0.13 27.6 Kentucky
  $3.97 $0.14 27.6 Colorado
  $3.47 $0.12 28.1 Tennessee
  $3.74 $0.13 28.1 New Mexico
  $3.47 $0.12 28.2 Arkansas
  $3.58 $0.12 28.7 Missouri
  $3.77 $0.13 29.0 South Dakota
  $3.42 $0.12 29.2 Louisiana
  $3.53 $0.12 29.8 Oklahoma
  $3.94 $0.13 30.7 Montana
  $3.68 $0.12 31.0 Nebraska
  $3.71 $0.12 31.7 North Dakota
  $3.83 $0.12 32.1 Wyoming
  $4.63 $0.13 35.8 Oregon
  $3.98 $0.11 36.8 Idaho
  $4.06 $0.11 37.4 Utah
  $4.97 $0.11 44.5 Washington