Energy Conservation - Efficiency In The Transportation Sector

The U.S. transportation system plays a central role in the economy. Highway transportation is dependent on internal combustion engine vehicles fueled almost exclusively by petroleum. The Energy Information Administration (EIA) of the U.S. Department of Energy (DOE) noted in its Annual Energy Review 2003 (2004) that the transportation sector accounted for 27% of all energy consumed in the United States in 2003. That year, Americans used 26.8 quadrillion Btu of energy for transportation (see Figure 1.9 in Chapter 1), of which petroleum made up 97%. Despite improvements in transportation efficiency in recent decades, the EIA's International Energy Outlook 2004 noted that the United States consumed 28% of total energy use for transportation in 2001 and is projected to consume 30% in 2025. This transportation share compares to 17% of total energy use for Canada and 23% for Western Europe.

Automotive Efficiency

Policymakers interested in transportation energy conservation have an array of conservation options. (See Table 9.2.) However, not all options are mutually supportive. For example, efforts to promote a freer flow of automobile traffic, such as high-occupancy vehicle (HOV) lanes or free parking for carpools, may sabotage efforts to shift travelers to mass transit or to reduce trip lengths and frequency. Policymakers must consider how the implementation of one strategy will fit into an overall transportation plan.

In the United States the automobile dominates the transportation sector; cars and light-duty vehicles used 63% of all transportation energy in 2004, as reported by the Bureau of Transportation Statistics in National Transportation Statistics, 2003 (updated September 2004). This report also noted that motor gasoline, which is divided among passenger cars, light and heavy-duty trucks, aircraft, and miscellaneous other modes of transportation, consumed about 67% of the oil used in the United States in 2004. The major growth in fuel use over the past thirty years has been that consumed by pickup trucks, and in more recent years that consumed by vans and sport utility vehicles (SUVs). In 2004 pickup truck, van, and SUV fuel use was approximately 75% of the amount used by automobiles and motorcycles. Meanwhile, automobile fuel use has remained fairly constant because of fuel efficiency increases that have offset the growth in car miles traveled. Boosting truck, van, and SUV efficiency will become increasingly important in holding down oil demand.

THE CORPORATE AVERAGE FUEL ECONOMY (CAFE) STANDARDS. The 1973 OPEC (Organization of the Petroleum Exporting Countries) oil embargo painfully reminded the United States how dependent it had become on foreign sources of fuel. This situation prompted Congress to pass

TABLE 9.2

Transportation conservation options
*U.S. transit subsidies, already among the highest in the developed world, may merely promote inefficiencies.
KEY: CAFE = corporate average fuel economy; E = economic incentive; HOV = highoccupancy vehicle; I = public investment; maglev = trains supported by magnetic levitation; R = regulatory action; RD&D = research, development, and demonstration; vmt = vehicle-miles traveled.
SOURCE: "Table 5-1. Transportation Conservation Options," in Saving Energy in U.S. Transportation, Office of Technology Assessment, 1994, http://www.wws.princeton.edu/cgibin/byteserv.prl/~ota/disk1/1994/9432/943208.PDF (accessed November 17, 2004)
Improve the technical efficiency of vehicles
Higher fuel economy requirements—CAFE standards (R) Reducing congestion: smart highways (E,I), flextime (E,R), better signaling (I), improved maintenance of roadways (I), time of day charges (E), improved air traffic controls (l,R), plus options that reduce vehicular traffic Higher fuel taxes (E) Gas guzzler taxes, or feebate schemes (E) Support for increased R&D (EJ) Inspection and maintenance programs (R)
Increase load factor
HOV lanes (I) Forgiven tolls (E), free parking for carpools (E) Higher fuel taxes (E) Higher charges on other vmt trip-dependent factors (E): parking (taxes, restrictions, end of tax treatment as business cost), tolls, etc.
Change to more efficient modes
Improvements in transit service New technologies—maglev, high speed trains (EJ) Rehabilitation of older systems (I) Expansion of service—more routes, higher frequency (I) Other service improvements (I)—dedicated busways, better security, more bus stop shelters, more comfortable vehicles Higher fuel taxes (E) Reduced transit fares through higher US. transit subsidies (E) Higher charges on other vmt/trip-dependent factors for less efficient modes (E)—tolls, parking Shifting urban form to higher density, more mixed use, greater concentration through zoning changes (R), encouragement of "infill" development (E,R,I), public investment in infrastructure (I), etc.
Reduce number or length of trips
Shifting urban form to higher density, more mixed use, greater concentration (E,R,I) Promoting working at home or at decentralized facilities (EJ) Higher fuel taxes (E) Higher charges on other vmt/trip-dependent factors (E)
Shift to alternative fuels
Fleet requirements for alternative fuel-capable vehicles and actual use of alternative fuels (R) Low-emission/zero emission vehicle (LEV/ZEV) requirements (R) Various promotions (E): CAFE credits, emission credits, tax credits, etc. Higher fuel taxes that do not apply to alternative fuels (E), or subsidies for the alternatives (E) Support for increased R&D (EJ) Public investment—government fleet investments (I)
Freight options
RD&D of technology improvements (E,I)

the 1975 Energy Policy and Conservation Act (PL 94-163), which set the initial Corporate Average Fuel Economy (CAFE) standards. The standards were modified in 1980 with the Automobile Fuel Efficiency Act (PL 96-425).

The CAFE standards required domestic automakers to increase the average mileage of new cars sold to 27.5 miles per gallon (mpg) by 1985. Under CAFE rules, car manufacturers could still sell large, less efficient cars, but to meet the average fuel efficiency rates, they also had to sell smaller, more efficient cars. Automakers that failed to meet each year's CAFE standards were fined. Those that managed to surpass the rates earned credits that they could use in years when they fell below the CAFE requirements. Faced with the CAFE standards, the car companies became more inventive and managed to keep their cars relatively large and roomy while increasing mileage with innovations like electronic fuel injection and using four valves per cylinder.

The CAFE regulations have had a significant effect on fuel efficiency. In the decades since the first oil shock in 1973, the fuel economy of motor vehicles (which includes passenger cars, vans, pickup trucks, SUVs, and trucks) increased from 11.9 mpg in 1973 to 17.0 mpg in 2002. (See Table 9.3.) Greater gains have been made in the economy of passenger cars. In 1974, just after the oil embargo, cars averaged 14.2 mpg (according to the Environmental Protection Agency); in 2003 the average newcar fuel economy was 24.6 mpg. (See Figure 9.3.) The total automobile fleet fuel economy is expected to increase as more fuel-efficient cars enter the market and older, less fuel-efficient autos drop out of the nation's fleet. However, new-car fuel economy has risen only slightly since 1986; since 1988 nearly all gains in automobile efficiency have been offset by increased weight and power in new vehicles.

The Persian Gulf War in 1991 was another strong reminder to the United States of its continuing heavy dependence on foreign oil, prompting some members of Congress to want to raise the CAFE standards to forty-five mpg for cars and thirty-five mpg for light trucks. Those in favor of raising CAFE standards claimed that this would save about 2.8 million barrels of oil per day. They also noted that if cars become even more fuel-efficient in the future, emissions of carbon dioxide would be significantly reduced. The domestic auto industry opposed the bill to raise CAFE standards, and actions to increase automobile efficiency failed in Congress. For model year 2001 passenger cars, the CAFE standard was 27.5 mpg and for light trucks it was 20.7 mpg. The efficiency standard for model year 2005 for light trucks had increased to 21.0 mpg. CAFE standards are set by the National Highway Safety Administration, unless Congress prohibits changes.

SUVs, vans, and pickup trucks make up the "light truck" automotive group, the fastest growing segment of the auto industry. Light trucks accounted for 48% of the U.S. light vehicle market in 2003 (see Figure 9.4) and produced most of the profits of the major auto companies. In 1999 the Environmental Protection Agency (EPA) imposed new regulations tightening emissions standards on cars, minivans, SUVs under 8,500 pounds, and small pickup trucks. This was the first time that SUVs and other light-duty trucks became subject to the same national pollution standards as cars. The standard of an average of

FIGURE 9.3

0.07 grams per mile for nitrogen oxides came into effect in 2004. Standards for hydrocarbons, nitrogen oxides, carbon monoxide, and particulates were phased in beginning in 1999 and ending in 2008.

The potential for savings from increased fuel economy in large trucks is huge, since their current fuel economy is so much lower than that of automobiles. In 2001 the EIA projected a small increase in fuel efficiency for the heavy-truck fleet and a larger (but still small) increase for the small-truck fleet. If the heavy-truck fleet were to reach a fuel efficiency of ten mpg through technological improvements, projected oil demand would drop by 300,000 barrels per day. Over the past few years, aerodynamically designed trucks have become more common on American roads.

Cheap gasoline prices throughout the 1990s took away the sense of urgency surrounding fuel efficiency, which was demonstrated by the high growth of large vehicle sales. In addition, when the federal fifty-five-mph speed limit law was repealed, many states allowed increased speed limits, lowering fuel efficiency. Carmakers have resisted building highly efficient cars, claiming that government mandates would saddle American motorists with car features they would not want and might not buy. In contrast, the European Commission has proposed an ambitious target of forty-seven mpg for gasoline-driven cars

TABLE 9.3

Motor vehicle mileage, fuel consumption, and fuel rates, selected years, 1949–2002
	Passenger cars1			Vans, pickup trucks, and sport utility vehicles2			Trucks3			All motor vehicles4
Year	Mileage (miles per vehicle)	Fuel consumption (gallons per vehicle)	Fuel rate (miles per gallon)	Mileage (miles per vehicle)	Fuel consumption (gallons per vehicle)	Fuel rate (miles per gallon)	Mileage (miles per vehicle)	Fuel consumption (gallons per vehicle)	Fuel rate (miles per gallon)	Mileage (miles per vehicle)	Fuel consumption (gallons per vehicle)	Fuel rate (miles per gallon)
1Through 1989, includes motorcycles.
2Includes a small number of trucks with 2 axles and 4 tires, such as step vans.
3Single-unit trucks with 2 axles and 6 or more tires, and combination trucks.
4Includes buses and motorcycles, which are not separately displayed.
R=Revised.
P=Preliminary.
Web Pages: For data not shown for 1951–1969, see http://www.eia.doe.gov/emeu/aer/enduse.html.
SOURCE: Table 2.8. Motor Vehicle Mileage, Fuel Consumption, and Fuel Rates, Selected Years, 1949–2002," in Annual Energy Review 2003, U.S. Department of Energy, Energy Information Administration, Office of Energy Markets and End Use, September 7, 2004, http://www.eia.doe.gov/emeu/aer/pdf/aer.pdf (accessed September 28, 20
1949	9,388	627	15.0	5	5	5	9,712	1,080	9.0	9,498	726	13.1
1950	9,060	603	15.0	5	5	5	10,316	1,229	8.4	9,321	725	12.8
1955	9,447	645	14.6	5	5	5	10,576	1,293	8.2	9,661	761	12.7
1960	9,518	668	14.3	5	5	5	10,693	1,333	8.0	9,732	784	12.4
1965	9,603	661	14.5	5	5	5	10,851	1,387	7.8	9,826	787	12.5
1970	9,989	737	13.5	8,676	866	10.0	13,565	2,467	5.5	9,976	830	12.0
1971	10,097	743	13.6	9,082	888	10.2	14,117	2,519	5.6	10,133	839	12.1
1972	10,171	754	13.5	9,534	922	10.3	14,780	2,657	5.6	10,279	857	12.0
1973	9,884	737	13.4	9,779	931	10.5	15,370	2,775	5.5	10,099	850	11.9
1974	9,221	677	13.6	9,452	862	11.0	14,995	2,708	5.5	9,493	788	12.0
1975	9,309	665	14.0	9,829	934	10.5	15,167	2,722	5.6	9,627	790	12.2
1976	9,418	681	13.8	10,127	934	10.8	15,438	2,764	5.6	9,774	806	12.1
1977	9,517	676	14.1	10,607	947	11.2	16,700	3,002	5.6	9,978	814	12.3
1978	9,500	665	14.3	10,968	948	11.6	18,045	3,263	5.5	10,077	816	12.4
1979	9,062	620	14.6	10,802	905	11.9	18,502	3,380	5.5	9,722	776	12.5
1980	8,813	551	16.0	10,437	854	12.2	18,736	3,447	5.4	9,458	712	13.3
1981	8,873	538	16.5	10,244	819	12.5	19,016	3,565	5.3	9,477	697	13.6
1982	9,050	535	16.9	10,276	762	13.5	19,931	3,647	5.5	9,644	686	14.1
1983	9,118	534	17.1	10,497	767	13.7	21,083	3,769	5.6	9,760	686	14.2
1984	9,248	530	17.4	11,151	797	14.0	22,550	3,967	5.7	10,017	691	14.5
1985	9,419	538	17.5	10,506	735	14.3	20,597	3,570	5.8	10,020	685	14.6
1986	9,464	543	17.4	10,764	738	14.6	22,143	3,821	5.8	10,143	692	14.7
1987	9,720	539	18.0	11,114	744	14.9	23,349	3,937	5.9	10,453	694	15.1
1988	9,972	531	18.8	11,465	745	15.4	22,485	3,736	6.0	10,721	688	15.6
1989	110,157	1533	119.0	11,676	724	16.1	22,926	3,776	6.1	10,932	688	15.9
1990	10,504	520	20.2	11,902	738	16.1	23,603	3,953	6.0	11,107	677	16.4
1991	10,571	501	21.1	12,245	721	17.0	24,229	4,047	6.0	11,294	669	16.9
1992	10,857	517	21.0	12,381	717	17.3	25,373	4,210	6.0	11,558	683	16.9
1993	10,804	527	20.5	12,430	714	17.4	26,262	4,309	6.1	11,595	693	16.7
1994	10,992	531	20.7	12,156	701	17.3	25,838	4,202	6.1	11,683	698	16.7
1995	11,203	530	21.1	12,018	694	17.3	26,514	4,315	6.1	11,793	700	16.8
1996	11,330	534	21.2	11,811	685	17.2	26,092	4,221	6.2	11,813	700	16.9
1997	11,581	539	21.5	12,115	703	17.2	27,032	4,218	6.4	12,107	711	17.0
1998	11,754	544	21.6	12,173	707	17.2	25,397	4,135	6.1	12,211	721	16.9
1999	11,848	553	21.4	11,957	701	17.0	26,014	4,352	6.0	12,206	732	16.7
2000	11,976	547	21.9	11,672	669	17.4	25,617	4,391	5.8	12,164	720	16.9
2001	R11,831	R534	22.1	R11,204	R636	17.6	R26,602	R4,477	5.9	R11,887	R695	17.1
2002P	12,203	551	22.1	11,365	645	17.6	27,062	4,637	5.8	12,172	715	17.0

FIGURE 9.4

(compared to the current average of twenty-nine mpg) and fifty-two mpg for diesel-powered cars by 2005. The general secretary of the European Council of Automotive Research and Development also announced in January 2001 that all ten European auto manufacturers plan to build cars with low carbon dioxide emissions and high mileage by 2008. In 2004 China issued compulsory fuel efficiency standards for its passenger cars, ruling that fuel consumption in Chinese passenger vehicles must decline by 10%. Cars under production will be granted a one-year grace period to meet the standard.

It must be noted that while European countries do not generally legislate fuel efficiency, the cost of gasoline in Europe is more than twice that in the United States. That serves as a powerful incentive to European drivers to buy fuel-efficient vehicles. Many experts also see Europe as having a history of energy consumption not matched by the United States.

Alternative Fuel Vehicles (AFVs)

MANDATING AFVS. Several laws have been passed to encourage or mandate the use of vehicles powered by fuels other than gasoline. The Clean Air Act Amendments of 1990 (PL 101-549) required certain businesses and local governments with fleets of ten or more vehicles in twenty-one metropolitan areas nationwide to phase in alternative fuel vehicles (AFVs) over time—20% of those fleets had to be AFVs by 1998. While great strides have been made in increasing the use of AFVs, there is no way to determine current compliance with the mandates because reporting and enforcement methods are inadequate.

The Energy Policy Act of 1992 (PL 102-486) was passed in the wake of the 1991 Persian Gulf War to conserve energy and increase the proportion of energy supplied domestically. It required the federal government to purchase 22,500 AFVs by 1995 and increase the percentage of AFV acquisitions from 25% of all acquisitions in 1996 to 75% in 1999 and thereafter. Agency budget cuts and inadequate enforcement have slowed compliance with these regulations. Still, many municipal governments and the U.S. Postal Service have put into operation fleets of natural gas vehicles, such as garbage trucks, transit buses, and postal vans.

NUMBERS AND TYPES OF AFVS. In 1995, 246,855 AFVs were on U.S. roads. Projections for 2004 showed 547,904 AFVs in use. (See Table 9.4.) These totals include vehicles originally manufactured to run on alternative fuels, as well as converted gasoline or diesel vehicles. The manufacture of new AFVs has been steadily increasing.

A number of different types of fuels are used in AFVs:

• Liquefied petroleum gas (LPG) is a mixture of propane and butane. LPG was the most common type of alternative vehicle fuel used in 2004. Thirty-five percent of all AFVs ran on LPG that year.
• Ethanol is ethyl alcohol, a grain alcohol, mixed with gasoline and sold as gasohol. The 85% formulation of gasohol was the second most common AFV fuel, powering 27% of all AFVs in 2004.
• Compressed natural gas (CNG) is natural gas that is stored in pressurized tanks. CNG releases one-tenth the carbon monoxide, hydrocarbon, and nitrogen of gasoline. It was the third most common AFV fuel in 2004, used by 26% of AFVs.
• Electricity, used by 10% of AFVs in 2004, can be used for battery-powered, fuel cell, or hybrid vehicles.
• Methanol is a liquid fuel that can be produced from natural gas, coal, or biomass (plant material, vegetation, or agricultural waste). The 85% formulation of methanol was used by only 0.8% of all AFVs in 2004. Its use is declining.
• Liquefied natural gas (LNG) is natural gas (mostly methane) that has been liquefied by reducing its temperature to -260 degrees Fahrenheit. It was used by only 0.6% of all AFVs in 2004.
• Biodiesels (not listed in Table 9.4) are liquid biofuels made from soybean, rapeseed, or sunflower oil, or from animal tallow. They can also be made from agricultural products, such as rice hulls.

TABLE 9.4

Estimated number of alternative-fueled vehicles in use, by fuel, 1995–2004
									2003	2004	Average annual growth rate (percent)
Fuel	1995	1996	1997	1998	1999	2000	2001	2002	(Projected)
1The remaining portion of 85-percent methanol and both ethanol fuels is gasoline.
2In 1997, some vehicle manufacturers began including E85-fueling capability in certain model lines of vehicles. For 2002, the EIA estimated that The number of E-85 vehicles that are capable of operating on E85, gasoline, or both, is about is 4.1 million. Many of these alternative-fueled vehicles (AFVs) are sold and used as traditional gasoline-powered vehicles. In this tble, AFVs in use include only those E85 vehicles believed to be intended for use as AFVs. These are primarily fleet-operated vehicles.
3Excludes gasoline-electric hybrids.
Notes: Estimates for 2003, in italics, are based on plans or projections. Estimates for historical years may be revised in fututure reports if new information becomes available.
SOURCE: "Table 1. Estimated Number of Alternative-Fueled Vehicles in Use in the United States, by Fuel, 1995–2004," in Alternatives to Traditional Transportation Fuels 2003 Estimated Data, U.S. Department of Energy, Energy Information Administration, February 2004, http://www.eia.doe.gov/cneaf/alternate/page/datatables/afvtable1_03.xls (accessed November 18, 2004)
Liquefied petroleum gases (LPG)	172,806	175,585	175,679	177,183	178,610	181,994	185,053	187,680	190,438	194,389	1.3
Compressed natural gas (CNG)	50,218	60,144	68,571	78,782	91,267	100,750	111,851	120,839	132,988	143,742	12.4
Liquefied natural gas (LNG)	603	663	813	1,172	1,681	2,090	2,576	2,708	3,030	3,134	20.1
Methanol, 85 percent (M85)1	18,319	20,265	21,040	19,648	18,964	10,426	7,827	5,873	4,917	4,592	−14.3
Methanol, neat (M100)	386	172	172	200	198	0	0	0	0	0	0.0
Ethanol, 85 percent (E85)1,2	1,527	4,536	9,130	12,788	24,604	87,570	100,303	120,951	133,776	146,195	78.8
Ethanol, 95 percent (E95)1	136	361	347	14	14	4	0	0	0	0	0.0
Electricity3	2,860	3,280	4,453	5,243	6,964	11,830	17,847	33,047	45,656	55,852	39.1
Non-LPG subtotal	74,049	89,421	104,526	117,847	143,692	212,670	240,404	283,418	320,367	353,515	19.0
Total	246,855	265,006	280,205	295,030	322,302	394,664	425,457	471,098	510,805	547,904	9.3

TABLE 9.5

Estimated number of alternative-fueled vehicles in use, by state and fuel type, 2002
State	Liquefied petroleum gases	Natural gas	Methanol	Ethanol	Electricity	Total
Notes: Natural gas includes compressed natural gas (CNG) and liquefied natural gas (LNG). Methanol includes M85 and M100. Ethanol includes E85 and E95. Excludes gasoline electric hybrids. Totals may not equal sum of components due to independent rounding.
SOURCE: "Table 4. Estimated Number of Alternative-Fueled Vehicles in Use, by State and Fuel Type, 2002," in Alternatives to Traditional Transportation Fuels 2003 Estimated Data, U.S. Department of Energy, Energy Information Administration, February 2004, http://www.eia.doe.gov/cneaf/alternate/page/datatables/afvtable4_03.xls (accessed November 18, 2004)
Alabama	4,289	1,341	0	2,713	636	8,979
Alaska	145	401	0	720	11	1,277
Arizona	1,082	7,243	201	1,583	1,662	11,771
Arkansas	2,199	340	0	300	0	2,839
California	21,537	24,990	4,787	9,517	10,670	71,501
Colorado	5,611	2,694	3	3,491	126	11,925
Connecticut	379	2,762	1	1,849	156	5,147
Delaware	85	489	10	783	11	1,378
District of Columbia	7	1,462	50	1,408	316	3,243
Florida	4,171	4,152	6	7,856	357	16,542
Georgia	4,418	4,484	39	2,076	4,550	15,567
Hawaii	842	0	0	1,467	204	2,513
Idaho	1,581	3,412	0	240	0	5,233
Illinois	5,259	3,120	17	6,916	89	15,401
Indiana	1,426	3,397	0	1,670	91	6,584
Iowa	2,179	18	27	1,903	12	4,139
Kansas	3,565	748	1	1,649	22	5,985
Kentucky	2,214	1,191	0	2,313	0	5,718
Louisiana	1,117	896	3	1,309	0	3,325
Maine	158	77	0	134	21	390
Maryland	2,570	3,634	7	2,901	45	9,157
Massachusetts	249	1,006	36	1,331	78	2,700
Michigan	4,822	991	48	4,840	1,606	12,307
Minnesota	2,162	509	0	3,361	0	6,032
Mississippi	1,193	140	0	543	0	1,876
Missouri	2,642	476	95	3,878	11	7,102
Montana	2,980	268	0	309	0	3,557
Nebraska	4,338	370	0	1,095	11	5,814
Nevada	1,487	3,111	0	973	0	5,571
New Hampshire	718	42	0	169	167	1,096
New Jersey	358	2,723	4	2,681	190	5,956
New Mexico	6,069	1,969	11	2,140	435	10,624
New York	6,213	13,100	88	3,723	9,299	32,423
North Carolina	4,560	559	0	4,539	112	9,770
North Dakota	1,310	155	0	354	0	1,819
Ohio	2,487	2,647	26	4,537	242	9,939
Oklahoma	17,839	3,322	0	1,122	0	22,283
Oregon	3,084	1,034	20	1,528	212	5,878
Pennsylvania	1,107	2,299	108	4,008	89	7,611
Rhode Island	122	331	0	391	0	844
South Carolina	3,047	362	0	4,051	0	7,460
South Dakota	1,374	44	0	384	0	1,802
Tennessee	2,623	763	0	3,068	200	6,654
Texas	39,279	9,961	162	6,706	82	56,190
Utah	3,227	1,961	8	1,966	0	7,162
Vermont	366	5	0	199	178	748
Virginia	927	4,735	7	3,740	1,086	10,495
Washington	4,397	1,925	73	2,760	11	9,166
West Virginia	39	378	0	595	0	1,012
Wisconsin	1,459	1,207	35	3,075	37	5,813
Wyoming	2,368	303	0	87	22	2,780
U.S. total	187,680	123,547	5,873	120,951	33,047	471,098

The largest numbers of AFVs are located in California, Texas, New York, and Oklahoma. Together, these four states account for 39% of the estimated number of AFVs in use in 2002. (See Table 9.5.) Transit buses are one type of heavy-duty vehicle that has seen much AFV activity. In 2003 in the United States, 9,278 alternative fuel buses were in use. Most of these were transit buses, rather than school buses, intercity buses, or trolleys ("Table 35: Reported Number of Onroad AFV Buses in Use, by Bus Type, Fuel Type and Configuration, 2003," Energy Information Administration, http://www.eia.doe.gov/ [accessed January 10, 2005]).

ALTERNATIVE FUEL AND THE MARKETPLACE. AFVs cannot become a viable transportation option unless a fuel supply is readily available. Ideally, an infrastructure for

TABLE 9.6

Alternative fuel station counts, by state and fuel type, as of November 22, 2004
State	CNG	E85	LPG	ELEC	BD	HY	LNG	Totals by state
Notes: CNG is Compressed Natural Gas, E85-85% is Ethanol, LPG is Propane, ELEC is Electric, BD is Biodiesel, HY is Hydrogen and LNG is Liquefied Natural Gas
SOURCE: "Alternative Fueling Station Counts by State and Fuel Type," U.S. Department of Energy, Alternative Fuels Data Center, November 22, 2004, http://www.eere.energy.gov/afdc/infrastructure/station_counts.html (accessed November 22, 2004)
Alabama	8	0	60	0	0	0	0	68
Alaska	0	0	9	0	0	0	0	9
Arizona	28	2	76	26	3	1	8	144
Arkansas	4	0	60	0	0	0	0	64
California	192	2	299	519	14	7	35	1,068
Colorado	25	10	74	4	11	0	0	124
Connecticut	14	0	26	4	1	0	0	45
Delaware	3	0	5	0	3	0	0	11
District of Columbia	1	0	0	0	0	1	0	2
Florida	26	2	109	6	3	0	0	146
Georgia	23	0	47	1	3	0	0	74
Hawaii	0	0	6	4	3	0	0	13
Idaho	8	1	31	0	2	0	1	43
Illinois	10	17	79	0	4	0	0	110
Indiana	12	0	45	0	11	0	0	68
Iowa	0	9	35	0	1	0	0	45
Kansas	3	2	52	0	4	0	0	61
Kentucky	0	4	21	0	0	0	0	25
Louisiana	12	0	25	0	0	0	0	37
Maine	0	0	14	0	3	0	0	17
Maryland	16	3	24	1	5	0	0	49
Massachusetts	12	0	35	33	1	0	0	81
Michigan	15	3	104	2	12	1	0	137
Minnesota	4	100	47	0	2	0	0	153
Mississippi	0	0	26	0	1	0	0	27
Missouri	6	6	104	0	1	0	0	117
Montana	3	2	38	0	2	0	1	46
Nebraska	1	5	26	0	1	0	0	33
Nevada	17	0	27	0	8	1	0	53
New Hampshire	1	0	23	11	4	0	0	39
New Jersey	18	1	20	0	0	0	0	39
New Mexico	9	3	62	0	2	0	0	76
New York	38	0	61	9	0	0	0	108
North Carolina	8	2	61	0	24	0	0	95
North Dakota	4	1	18	0	0	0	0	23
Ohio	17	1	74	0	8	0	0	10
Oklahoma	54	1	81	1	0	0	0	137
Oregon	16	0	47	4	5	0	0	72
Pennsylvania	47	0	87	0	2	0	1	137
Rhode Island	6	0	6	1	0	0	0	13
South Carolina	4	1	42	0	1	0	0	48
South Dakota	0	6	25	0	0	0	0	31
Tennessee	2	1	49	0	3	0	0	55
Texas	39	0	787	6	2	0	6	840
Utah	65	3	32	0	1	0	0	101
Vermont	1	0	14	9	0	0	0	24
Virginia	16	2	39	0	7	0	2	66
Washington	21	1	74	4	14	0	0	114
West Virginia	3	0	8	0	0	0	0	11
Wisconsin	20	5	59	0	1	0	0	85
Wyoming	12	1	36	0	3	0	0	52
Totals by fuel:	844	197	3,209	645	176	11	54	5,136

supplying alternative fuels would be developed simultaneously with the AFVs. Table 9.6 shows the types and numbers of alternative fuel stations available in each state. As of November 22, 2004, there were 5,136 alternative refueling sites in the United States. In 2004 privately owned vehicles used 71% of alternative fuel, state and local vehicles used 26%, and federal vehicles used 3%. (See Table 9.7.)

Many state policies and programs encourage the use of alternative fuels. California, for example, required that 10% of vehicles for sale in the state by 2003 be zero-emission vehicles, such as hybrid electric vehicles. This has caused vehicle manufacturers to expedite vehicle research and development. In fact, electric vehicles are already selling in California, and some rental car agencies now offer them to customers at prices only slightly higher than those for gasoline-powered cars.

Chrysler Corporation stopped making natural gas–powered vehicles after the 1997 model year because it had

TABLE 9.7

Estimated consumption of alternative transportation fuels, by vehicle ownership, 2000, 2002, and 2004
(Thousand gasoline-equivalent gallons)
Fuel	Federal	State/local	2000 Private	Total	Federal	State/local	2000 Private	Total	Federal	State/local	2000 Private	Total
*The remaining portion of 85-percent methanol and both ethanol fuels is gasoline. Consumption data include the gasoline portio of the fuel.
Notes: Fuel quantities are expressed in a common base unit of gasoline-equivalent gallons to allow comparisons of different fuel types. Gasoline-equivalent gallons do not represent gasoline displacement. Gasoline equivalent is computed by dividing the lower heating value of the alternative fuel by the lower heating value of gasoline and multiplying this result by the alternative fuel consumption value. Lower heating value refers to the Btu content per unit of fuel excluding the heat produced by condensation of water vapor in the fuel. Totals may not equal sum of components due to independent rounding. Estimates for 2004, in italics, are based on plans or projections. Estimates for historical years may be revised in future reports if new information becomes available.
SOURCE: Table 13. Estimated Consumption of Alternative Transportation Fuels in the United States, by Vehicle Ownership, 2000, 2002, a nd 2004," in Alternatives to Traditional Transportation Fuels 2003 Estimated Data, U.S. Department of Energy, Energy Information Administration, February 2004, http://www.eia.doe.gov/cneaf/alternate/page/datatables/afvtable13_03.xls (accessed November 18, 2004)
Liquefied petroleum gases (LPG)	458	19,730	192,388	212,576	213	20,097	202,833	223,143	164	19,277	222,927	242,36
Compressed natural gas (CNG)	6,294	34,061	46,390	86,745	6,142	52,482	62,046	120,670	7,449	73,217	78,798	159,464
Liquefied natural gas (LNG)	101	6,031	1,127	7,259	124	7,797	1,461	9,382	146	9,035	1,687	10,868
Methanol, 85 percent (M85)*	2	193	390	585	2	103	232	337	1	82	174	257
Methanol, neat (M100)	0	0	0	0	0	0	0	0	0	0	0	0
Ethanol, 85 percent (E85)*	2,661	5,482	3,928	12,071	3,495	9,215	5,073	17,783	4,331	12,713	5,361	22,40
Ethanol, 95 percent (E95)*	0	13	0	13	0	0	0	0	0	0	0	0
Electricity	639	595	1,824	3,058	191	1,165	5,918	7,274	291	1,461	10,084	11,836
Total	10,155	66,105	246,047	322,307	10,167	90,859	277,563	378,589	12,382	115,785	319,031	447,198

lost money on the vehicles, selling only 4,000 after production began in 1992. General Motors, which had suspended sales of natural gas vehicles in 1994, resumed sales in 1997. Ford began selling some natural gas versions of its cars and trucks in 1995. Commercial fleets, not retail customers, are the main buyers of natural gas vehicles.

Market success of alternative fuels and AFVs depends upon public acceptance. People are accustomed to using gasoline as their main transportation fuel and it is readily available. As federal and state requirements for alternative fuels increase, so will the fuels' visibility and acceptance by the general public.

ELECTRIC CARS: PROMISE AND REALITY. In the early days of the automobile, electric cars outnumbered internal-combustion vehicles. With the introduction of technology for producing low-cost gasoline, however, electric vehicles fell out of favor. But as cities became choked with air pollution, the idea of an efficient electric car emerged. To make it acceptable to the public, however, several considerations had to be addressed: How many miles could an electric car be driven before needing to be recharged? How light would the vehicle need to be? And could the electric car keep up with the speed and driving conditions of busy freeways and highways?

Electric vehicles (EVs) are of three types: battery-powered; fuel cell; and hybrids, which are powered by both an electric motor and a small conventional engine. EV1, a two-seater by General Motors (GM), was the first commercially available electric car. In 1999 GM introduced its second-generation EV1, the Gen II. It used a lead-acid battery pack and had a driving range of approximately ninety-five miles. The Gen II was also offered with an optional nickel-metal hydride battery pack, which increased its range to 130 miles. However, the California Air Resources Board relaxed automobile-emissions requirements and GM subsequently found that it could no longer market the EV1 effectively. When leases on the cars ran out in 2003, GM began reclaiming the cars.

Fuel cell electric vehicles use an electrochemical process that converts a fuel's energy into usable electricity. Some experts think that in the future vehicles driven by fuel cells could replace vehicles with combustion engines. Fuel cells produce very little sulfur and nitrogen dioxide and generate less than half the carbon dioxide of internal-combustion engines. Rather than needing to be recharged, they are simply refueled. Hydrogen, natural gas, methanol, and gasoline can all be used with a fuel cell.

DaimlerChrysler's Mercedes-Benz division produced the first prototype fuel cell car. The NECAR4 produces zero emissions and runs on liquid hydrogen. The hydrogen must be kept cold at all times, which makes the design impractical for widespread use. However, the company plans to replace the NECAR4 with the NECARX, which will run on methanol and is expected to be more practical. The NECAR4 prototype travels 280 miles on a full eleven-gallon tank. It was unveiled in 1999, and was still being road tested in late 2004. Ecostar, an alliance between Ford, DaimlerChrysler, and Ballard Power Systems, is also working on developing new fuel cells to power vehicles.

Hybrid cars have both an electric motor and a small internal-combustion engine. A sophisticated computer system automatically shifts from the electric motor to the gas engine, as needed, for optimum driving. The electric motor is recharged while the car is driving and braking. Because the gasoline engine does only part of the work, these cars get very good fuel economy. The engines are also designed for ultralow emissions.

As of 2002 two hybrid passenger cars were introduced in the United States: the Toyota Prius, a sedan with front and back seating, and the two-passenger Honda Insight. Both cars were sold in Japan for several years before being introduced to the U.S. market. In the 2005 model year, Ford offered the first hybrid SUV, the Escape, which won the 2004 North American Truck of the Year award. The vehicle is reported to get thirty-five mpg with city driving, traveling about four hundred miles on a fifteen-gallon tank.

Air Travel Efficiency

Flying carries an environmental price, as it is a very energy-intensive form of transportation. In much of the industrialized world, air travel is replacing more energy-efficient rail or bus travel. The U.S. Department of Transportation Bureau of Transportation Statistics reported that despite a rise in the fuel efficiency of jet engines, jet fuel consumption rose 75% between 1995 and 2002, from 2.1 billion liters to 3.7 billion liters.

Jet fuel consumption can affect global warming. Airplanes spew nearly four million tons of nitrogen oxide into the air, much of it while cruising in the tropospheric zone five to seven miles above the earth, where ozone is formed. (See Figure 9.5.) The EPA estimated that air traffic accounts for about 3% of all global greenhouse warming. The Intergovernmental Panel on Climate Change (IPCC) for the United Nations noted that emissions deposited directly into the atmosphere do greater harm than those released at the earth's surface.

In 1996 Pratt and Whitney, a designer and manufacturer of high performance engines, announced plans to introduce a radical new engine design that would be cleaner, more efficient, quieter, and more reliable than conventional designs. The new engine underwent detailed design in 2002, was tested in 2004, and is expected to take its first flight in 2006. The engine would reduce emissions by 40% and exceed noise restriction standards that took

FIGURE 9.5

effect in 2000. The engine is designed for use on single-aisle planes carrying 120 to 180 passengers, such as the Airbus A320.

Although each generation of airplane engines gets cleaner and more fuel-efficient, there are also other engines in the airline industry—those in the trucks, cars, and carts that service airplane fleets. Electric utility companies, including the Edison Electric Institute and the Electric Power Research Institute, launched a program in 1993 to electrify airports. By converting terminal transport buses, food trucks, and baggage-handling carts to electricity, airports could reduce air pollution considerably. As of December 2004, only a few U.S. airports and airlines were operating significant numbers of electric ground support equipment and the associated electric charging stations. However, airport electrification implementation and research were ongoing.