Why EV Charging Cost Varies So Much by State
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.
The same EV, priced in both states
Lucid Air Pure RWD with 19 inch wheels in North Dakota and the same car in Hawaii run the identical EPA efficiency number through two very different electricity rates, the gap between them is the state rate alone. Vinfast VF 8 Plus in Hawaii stacks a high rate on a low-efficiency EV, the combination most likely to cost more than gas.