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Hybrid vs. Hummer: Which is greener?
A Q&A with EarthTalk, republished with permission.
Q. I read that hybrid cars are actually less green-friendly than even Hummers, because they have two motors and very environmentally damaging batteries. Is this true?
– Renee Sweany, Indianapolis, Ind.
A. The claim you read about was from “Dust to Dust: The Energy Cost of New Vehicles from Concept to Disposal,” a controversial study by researcher Art Spinella of Oregon-based CNW Marketing. It ranks more than 300 vehicles for their energy use over their entire lifecycles—from raw materials extraction and manufacturing, to driving and burning fuel, to the recycling and disposal of parts. What surprised even Spinella was how the Toyota Prius, the world’s most successful gasoline-electric hybrid car, stacked up against General Motors’ behemoth Hummer, the modern poster child for unsustainable transportation.
“The Hummer over the lifetime of the vehicle ends up being less of a drain of energy on society in general than does the Prius,” wrote Spinella in his report. A key-determining factor was the hybrid battery’s use of nickel extracted from a Sudbury, Ontario mine that has emitted so much sulfur dioxide that acid rain has turned a once healthy nearby forest into a bleak landscape. That mine, however, which supplies nickel for many industrial purposes and not just hybrid batteries, has cut pollution 90 percent since the 1970s.
Another common criticism of hybrids is that their batteries will be a pollution threat once they land in the junkyard. But hybrid advocates insist that the nickel-metal hydride batteries found in the Toyota Prius, Honda Insight and other hybrids contain far fewer pollutants than the lead-acid varieties used in traditional cars. And initial worries that hybrid batteries would need replacement every few years have not borne out; Toyota says the batteries should go for 150,000 miles, which they predict to be the car’s life expectancy.
Spinella pegs the life of the typical Prius bought new today at only 100,000 miles, and contrasts that against a predicted 300,000 for Hummers—meaning that, though Hummers burn more gas and emit more pollutants, they will last much longer. Additionally, Spinella factors in the added production costs of including two separate engines in the Prius—one that runs on gas and the other on electricity.
Most environmentalists challenge Spinella’s conclusions. Jim Kliesch, research analyst with the American Council for an Energy-Efficient Economy (ACEEE), which publishes a yearly rating of the “Greenest and Meanest” cars, says the CNW study contradicts many other studies, including those conducted by the Massachusetts Institute of Technology (MIT), Carnegie Mellon, Argonne National Labs, the Union of Concerned Scientists and others that place the green-friendliness of the Prius and other hybrids head and shoulders above many other vehicles and certainly the Hummer.
Spinella is “way off the mark,” says Kliesch, and scolds CNW for not having “Dust to Dust” peer-reviewed for accuracy. “If you do some back-of-the-envelope calculations on their claims,” he says, “you’ll find that it takes about $286,500 in energy to produce and assemble a Prius, [which is] absurd.”
Toyota itself also disputes CNW’s findings. In a short rebuttal published in the Washington Post, Toyota vice-president Irv Miller said that the increased energy requirement to build a hybrid with two engines under the hood “is overwhelmingly made up for in the driving stage.”