Yesterday, the City of San Francisco celebrated achievement of goals set by its 2008 Green Taxi law aimed at curbing fuel consumption and greenhouse gas emissions by 20 percent by 2012.

These standards were set using 1990 levels as the baseline, and having hit the target of becoming the “Greenest Taxi City in America,” former city Taxi Commission President Paul Gillespie noted the city’s strong commitment.

“Cutting global carbon dioxide emissions is one of the most crucial issues of our time,” Gillespie said, “and the San Francisco taxi experience has shown that taking aggressive, collaborative action at the local level can be both profitable and effective.”

The accomplishment came also thanks to Ford, which announced with a press release that 67 percent of San Francisco’s “green” taxi fleet is made up of Ford vehicles, noting also its taxis are popular also in other major metro areas.

As for taxis on the streets of San Francisco, Ford said they have now cut annual gasoline consumption by 2.9 million gallons, and annual emissions by 35,000 tons.

The standard Ford Transit Connect – 2010 North American Truck of the Year – features a 2.0-liter I-4 engine that gets 22 mpg in the city and 27 mpg on the highway, an estimated 30 percent improvement in fuel economy compared with traditional taxis.

CNG-powered Transit Connect Taxis, for example, are available and soon will hit the streets of San Francisco. CNG-powered Transit Connect Taxis are being used in other parts of the country as well, servicing places such as Los Angeles, Chicago, Las Vegas and St. Louis.

The estimated fuel economy of a CNG-powered Transit Connect Taxi is the same as the standard gasoline version. However, operating costs are lower because the cost of a gasoline gallon equivalent of CNG is roughly half the cost of a gallon of regular gasoline. In addition to CNG, Transit Connect Taxi is available with an engine preparation package for conversion to liquefied propane gas (LPG).

CNG has been a popular choice for fleet and taxi companies for years because it’s readily accessible, doesn’t require extensive modifications to vehicles, and also costs (in terms of a gallon) around half the price of regular gasoline.

According to Ford, instead of the once-ubiquitous Crown Victoria however, vehicles such as the Ford Transit Connect are increasingly popular. This small commercial van is imported from Europe and has proven quite successful as a next-generation taxi.

In fact, some Transit Connects have been designed to run on CNG with fuel economy comparable to their gas-fueled counterparts, though with 22 mpg city/27 mpg highway, that results in a 30-perceent fuel mileage improvement compared to a Crown Vic.

In addition, a conversion package is also available to fleet buyers allowing the vans to run on Liquified Propane Gas, a common alternative fuel source for fleets in Europe.

These announcements come also as Ford, like many other automakers, hedges its green car bets between electrified vehicles and vehicles that can make use of CNG.

Ford is also using this same van in electrification projects, as perhaps you’ve seen with the Ford Transit Electric, but this week it was the natural gas version that was in the spotlight.

This “all of the above” approach is also in lockstep with government policymakers also hoping to wean away from petroleum dependence, and CNG represents a major possibility yet in the alternative energy shakeout process as we head into the future.