The promise of environmentally friendly, battery-powered cars has long made electric power seem like the best solution for saving gas. But because batteries have a short cruising range and long recharge time, some carmakers promote gas/electric hybrids as a better choice, according to the Chicago Tribune. A regular gas/electric hybrid uses the batteries to start the vehicle, get it up to cruising speed and provide a power boost when needed. These hybrids recharge the batteries as you drive by capturing the energy used in braking and sending it back to the pack. No need to plug into a socket overnight, but, of course, they burn gas. Now that consumers question getting enough mileage to offset the $2,000 to $5,000 premium for a hybrid, the new "answer" is plug-in hybrids, the Tribune reports. A plug-in is an electric car with a gas engine as a backup to increase driving range when needed. "It may be one technology that makes sense for certain customers," says Nancy Gioia, director of Sustainable Mobility Technologies and Hybrid programs at Ford. "But to run on batteries only for an extended period of time brings down the charge fast unless you double or quadruple the size of the batteries. And if you do, you added 200 to 400 pounds to the weight of the car." Some suggest a better way to conserve gasoline would be hybrids that run on E85 fuel, the blend of 85 percent ethanol and 15 percent gas. But E85 requires higher heat than regular lead-free gas to treat exhaust emissions, presenting a conflict when the car runs on battery power, shutting off the gas engine and dropping temperatures in the catalytic converter.