washington

A joint initiative between the US government and the car industry to develop more economical cars is putting too much effort into ‘hybrid’ vehicles that will be costly to build and maintain. That is the conclusion of a panel of the National Research Council (NRC), part of the National Academy of Sciences complex

The Partnership for a New Generation of Vehicles (PNGV) programme decided earlier this year to pursue hybrid vehicles as the most promising route to developing a prototype passenger car that will do 80 miles per gallon (m.p.g.) by the year 2004.

PNGV is a flagship of the Clinton administration's technology policy, and involves government laboratories working in collaboration with researchers at Ford, General Motors and Chrysler. It chose hybrid electric vehicles, which can switch between a diesel engine and a battery depending on conditions, because more sophisticated technologies, such as fuel cells, will not be ready by 2004.

But the hybrid approach may never be economical, says the NRC panel in its fourth annual assessment of the project. This is because of the extra costs of building and maintaining a car with two power systems. Despite the better fuel economy of a hybrid vehicle, the panel says, “the difference is probably not enough to offset the higher cost” of building and maintaining it.

The panel was chaired by Trevor Jones of Echlin, a car component supplier based in Cleveland, Ohio. It says that PNGV partners should put more effort into technologies with greater long-term potential for big improvements in fuel economy, such as fuel cells. It adds that, while awaiting such breakthroughs, the partners should try to develop a non-hybrid vehicle with a more realizable fuel economy target of 60 m.p.g.

The panel suggests that some of the project's effort should be directed to increasing the fuel economy of light trucks and sport-utility vehicles, which together now account for half of the car market in the United States. The project is currently focused on increasing the economy of a standard four-door family car, such as the Ford Taurus.

William Daley, the commerce secretary, and Federico Peña, the energy secretary, issued statements that welcomed the NRC report but failed to address the issues it raises. But Eric Clark, a spokesman for the Department of Commerce, said that PNGV was only four years into a ten-year project, and that it would now start to focus more on questions of cost. “The affordability issue is now at the forefront of our work,” he said.