Next month, Tesla plans to deliver the first of its electric Semi trucks that are able to haul a full 40 ton-load some 500 miles on a single charge. These massive batteries-on-wheels may accelerate the transition to electrified transport, but those responsible for delivering the power are starting to ask: Are we ready for this?

Probably not, according to a sweeping new study of highway charging requirements conducted by utility company National Grid. Researchers found that by 2030, electrifying a typical highway gas station will require as much power as a professional sports stadium — and that’s mostly just for electrified passenger vehicles. As more electric trucks hit the road, the projected power needs for a big truck stop by 2035 will equal that of a small town.

Even the authors who planned the study were caught off guard by how quickly highway power demands will change. A connection to the grid that can handle more than 5 megawatts takes up to eight years to build, at a cost tens of millions of dollars. If power upgrades don’t start soon, the transition to electric vehicles — let alone electric trucks — will quickly be constrained by a grid unprepared for the demand, warned Bart Franey, vice president of clean energy development at National Grid.