My husband claims that hybrids are greener than natural-gas-powered cars. What’s your take on this?
—Naomi, in Berkeley, California
I’ve noticed that male declarations about vehicles are often not just wrong, but off by an order of chest-beating magnitude, but your hubby’s on target here. The hybrid is the clear winner because of its greater efficiency, as you can see by comparing the two types of Honda Civic. The natural-gas-powered Civic gets a fuel economy of the equivalent 31 miles of gasoline per gallon in combined city and highway driving, while producing 227 grams of greenhouse gas emissions per mile. By contrast, the hybrid Civic’s combined mileage is 44 mpg, with lower emissions of 202 grams per mile, according to the EPA. They are tied in EPA’s smog score, with an excellent 9. In terms of sheer energy consumption, the natural-gas Civic uses around 4,000 British thermal units (Btus) per mile, whereas the hybrid requires only about 2,820.
The Prius C hybrid, which won the 2013 greenest car of the year honors from the estimable American Council for an Energy Efficient Economy, beats them all, with a combined fuel efficiency of 50 mpg, while requiring 2,480 Btus per mile, and producing 179 grams per mile of greenhouse gas emissions. It scores just a notch lower on the smog index, garnering an 8.