DENVER - At a time when city managers across the country are grappling with record high fuel prices, the City and County of Denver is preparing to test one of the nation’s first hybrid-hydraulic trash trucks expected to result in fuel savings, lower maintenance costs, and reduced 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,” said Denver Public Works Manager Bill Vidal.

Denver’s 115 refuse trucks travel an average of 8,400 miles a year and get about 2.3 miles to the gallon. With fuel prices at all-time highs, Denver is welcoming the opportunity for cost savings within its heavy duty truck fleet. “If this hybrid trash truck goes 15-30% percent further on a gallon of fuel, the monetary savings with a fleet of these units could be dramatic,” said Fleet Maintenance Director Ernie Ivy.

In addition to saving money, Denver will be realizing emissions reductions with its new heavy-duty hybrid trash truck – a goal strongly supported by Mayor John Hickenlooper’s Greenprint Denver initiative. “The Green Machine is right in line with Denver’s Greenprint Program,” said Michele Weingarden, “Public Works continues to find new and innovative ways to reduce greenhouse gas emissions, which support Denver’s Climate Action Plan.”


How the Hybrid-Hydraulic Technology Works

In contrast to hybrid-electric technology, Denver’s “green machine” utilizes hybrid-hydraulic technology ideal for stop-and-go trash collection operations.  The hybrid-hydraulic system 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 is also expected to double. Peterbilt Motors Company manufactured the refuse truck utilizing Eaton Corporation’s Hydraulic Launch Assist (HLA) technology.

Newest Addition to Denver’s Green Fleet

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

  • Has 120 hybrid-electric vehicles
  • Utilizes alternatives fuels including propane and E-85 and runs its entire fleet of diesel units (about 1,000 of them) on cleaner-burning biodiesel fuel
  • Utilized 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 one ton in 2007 with the purchase environmentally sound parts washers
  • Utilizes water-based automotive paint free of hazardous air pollutants

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 as about $38,000. The City and the truck’s manufacturers will be gathering fuel data and monitoring vehicle performance and brake wear in Denvers 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.