Below is Day 3 of the fuel cell vehicle rally covered by MSNBC.com's Miguel Llanos and photographer James Cheng.
COSTA MESA, Calif. — Another ride-and-drive was held the next day at the fairgrounds in Costa Mesa, where those in line included novices asking questions like, "So you put water in it?", as well as early adopters like Don White, who said he was from Cedar Rapids, Iowa, and had timed his California vacation so that he could test drive a fuel cell car.
"He's not as excited about this, but his dad is," White said of his 4-year-old son standing next to him.
White was particularly interested in hydrogen's potential to reduce carbon dioxide, a gas that many scientists tie to global warming. And coming from a corn-growing state, he was well aware that even crop residue could be burned to create the energy needed to extract hydrogen from water.
Not all hydrogen is created equal
But Romm, the former Clinton administration hydrogen expert, is quick to caution that not all hydrogen is clean. Unless renewable energy like solar or wind power — still very expensive — is used, other options still mean indirect pollution.
Romm fears that widespread use of fuel cell cars could actually worsen air quality if most hydrogen continues to be extracted from natural gas. For one, the extraction process also releases polluting hydrocarbons from natural gas.
Moreover, since natural gas is used to fire power plants across the country, any significant use for hydrogen would encourage utilities to use more of the much dirtier coal-fired power plants to keep up with power demand, Romm says.
Terry Tamminen, the head of California's EPA, isn't deterred by that thinking, however. He prefers to focus on the fact that, while still expensive, hydrogen can be extracted from a variety of sources — fossil fuels, crop residue and, of course, water — potentially allowing a place like the Midwest, for example, to some day make it from corn if that becomes feasible.
"That's the beauty of hydrogen," he told MSNBC.com. "It can be made from whatever you have locally."
Marine base, but no Marines
Next on the rally tour was Camp Pendleton, the huge Marine base near San Diego.
The rally support teams — some 70 engineers and spokespeople — arrived with their eight vehicles only to find they vastly outnumbered their hosts.
Gary Funk, the regional fleet manager for the Marines, attributed the low turnout to the fact that most of the Marines had been deployed to Iraq. But he welcomed the tour, noting that the base was about to put in a hydrogen station, one of the military's first and the only one on the West Coast.
"We're trying to get our foot in the door," he said, noting that one potential advantage is that hydrogen could be made on the battlefield from water or some other non-petroleum source.
Buckney Wilson, an automotive technician on the base, was one of the handful who drove the cars. He, too, came away impressed, saying he sees the potential to get America beyond oil, especially if oil supplies were suddenly threatened.
"During every emergency situation, we've always come together," he said. "Instead of Rosie the Riveter it'd be Mike the Electrical Engineer."
The mechanic in him loved the fact that fuel cell vehicles, which essentially are electric and have few moving parts, are "repair friendly."
"It benefits everybody," he said of the technology, "it should be a full-force effort."