Despite rapidly falling diesel fuel costs, waste haulers are sticking to their plans to will continue to use compressed natural gas (CNG) and liquefied natural gas (LNG) to power their fleets.

Clean Energy Fuels Corp. in Newport Beach, Calif., works with more than 100 different waste haulers across the country and is seeing continued cost-savings and demand for CNG.

“Fleets are still saving up to $1 per gallon-equivalent by using cleaner-burning natural gas,” says Patric Rayburn, corporate communications manager for Clean Energy Fuels Corp.

“Our objective to convert to CNG has not changed and is a key objective for Waste Pro’s long term future,” says Harland Chadbourne, Waste Pro USA purchasing director. “We believe that diesel prices will remain low for a while but will come back to a higher price range in the future.”

Waste Pro USA, based in Longwood, Fla., currently has more than 2,000 vehicles in its fleet. About 190 trucks, or 10 percent of its fleet, are CNG-powered. Chadbourne says the company purchases about 100 CNG vehicles a year, and will continue to do so for the next three years.

Meanwhile, at of the end this month, Houston-based Waste Management is on track to have more than 4,000 of its fleet of 18,000 vehicles using CNG and LNG fuels.

“(The company) understands the volatility of oil prices and we remain committed to our strategy of transitioning at least 90 percent of our fleet to natural gas vehicles,” says Marty Tufte, Waste Management corporate fleet director. “There are a number of significant benefits we, our customers and communities see from our use of natural gas fueled trucks.”

Those benefits include reducing greenhouse gas emissions by about 22 metric tons per year for each diesel truck that is replaced with a CNG-powered vehicle. The trucks also are quieter than diesel and cut smog-producing nitrogen oxide emissions by up to 50 percent compared to the cleanest diesel trucks, Tufte says.

“By using natural gas our trucks emit minimal amounts of carbon monoxide and nitrogen oxide into the environment,” Chadbourne adds. “Also, there have been federal, state, and regional programs that support the purchase of natural gas fuel and alternative fuel vehicles.”

Russ Knocke, director of field communications and public affairs for Phoenix-based Republic Services, says the company also will continue to use CNG.

“The technology can be less complex than diesel emission after-treatment counterparts. CNG engines are generally quieter to operate, which customers appreciate. CNG fuel is a domestic source that continues to offer fuel savings. It also can enhance driver productivity with on-site and overnight fueling options,” he said.

Republic Services has about 15,400 vehicles in its fleet, with more than 2,200, or about 14 percent, using CNG.

“We plan to add more than 200 this calendar year, and we are evaluating the possibility of continuing or increasing that pace in subsequent years,” Knocke says.

In addition to CNG and LNG, Republic Services has been testing hydraulic hybrid technology, and is currently exploring a partnership to purchase an electrically (EV) powered refuse truck.

The company also continues to use bio-diesel at some of its Midwest-based operations, according to Knocke.

Waste Pro USA will continue its use of CNG-powered vehicles, and has no plans to explore other alternative-fuel options.