Despite declining mail volumes, the U.S. Postal Service delivers mail to more addresses each year, which makes it challenging to cut fuel consumption.

The Postal Service has a goal to cut petroleum usage by 2 percent annually through 2015, compared with a 2005 baseline. Yet petroleum consumption increased 4 percent between 2005 and 2008.

Accounting for the overall increase in fuel use since 2005, managers going forward must achieve a 4.5 percent annual reduction in petroleum consumption to meet the 2015 goal, said Sam Pulcrano, the Postal Service's vice president for sustainability.

"We're growing the number of delivery points each and every year, and we're moving postal vehicles from lower mileage routes to higher mileage routes," he said.

Since 2004, the Postal Service has been shifting 3,000 right-hand drive vehicles annually from city routes that have been consolidated to rural letter carriers, replacing the personal vehicles rural carriers typically drive. Vehicles on rural routes clock between 35 and 40 miles a day, or 1½ times the 16 miles driven by those vehicles on city routes.

In addition, the Postal Service is adding about 1.2 million new delivery addresses each year. Coupled with the shift in vehicles from city to rural routes, that's translated into a 5 percent increase in miles traveled by postal-owned vehicles since 2005.

To tackle the increase in fuel use, the Postal Service is attempting to consolidate routes so it needs fewer vehicles to deliver the mail. It cut 10,000 routes this year, which took about 7,000 vehicles off the road, and has set a 2010 target to take another 5,000 vehicles out of commission.

Additionally, the Postal Service has included reducing fuel consumption as a performance goal for managers. Those who don't meet the annual goal receive smaller pay raises, while those who exceed the goal are rewarded with higher increases, Pulcrano said.

"Like most organizations, what gets measured gets results," he said.

The Postal Service has had better results meeting the government's goal to increase use of alternative fuels by 10 percent annually compared with a 2005 baseline. By the end of fiscal 2009, the Postal Service had increased its use of alternative fuels by 113 percent since 2005.

The Postal Service has purchased more than 11,000 vehicles since 2005 that run on a mix of 85 percent ethanol and 15 percent gasoline and, where possible, has put those vehicles in locations where E-85 fuel is available, Pulcrano said.

In addition, the Postal Service received 6,555 fuel-efficient vehicles through the Recovery Act — more than any other agency. Those vehicles include hybrid, E-85 and high-mileage petroleum vehicles and will help the Postal Service continue to increase its alternative fuel consumption, he said.

The agency doesn't plan to make any large vehicle buys for the next five years or so, in hopes that a leading alternative will become widely available by then.

"We're testing just about any type of alternative fuel vehicle that's available on the marketplace. We're studying and watching very carefully at what would be the next appropriate vehicle to purchase," Pulcrano said.

Some of those alternatives are vastly different from a typical carrier vehicle. For instance, the Postal Service is testing three-wheeled, low-speed electric vehicles in three states — California, Arizona and Florida. The vehicles travel 15 mph and are deployed near post offices where carriers can ride on bicycle or golf cart paths. The vehicles run on lithium ion batteries and cost 4 cents per hour to charge.

The Postal Service this year became the first federal agency to publish a study of its greenhouse gas emissions and to report on its efforts to become environmentally sustainable. In fiscal 2009, the agency rolled out green teams at its headquarters and in its eight area offices to tackle reductions in electricity, petroleum, consumables, water and solid waste. Costs were reduced $2.1 million at headquarters and $5 million across the eight area offices combined.