A traffic jam of green-vehicle announcements has accompanied the start of the North American International Auto Show in Detroit.

The show began Sunday with a three-day press preview and opens to the public Saturday. It’s one of the world’s largest auto shows and the first major show since the country set new fuel-economy standards in December (see President Signs Energy Bill and Senate Rejects Incentives to Pass Energy Bill).

And in spite of a hard year -- or perhaps because of it -- automakers appear determined to distinguish themselves with cleaner vehicles.

"We’ll be seeing the obligatory green mobiles all over the place," Global Insight analyst John Wolkonowicz told Yahoo News. "It’s high fashion now. You’re going to see a lot of concept vehicles that have these way-out high-tech power trains that deliver either exceptional fuel mileages, or are exceptionally clean, or both."

But as automakers jockey to "out-green" their competitors, the Union of Concerned Scientists warned that there’s a big difference between PR glitz and reality.

"It’s not enough to simply make a green concept car," said Jim Kliesch, senior vehicles analyst for the group, in a written statement. "Every time an automaker introduces something new at the auto show, consumers should ask how many and how soon. With gas prices hovering around $3 a gallon and a new fuel economy law in place, successful automakers will be those with sound business plans to put millions of fuel-efficient cars on the road in the next few years."

Here is some of the green news rolling out of the Detroit show:

BYD Auto

BYD Auto, a subsidiary of the battery giant BYD Group, on Monday announced it has made a ferrous-battery breakthrough that will give dual-mode hybrids a range of 250 miles and the ability to recharge 50 percent in 10 minutes.

Vice President Micheal Austin said the battery also is safer than the lithium-ions being considered today. Even more alluring, the duel-mode option using the battery can be added to any of the four hybrid and electric vehicles BYD is showcasing for $6,000 -- a price "unheard of in the market," he said.

The Shenzen, China-based company plans to launch vehicles using the batteries in October and to bring such vehicles to the United States in three to five years.

After the press conference, Austin gave Greentech Media more details on the battery, saying it’s based on an iron-phosphate chemistry with a modified electrolyte. Other phosphate-based batteries have suffered from low efficiencies, but -- while he didn’t have the efficiency numbers on hand -- Austin said BYD has overcome that problem.

BYD had been developing the battery technology for 10 years, in cordless power tools, and has worked to apply the technology to automobiles in the last two, Austin said.

Fisker Automotive

Fisker Automotive on Monday unveiled its plug-in hybrid with a solar panel on the roof and announced that Kleiner Perkins Caufield & Byers had invested an undisclosed sum.

CEO Henrik Fisker, who previously designed sports cars such as the Aston Martin DB9, said the Fisker Karma can drive the first 50 miles with no gasoline or emissions -- enough to get more than 60 percent of Americans and Europeans through their daily commutes.

With a different chemistry than its competitors, as well as its own control software, Fisker claimed the company would be the first company in the world to bring a car with a "true lithium-ion battery" to the market. The company plans to begin producing the Karma -- expected to start at $80,000 -- in the fourth quarter of 2009.

The company’s technology comes from research developed by Quantum Fuel Systems Technolgies Worldwide and Asola.

Changfeng Motors

Changfeng Motors, a Chinese manufacturer of SUVs and pickup trucks, said it will bring its vehicles to the U.S. market in the next few years -- and possibly as early as next year.

The company, which showed its Leibao CS6 SUV, Feibao CT5 pickup truck and a three-wheeled concept vehicle at the show, said it has made major strides toward its goal and already is exporting vehicles to the Middle East and Africa.

"Last year, we brought prototypes here," Changfeng Motors Chairman Li Jianxian said, speaking through a translator at a press conference Monday. "This year, all those models are rolled out on production lines. We believe we do have the quality [to enter the U.S. market]."

That comment came after Mitsubishi Motor Corp. last month recalled 169 Pajero SUVs made as part of its joint venture with Changfeng due to an engine-hood lock problem. Aside from Mitsubishi, Jianxian said Changfeng is continuing to look for additional industry partners.

Jianxian said that he thinks fuel efficiency and safety will distinguish Changfeng’s cars from the SUVs already prevalent in the American market. The CS6 SUV gets 30 miles per gallon, he said.

General Motors

On Monday, General Motors showcased its Saturn two-mode hybrid Vue -- its first front-wheel drive vehicle with a two-mode hybrid - as well as the Saturn Flex-Stream concept and the Saturn Vue Green Line plug-in hybrid concept.

The Flex-Stream will be all-electric for up to 35 miles and will be paired with the ability to use different fuels, including diesel, said Tom Stephens, vice president of GM North America. The Vue Greenline plug-in hybrid, which can fully recharge in four to five hours, could go into production as early as 2010, he said.

The efforts show GM’s commitment to being part of the solution, said Troy Clarke, GM North America’s president, at the debut Monday. "If 2007 is the year it all started, 2008’s the year we double down," he said, referring to the company’s strategy to roll out greener vehicles.

The company also announced an investment in -- and partnership with -- biofuel startup Coskata and unveiled a Hummer prototype that can run on a blend of up to 85 percent ethanol. All this after it showcased its Cadillac Provoq fuel-cell concept at the Consumer Electronics Show in Las Vegas last week (see With GM Deal in Hand, Coskata Promises $1 Ethanol and CES Flaunts its Green). And GM still plans to bring its sporty plug-in Chevrolet Volt to the market by 2010.

Toyota Motor Corp.

Toyota Motor Corp. said Sunday it would build plug-in hybrids for commercial customers by 2010, the same year GM has said it plans to roll out its Chevrolet Volt.

That’s after Toyota President Katsuaki Watanabe earlier this month said the company plans to offer a hybrid model in every vehicle series it makes and announced plans to sell 1 million hybrids per year starting in a few years.

The company already has been testing plug-in versions of its Prius using nickel-metal-hydride batteries, but the plug-ins aimed to hit the market by 2010 will use lithium-ion batteries, Watanabe said at the show.

Chrysler

Chrysler introduced a Dodge Ram hybrid and also showed three concepts developed by its electric-vehicle subsidiary, ENVI: the Jeep Renegade, a plug-in diesel-electric hybrid, the Dodge Zeo, an all-electric sports car, and the Chrysler ecoVoyager, which has a hydrogen fuel cell (see Chrysler Headed to Greener Pastures).

Ford Motor Co.

Ford Motor Co. unveiled its EcoBoost system, which it claims boosts fuel efficiency up to 20 percent using direct gasoline injection and superchargers, at the show. The company is showcasing its 2009 Lincoln MKS, the first vehicle to use the EcoBoost technology. The company has said it plans to put the system on up to 500,000 vehicles in the next five years.

President Bill Ford said the company wants to become the "leader in sustainability." Aside from the Lincoln, Ford’s Volvo and Land Rover brands brought diesel-electric hybrid concepts to the show.

Volvo is showing a diesel version of its ReCharge plug-in hybrid concept car. Land Rover is showing a three-door LRX, a small SUV, that it claims can surpass U.S. emission standards, run on biodiesel and also deliver 30 percent better fuel economy.

Honda Motor Co.

After announcing a plan to make hybrids 10 percent of Honda’s global sales by 2010, CEO Takeo Fukui on Monday announced the company would begin selling low-cost, lightweight hybrids next year.

Fukui said Monday that Honda also is on track to launch its first ultra-clean diesel car in the United States in 2009 -- an Acura -- and that it expects the cars to be profitable right away, according to Reuters.

"We think the ultimate solution is a fuel-cell vehicle that sets a new world standard for cleaner emissions and high fuel efficiency through alternative fuel technology," Fukui said in a press conference.

The company also unveiled its FCX Clarity fuel-cell powered sedan at the show, which it plans to test in California -- via a small number of leases - later this year.