Ford Motor Co., the second-largest U.S. automaker, began taking orders yesterday for a hybrid version of its Mercury Mariner sport-utility vehicle a year earlier than planned in response to increased interest.

The vehicle follows the Ford Escape Hybrid SUV, which was introduced last fall. Production of the Mariner will begin in October, with 2,000 vehicles available in the first model year. The company expects to double production the following year.

"With the demand for the technology both in showrooms and from environmental communities, we just want to do as much as we can as soon as we can," said Sara Tatchio, spokeswoman.

Toyota Motor Corp. and its popular Prius sedan established an early lead in the hybrid market, forcing Ford and the other U.S. carmakers to scramble to catch up. American manufacturers and their foreign rivals are now increasingly pushing the gas-electric technology beyond the early sedans to an array of SUVs and eventually trucks. Toyota has moved beyond the Prius to produce hybrid versions of two SUVs: the Highlander and the Lexus RX. General Motors Corp. plans to introduce full-size hybrid SUVs, such as the Yukon and Tahoe, in 2007.

The Mariner hybrid gets 33 miles per gallon in the city and 29 miles per gallon on the highway, a 50 percent improvement over the base vehicle, according to Ford. The vehicle sells at a base price of $29,840, while the traditional version with standard trim starts at $22,040.

The Sierra Club yesterday sent an e-mail to 300,000 of its members praising the Ford announcement. "We think it's a major step forward and we are encouraging people to go kick the tires," said Daniel Becker, director of the club's global warming program. The group will have the Mariner at its annual summit in September. "Obviously we don't always say nice things about what Ford does, but we've been urging them to make clean cars and they did. And we applaud it."

Other environmentalists were unimpressed. "The introduction of the hybrid is a nice gesture, but it represents 6/100ths of 1 percent of Ford's entire fleet," said Michael Brune, executive director of the Rainforest Action Network.

Hybrid production is running at too low a level to make a difference in environmental issues, said Karl Brauer, editor in chief of "There's kind of a lot of PR going on here versus a lot of functional change in America's dependency on oil. This is not going to have an impact on how much oil we use. It's not easy to produce hybrids. It's not a demand problem, it's a supply problem."

Sales of the Prius totaled 53,308 in the first half of 2005, while Ford sold 7,634 hybrid Escape SUVs, according to

Ford shares were up 29 cents, or 2.8 percent, to close at $10.71.