After a year with 88,000 hybrid units sold through just three brands -- Toyota Motor Corp., Honda Motor Co. and Ford Motor Co. -- sales of vehicles with hybrid gasoline-electric engines are expected to more than double to at least 200,000 units in 2005 as high oil prices grab more consumer attention.

Some rosy forecasts for the end of the decade range from 500,000 units to 1 million. But while pioneer Toyota has aggressive goals to eventually offer the hybrid option on its entire fleet, many major players remain cool on the vehicles, opting instead to promote other forms of fuel-saving technology such as cleaner diesel, hydrogen-powered fuel cell vehicles (FCVs) and advanced direct injection systems.

Still, the powertrain got another boost this week as Ford, whose gasoline-electric Escape sport utility vehicle (SUV) was crowned North American Truck of the Year on Sunday, unveiled plans to add three more hybrid models by 2008.

Its Japanese partner Mazda Motor Corp. will also roll out a hybrid Tribute SUV using Ford's technology.

HYBRID TECHNOLOGY -- THE WINNER FOR NOW

Hybrid vehicles twin a combustion engine with an electric motor and battery in which the act of braking captures lost energy, enabling it to save fuel and emit fewer pollutants.

With the hype surrounding hybrids picking up steam and consumers still lining up months to get their hands on Toyota's Prius sedan, analysts like Thad Malesh at Automotive Technology Research Group are optimistic about their prospects.

Malesh projects US hybrid sales at 1 million units at the turn of the decade -- or 6 percent of the overall auto market -- with a projected 50 models available by then.

Last month, top automaker General Motors Corp. made headlines by announcing a tie-in with rival DaimlerChrysler AG on hybrids in an apparent about-face after being one of the most vocal skeptics of the technology.

"The GM-Daimler agreement makes the 1-million-unit forecast conservative," he said. "GM is really the question mark. If they really get serious -- and this is the first sign that they are -- the hybrid market could really take off."

GM now sells only "mild" hybrid versions of the Chevrolet Silverado and GMC Sierra pickup truck in limited numbers, but has plans to expand its hybrid line-up to 12 models over the next several years. So-called mild hybrids achieve only about half the fuel savings of full hybrids.

Toyota has received more than 11,000 orders so far for the Lexus RX400h ahead of its April launch, more pre-sale interest than it has had for any other model. The Highlander SUV hybrid due in September has counted nearly 100,000 interested buyers. BUMPS IN THE ROAD?

But consumer research firm J.D. Power and Associates foresees slower growth for hybrids. The roughly $3,000 price premium on hybrid cars will likely put off most customers, said Anthony Pratt, manager of J.D. Power's Global Powertrain arm, noting that 40 percent of Prius buyers made six-digit income.

Cleaner diesel and other alternative powertrains and fuel options may also emerge in the next few years to compete with hybrid technology, limiting the sales rise, he said.

Volkswagen AG is planning to make cleaner diesel engines available on almost every model offered in the United States. The engine now accounts for a tenth of US sales.

Nissan Motor Co., another vocal nay-sayer, said hybrid systems are too costly. Experts estimate the dual-engine system costs up to $7,000 more to make than conventional gasoline-only engines, with only half the costs passed on.