A 277% spread between the cheapest and priciest state

Hawaii charges residential customers about 45.95¢/kWh — roughly 3.8x what North Dakota charges at 12.19¢/kWh. The same EV costs proportionally more or less to charge purely on that basis, before efficiency even enters the picture.

What drives the spread

State electricity rates reflect generation mix, transmission distance, regulatory structure, and — for island and remote grids like Hawaii's — the cost of importing fuel at all. This site doesn't model why a state's rate is what it is, only reports EIA's own published figure for it, state by state.

It changes the answer, not just the number

Because gasoline's price is treated as one national constant here (see the methodology guide), a state's electricity rate alone can flip whether charging comes out cheaper or pricier than gas for the same car — see the guide to when charging costs more for real examples.