DETROIT —  Ford Motor Co. (F) began selling its second hybrid vehicle on Monday, a more fuel efficient version of its Mercury Mariner sport utility vehicle.

The 2006 Mercury Mariner Hybrid SUV (search), which starts at $29,840, will be sold almost exclusively online, the company said. Customers can order the vehicles through Mercury's Web site and pick them up from a local dealer when they are delivered.

The Mariner Hybrid's fuel economy is nearly 50 percent higher than a conventional Mariner, the company said. The Mariner Hybrid gets an estimated 33 miles per gallon in the city and 29 mpg on the highway and meets the most stringent emissions standards, Ford said.

The Mariner Hybrid is Ford's second hybrid SUV. The company introduced the Ford Escape Hybrid (search) last fall and sold 2,566 vehicles in 2004, or about 3 percent of the total hybrid market, according to R.L. Polk & Co., a Southfield-based automotive data firm. Japanese brands accounted for more than 96 percent of the hybrid vehicles registered.

The Escape Hybrid was the first hybrid SUV on the market and the first hybrid produced by a U.S. automaker.

Ford said it moved up the release of the Mariner Hybrid because of the strong response to the Escape Hybrid. The company plans to produce 2,000 Mariner Hybrids at its Kansas City, Mo., plant for the 2006 model year. The company believes volume will eventually grow to 4,000 vehicles annually.

"We are taking a very nontraditional approach to marketing the Mercury Mariner Hybrid because our target customers are very progressive," said Al Giombetti, president of Ford's Lincoln Mercury division.

Ford plans extensive advertising on the Web sites of several environmental organizations, including the Sierra Club (search).