Denver couldn’t refuse opportunity to test hybrid-hydraulic trash truck

At a time when city managers across the country are grappling with record-high fuel prices, officials with the city and county of Denver are hopeful that the hybrid-hydraulic truck will save gasoline while lowering maintenance costs and reducing emissions.

“With its potential to increase fuel efficiency and improve air quality, this hybrid trash truck epitomizes the Mile High City’s commitment to environmental responsibility,” Denver Public Works Manager Bill Vidal said.

The refuse truck was manufactured by Denton, Texas-based Peterbilt Motors Co. and uses Eaton Corp.’s Hydraulic Launch Assist technology. The technology recovers energy normally lost as heat by the vehicle’s brakes and stores the energy in the form of pressurized hydraulic fluid utilized when the driver accelerates. Hydraulics help slow the vehicle as well. 

Since the operator is engaging the hydraulic system during stop-and-go driving, less diesel fuel is consumed and emissions are reduced. Brake-life also is expected to double.

The new hybrid-hydraulic trash truck replaces an old refuse unit that was due to be retired in 2008. Since the trash truck is considered a test unit, Denver paid nothing extra for the hybrid technology, which is valued at about $38,000, according to the city and county of Denver. 

City and company officials will be gathering fuel data and monitoring vehicle performance and brake wear in Denver’s high-altitude, cold-climate conditions. Peterbilt is testing about a dozen of the trucks in 2008, but Denver’s unit is the only one operating outside of Texas.

“If this hybrid trash truck goes 15 to 30 percent farther on a gallon of fuel, the monetary savings with a fleet of these units could be dramatic,” Denver Fleet Maintenance Director Ernie Ivy said.

Newest addition to Denver’s green fleet

The hybrid trash truck is just the latest addition to Denver’s ever-expanding green fleet. The city:

• Has 120 hybrid-electric vehicles.
  
• Uses alternatives fuels including propane and E85 and runs its entire fleet of diesel units (about 1,000 of them) on cleaner-burning biodiesel fuel.
  
• Used grant money to retrofit more than 80 vehicles/off-road equipment with emissions-control technology.
  
• Used grant money to install pre-heaters on 17 refuse trucks to reduce cold-weather idling time and associated emissions.
  
• Reduced hazardous waste generation at the Fleet Maintenance Division by 1 ton in 2007 with the purchase environmentally sound parts washers.
  
• Utilizes water-based automotive paint free of hazardous air pollutants.

“The ‘Green Machine’ is right in line with Denver’s Greenprint rogram,” said Michele Weingarden, director of Greenprint Denver, the city’s action plan for sustainable practices. “Public Works continues to find new and innovative ways to reduce greenhouse gas emissions, which support Denver’s climate action plan.”