Now that the market for greener American cars finally is arriving, it looks a little different from what was expected.
Some green-vehicle technologies that looked like sure bets for the second half of this decade are lagging. And some technologies that seemed like long shots seven model years ago have become viable.
Coming up on the outside in this horse race for higher fuel economy: diesel engines, aluminum bodies and -- still a long shot -- hydrogen fuel cell-powered vehicles.
Struggling to live up to expectations: electric vehicles and plug-in hybrids.
And the big-selling fuel-reducing technology of the moment has turned out to be a more efficient gasoline engine.
"There's definitely a future for electric vehicles and plug-in hybrids," says Doug Skorupski, Volkswagen of America product strategy manager, recalling the widespread outlook for alternative power in 2008.
"But a few years ago, as we were thinking through all this, I don't think people said this loudly enough: There is a lot of life left in the internal combustion engine. You really have to give the customer a good reason to move away from it."
Morgan Stanley analyst Ravi Shanker is more blunt: "EVs have been a disappointment, compared to what we expected."
"Their cost hasn't come down enough. Batteries haven't gotten better. And gas prices haven't gone up like everyone expected. And at the same time, the automakers have done a great job of making the internal combustion engine better."
It isn't that the auto industry got the green forecast wrong. It's that the world is different in 2014, says Andy Palmer, Nissan Motor Corp.'s global product planning chief.
"Things have continued to change," Palmer says. "A few years ago, a couple of my competitors believed that hybridization was the only realistic path to improve fuel economy, and I don't think anyone believes that now.
"Americans are now more open to diesels, and we're testing that possibility. And five years ago, we'd probably have dismissed the idea of downsizing in North America. We've proven that downsizing is a reality now."
Downsizing comes in two forms. Under the hood, it is the strategy of putting smaller, sometimes turbocharged engines into vehicles that previously used larger, more gas-thirsty engines. U.S. sales of four-cylinder-powered vehicles rose 12 percent in 2013 from a year before, according to IHS Automotive, while sales of those with six-cylinder engines declined slightly, despite a growing vehicle market. (See chart, Page 4.)
Over the past few years, some automakers have made hay offering four cylinders instead of six -- in the Hyundai Sonata and Nissan Frontier pickup, for example -- or allowing consumers to opt for six cylinders instead of eight. And Ford has introduced a 1.0 liter, three-cylinder engine on the 2014 Fiesta.