Oct. 1, 2011

Hydraulic Hybrids: A Success in Ann Arbor

One year after the City of Ann Arbor, Michigan, began using hydraulic hybrid technology in four of its recycling trucks, the investment is paying off with fuel savings, lower maintenance costs, and increased productivity.

American Recovery and Reinvestment Act funding was provided through the Ann Arbor-based nonprofit Clean Energy Coalition, which manages both the Ann Arbor and Detroit Area Clean Cities coalitions. The funding helped defray the incremental costs when the city purchased the hydraulic hybrid recycling trucks to launch its single stream recycling program in July 2010.

The innovative trucks are built using a technology pioneered by the U.S. Environmental Protection Agency's National Vehicle and Fuel Emissions Laboratory, also based in Ann Arbor. The City of Ann Arbor was one of the first municipalities in the country to deploy this advanced vehicle technology, which uses hydraulic tanks to store energy that would otherwise be lost to braking. The stored energy is then used to power the vehicle when it moves again.

This regeneration of braking energy improves fuel economy by 15%, saving the city almost 1,800 gallons of fuel each year. The hydraulic regenerative braking system also means huge savings in brake maintenance. Normally, a truck that stops and starts frequently (like a refuse truck does) requires replacement brakes several times a year. The new technology significantly increases the life span of brakes: In the year that Ann Arbor has been using the trucks, the brakes have never had to be replaced. That's an annual savings of almost $12,000.