USPS - California Hybrid Tests in Progress
PE Helps Postal Service Innovate In Alternative Fuel
p.e.© Published by the National Society of Professional Engineers,
2007 January - February
As gasoline prices have risen in the past few years, alternative energy sources have been receiving increased attention. However, the U.S. Postal Service has been innovating in this arena long before it became popular.
The first electric mail truck was commis-sioned in 1899 in New York City, explains Han Dinh, P.E., the organization’s program director of vehicle engineering. Since then, the Postal Service has continued to investi-gate alternative energy technologies, using compressed natural gas, ethanol, propane, and biodiesel. It is also experimenting with electric, hybrid electric, and hydrogen fuel cell vehicles.
Such technologies, says the NSPE member, help the Postal Service decrease air pollution and dependence on foreign oil. They also help reduce costs. With the largest vehicle fleet in the nation—210,000 vehicles—energy is a major concern for the Postal Service. It is the third-largest cost center after salaries and benefits and automation.
Additional motivation for the Postal Service’s alterna-tive energy programs came from the 1992 Energy Policy Act. The law mandated that beginning in 1999, 75% of newly acquired federal fleet vehicles must be powered by alternative fuels. Dinh, who joined the organization in 1988 and helped launch the compressed natural gas program in the early 1990s, explains that the Postal Service began investing heavily in that program following the law’s enactment.
The agency had 7,500 vehicles converted to compressed natural gas operation, making up the largest CNG fleet in the U.S. The program worked well and recouped the cost of the investment, Dinh explains, but the infrastructure is now deteriorating. Because many of the conversion companies have gone bankrupt, it is hard to maintain the vehicles. Thus, the Postal Service is not converting any more vehicles to natural gas, although it has retained more than two-thirds of the original fleet.
In 1993, Dinh established an electric vehicle program to test and evaluate the technology. Subsequently, in 2000, the Postal Service awarded Ford Motor Company what Dinh says is the largest electric vehicle contract in U.S. history, for 500 vehicles. However, just two years later the program had to be abandoned because the batteries were no longer being manufactured. Ford provided replacement vehicles and now only 28 electric vehicles manufactured by Solec-tria are operating in New York City.
Another technology the Postal Service explored in the mid-1990s was propane. Thirty-five vehicles were converted to propane operation and still operate out of Key West, Florida.
The Postal Service has taken advantage of ethanol. Currently, more than 30,000 vehicles in the Postal Service’s fleet can run on ethanol or a combination of ethanol and gasoline. Expansion of the ethanol program is limited, however, by the lack of refueling stations.
As part of the effort to reduce fuel costs, the Postal Service is testing hybrid electric vehicles, including 10 hybrid electric vans in California.
Dinh notes that the incremental costs of hybrid electric vehicles are still fairly high—about $5,000 or more. But the agency will continue to test the tech-nology, he says, hoping that the fuel savings will compensate for the higher cost.
Dinh and the Postal Service have received the most recognition for the agency’s biodiesel program. The organization is one of the first federal agencies to embrace biodiesel as a motor vehicle fuel, Dinh says. Over the last five years, biodiesel consumption in the agency’s fleet has risen from about 400,000 gallons in 2000 to almost 1.2 million gallons in fiscal year 2005. The Postal Service fleet has 1,000 biodiesel vehicles, and the program is slated to expand to other locations.
Dinh and the Postal Service received the 2006 White House Closing the Circle Award, for environmental stewardship in the federal government, for research his team undertook on biodiesel engine wear in 2004. The engineering depart-ment worked with the National Renew-able Energy Labs to compare four vehicles operating on biodiesel with four others with similar mileage operating on conventional diesel. After three years, the department’s team pared down all the vehicles into 1,000 components and evaluated them for structural and mechanical damage, carbon deposits, and other signs of wear.
The results indicated no significant problems with the vehicles operating on biodiesel. That was important because little information existed on the long-term wear of biodiesel vehicles. Dinh’s team is now sharing their findings with other federal agencies and industry organizations.
Dinh sees much promise in the hydrogen fuel cell vehicle. For the past two years, the Postal Service has been testing a General Motors hydrogen fuel cell vehicle in the Washington, D.C., area. That vehicle has delivered more than 650,000 pieces of mail and packages. In September 2006, another hydrogen fuel cell vehicle was added to the Postal Service fleet in Irvine, California.
What needs to happen for more people and organizations to become interested in alternative energy? Dinh says the country will get a wake-up call if the price of gaso-line tops $5 a gallon. Otherwise, he says, Congress will need to pass legislation that forces the nation to increase its indepen-dence from oil.