ACEEE factors in the lifetime emissions of the chemistry of the battery. Some batteries, like NCA, have worse emissions than others. Also: the grid is mostly

ACEEE factors in the lifetime emissions of the chemistry of the battery. Some batteries, like NCA, have worse emissions than others. Also: the grid is mostly coal and nat. gas today. Case in point: the Hummer EV burns more fossil fuels on electricity because it weighs 4 tons. EV doesn't make anything automatically more efficient. Only the smallest and lightest EVs, like the Leaf, have high environmental scores.