Turbines for EV range extenders

VIDEO: Turbines are Back, But This Time to Charge Electric Vehicles

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Turbines for EV range extenders

As early as the 1950s Ford, GM, and Chrysler were all working on turbine engines for cars.  Turbines are back, but with a green-car twist.

Turbines were considered for automobile engines back when the race car tires were skinny, and the drivers were fat.   Chrysler had a turbine car it showed at the 1964 World’s Fair in New York.  Car-guy Jay Leno went there as a kid to see it with his parents and now owns one.  Ford built a T-Bird Turbine and GM also had a long-lasting turbine powered car program.   The time was not right for turbines in the 1960s, but interestingly, our present day search for cleaner power sources may lead us right back to the turbine.  Not as a means of moving a car through thrust, but as an on-board range extender for electric vehicles (EVs).

BMW range extender - rex


Range extenders like the one used in the Chevy Volt, or in the BMW i3 (photo above) act as generators.  They come on and turn a shaft that generates electricity to charge the batteries in EVs when the power runs low.  In the i3, the split between customers who buy range-extended models  vs.  purely electric cars was running roughly 60-40 at last check.  The big benefit to the range-extended model is that it can travel farther without having to re-charge the batteries using a plug.  The downside has been that gasoline is the fuel.

But what if the fuel was also green.  Say, landfill gas, or biodiesel, corn-ethanol, or even hydrogen?  What if the on-board generator was flexible and could easily adapt to any of these green fuels?  Turbines might be the answer.
Turbines offer some excellent advantages as vehicle power sources.  First, they are much lower in maintenance than are piston engines, just like electric vehicle drivetrains.  Second, they are cleaner than piston engines and don’t require catalytic converters.  Finally, they can run on a variety of fuels, so whatever green liquid or gas is in vogue could be the fuel.  Companies that work on technology call that “future-proofing.”  Today’s darling may be tomorrow’s also-ran, so a flexible device is always better.   One negative of turbines that hurt the applicability to older cars was that turbines prefer to run at one speed.  That is a not a problem for a generator application.

A co-founder of Tesla Motors, Ian Wright, and his company Wrightspeed are now using turbines as part of the drivetrain in range-extended EV powertrains for vehicles like delivery trucks and in garbage trucks.  Wright says, “For many of the same reasons that aviation changed from piston engines to turbines decades ago, we believe turbines will begin to replace piston engines in range-extended electric vehicle applications.”  If turbine technology of this type matures and is later scaled down to fit into a pickup truck or mini-van, two of the toughest vehicles to cost-effectively electrify might suddenly be in play.  Anyone watching the green-vehicle movement knows that until the pickups are green the U.S. fleet will always be primarily reliant on gasoline.

The current debate over electric vehicles, hydrogen-powered fuel cell EVs and alternative green fuel vehicles like those that run on biogas may not result in one overall winner or loser.  Perhaps what might result is that vehicles like pickup trucks and minivans will use primarily battery power with a clean turbine generator on-board and the car fleet will remain a mix of technologies.  If a co-founder of Tesla Motors is part of the group that thinks turbines might be part of the green-vehicle solution, we won’t bet against that outcome.