EIA wrote:
ELECTRICITY DEMAND IN TRANSPORTATION REMAINS LOW
We project that demand for electricity grows fastest in the transportation sector, even as consumption in that sector remains less than 3% of economy-wide electricity consumption in the Reference case. Fully electric vehicles grow from less than 1% of the on-road LDV fleet in 2021 to a little over 7% in 2050 in the Reference case. The increase in demand primarily follows evolutionary electric vehicle (EV) technology and market developments, as well as current fuel economy regulations. Both vehicle sales and utilization (miles driven) would need to increase substantially for EVs to raise electric power demand growth rates by more than a fraction of a percentage point per year. The transportation sector’s share of electricity consumption is greatest in the High Oil Price case, where it reaches 5% of the total in 2050.
Link
Perhaps EVs are not causing the biggest issue for the grid or the EIA is wrong.