In North America, most discussions about which powerplants are the best short-term alternatives for reducing petroleum consumption generally come down to gasoline-electric hybrids vs. diesels.
Hydrogen has some backers, especially for use in fuel cells, but most engineers acknowledge that hydrogen use is still a ways down the road. Though having just put some miles on a Honda FCX fuel-cell car, I can say it may not be all that far off.
Toyota is the biggest proponent of hybrids, with plans to build 1 million a year, while the Europeans support diesels. That's because half the cars in Europe already have diesels.
But that could change. Rinaldo Rinolfi, director of Fiat's engine research program, told Automotive News Europe he expects diesel usage in Europe to peak at about 65 percent in 2010 -- before plummeting back below 40 percent within five years.
New European emission rules that go into effect in five years will make diesels too expense.
So what will replace all those diesels?
Cleaner, more fuel efficient gasoline engines, Rinolfi says.
Isn't that a hoot?