A researcher at Oak Ridge National Laboratory devises a formula that makes it easy to determine how long hybrid vehicles take to recoup their premium cost.

Robert G. Boundy, of the lab's Center for Transportation Analysis, says payback takes anywhere from no time for the Buick LaCrosse eAssist and Lincoln MKZ hybrids to 5.2 years for the GMC Yukon Denali Hybrid 4WD.

Each of the vehicles is a ’12 model. Annual fuel savings and years to payback are based on 15,000 miles (24,150 km) traveled annually, a driving mix of 55% city and 45% highway and a national average fuel price of $3.75 per gallon.

David L. Greene, head of the fuel-economy project at Oak Ridge, requested Boundy to undertake the project because of what he calls the negative and unfair portrayals of hybrid vehicles in the news media. Greene claims the difference in costs between hybrids and conventionally powered vehicles is exaggerated.

“Many articles failed to take into consideration that hybrid vehicles are very well equipped and that they should be compared to models with similar equipment and features,” he says.

“The payback period of a hybrid vehicle can depend greatly on how the vehicle is used,” Boundy notes. His calculations allow motorists to see how fuel prices, annual miles traveled and city/highway driving mix affect fuel savings and payback periods.

He acknowledges some of the vehicle pairings were arbitrary, but adds: “My goal was to be as fair as possible in comparing the hybrid versus the conventional model.

“In truth, the Toyota Prius offers a lot that the Matrix does not, but it seemed to be the closest match I could come up with. So I stuck with that instead of comparing it to a different model like the Camry, which would have given the Prius a much faster payback period.”

Boundy says the project was labor-intensive, requiring visits to dealerships and contacting auto makers to validate the pairings.