How to Buy a Hybrid Car
Greentips: May 2005
Hybrid vehicles, which combine a gasoline engine and electric motor, have the potential to increase fuel economy and reduce emissions. But not all vehicles being marketed as hybrids take advantage of the full range of hybrid technology. If you care about having a car with the least harmful environmental impact, it’s important to know what’s under the hood.
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There are currently five types of hybrid technology available to automakers:
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Idle-off capability. The engine turns off when the vehicle is stopped in traffic or at a light, and turns back on when you move your foot from the brake to the gas pedal.
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Regenerative braking. The electric motor helps slow the car, and functions as a generator to convert some of the energy typically lost during braking into electricity (thereby recharging the vehicle’s battery).
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Power assist and engine downsizing. The electric motor helps propel the car, in particular during acceleration. Because the motor and engine share the power load, the engine’s size can be reduced, saving even more fuel.
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Electric-only drive. The electric motor can power the vehicle by itself at low speeds and when first starting the car.
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Extended battery-electric range. The car runs solely on electric power for 20 to 60 miles before engaging the gasoline engine. You have to recharge the car’s battery by plugging it into an external electricity source.
According to the Union of Concerned Scientists, “mild” hybrids such as Honda’s Insight and Civic Hybrid employ the first three technologies above. “Full” hybrids, including the Toyota Prius and Ford Escape Hybrid, go one step further and feature electric-only drive. “Plug-in” hybrids that utilize all five technologies are not currently available as passenger vehicles.
Hybrid technology is also being used to increase power and performance rather than fuel economy. The resulting “muscle” hybrids, such as the Toyota Highlander Hybrid and Lexus RX 400h, provide only a fraction of the potential fuel economy and environmental benefits. The Honda Accord Hybrid falls between mild and muscle hybrids.
"Hollow" Hybrids
Some automakers are trying to create a “green” image by putting one or two of these technologies into their conventional vehicles and calling them hybrids. The Chevrolet Silverado Hybrid and GMC Sierra Hybrid, for example, have idle-off capability but improve fuel economy by only one or two miles per gallon. Such improvements might be lauded if they were made standard options in every Silverado and Sierra, but producing a limited quantity and marketing them as hybrids will only dilute the term’s meaning and soften demand for hybrid technologies.
When evaluating hybrids, keep in mind that the environmental performance of specific models can vary. For example, Honda Civic Hybrids sold in California rate an exemplary 9.5 out of 10 on the EPA’s smog-forming emissions scale, while others currently rate just a 2. For a customized, side-by-side comparison of hybrid models—along with useful tips from technology experts and hybrid drivers—visit the Union of Concerned Scientists’ Hybridcenter.org website.
