Even this year, news leaked that GM was considering launching a commercial fuel cell vehicle in 2015, despite lack of support for the hydrogen movement from U.S. President Barack Obama.  However, of late, the big automakers like Toyota and Honda have backed off the effort to push hydrogen vehicles onto the market.

A new study might put another road block in front of the prospect of a near term commercial hydrogen vehicle release, while giving the plug-in vehicle movement a nice boost.  The study was authored by Ryan McCarthy at the University of California, Davis and published in the Journal of Power Sources. The ground-breaking study, entitled "Determining marginal electricity for near-term plug-in and fuel cell vehicle demands in California: Impacts on vehicle greenhouse gas emissions", examines the emissions impact of hydrogen and plug-in vehicles versus their gas counterparts.

Lowering carbon emissions to fight warming, along with high fuel prices and global-political instability, has been a key driving factor for the adoption of hybrids and alternative fuels.  The new study, though, judged hydrogen vehicles to be an utter failure at that objective, in their current state.  The study concluded, "All of the pathways except for [fuel cell vehicles] using hydrogen from electrolysis reduce [greenhouse gas] emissions compared to ICEs and [hybrid electric vehicles]."

It doesn't dissuade further research into hydrogen vehicles; it simply indicates they are unlikely to be ready for showtime anytime soon.  It points out that steam methane reforming is a promising emerging method of hydrogen production that may one day allow hydrogen driven vehicles to actually live up to their emissions promises.

In the near term, the study finds that plug-in electric vehicles are the best option in terms of lowering carbon emissions.  Despite using electricity mostly generated by "relatively inefficient steam- and combustion-turbine plants" the well-to-wheel carbon impact of EVs is still significantly lower than hybrids.

While by no means the definitive study on the topic, the new work does much to fill in the gap in knowledge about what exactly the true impact of green vehicles are.  While the topic of on-the-road emissions has been well researched, there's been much less progress in examining the full lifetime impact of vehicles.  Now, that lifecycle has been examined in depth and EV advocates can put another feather in their caps, while hydrogen advocates are once again handed another setback.

The study may play a crucial role in forming the policy of California's Low Carbon Fuel Standard, an effort to reduce the carbon impact of transportation.  And given that President Barack Obama's Environmental Protection Agency has embraced California's emissions policy, the new study could have a profound impact on the course of regulations and the auto market nationally, as well.