Hey Mr. Green,

Are electric and pedal-assist bikes sustainable, especially with regard to their batteries?

—Rob in Dubuque, Iowa

Almost any transportation that can lure us out of our cars, with the possible exception of army tanks, could be called sustainable in comparison to driving.

The electric bike and its battery require far fewer resources to manufacture than an automobile that weighs 70 times as much. In terms of energy use and pollution, electric bikes also beat the typical electric car, being responsible for about one-tenth the amount of carbon dioxide and other pollutants. (They trounce gas-powered vehicles that get less than 40 miles per gallon, and in areas where renewable power generates a sizable chunk of the energy mix, they obliterate all gas-powered cars.)

I hear some genius out there saying, "If you don't use the bike enough to offset the energy needed to make it, you're losing." True. But there's no excuse for not using it. An astounding fact: More than 60 percent of automobile trips are under six miles and easily bikeable. An electric bike can make some of those pedal trips more appealing—you will arrive home from work or shopping, even after climbing hills, without having broken a sweat.

Most types of bike batteries can be recycled after they perish. The battery-recycling outfit Call2Recycle accepts batteries at 34,000 locations. To find the one nearest you, go to call2recycle.org.