Report Calls for Separate Emissions Rule for Heavy Trucks Powered by Natural Gas

This story appears in the April 14 print edition of Transport Topics.

Federal regulators should develop a separate standard for natural gas-powered vehicles when they finalize the second phase of the government’s emissions reduction and fuel-efficiency standards for medium- and heavy-duty trucks, according to a new report by the National Research Council of the National Academy of Sciences.

Released April 3, the report’s recommendations are intended to assist federal regulators in finding ways to lower greenhouse-gas emissions and to improve fuel efficiency as they develop the new Phase 2 rule.

The joint rule of the National Highway Traffic Safety Administration and Environmental Protection Agency is due to be finalized in March 2016, but not likely take effect until 2020.

Although the report encourages the use of natural gas as a transportation fuel, because of its low carbon content compared with diesel, it does not go so far as to suggest that the natural-gas emissions and fuel-efficiency standard be relaxed, said Andrew Brown Jr., committee chairman and executive director and chief technologist at Delphi Corp.

“It’s not so much as to give natural gas a leg up,” Brown told Transport Topics on April 9. “The abundance of natural gas has really made it a viable alternative, especially for commercial vehicles.”

But there are concerns about methane leakage as high as 3% during the production and transmission process, Brown said.

“So the reductions in greenhouse-gas emissions and fuel consumption could be offset by this leakage,” Brown said.

For that reason, the issue needs more study to be sure that regulators understand the implications of using natural gas in commercial vehicles, Brown said.

“We’re not suggesting that we hold off on using natural gas until the results of those studies are available,” Brown said. “We need to encourage the Department of Energy, NHTSA and EPA to do more research and development, and do that concurrent with their rulemaking.”

NRC’s research, mandated by Congress to be conducted every five years, was released nearly two years early so its recommendations could be considered for incorporation in the Phase 2 rule.

The Phase 1 rule, which began taking effect this year, incorporated some of the ideas outlined in NRC’s first report, released in 2010.

The plan for the second phase, announced Feb. 14 by President Obama, will demand even tougher carbon dioxide emissions and fuel-consumption improvements in heavy- and medium-duty trucks.

The NRC report touts natural gas as a promising technology for several reasons including its relatively low carbon content — releasing from 5% to 20% less CO2 than diesel fuel engine emissions, according to the report.

“Currently, natural-gas engines are well-developed although improvements can be pursued in engine efficiency, maintenance costs, and onboard vehicle storage costs,” the report said.

Richard Kolodziej, president of Natural Gas Vehicles for America, said the report increases the focus on alternative-fuel vehicles.

“We’re looking at it now,” Kolodziej told Transport Topics on April 8. “It’s obviously very supportive.”

But Kolodziej said he was uncertain whether a separate standard would be advantageous for broadening the use of natural-gas trucks. “There are some things in the diesel and gasoline standards that are good for us,” Kolodziej said.

One of the challenges is improving fuel consumption in natural-gas vehicles, he said.

“We have been doing catch-up on fuel-efficiency technology,” Kolodziej said. “Diesel has been around 100 years, and they’ve honed that technology.”

The report also noted some of the biggest obstacles to natural-gas use for longhaul freight transportation are the lack of widespread and dependable infrastructure, the substantial increase in weight and cost of fuel tanks compared with diesel tanks and the availability of natural-gas vehicles.

The report said the federal government should consider adopting regulations to require the use of such trailer aerodynamics as side skirts, tails and trailer gaps that the report said can provide

a full return on investment through fuel savings in about one year, on average.

Currently, the majority of trailer owners do not use the fuel-saving devices, the report said.

“When a trailer is not owned by the tractor owner-operator, who pays for fuel, there is little incentive for the trailer owner to purchase fuel-saving devices,” the report said.

Glen Kedzie, energy and environmental affairs counsel for American Trucking Associations, said he already is in discussions with engine makers and natural-gas executives about the Phase 2 rule.

“Our assessment is that the NAS panel desires to promote increased use of natural-gas trucks under Phase 2. However, the panel is also being extremely cautious in its recommendation by seeking further study of the life cycle carbon emission associated with the use of such fuel,” Kedzie added.