Mention fuel cells to people in the automotive industry and you get an illuminating range of reactions.
True believers talk about a future free of imported oil and nasty tailpipe emissions. Cynics scoff that "hydrogen economy" talk is just a tactic to prevent higher fuel-economy standards.
After a recent dive into the world of fuel-cell development, I've come away with a different view.
Fuel cells may or may not represent the automotive powertrain of the future, but the pressure to move away from the petroleum-fueled internal combustion engine will only increase.
If the industry's projections of strong global growth prove true, the cost-benefit calculations for alternate powertrains will change profoundly. Expect political pressure to intensify too.
1.1 billion vehicles
There are an estimated 835 million motor vehicles on the world's roads, according to consultant J.D. Power and Associates.
Nearly all burn either gasoline or diesel fuel. Both are petroleum products. Both produce undesirable tailpipe emissions.
Now consider Power's forecast. China is projected to add 68 million motor vehicles to its roads within 15 years. India, is expected to add 14 million vehicles within 15 years.
Analysts foresee more growth from Brazil and other Latin American countries; smaller Asian nations such as Thailand; eastern Europe, and, surprisingly, the US.
The total vehicle count in the US will expand from the current 230 million to 260 million within 15 years, if Power predictions are correct.
Global vehicle count is expected to swell from today's 835 million to 1.1 billion within 15 years. That would be an increase of 265 million vehicles -- more than the total number on US roads today.
Garel Rhys, director of the Centre for Automotive Research at Cardiff University in Wales, predicts that the industry will crank out more vehicles in the next 20 years than the 1.8 billion it built in its first 110 years.
Dark side of success
Irv Miller, group vice president for Toyota Motor Sales USA, recently said growth will force the industry to deal with "the dark side of our great success -- air quality and congestion.
"Increasing vehicle production and use will place a heavy burden on the global environment," he said. "It's a major challenge for all of us because our entire industry could become a prime target for a backlash at any time."
Miller also said China has become the world's third-largest oil consumer.
The statistical agency of the US Department of Energy says growing demand for oil will increase global consumption 57 percent -- from 77 million barrels daily in 2001 to 121 million barrels daily by 2025.
And remember -- a petroleum-thirsty world sucking up reserves at that rate would be increasingly vulnerable to the political extremism of the Middle East.
Air-quality concerns also are likely to gain force. Carbon dioxide emissions will increase, from 23.9 billion metric tons in 2001 to 37.1 billion metric tons in 2025, the energy administration says. That's a 55 percent increase. Factor in comparable increases in diesel soot and nitrogen oxides.
Projections can be wrong, but we have to look at what is visible today. What we can see coming vastly increases the pressure to replace petroleum-fueled engines with fuel cells, ethanol, electric vehicles, compressed natural gas or some combination of those.
As Larry Burns, General Motors' fuel-cell point man, put it: "We really have to ask ourselves, can the world sustain 1 billion automobiles?"
If they all burn petroleum, probably not.