Are electric vehicles getting too big and heavy? Modelling future vehicle journeying demand on a decarbonized US electricity grid

In the US a complete transition to electric vehicles (EVs) would increase demand for carbon-free electricity by around 30% if the future fleet has the same average size, weight and horsepower as current EVs. However, these dimensions for today's EVs are substantially lower than for conventional vehicles, so as EVs replace them, EV's average size, weight and horsepower are likely to increase substantially. Further, major automakers are introducing a new class of very large, powerful "super"-EVs of up to 1000 horsepower. These factors will lead to higher demand for carbon-free electricity. This interdisciplinary paper first examines the social pressure for increasing EV size and power. It then uses data from the 255 EVs tested by the US EPA in 2011-2021, to estimate the effect of increased weight and horsepower on EVs' electricity consumption. It finds that each 1% increase in weight leads to an increase in electricity consumption of about 1%. The transition to EVs could therefore increase electricity consumption by 35% or more and compromise the transition to a decarbonized electricity grid. Policymakers need to plan for a larger decarbonised grid, disincentivise production of large, heavy EVs and promote positive social discourse on the value of smaller, lighter vehicles.