In alliance with state and local governments, public interest groups, and industry partners, the Environmental Protection Agency (EPA) has established a goal of reducing emissions from the more than 11 million diesel engines in the existing fleet by 2014.
Diesel exhaust is a proven health risk to humans, particularly the elderly and children with asthma and other respiratory problems. The large amounts of nitrogen oxides (NOx), particulate matter (PM), and other pollutants emitted by diesel exhaust causes lung damage, cancer, premature death and aggravates conditions such as asthma and bronchitis.
According to John Millett, an EPA spokesman, one of its principal goals is to reduce diesel emissions from heavy equipment, trucks and buses by lowering sulfur in diesel fuel, which will allow a new generation of cleaner burning engines.
“The availability of ultralow-sulfur diesel fuel will result in the widespread introduction of emission control systems on newly built diesel engines,” Millett said, “These new fuel and engine standards are comparable to the phase out of lead in gas which allowed the addition of catalytic converters to cars in the 1970s.”
The new fleet of clean diesel engines should reduce NOx and PM emissions by more than 90 percent.
“This is important because on hot sunny days, NOx can combine with volatile organic compounds in the air and create ground level ozone [smog],” Millett said. “Diesels also can directly emit fine particles or fine particles can form from these emissions. At elevated levels, both pollutants can pose serious health threats.”
He said refiners and fuel suppliers are working toward the goal of reducing sulfur in highway fuel diesel to 15 parts per million by the summer of 2006 and cleaner off-road diesel equipment will start being phased in by 2011.
Historically, efforts to reduce hazardous emission from diesel fuel was driven by the 1990 Clean Air Act, which set the air quality standards and acceptable limits of emissions.
However, in May 2004, the EPA adopted a comprehensive national program to improve air quality — The Clean Air Rules of 2004.
As part of that effort, the National Clean Diesel Campaign (NCDC) was created to target reductions of pollution emitted from diesel engines.
The principle strategies of the campaign include:
• Successful implementation of the 2007 highway engine rule 22.2
• Successful implementation of the Clean Air Non-road Diesel Rule
• Developing new emissions standards for locomotive and marine diesel engines
• Promoting the reduction of emissions for existing diesel engines
The Clean Air Non-road Diesel Rule was incorporated into this plan because non-road diesel engines contribute greatly to air pollution in many of the nation’s cities and towns. This rule sets emission standards for the engines used in most construction, agricultural and industrial equipment, along with adopting non-road diesel fuel requirements to decrease the allowable levels of sulfur, which can damage advanced emission control technologies.
The most recent non-road engine and fuel regulations complement regulations for diesel highway trucks and buses and highway diesel fuel for 2007. It will allow advanced emission control systems to be used on the engines used in construction, agricultural, industrial and airport service equipment.
These measures will apply to most non-road diesel fuel by 2010 and to fuel used in locomotives and marine vessels by 2012.
One State’s Efforts
In the early 1990s, North Carolina began looking at alternative fuels for its public fleet of diesel operated vehicles as a way of lowering emissions, particularly in areas of the state with non-attainment levels of air quality.
According to Bruce Thompson, specification and procurement manager for the North Carolina Department of Transportation (NCDOT), and 33 of the 100 counties in North Carolina are non-attainment.
According to Drew Harbinson, director of NCDOT’s equipment and inventory control unit, the conversion of the public fleet to the use of alternative fuels was driven by the 1990 Clean Air Act and the 1992 EPAC Energy Act, which attempts to limit the dependence of the United States on foreign oil.
“The primary form of alternative fuel chosen for our diesel powered fleet is bio-diesel fuel,” Harbinson said. “It is a B-20 blended fuel made of virgin soy-based oil, mixed with stranded diesel fuel. It typically reduces PM by 19 to 21 percent. The downside to using bio-diesel is it slightly increases the NOx levels by approximately 3 percent. We are currently sponsoring research through North Carolina State University for ways to reduce the NOx levels of bio-diesel as well.”
NCDOT obtains its fuel from World Energy and the Potter Oil Company of North Carolina. It uses approximately 2.5 million gallons of bio-fuel diesel each year.
“Converting to bio-diesel fuel is quite simple and it can be used in any standard diesel engine regardless of when it was manufactured,” Harbinson said. “All that is required is a filter change at the pump and the fuel filter on the unit using the bio-diesel after the first tank full is burned. This is required because the soy product acts as a cleaning agent in the dispensing and fuel systems. The filters tend to clog with residue left from years of burning regular diesel fuel.
By 2006, North Carolina expects to switch completely over to ultralow sulfur diesel fuel, Harbinson emphasized.
Its fleet also uses propane and compressed natural gas (CNG).
An Expensive Proposition
“CNG is probably the cleanest fuel available, but, because of the retrofit and infrastructure cost, was not chosen as the primary alternative fuel,” Harbinson said. “Conversion of each of the 122 NCDOT fuel sites to ’fast fill’ CNG fueling sites would have cost approximately $400,000 per site. To retrofit each of the approximate 15,000 pieces of on- and off-road equipment would have cost an additional $8,000 to $15,000 to convert,” Harbinson explained.
NCDOT’s gasoline powered equipment is being run with E-85, a blend of ethanol and gasoline. as the alternative fuel of choice.
Examples of equipment using the alternative fuel include a 1500 series Silverado Chevrolet E-85 flex fuel pickup truck. In previous years, NCDOT purchased F150 Ford bi-fuel pickup trucks that used gasoline or propane. The CNG powered units were F150 Ford bi-fuel pickups that were retrofitted units.
“The future of alternative fuels appears to be leaning towards hybrid electric and hydrogen driven vehicles,” Harbinson said. “In the next eight to 10 years, we will see major changes in fuel and engine technologies which may eventually lead to the industry moving away from diesel driven to hydrogen driven heavy construction equipment.”
What ever the path, Harbinson is sure of the end result.
“One thing is for sure, reduction of harmful emissions being produced from on- and off-road heavy construction equipment will continue as new standards are implemented and as new fuel and engine technologies improve.”
However, he doesn’t see the industry moving completely away from diesel powered equipment for many years to come.
“It appears that General Motors, Ford and Chrysler will continue to experiment with hybrid units,” Harbinson added. “As fuel cell technology advances and as the infrastructure for distributing and dispensing alternative fuels expands we will see a gradual shift away from traditional fossil fuels.”
According to Millett, EPA estimates that by the year 2030 most of the current fleet of off-road vehicles will be retired and the implementation of low emission standards will be in place. EPA estimates this will annually prevent up to 12,000 premature deaths, 1 million lost work days, 15,000 heart attacks and 6,000 children’s asthma-related emergency room visits.
According to the EPA, recent data shows that nationally, approximately 160 million people live in non-attainment areas for ground-level ozone. Approximately 65 million people live in areas that violate air quality standards for PM.
The EPA estimates that by 2030, when the engine fleet has been fully turned over, PM and NOx will be reduced by 250,000 tons/year and 4 million tons/year, respectively.
“Another significant benefit is that by reducing PM, sulfur, nitrogen and ultimately ground level ozone in areas meeting federal air quality standards, we help those communities continue to breathe clean air,” Millett said.