Nick Zielinski, the chief engineer at GM responsible for advanced vehicle concepts, says that GM released the fuel-cell version in China because hydrogen has a better chance of taking hold there. In China, energy infrastructure is still being developed, and gasoline and electricity may not be available everywhere. “They could develop a hydrogen infrastructure much sooner than we do here. And a fuel-cell vehicle may make more sense than a plug-in-to-grid option because hydrogen may be much more accessible,” Zielinski says. He adds that “hydrogen, when it’s generated in a renewable way, produces no emissions. And that’s where I think we’d like to get to.”
With the Volt, the power source can vary according to the proposed market. In the original version revealed in January, likely to attract customers in the United States, the first 40 miles of driving are powered by energy stored in a battery pack that can be recharged by plugging it in. (See “GM’s New Electric Vehicle.”) That’s enough range for a typical daily commute. For longer trips, a gas- or ethanol-powered generator recharges the battery, allowing for an additional 600 miles of range. In Europe, diesel generators can be used, rather than gasoline generators or fuel cells.
Other major automakers are also developing plug-in fuel-cell and battery-powered vehicles. In January, Ford unveiled a vehicle that runs off stored power in the battery for the first 25 miles before a fuel cell starts recharging the battery, which can add an additional 200 miles of range. As with GM’s Volt, the fuel cell could be replaced by a gas or diesel generator.
Both the fuel-cell and generator versions of the Volt will face challenges, but it’s likely that the fossil-fuel versions will reduce carbon-dioxide emissions more than the fuel-cell versions. The Volt equipped with a gas-powered generator has a large battery pack that will allow most drivers to skip the gas station altogether for daily commuting. And because the generator is very efficient, even for trips longer than 40 miles it may use less gas than ordinary cars. Of course, total carbon emissions will depend on the source of the electricity for charging the battery, but the relatively high efficiency of power plants compared with conventional vehicles will likely lead to lower carbon-dioxide emissions overall.
The main challenge with this vehicle is that a big enough lithium-ion battery pack, made to withstand the abuse of automotive applications, hasn’t yet been created. Zelinski says that no more major breakthroughs in battery-cell technology are needed. All that’s left is to integrate hundreds of these cells to make a big battery pack. That’s going to be challenging, but, he says, “it’s something that can be handled in a straightforward, solid-engineering way.”