News reports say snags in developing a new battery system have delayed the third-generation Toyota Prius (above) until early 2009.
The Ford Escape Hybrid is redesigned for the 2008 model year.

Toyota passed a milestone in mid-2007 when it sold its 1 millionth hybrid car. Other manufacturers such as Honda, Nissan, Ford and General Motors also offer hybrids to an increasingly fuel-conscious clientele. Every manufacturer claims to be developing more-efficient batteries, more-efficient engines and better designs.

But the hybrid class is not growing as fast as Toyota's sales achievement might suggest. In fact, looking ahead to 2008, what's notable is not a bunch of new models. What's notable is what is missing. Where are the 70-, 80- and even 100-miles-per-gallon vehicles we've been promised?

A third generation of the Toyota Prius gas/electric hybrid car - first introduced seven years ago and most recently redesigned in 2004 - has been eagerly anticipated. Though Toyota has not officially announced when the redesigned Prius will appear, unofficially, automotive journalists had been tipped to expect it sometime in 2008 as a 2009 model.

However, news reports from Japan recently said the car has been delayed at least six months, to early 2009. A Toyota spokesman said the company would not comment because no official launch date had ever been confirmed, so there was no way to officially confirm a delay.

The delay was reportedly caused by snags in developing new batteries for the electric system. The next Prius was expected to use new lithium-ion batteries. Currently, the Prius uses nickel metal hydride batteries, which take up more space and aren't as efficient. Previously, Toyota set a goal of reducing the size of the battery pack in the next Prius by 50 percent while increasing its efficiency.

The delay is apparently intended to give Toyota engineers time to retrofit the new Prius design with the old-style nickel metal hydride batteries they had hoped to get rid of. At least initially, the new Prius will still have nickel metal hydride batteries. Lithium-ion power gets unstable under extreme pressure - apparently too unstable for automotive use at this stage.

Toyota says the new Prius will be a little more powerful, with fuel-economy improvements of at least 15 percent, which would mean 60-plus miles per gallon.

It also seems Toyota will announce the return of the "plug-in hybrid." Such vehicles run on electric charges supplied by external sources like household electric current. Typically, plug-in hybrids have had appeal-limiting short ranges of operation - 100 miles or less - between recharges.

The Prius uses a combination of an electric motor with a small gasoline motor that provides "onboard charging." But the gasoline engine needs fuel and the gas stations that provide it.

Is a Prius-like vehicle that runs entirely on electricity in the offing? It would appear so. "We are taking a close look - a very close look - at plug-in hybrids," said Toyota's Mike Michaels, a specialist on future products. "A lot of other technologies, too, like fuel cells. But expect to hear more from us soon about plug-in hybrids."

Will Toyota's competitors try to use its setback in developing a next-generation Prius battery pack to seize a competitive advantage? In August, Chevrolet selected a manufacturer to provide lithium-ion batteries for its new Volt electric concept car - to be shown at the Orange County Auto Show this year. But a production date has not been announced.

Nissan, which this year came out with a hybrid version of the Altima, seems lukewarm on the technology. The Altima Hybrid, despite good mileage (up to low 40-miles-per-gallon range) and good reviews, is being offered in just eight states. Nissan says it has no plans to expand its distribution of the car, and no plans for more hybrids.

Ford has brought out a redesigned Escape Hybrid for 2008, with slightly improved mileage (lower 30s), but Honda - second to Toyota in sales of hybrid cars - has killed both the Accord Hybrid and the Insight in less than a year. The Accord Hybrid apparently was hurt by its high price and relatively small fuel-economy gain. The 70-mpg Insight has been out for several years, has very odd styling and little utility (including no trunk), which likely limited its appeal.

So what's next for Honda's hybrids? The company, which is enjoying tremendous sales success with its new 51-mpg Civic Hybrid, is moving ahead with plans for a new high-mileage hybrid to compete with the Prius. "In 2009, we will introduce an all-new hybrid model," said Honda spokesman Sage Marie. "It will be priced below the Civic Hybrid and it will have a unique, dedicated platform."

A dedicated platform is one that no other vehicle shares. That would seem to end rumors that Honda would bring out a hybrid version of its Fit subcompact. Whatever form the new, small Honda hybrid might take, it's likely to get 60 to 80 mpg.

Other hybrids currently on the market, such as the Toyota Highlander Hybrid, Lexus RX 400h, Ford Escape Hybrid and some General Motors "mild hybrids," aren't selling extraordinarily well. Fuel savings are minimal with those vehicles, many need premium fuel, and the hybrid package adds thousands of dollars to the price. For example, the Escape Hybrid sport utility vehicle costs about $3,500 more than its priciest gas-only stablemate.

Ford's conclusion from the experience is that it overestimated the popularity of gasoline hybrid vehicles and says it is taking a second look at other technologies, such as E85 ethanol, clean diesels, fuel cells, hydrogen power and dual-fuel vehicles that could run either on gasoline or compressed natural gas.

None of those technologies, however, offers the near-term results that more-efficient gasoline/electric hybrids can offer. "People need to just be patient," said John Hanson, a Toyota spokesman. "They're going to like what's going to happen next."