SAN JOSE, Calif. - The electrification of the automobile is not only inevitable, advocates and experts say, it is essential because plug-in hybrids and electric vehicles offer our best chance to address global warming, achieve energy security and move us beyond oil.

That isn't to say we'll all be plugging our cars into electrical sockets by the end of this decade, or even the next. But many experts agree plug-ins and EVs will only become more prevalent and could comprise half of all cars sold in America by 2050.

"We can no longer rely on oil to provide the bulk of our transportation fuel. It's just that simple and that obvious," Jon Lauckner, head of global vehicle development for General Motors, said during the opening of the Plug-In 2008 conference in San Jose. "We believe the ultimate solution involves the electrification of the automobile as soon as possible. The discussion has shifted from if this happens to when this happens."

The road ahead is long and marked by technological, political and market challenges, which is why utility companies, battery manufacturers and automakers joined EV advocates at the conference to figure out how we get there from here.

Petroleum accounts for 96 percent of the nation's transportation fuel, a position Lauckner says is untenable given the world's growing thirst for the stuff. The domestic auto market is in the dumps, but sales are booming in the developing world. China is poised to become the world's largest auto market by 2014, Lauckner said, and 15 percent of the world's population will be driving by 2020. "That's over 1 billion vehicles," he said. The only way to ensure all those cars don't destroy the planet is to start giving them electric motors.

Critics argue 70 percent of our electricity is generated from fossil fuels and so plug-ins and hybrids don't reduce carbon dioxide, they just move it around. Not so, says the Electric Power Research Institute and the National Resources Defense Council. Their research shows plug-ins and EVs could cut greenhouse gas emissions by more than 450 million metric tons annually by 2050. That's the equivalent of eliminating 82.5 million gasoline vehicles – about a third of the number currently on the road in America. The benefits will grow as nuclear and renewable sources of power become more prevalent, said Mark Duvall, one of the authors of the study.

Don't look for that to happen anytime soon. "Renewables, nuclear and clean coal will be slow in coming," said Peter Schwartz, a futurist and co-founder of Global Business Group. "So for the next decade or so, coal will be dominant." Still, he says, the environmental and energy security benefits of plug-in hybrids outweigh the downsides to getting our power from coal, and "we need to move aggressively to all-electric ground-based transportation."

The auto industry is beginning to respond, and most of them are working on plug-in hybrids that could be on the road beginning in 2010. But their success is by no means guaranteed. There are concerns about the reliability and longevity of the lithium-ion batteries they'll use, and the cars will be expensive.

Advocates say its time for policymakers to get with the program and ensure plug-ins have a fighting chance. Everyone at the conference has suggestions for what Uncle Sam ought to do, and Dan Sperling – the chairman of the California Air Resources Board – laid them out in a sweeping plan. It includes stronger fuel efficiency and emissions regulations, a tougher mandate requiring automakers to build non-polluting vehicles and some serious government spending on battery and alt-fuel research and development.

Of course, interest in electric vehicles could evaporate if gas prices ever return to Earth, which is why Sperling suggests the government adopt policies to establish a "price floor" on gasoline – a price beyond which it would not fall. It's highly unlikely that'll ever happen, but Sperling says it would encourage the development of green vehicles by assuring automakers and consumers they won't not lose their shirts if gas ever becomes cheap again.

"If we do all of that," Sperling said of his proposal, "we'll see millions of plug-ins on the road."

Photo courtesy Ford.