Blanket subsidies for hybrid electric vehicles won't get drivers out of their old gas guzzlers and into the new energy efficient cars, according to a new study in Energy Policy.  When it comes to pumping up the appeal of plug-in hybrid electric vehicles (PHEVs), researchers say some regions are more ripe for the cars than others, and some consumers' buttons need more pushing than others.

The study found that giving consumers who live and drive in regions where the social benefits of electric–boosted cars are strongest, and recognizing the circumstances of consumers – such as their income, life stage and family size – gives PHEVs a better shot at both sales and environmental and energy security effectiveness.

"The idea of a one-size-fits-all technology has failed us many times before in automotive policy," said Steven Skerlos, director of the U-M Environmental and Sustainable Technologies Laboratory. "PHEVs that make sense in urban areas where the grid is fairly clean may make much less sense compared to other technology approaches for areas of long distance rural driving. We want to get beyond the notion of a universal 'silver bullet' and understand where PHEVs are most likely to going to work."

Currently, such subsidies exist for various types of alternative fuel vehicles, although the paper uses the example of new federal subsidies for PHEVs to make its case.

"Subsidies for alternative fuel vehicles, such as PHEVs, are needed in order to move our transportation sector away from petroleum and towards more sustainable technologies and fuels," said James Winebrake, who also co-directs the RIT Laboratory for Environmental Computing and Decision Making. "However, blanket subsidies such as those currently in place, are clearly sub-optimal. The administration needs to target its subsidies in areas that maximize social benefit."

Skerlos and Winebrake explain that PHEVs can make the biggest environmental and energy bang for the buck in specific locations. Areas that use low-carbon fuels for electricity production, such as renewable fuels, nuclear power, or natural gas, make more sense than areas that generate electricity from coal.

Second are areas where people drive more, so that the PHEVs displace a greater amount of petroleum. Third are areas where air quality is sub-standard.  Other attributes, such as population density and driving habits are also important.

Buyer demographics, such as income levels, count too.  For instance, high-income consumers are more likely to buy a cutting-edge green car with less resistance to cost, sending a flag that subsidies could be more effective to enable lower income consumers buy PHEVs.

The use of tax dollars to subsidize purchases of PHEVs by people who would have bought them anyway should be questioned," Skerlos said.

Winebrake and Skerlos are actively working on the next phase of this research, which is to quantify many of these attributes in order to provide insights into the particular geographic regions and demographic groups that would be optimal targets for PHEV subsidies.