Proposal:

AQMD Position Regarding U.S. Department of Energy’s Proposed Greater Utilization of Diesel Engines for Sport Utility Vehicles

Synopsis:

The U.S. Department of Energy has proposed greater utilization of diesel engines in the growing sport utility sector of the vehicle market to enhance energy efficiency and help reduce global warming. However, air pollution concerns associated with diesel emissions must be addressed. This action is to adopt a position to encourage federal agencies to assess air quality impacts of the program, and to promote advancement of engine design, exhaust treatment and clean fuel usage to meet emission requirements.

Committee:

Technology, February 28, 1997, Recommended for Approval

Recommended Action:

Adopt a position to encourage federal agencies to assess the air quality impacts of the U.S. Department of Energy’s proposal to increase utilization of diesel engines for sport utility vehicles, and to promote advancement of engine design, exhaust treatment and clean fuel usage to meet emission requirements.

James M. Lents, Ph.D.
Executive Officer

Background

The sport utility vehicle (SUV) market in the U.S. has been growing at a faster rate than any other segment of the automotive industry. Almost every vehicle manufacturer produces at least one model of SUV and, due to consumer demand, the trend is towards production of roomier, more powerful vehicles, utilizing large engines with relatively poor fuel economy. As a result, SUV product lines tend to lower manufacturers’ overall Corporate Average Fuel Economy (CAFE) standings, in turn affecting the applicability of federal "gas guzzler" taxes.

In an effort to address CAFE as well as other important issues such as global warming and energy independence, the U.S. Department of Energy (DOE) and the vehicle manufacturers have embarked on an ambitious program to promote the commercialization of diesel-fueled SUVs within five years. The program hopes to achieve ultra-low emission levels from lighter diesel engines, primarily by "down-sizing" emission control technologies originally developed for heavy-duty diesel engines. A report prepared for the AQMD by policy consultant Bob Rose (attachment) includes additional information and has a more detailed analysis.

Heavy-duty trucks and SUVs are expected to account for the most growth in vehicle-related energy use over the next decade. Therefore, it is critical that emissions from these vehicles be controlled to the lowest levels technologically feasible. The DOE program would dramatically increase the number of diesel-fueled vehicles in the fleet, and there could thus be a negative air quality impact because of increased NO_x, particulates, and toxics emissions. It is important that prior to implementing this commercialization plan, a detailed assessment of such impacts be completed. In addition, because of health concerns associated with diesel emissions, additional emphasis is needed in the areas of engine design, exhaust treatment, and use of clean fuels to meet emission requirements.

The following discussion is intended as an overview of possible implications associated with increased commercial penetration of diesel-fueled SUVs.

Characteristics of Diesel Vehicles

Compression ignition diesel-fueled engines are more durable and more energy efficient than their gasoline counterparts. As a result, they produce lower emissions of HC, CO, and CO₂, while yielding better vehicle mileage. Advanced compression ignition engines appear to be one of the leading technologies under consideration by the national Partnership for a New Generation of Vehicles as showing promise for meeting a 10-year goal of tripling automobile mileage. However, diesel-fueled engines produce higher emissions of NO_x than comparable gasoline engines. In addition, as discussed previously, the combustion of diesel fuel produces much higher emissions of particulates.

Properties of Diesel Exhaust

Whole diesel exhaust is a complex mixture of gases, vapors, and fine particles in a wide range of organic and inorganic compounds. It contains harmful substances such as CO, NO_x, SO_x, HC, particulate matter, aldehydes, ketones, sulfates, cyanides, phenols, metals and ammonia. Some of the exhaust components, such as arsenic, benzene and nickel, are known to cause cancer in humans, and at least 38 other components of the exhaust, including substances like benzo[a]pyrene, 1,3-butadiene, and formaldehyde, have been listed as Toxic Air Contaminants by the ARB and as hazardous air pollutants by the EPA. Most of the particulate emissions are very small in size (less than 1 µm) in size and are both readily inhalable and a major source of ambient fine particulate matter (PM).

According to the ARB, approximately 58,000 tons of diesel exhaust PM are emitted each year in California. This represents approximately 24 percent of the statewide PM emissions from all fuel combustion sources. There is an increasing concern about adverse public health impacts of diesel exhaust, including both ambient PM effects and potential cancer risk. The primary reason for the proposed revision of national ambient air quality standards (NAAQS) for PM (PM_2.5) is the observed association of increased morbidity and premature mortality with ambient levels of PM below the current NAAQS levels. The morbidity effects of concern include exacerbation of preexisting disease, increase in hospital admissions and emergency room visits, respiratory symptoms, and altered lung defense, all of which tend to have a high impact on public health and health care utilization. In addition, with the introduction of more diesel-fueled vehicles to the fleet, it will be still more difficult to meet the proposed NAAQS for PM_2.5.

Diesel exhaust is considered a potential or a probable human carcinogen by several health agencies, including the National Institute of Occupational Safety and Health and the International Agency for Research on Cancer. The EPA has also proposed a similar consideration. In California, the Office of Environmental Health and Hazard Assessment and the ARB have initiated the process of identifying diesel exhaust as a Toxic Air Contaminant.

Proposal

As mentioned in the attachment, DOE and vehicle manufacturer efforts currently underway to promote diesel-fueled SUVs seem to be taking place rather quietly. At this time, regulatory agencies and legislators do not seem to be aware of, or have been slow to react to, these commercialization plans. It is possible that without proper public notification and education, diesel-fueled SUVs will be built and introduced into the market before appropriate analysis is conducted, and/or before needed control technologies are developed. This trend may even extend into the passenger car segment. It is therefore proposed that the Board adopt a position to encourage federal agencies to assess the air quality impacts of the DOE proposal to increase utilization of diesel engines, and to promote advancement of engine design, exhaust treatment and clean fuel usage to meet emission requirements.

Attachment

Report from Bob Rose, Policy Consultant

/ / /

Attachment

Rose Communications, Inc. 1625 K Street, NW, #790
Robert Rose Washington, DC 20006

Phone: 202/293-7800
Fax: 202/293-7808

MEMORANDUM

TO: Chung Liu
FROM: Bob Rose
DATE: February 13, 1997
SUBJECT: Diesel for Passenger Vehicles

Summary

Two Department of Energy (DOE) programs support the development of advanced diesel engines for passenger vehicles. DOE has a small but ambitious program to support the commercialization of these engines in Sport Utility Vehicles (SUV) "within five years," primarily by down-sizing technology developed to reduce emissions from heavy duty diesel engines. In the longer term, the Partnership for a New Generation of Vehicles (PNGV) includes advanced compression ignition engines as perhaps its leading technology for meeting a 10-year goal of tripling auto gasoline mileage.

There is also abundant evidence that the industry itself has been moving in the direction of diesel regardless of federal R&D support.

Regulators at the Environmental Protection Agency (EPA) are just turning their attention to the implications of these developments, and have expressed misgivings while not taking a position in active opposition. EPA believes diesel technologies might be acceptable given reformulated or alternative fuels. EPA has vowed not to relax emission standards.

The health and environmental communities have only a superficial knowledge of the trend toward diesel and to the extent they know of it, they believe it is connected solely to PNGV. There is a similar lack of knowledge in Congress.

A shift to diesel engines would have significant implications for the District. Diesel powered passenger cars make up virtually none of the current particulate, NOx or air toxic inventory at present. While developers claim to be able to meet "Ultra Low Emission Vehicles (ULEV) equivalent" standards via engine design improvements and aftertreatment, the technologies are not yet demonstrated.

DOE Programs

DOE has a relatively small but ambitious program to support the commercialization of diesel engines in SUVs, vans and light trucks "within five years," primarily by down-sizing technology developed to reduce emissions from heavy duty diesel engines. DOE's support is based on the belief that these engines will yield double the energy efficiency of gasoline engines in the same application.

The program is managed by the newly formed "Office of Heavy Vehicle Technologies." The FY 1997 budget supporting diesel is $19.5 million, most of which is matched by the engine manufacturers. The three major engine companies (Penske, Cummins and Caterpillar) all are enthusiastic supporters. President Clinton has asked $18 million for the diesel program in FY 1998, and requested another $40.4 million for various biofuels R&D programs, including "biodiesel."

The program goal is increased SUV fuel economy with ULEV-level emissions, achieved by applying knowledge gained in controlling heavy duty engines to EPA's 1998 standards. DOE's emission research focuses on plasma technologies that reduce particulate and NOx simultaneously. DOE is not addressing toxic emissions.

In the PNGV, advanced compression ignition, direct injection (CIDI) engines are one of the candidate technologies for meeting a goal of tripling auto gasoline mileage in 2003-2004. PNGV spending on diesel is $30 million in 1997 (including development work being done at EPA's Ann Arbor lab). NOx emissions and engine weight are listed as the key technical barriers. PNGV is financing work on "lean NOx" catalysts as a possible exhaust gas treatment for diesel. It is widely believed CIDI technology will be the "winner" when PNGV managers "downselect" a technology later this year to be the focus of advanced engineering and demonstration vehicle activity. (Given the interest in fuel cells, there likely will be more than one winner.)

Big Three

There is also abundant evidence that the industry itself would be moving in the direction of diesel fueled compression ignition engines and turbines even without Federal financial support. Here are a few reasons:

• Every engine company and every major exhaust treatment technology manufacturer has been working for nearly a decade now on engine modifications, "traps" and tailpipe systems to meet the current heavy duty particulate and NOx emissions standards. The new body of knowledge is substantial. New "breakthrough" technologies are announced almost weekly.

• Given development costs, it is only natural the engine companies will try to maximize the application of the technologies they develop.

• Negotiated heavy duty standards for 2004 and beyond now appear easily in reach of the new technologies, offering the engine companies a "breathing space" and the time to look toward new markets.

• Europe is in love with diesel for its energy efficiency. (One can purchase a production Audi in Europe that claims more than 80 m.p.g.) Consumers benefit from lower operating costs. Regulators, who are pushed harder on CO2 reductions than on smog, have embraced diesel as a viable short term CO2 reduction technology.

• While Chrysler stole much of the press attention at the Detroit auto show in unveiling its model of a fuel cell vehicle, General Motors (GM) was unveiling its 2.2 liter, direct injection diesel engine, which will "debut [commercially] in the near future."

• GM executive vice president Louis R. Hughes said the engine "has a very significant immediate market potential virtually everywhere in the world. Should conditions change in the United States," Hughes said, "GM is ready to integrate this engine into North American products as well." Hughes elsewhere has called for a relaxation of U.S. diesel engine emission standards.

• GM also announced tentative plans to produce a "saleable" hybrid vehicle using a small turbine engine, with diesel fuel the leading candidate to power the engine.

Regulatory Agencies

The Environmental Protection Agency is only now turning its attention to the implications of these technologies, and has expressed grave misgivings while not taking a position in active opposition. EPA has high hopes that dimethyl ether used as a diesel fuel will be the "magic bullet" that solves the diesel emissions problem. Indeed, EPA in Ann Arbor is working actively on diesel engine development, with alternative fuels in mind. EPA has vowed not to relax emission requirements.

The potential impact of toxic emissions is not high on EPA's agenda, though the impact of emissions increases has not been examined. Tailpipe treatment manufacturers have some data suggesting that toxic constituents of diesel exhaust are effectively destroyed by the add-on cleanup devices.

State and local air quality officials have only a preliminary understanding that the auto industry is turning again toward diesel, and has even less data on the potential burden this might place on them should the proposed tightening of National Ambient Air Quality Standards (NAAQS) particulate and ozone standards be approved.

Emissions Considerations

Light duty diesels can meet European standards because those standards use a "HC+NOx" approach. Significantly, EPA is adopting this approach in its pending 2004 heavy duty engine standards. A change in the light duty standard would open the door for diesels in the US.

In the US, light duty diesel standards are set at 1.0 grams per mile (gpm) through 2003. A policy that extended this "NOx waiver" beyond 2003 might be sufficient to allow diesels into the US market. At the most recent North American Motor Vehicle Control Conference, Charles Gray showed results of engine tests at EPA in Ann Arbor that suggest the new light duty diesel engines can operate at or near 1.0 gpm NOx over most of their operating range.

Light duty vehicles are only 20 percent of the current NOx inventory, and less than 4 percent of the current PM10 inventory. Gray made the following projection: should diesel engines increase to 40 percent of the light duty VMT in the year 2020, they would become the dominant source of mobile source PM (44% of the inventory v. 13% for heavy duty on-road and 34% of off-road).

Sales of SUVs, vans and light trucks (under 6,000 pounds) totaled 4.4 million in 1995, compared to 6.1 million passenger cars.

Case for Diesels

The best arguments supporting a switch to diesel engines in light trucks and eventually cars are as follows:

1. Increased fuel economy. We heard one off-hand estimate that diesel engines would increase the fuel economy of a SUV from 17 miles per gallon to 25 miles per gallon. Such an improvement would be significant in energy conservation terms and would help auto manufacturers meet corporate fleet average fuel economy standards that have proved increasingly difficult to achieve.

2. Lower CO2 emissions. Higher engine efficiency will lead to lower CO2 emissions per mile. Thus a shift to diesel will help stabilize and ultimately reduce CO2 emissions to combat global warming.

3. Better durability. Proponents argue that since diesel engines are more sturdy they should deteriorate less in use than conventional gasoline engines. (Diesel engines must be built to withstand higher compression ratios.) A forthcoming study by Argonne National Laboratory will conclude that after the first year, even conventional diesel engines have lower emissions in use than gasoline engines.

4. Diesels can be "clean." This argument relies not only on impressive improvements in engine design but also on the emergence of advanced aftertreatment technologies which are still untried and which, in some cases, are still in the lab.

Concerns

Major concerns about diesel engines are

• their current inability to meet even the relaxed current light duty vehicle standards;
• the lack of demonstrated "clean" engines or technologies;
• engineering and infrastructure considerations with alternative fuels;
• the unquantified impact on air quality of a shift in the PM and NOx inventories; and
• the unknown impact of toxic emissions on public health.

Interest Groups

The health and environmental communities have only a superficial knowledge of the trend toward diesel. To the extent they know of it, they believe it is connected to PNGV. The SUV program is completely outside their view. Major environmental organizations are giving consideration to opposing future funding of PNGV. In the Northeast, where interest groups have been most active in promoting California light duty vehicle standards and Zero Emission Vehicles, and where there is an active "dump diesel" program, the leading regional organizations had no knowledge of the SUV program.

Congress

Congress is generally unaware of the move to diesels. The auto industry has not begun a visible education campaign oriented toward legislation.

Conclusions

Any additional emissions from diesel vehicles would provide a challenge to regulators, a challenge exacerbated by the pending NAAQS changes. Yet the development of diesel engines as an alternative for passenger vehicles is a virtual "stealth" program at present. The South Coast Air Quality Management District may wish to facilitate a public discussion of the implications of the potential switch to diesel for passenger vehicles.