Auto workers worry it takes less labor to build electric cars. Maybe not, some researchers say

A traditional car engine is a complex wonder of engineering, with pistons moving up and down, springs compressing and decompressing, spinning shafts, opening and closing valves and spinning gears meshing together. That's not to mention a transmission, connecting the engine to the wheels, that's a complex machine all its own. An electric motor, on the other hand, is really just some magnets wrapped in wires and it only needs a single speed transmission. That simplicity worries the United Auto Workers union.

A commonly repeated estimate is that, with fewer parts under the hood, EVs require 30% to 40% less labor than gasoline cars. It's not that simple, though, and some researchers argue that the labor savings of electric vehicles have been greatly overstated.

People assume those estimates are true, said researcher Turner Cotterman, because they're based largely on the number of moving parts in an EV. Since there are fewer parts in electric cars than in gas-powered ones, people figure that they're less work to manufacture, said Cotterman, who worked on a Carnegie Mellon University report into the issue and is now an associate with McKinsey and Company.

"There was an assumption that there is a linear relationship between the number of parts and the labor to make them," said Cotterman.

But making the powertrain of electric vehicles - the batteries, electric motors and power management systems - requires more total labor, not less, than that involved in making engines and transmissions, said Erica Fuchs, a labor researcher at Carnegie Mellon. She worked on the research paper with Cotterman that analyzed the labor requirements of electric versus gasoline powertrains.

Researchers at the Boston Consulting Group reached a similar conclusion. They found that manufacturing a complete electric vehicle - beyond just the powertrain - requires, in total, only slightly less labor than making a gasoline-powered car.

"When you look, like for like, at the vehicle today - an electric vehicle versus [internal combustion] - there is on the order of a percent or a couple percent difference, in the labor hours required to manufacture that vehicle," said Nathan Niese, global topic leader for electric vehicles at Boston Consulting.