Section 3.

Fleets of Alternative

Fuel Providers
422

284

78

41 18 1

All Fuels Gasoline Diesel Propane CNG Other

Fuel

0

100

200

300

400

500

Thousand Vehicles

 Sources: Energy Information Administration, Form EIA-885, Propane Provider Fleet Survey; Form 

EIA-861, Schedule VII, Electric Utility Fleet Survey; and Form EIA-176, Schedule B, Natural Gas 

Supplier Fleet Survey.

Energy Information Administration/Describing Current and

Potential Markets for Alternative-Fuel Vehicles 3-3

Figure 3.1.1. Alternative Fuel Provider Fleets by Fuel, 1993

3.1. Introduction

The EPACT established vehicle purchase mandates for particular subsets of the U.S. vehicle fleet population. These

mandates, which go into effect at different times for various fleet subpopulations, required that an incremental

percentage of new vehicle purchases must be alternative-fuel vehicles (AFV’s). The Federal government fleets were the

first to be affected, with their purchase requirements going into effect with model year 1993. Beginning with model year

1996, providers of alternative fuels also will fall under AFV purchase mandates.

 EIA established three surveys to collect information about the fleets operated by providers of propane, natural gas, and

electricity. The reason for focusing on alternative-fuel providers is that they would likely be important early users of

AFV’s because they would derive publicity and public relations benefits from using their energy source as a vehicle fuel.

The EIA surveyed only providers of propane, natural gas, and electricity because there were existing EIA databases that

made the population of those providers easily accessible. At the time the surveys were conducted, there was no database

in existence for easy access to the methanol and ethanol providers, and it was still uncertain (due to pending Rules)

whether the oil providers/refiners would be covered under the EPACT as alternative fuel providers.

Survey data reveal that alternative-fuel providers are making use of alternative-fuel vehicles. The three classes of

providers covered in this report operate a total of 422,127 vehicles in their fleets. Of those, approximately 60,000

vehicles (14 percent) are fueled by alternative fuels, with propane being the most common (Figure 3.1.1). Detailed tables

display the complete survey results, and summary descriptions of survey methodologies and results are presented for each

type of provider. Throughout this section of the report the term “multifuel” is used to refer to all AFV’s that are capable

of operating on more than one fuel type (i.e., bi-fuel, flex-fuel, dual-fuel, and hybrid).

Highlights

Propane Provider Fleet Survey

C The top 35 propane providers (as measured by sales volume) are responsible for nearly two-thirds of the propane

deliveries in the United States, but they operate only about one-third of all propane provider fleet vehicles. The

smaller companies operate approximately 70 percent of the total vehicle stock. However, the top 35 companies are

much more likely to operate AFV’s. Overall, about 80 percent of the top 35 companies’ fleet vehicles use propane,

while slightly less than one-third of those of the smaller companies use propane.
Energy Information Administration/Describing Current and

3-4 Potential Markets for Alternative-Fuel Vehicles

C On average, costs to acquire conventional-fuel vehicles were 42 percent higher than the costs of acquiring AFV’s;

however, acquisition costs varied widely over vehicles types. Respondents also reported lower maintenance costs

for propane vehicles than for conventional-fuel vehicles, regardless of vehicle type. 

Electric Utility Fleet Survey

C Although one may expect that electric utilities would use electric vehicles in order to promote their energy source

as a transportation fuel, only 237 electric vehicles (4.2 percent of all AFV’s) were reported in the Electric Utility Fleet

Survey. One could speculate that this is probably because many electric utilities are opting to operate the more

economical compressed natural gas (CNG) vehicles until electric vehicle technology develops further. Also, some

of the utilities reporting data on the fleet survey are combined utilities, which provide natural gas as well as electricity.

These utilities may be choosing to operate CNG vehicles and still are able to promote their energy source.

C After CNG, methanol/ethanol was the most common alternative fuel in electric utility fleets, followed by propane,

and then electricity. 

Natural Gas Supplier Fleet Survey

C Natural gas suppliers appear to be farther along than electric utilities in integrating AFV’s into their fleets. Survey

data indicate that nearly 12 percent of the fleet vehicles operated by natural gas suppliers are AFV’s. This proportion

is substantially higher than the 3 percent found in the electric utility fleets, but much lower than the 46 percent

penetration realized by the propane providers.

C Vehicles fueled by CNG were predominantly multifuel vehicles--vehicles capable of using more than one type of fuel.

Most AFV’s were converted from the use of conventional fuels to the use of alternative fuels.
 “Top 35 U.S. LPG Retailers,” LP-Gas Magazine, June 1993, pg. 22. 1

Energy Information Administration/Describing Current and

Potential Markets for Alternative-Fuel Vehicles 3-5

3.2. Survey Operations

Propane Provider Fleet Survey

The Propane Provider Fleet Survey collected information from a sample of the approximately 7,800 propane providers

in the United States. The top 35 propane providers in the United States (as determined by 1992 sales volumes ) were 1

asked to provide detailed information on fleet characteristics and operating practices. These providers, who in 1992

accounted for two-thirds of total residential and commercial propane sales, were mailed a questionnaire that collected

the following information:

• Distribution of fleet vehicles among size classes, fuel types, and AFV engine technologies (i.e., multifuel vs.

dedicated)

• Fleet vehicle retirements, acquisitions, and conversions planned for 1994

• Source of AFV’s (original equipment manufacturer vs. conversion)

• Fleet vehicle fueling practices for conventional-fuel and alternative-fuel vehicles

• Fuel consumption

• Vehicle miles traveled

• Employee usage of fleet vehicles

• Average length of service of fleet vehicles before retirement (in months and miles)

• Fuel storage capacity in fleet vehicles

• Vehicle acquisition costs

• Vehicle conversion costs (for converted AFV’s)

• Comparison of maintenance costs between AFV’s and conventional-fuel vehicles.

A stratified random sample of 100 of the remaining smaller providers was selected to provide basic information about

their vehicle stock and 1994 acquisition plans by means of a brief telephone interview that collected only the first three

items in the above list. These smaller providers were separated into four strata corresponding to the four Census regions.

The sample was then drawn using proportional allocation.

Electric Utility Fleet Survey

Approximately 1,000 electric utilities provided information on their fleets and fleet vehicles in response to the Electric

Utility Fleet Survey. This survey was conducted as a supplement to the EIA survey “Annual Electric Utility Report”

(Form EIA-861), a census survey of about 3,200 electric utilities in the United States. Only utilities operating a fleet

of 10 vehicles or more were required to provide information on the fleet portion of the survey. The respondents to the

Electric Utility Fleet Survey were asked (via a mail questionnaire) to report the following:

• Distribution of fleet vehicles among size classes, fuel types, and AFV engine technologies (i.e., multifuel vs.

dedicated) and

• Fleet vehicle retirements, acquisitions, and conversions planned for 1994.

Natural Gas Supplier Fleet Survey

As with the Electric Utility Fleet Survey, the Natural Gas Supplier Fleet Survey was conducted as a supplement to an

existing EIA survey, “Annual Report of Natural and Supplemental Gas Supply and Disposition” (Form EIA-176). This

form is a census survey of all companies in the United States that take custody of natural gas, excluding consumers and

producers. For the 1993 survey, there were approximately 2,064 respondents that completed Form EIA-176. Of those

companies, only 553 which operated a fleet of 10 vehicles or more were required to complete the fleet survey.
Energy Information Administration/Describing Current and

3-6 Potential Markets for Alternative-Fuel Vehicles

The respondents to the Natural Gas Supplier Fleet Survey were asked to provide the following information:

• Distribution of fleet vehicles among size classes, fuel type, and AFV engine technologies (i.e., multifuel vs.

dedicated)

• Fleet vehicle retirements, acquisitions, and conversions planned for 1994

• Fleet vehicles fueling practices for conventional-fuel and alternative-fuel vehicles

• Fuel consumption

• Daily vehicle miles traveled range

• Employee usage of fleet vehicles

• Average length of service of fleet vehicles before retirement (in months and miles)

• Source of AFV’s (original equipment manufacturer vs. conversion).
Gasoline

(30%)

Diesel

(24%)

Propane

(47%)

CNG

(0%)

Source: Energy Information Administration, Office of Energy Markets and End Use, Form 

EIA-885, Propane Provider Fleet Survey.

Energy Information Administration/Describing Current and

Potential Markets for Alternative-Fuel Vehicles 3-7

Figure 3.3.1. Propane Provider Fleet Vehicles by Fuel, 1993

3.3. Fleet Size and Composition

Propane Provider Fleet Survey

At the end of 1993, propane providers in the United States operated approximately 82,000 fleet vehicles. More than

two-thirds of these vehicles were medium-duty and heavy-duty trucks, i.e., trucks with a Gross Vehicle Weight (GVW)

greater than 8,500 pounds. These large vehicles tended to be trucks for making deliveries of propane to households and

businesses. Large pickup trucks made up the next largest share of fleet vehicles.

Nearly half (47 percent) of the propane provider fleet vehicles were fueled by alternative fuels, more than were fueled

by either gasoline or diesel alone (Figure 3.3.1). As expected, the primary alternative fuel used by propane providers

in their fleet vehicles was propane. Only a small number (less than one percent) of their AFV’s were fueled by

compressed natural gas (CNG).

Nearly all of the propane vehicles reported by the propane providers (89 percent) were dedicated vehicles, that is,

vehicles that operate solely on one fuel--in this case, propane. Multifuel vehicles, meaning AFV’s capable of operating

on more than one fuel, i.e., bi-fuel, flex-fuel, dual-fuel, and electric hybrid vehicles, made up the rest of the AFV’s. 

Considerable disparity in the proportion of AFV’s in fleets existed between the fleets operated by the top 35 providers

and the smaller providers. The top 35 providers operated about three times as many light-duty vehicles fueled by

propane as light-duty vehicles fueled by gasoline or diesel alone. The top 35 providers operated nearly five times as

many propane vehicles as gasoline or diesel vehicles within the medium- and heavy-duty classes. In contrast, the fleets

operated by the smaller providers contain twice as many conventional-fuel vehicles as propane vehicles in these classes

(Table 3.3.1).
202

20

15

3

7

12

23

39

12

70

Total

Compact Cars

Mid-Size Cars

Large Cars

Mini-Vans

Full-Size Vans

Small Pickups

Large Pickups

Sport/Utility

Medium/Heavy Duty

Vehicle Size Class

0 50 100 150 200 250

Thousands of Vehicles

 Source: Energy Information Administration, Office of Coal, Nuclear, Electric, and Alternative 

Fuels, Form EIA-861 Schedule VII, Electric Utility Fleet Survey.

Energy Information Administration/Describing Current and

3-8 Potential Markets for Alternative-Fuel Vehicles

Figure 3.3.2. Electric Utility Fleet Vehicles by Size Class, 1993

Table 3.3.1. Propane Provider Fleet Vehicles by Provider Category, 1993

(Number of Vehicles)

Provider Category Medium-/Heavy-Duty

and Vehicle Type Total Light-Duty Vehicles Vehicles

Total ........................... 81,967 25,648 56,319 

Top 35 Providers

Total Vehicles ................. 24,236 6,730 17,506 

Conventional-Fuel Vehicles ...... 4,694 1,685 3,010 

Propane Vehicles .............. 19,448 4,956 14,492 

Remaining Providers

Total Vehicles ................. 57,731 21,057 36,674 

Conventional-Fuel Vehicles ...... 39,005 14,375 24,631 

Propane Vehicles .............. 18,726 6,682 12,044 

 Source: Energy Information Administration, Office of Energy Markets and End Use, Form EIA-885, Propane Provider Fleet Survey.

Fleets can acquire alternative-fuel vehicles in two ways: by purchasing them from an original equipment manufacturer

(OEM) or by converting a conventional-fuel vehicle to operate on an alternative fuel. The propane providers used both

methods to place AFV’s in their fleets, but for the most part the propane providers tended to operate converted AFV’s.

Among dedicated AFV’s, only 27 percent were OEM vehicles and only 17 percent of multifuel vehicles were obtained

from OEM’s. Overall, three-fourths of the AFV’s operated by propane providers were converted from conventional-fuel

vehicles.

Electric Utility Fleet Survey 

 As of December 31, 1993, electric

utilities with fleets of 10 vehicles or more

operated a total of 201,836 vehicles.

These vehicles were widely distributed

among the different vehicle size classes,

although nearly one-third of the vehicles

(70,448 vehicles) were medium-duty and

heavy-duty trucks. Pickup trucks were the

next largest category of vehicles, followed

by compact and mid-size passenger cars.

Nearly 20 percent of all fleet vehicles in

electric utility fleets were passenger cars,

in contrast to the propane provider fleets,

which had only three percent passenger

cars (Figure 3.3.2).
CNG

(67.1%)

Other

(0.2%) Methanol/Ethanol

(16.7%)

Propane

(11.8%)

Electricity

(4.2%)

 Note: Alternative-Fuel vehicles represent only three percent of the total fleet vehicles operated by 

electric utilities.

 Source: Energy Information Administration, Office of Coal, Nuclear, Electric, and Alternative Fuels, 

Form EIA-861 Schedule VII, Electric Utility Fleet Survey.

138

11

12

4

6

15

16

31

6

36

Total

Compact Cars

Mid-Size Cars

Large Cars

Mini-Vans

Full-Size Vans

Small Pickups

Large Pickups

Sport/Utility

Medium/Heavy Duty

Vehicle Size Class

0 20 40 60 80 100 120 140 160

Thousands of Vehicles

 Source: Energy Information Administration, Office of Oil and Gas, Form EIA-176 Schedule B, 

Natural Gas Supplier Fleet Survey.

Energy Information Administration/Describing Current and

Potential Markets for Alternative-Fuel Vehicles 3-9

Figure 3.3.3. Electric Utility Fleet Alternative-Fuel

Vehicles by Fuel, 1993

Figure 3.3.4. Natural Gas Supplier Fleet Vehicles by Size

Class, 1993

Nearly all fleet vehicles (97 percent) operated

by electric utilities were conventional-fuel

vehicles, with the vast majority of those being

dedicated gasoline vehicles. Approximately

21 percent of the conventional-fuel vehicles in

electric utility fleets were diesel vehicles.

Only 3 percent of the fleet vehicles were

alternative-fuel vehicles, and two-thirds of

these AFV’s were fueled with CNG. These

CNG vehicles were mostly multifuel vehicles

(78 percent), with only 821 of the 3,756 CNG

vehicles being dedicated vehicles. The next

most common alternative fuel used in electric

utility fleets was methanol/ethanol (used in

935 vehicles), followed by propane (658

vehicles), and then electricity (237 vehicles).

An insignificant number of alternative-fuel

vehicles are fueled by other alternative fuels,

mostly liquid natural gas (Figure 3.3.3).

Natural Gas Supplier Fleet Survey

At the end of 1993, natural gas suppliers with fleets of 10 or more vehicles operated a total of 138,324 fleet vehicles.

As with the fleets operated by electric utilities, the fleet vehicles operated by natural gas suppliers were well distributed

among the various vehicle size classes. However, pickup trucks and full-sized vans made up nearly half (45 percent)

of the fleet vehicles used by natural gas suppliers. Medium-duty and heavy-duty vehicles represented a substantial 26

percent of the fleet vehicles in use. Passenger cars made up another 20 percent (Figure 3.3.4).

Gasoline vehicles dominated the conventional-fuel vehicles with 85 percent of the total. These vehicles were mostly

light-duty vehicles, with medium-duty and heavy-duty vehicles representing only 17 percent of the gasoline vehicles.

The remaining 15 percent of the conventional-fuel vehicles were mostly medium-duty and heavy-duty diesel vehicles.

Predictably, most AFV’s (87 percent) were fueled by CNG, but the natural gas providers did make significant use of

propane as a vehicle fuel. Of the 14,032 CNG vehicles in natural gas supplier fleets, 84 percent (11,809 vehicles) were
Conversions OEM

Alternative-Fuel Vehicle Source

0

20

40

60

80

100

Percent of Alternative-Fuel Vehicles

Multifuel Dedicated

Source: Energy Information Administration, Office of Oil and Gas, Form EIA-176 Schedule B, 

Natural Gas Supplier Fleet Survey.

Energy Information Administration/Describing Current and

3-10 Potential Markets for Alternative-Fuel Vehicles

Figure 3.3.5. Natural Gas Supplier Alternative-Fuel Vehicles

by Technology and Source, 1993

multifuel vehicles. Conversely, dedicated propane vehicles outnumbered multifuel propane vehicles. Fewer than 1

percent were fueled by electricity and other alternative fuels.

The alternative-fuel vehicles in natural gas supplier fleets were almost all converted vehicles. The few OEM vehicles

in use in natural gas supplier fleets tended to be dedicated vehicles--only 55 were reported to be OEM multifuel vehicles.

The dedicated vehicles in operation were fairly evenly split between OEM and conversion vehicles: 1,582 OEM vehicles

and 1,401 converted vehicles (Figure 3.3.5).
Energy Information Administration/Describing Current and

Potential Markets for Alternative-Fuel Vehicles 3-11

3.4. Fleet Vehicle Retirement/Acquisition Plans

Propane Provider Fleet Survey

The propane providers were asked to report their plans for vehicle retirements and acquisitions during 1994. Only 6

percent (5,592 vehicles) of the fleet vehicles operated by propane providers were planned for retirement, nearly half (47

percent) of which were AFV’s. The planned acquisitions, 6,970 vehicles, would more than make up for the vehicles

being retired.

In addition to the acquisitions, 1,475 vehicle conversions were planned for 1994. There is some double counting in the

acquisitions and conversions data. Analysis of the reported data revealed that if a respondent had plans to acquire a new

vehicle in 1994 and then immediately convert that vehicle to an alternative fuel, in some cases that vehicle was reported

as both an acquisition and a conversion. Analyzing the data to correct the double counting shows that of the 1,475

conversions planned for 1994, 921 were conversions of newly acquired conventional-fuel vehicles and 554 were

conversions of vehicles previously operated within the fleet as conventional-fuel vehicles. Overall, more new AFV’s

were planned for service in 1994 than conventional-fuel vehicles, including both new vehicles and old vehicles being

converted to use alternative fuels.

Electric Utility Fleet Survey

Only about 9 percent of the fleet vehicles operated by electric utilities (18,956 vehicles) were planned for retirement

during 1994. Most retirements were planned for gasoline vehicles; of the total of 16,438 gasoline vehicles planned for

retirement, 2,736 were medium/heavy-duty vehicles, 5,675 were pickup trucks, and 3,052 were compact passenger cars.

Only 455 AFV’s were planned for retirement, and most of these were large pickup trucks. The acquisitions planned for

1994 (18,182 vehicles) would not completely replace all vehicles being retired. Only 724 conversions of conventionalfuel vehicles to alternative-fuel vehicles were planned.

As with the propane survey data, there is double counting within the data regarding fleet vehicle acquisitions and

conversions. A similar analysis to the one conducted with the propane provider fleet data revealed that of the 724

conversions planned for 1994, only 159 were conversions of existing fleet vehicles. The other 565 planned conversions

were of vehicles newly purchased as conventional-fuel vehicles. Further, only 1,003 of the planned new vehicle

acquisitions (6 percent) were AFV’s. The remainder were conventional-fuel vehicles, some of which were planned for

subsequent conversion.

Natural Gas Supplier Fleet Survey

The natural gas suppliers planned to retire a larger percentage of their fleet vehicles than either the propane providers

or the electric utilities. About 12 percent (17,088 vehicles) of the fleet vehicles operated by natural gas suppliers were

planned for retirement during 1994. In addition, only 14,374 vehicle acquisitions were planned, indicating that the fleets

operated by natural gas suppliers tended to downsize in 1994. Only 7 percent of the planned vehicle retirements included

alternative-fuel vehicles.

A total of 4,623 newly acquired AFV’s and conversions of existing vehicles to AFV’s were planned for service in 1994.

Almost 80 percent of those planned vehicles were multifuel CNG vehicles. Most CNG vehicles were light-duty vehicles,

with the largest proportion (40 percent) being large pickup trucks. The Natural Gas Supplier Fleet Survey did not

experience the double counting problems encountered in the Propane Provider Fleet Survey and the Electric Utility Fleet

Survey, so all of the 1,623 planned conversions represent conversions planned for existing fleet vehicles.
69

2

4

25

0

94

2

0

4

0

Company Site

Private

Restricted Public

Unrestricted Public

Other

Type of Facility

0 20 40 60 80 100

Percent of Vehicles

Conventional-Fuel Vehicles

Alternative-Fuel Vehicles

Source: Energy Information Administration, Office of Oil and Gas, Form EIA-176 Schedule B, 

Natural Gas Supplier Fleet Survey.

Energy Information Administration/Describing Current and

Potential Markets for Alternative-Fuel Vehicles 3-13

Figure 3.5.1. Types of Fueling Facilities Used by Natural

Gas Supplier Fleets, 1993

3.5 Fleet Operating Characteristics

In addition to the fleet size and composition characteristics covered above, the Propane Provider Fleet Survey (top 35

providers only) and the Natural Gas Supplier Fleet Survey also collected information regarding operating characteristics.

Information collected included data concerning fleet vehicle fueling facilities, vehicle usage by employees, vehicle

replacement cycles, vehicle fuel storage and consumption, and vehicle miles traveled. In addition, the top 35 propane

providers responded to questions about vehicle costs.

Fleet Vehicle Fueling Facilities

A company has several ways to fuel its fleet vehicles. Large commercial fleets tend to use their own fuel tanks located

on a company site to fuel their vehicles. Fleets can also fuel at public fueling stations in the same manner as personal

vehicles are fueled, or at private facilities that are designed for use by fleets and are not open to the general public. Fleets

sometimes enter into fuel-purchase agreements with their fueling facilities, stipulating that the fleet agrees to purchase

its fuel from a specific facility. If the fleet has a credit card for use at a facility but has no commitment to purchase fuel

there, then such an arrangement is not considered a fuel purchase agreement. 

The EPACT purchase mandates use central fueling as a criterion for determining which fuel provider fleets would be

covered by vehicle purchase requirements, so questions about fueling arrangements were asked in order to determine

whether alternative-fuel providers were centrally fueled or were capable of being centrally fueled. 

Propane Provider Survey

Conventional-fuel vehicles, for the most part, were fueled either at a company-owned location or at a public fueling

location without any type of fuel-purchase agreement. A small number of conventional-fuel vehicles also obtained their

fuel at private facilities not open to the public. The data indicate that the propane provider fleets tended not to enter into

fuel-purchase agreements with the facilities that provide their fuel.

Only a very small number of the AFV’s operated by propane providers fuel at facilities other than company-owned sites.

This is probably because almost all of the AFV’s operated by propane providers run on propane and therefore use the

company’s fuel. Vehicles that do obtain their fuel off-site generally purchase the fuel through a fuel-purchase agreement

with private facilities.

Natural Gas Supplier Survey

Natural gas suppliers tended to fuel their

fleet vehicles at a variety of types of

facilities. For both the conventional-fuel

vehicles and the alternative-fuel vehicles,

the majority of vehicles were fueled on

company-owned sites, but significant

numbers of vehicles fueled at other types of

facilities. More than one-quarter (35,370

vehicles) of the conventional-fuel vehicles

operated in fleets belonging to natural gas

suppliers were fueled at public fueling

facilities. Nearly all of those (88 percent)

were fueled without any commitments to a

fuel purchase agreement.
Q = Data withheld because fewer than three companies are represented.

Source: Energy Information Administration, Office of Energy Markets and End Use, Form 

EIA-885, Propane Provider Fleet Survey.

84

51

57

68

77

82

93

99

79

96

100

91

60

80

55

84

77

99

91

93

95

All Vehicle Types

Compact Cars

Mid-Size Cars

Large Cars

Mini-Vans

Full-Size Vans

Small Pickups

Large Pickups

Sport/Utility

Medium-Duty Trucks

Heavy-Duty Trucks

Vehicle Type

0 30 60 90 120

Months

Conventional-Fuel Vehicles Propane Vehicles

Q

Energy Information Administration/Describing Current and

3-14 Potential Markets for Alternative-Fuel Vehicles

Figure 3.5.2. Months-Based Replacement Cycles for

Propane Provider Fleet Vehicles

Only 6 percent of AFV’s, or 1,004 vehicles, were fueled off-site, a much lower percentage than for conventional-fuel

vehicles (Figure 3.5.1).

 

Fleet Vehicle Usage by Employees

Company vehicles parked overnight at an employee’s residence and not centrally fueled from the provider’s facility are

excluded from a provider’s fleet for purposes of determining whether a fleet is subject to EPACT’s purchase mandates.

For that reason, the Propane Provider Fleet Survey (top 35 providers) and the Natural Gas Providers Survey collected

information regarding the availability of fleet vehicles to company employees. 

Propane Provider Survey

Nearly all vehicles (87 percent) operated by propane providers were available to their employees for business use only,

and those vehicles were garaged overnight at a company site. The remaining vehicles were available to employees for

commuting and business use or for unrestricted business and personal use, and would most likely be garaged overnight

at the employees’ residences. The respondents also indicated that 99 percent of employees who had the unrestricted

use of company vehicles were required to keep a log to record personal and business use.

Natural Gas Supplier Survey

Fleet vehicles operated by natural gas suppliers tended not to be available to company employees for uses other than

business. Three-fourths of the fleet vehicles were designated as for business use only. Employees were allowed to use

another 16 percent (22,662 vehicles) for commuting to and from work in addition to using them for business. A

relatively small number of vehicles were available to employees for unrestricted or other uses. These data indicate that

the fleets belonging to natural gas suppliers were, for the most part, garaged at a company site.

Fleet Vehicle Replacement Cycles 

Replacement cycles refer to the amount of time (or other measure) a company keeps its vehicles before retiring and/or

replacing them. A company may retire or replace a vehicle after a certain number of months or after the vehicle has been

driven a certain number of miles. In these surveys, respondents could provide replacement cycle data in months, miles,

or both. 

Propane Provider Survey

The average months-based cycle for

conventional-fuel vehicles in propane

provider fleets was 84 months, although

propane vehicles were in service for an

average of 91 months (Figure 3.5.2). The

average miles-based cycle for

conventional-fuel vehicles (216,482

miles) was higher than for propane

vehicles (179,866 miles) (Figure 3.5.3).

Analysis of the miles-based cycles for the

individual vehicle types reveals that this

was completely due to the miles-based

cycle for the heavy-duty trucks. The

miles-based replacement cycle for

conventional-fuel heavy-duty vehicles
Q = Data withheld because fewer than three companies are represented.

Source: Energy Information Administration, Office of Energy Markets and End Use, Form 

EIA-885, Propane Provider Fleet Survey.

216

112

94

121

121

131

125

142

150

322

180

167

177

233

188

181

182

174

All Vehicle Types

Compact Cars

Mid-Size Cars

Large Cars

Mini-Vans

Full-Size Vans

Small Pickups

Large Pickups

Sport/Utility

Medium-Duty Trucks

Heavy-Duty Trucks

Vehicle Type

0 50 100 150 200 250 300 350 400

Thousand Miles

Conventional-Fuel Vehicles

Propane Vehicles Q

Q

Q

Q

Energy Information Administration/Describing Current and

Potential Markets for Alternative-Fuel Vehicles 3-15

Figure 3.5.3. Miles-Based Replacement Cycles for Propane

Provider Fleet Vehicles

was nearly twice that of the propane heavyduty vehicles. This is most likely because

the conventional-fuel heavy-duty

vehicles travel longer distances than the

heavy-duty vehicles fueled by alternative

fuels, but the miles traveled data

(discussed below) for light-duty vehicles

are much more similar. 

Analysis of the replacement cycle data

reported by the respondents to the Propane

Provider Fleet Survey reveals that there is

a discrepancy within the reported data.

The propane providers reported that

approximately 6 percent of their fleet

vehicles were planned for retirement in

1994. If 1994 was a typical year for

vehicle retirements, then about 100 percent

of the fleet vehicles would have been

retired and replaced every 17 years. However, data indicate that the typical reported replacement cycle for vehicles is

approximately every 7 years. The data collected in the survey cannot positively explain this discrepancy, but possible

explanations can be offered. One explanation is that nearly half of all retirements and/or replacements are unplanned;

that is, although only 6 percent of the vehicles are planned for retirement at the beginning of a given year, another 6

percent may be retired or replaced due to vehicle condition or other unforeseen circumstances. Four respondents

reported that they did not retire their vehicles on a cycle, but rather they retired or replaced them when the condition of

the vehicle dictated that it was necessary. Another possible explanation is that 1994 was an abnormal year for

retirements, and in a normal year, twice that many vehicles tend to be retired or replaced.

Natural Gas Supplier Survey

The replacement cycles for fleet vehicles reported by the natural gas suppliers indicated that fleet vehicles tended to be

replaced more often in natural gas supplier fleets than in propane provider fleets. On average, vehicles are replaced after

about 6 years of use or after 94,530 miles have been traveled, slightly less than the average replacement cycles for the

vehicles in propane provider fleets. A possible explanation may be that propane provider fleets contain more mediumduty and heavy-duty vehicles, which tend to be replaced less often than the light-duty vehicles that are more prominent

in natural gas supplier fleets.

There also appears to be a small discrepancy between the planned vehicle retirements and the reported replacement

cycles among natural gas suppliers. The natural gas suppliers reported that they planned to retire approximately 12

percent of their fleet vehicles in 1994. Using the same logic as with the propane provider fleet data, one could conclude

that the entire fleet is replaced approximately every 8 years. However, the natural gas suppliers reported that the average

replacement cycle for their fleet vehicles is about 6 years. In addition to the possible explanations provided with the

propane provider fleet data, another reason for the discrepancy could be that the suppliers report the replacement cycles

that the company would like to adhere to, but, due to budgetary or other constraints, those cycles cannot be met and fleet

vehicles are actually kept in service longer than the replacement cycles indicate. However, none of the possible

explanations provided in this report can be confirmed using the data collected on the fuel provider surveys.

Fleet Vehicle Fuel Storage Capacity

One of the most prominent drawbacks of alternative-fuel vehicles is that the vehicles cannot be driven as far between

refuelings as conventional-fuel vehicles. Additional fuel tanks are often placed in the vehicles in order to provide

additional fuel. Information on fuel storage capacity was collected only from the propane providers. 
2,640

1,029

3,583

1,696

1,745

3,402

All Vehicles

Light-Duty

Medium/Heavy-Duty

Vehicle Size Class

0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000

Consumption (gallons)

Dedicated Vehicles

Multifuel Vehicles

Source: Energy Information Administration, Office of Energy Markets and End Use, Form 

EIA-885, Propane Provider Fleet Survey.

Energy Information Administration/Describing Current and

3-16 Potential Markets for Alternative-Fuel Vehicles

Figure 3.5.4. Annual Propane Consumption per Vehicle by

Vehicle Size Class for Propane Provider Fleet

Vehicles

The survey data reveal that the propane vehicles indeed had more fuel storage capacity than the conventional-fuel

vehicles. The average fuel storage capacity for dedicated vehicles in the light-duty category was approximately 91

percent higher for propane vehicles than for conventional-fuel vehicles. The difference between multifuel vehicles and

conventional-fuel vehicles was much smaller. For the multifuel light-duty vehicles, the average fuel storage capacity for

propane was only approximately 22 percent higher than the storage capacity for conventional fuels in conventional-fuel

vehicles. This may be due to the fact that in multifuel vehicles, capacity is needed for both propane and gasoline or

diesel. Meaningful comparisons between the reported propane and conventional fuel storage capacities for the mediumand heavy-duty vehicles cannot be made, because these vehicles are often fueled from the large delivery tanks they carry,

which can hold thousands of gallons of propane. 

Fleet Vehicle Fuel Consumption 

Propane Provider Survey

Of the three fuels that are significantly represented in propane provider fleets (gasoline, diesel, and propane), the most

heavily consumed per vehicle is diesel (6,512 gallons per vehicle per year). Diesel fuel is used, for the most part, in the

heavy-duty trucks that tend not only to travel long distances, but also to achieve low fuel economies--even though diesel

is more efficient than gasoline for similar

vehicle types. Gasoline tends to be the

least consumed fuel, with dedicated

gasoline vehicles only consuming an

average of about 1,100 gallons per

vehicle per year. Multifuel AFV’s

consume an average of another 200

gallons of gasoline per vehicle per year.

Annual consumption of propane per

vehicle was about 2,640 gallons in

dedicated propane vehicles and 1,696

gallons in multifuel vehicles. As

expected, the largest consumers of

propane were the medium-duty and

heavy-duty trucks. The dedicated

medium-duty and heavy-duty propane

vehicles consumed an average of 3,583

gallons of propane per vehicle per year,

while the multifuel vehicles consumed

3,402 gallons per vehicle per year.

Although over all vehicle types the

dedicated vehicles tended to be heavier consumers per vehicle of propane than the multifuel vehicles, among just lightduty vehicles, the multifuel propane vehicles consumed about 70 percent more per vehicle per year than the dedicated

propane vehicles (Figure 3.5.4).

Natural Gas Supplier Survey

This Section deleted due to concern over unreliability of data.
19

48

24

3

19

Gasoline

Diesel

Propane

Fuel

0 10 20 30 40 50

Thousand Miles Traveled

Dedicated Vehicles

Multifuel Vehicles

Q

Q = Data Withheld because fewer than three companies are represented.

Source: Energy Information Administration, Office of Energy Markets and End Use, Form 

EIA-885, Propane Provider Fleet Survey.

Energy Information Administration/Describing Current and

Potential Markets for Alternative-Fuel Vehicles 3-17

Figure 3.5.6. Annual Vehicle Miles Traveled per Vehicle on

Gasoline, Diesel, and Propane by Vehicle

Technology for Propane Provider Fleet

Vehicles

Fleet Vehicle Miles Traveled 

Propane Provider Survey

In the analysis of annual vehicle miles

traveled, the diesel vehicles tended to

stand out. On average, over all vehicle

types, the diesel vehicles traveled twice as

far per year than the next closest category,

dedicated propane vehicles, averaging

slightly less than 48,000 miles per year per

vehicle. Dedicated gasoline vehicles

traveled about 20,000 miles per year, and

approximately 3,500 additional miles were

traveled on gasoline in multifuel AFV’s

(Figure 3.5.6). Because little gasoline was

consumed in multifuel vehicles and

multifuel vehicles traveled relatively few

miles on gasoline, one can conclude that

the multifuel propane vehicles operated by

propane providers were more likely to run

on propane than gasoline. Overall, the

propane vehicles traveled an average of

about 21,000 miles per year per vehicle. The dedicated propane vehicles (23,997 miles per year) do tend to travel

slightly more in a year than the multifuel propane vehicles (18,768 miles per year).
54

56

48

35

52

48

54

41

58

72

37

42

45

42

39

46

40

43

33

24

8

2

7

24

9

6

6

16

9

4

All Vehicle Types

Compact Cars

Mid-Size Cars

Large Cars

Mini-Vans

Full-Size Vans

Small Pickups

Large Pickups

Sport/Utility

Medium/Heavy Duty

Vehicle Type

0 20 40 60 80 100

Percent of Vehicles

 0 to 50 Miles

51 to 100 Miles

More than 100 Miles

Source: Energy Information Administration, Office of Oil and Gas,Form EIA-176 Schedule B, 

Natural Gas Supplier Fleet Survey.

Energy Information Administration/Describing Current and

3-18 Potential Markets for Alternative-Fuel Vehicles

Figure 3.5.7. Daily Miles Traveled by Natural Gas Supplier

Fleet Vehicles

Natural Gas Supplier Survey

Natural gas supplier fleet vehicles tended not to travel long distances on a daily basis. Miles traveled data were collected

from the respondents to the Natural Gas Supplier Fleet Survey in the form of ranges of daily miles traveled. Nearly all

fleet vehicles (92 percent) traveled between 0 and 100 miles per day on average. The vehicles that traveled more miles

in a day tended to be large passenger cars and large pickup trucks (Figure 3.5.7).

Fleet Vehicle Operating Costs

Proponents of alternative-fuel vehicles often cite lower operating costs as a benefit of these vehicles, so the Propane

Provider Survey asked respondents about their vehicle operating costs. The Natural Gas Supplier Fleet Survey did not

include these questions.

Operating costs were separated into three types of costs: vehicle acquisition costs, costs to convert vehicles to an

alternative fuel, and maintenance costs. Data on acquisition costs and conversion costs were collected in dollars, and

data on maintenance costs were collected as a comparison between conventional-fuel vehicles and alternative-fuel

vehicles; that is, the respondents were asked to report if the maintenance costs for a particular alternative-fuel vehicle

were more or less than a comparable conventional-fuel vehicle and by what percentage.

No clear trend appears between conventional-fuel vehicle acquisition costs and the cost to acquire propane vehicles. For

example, the costs were about equal for large pickup trucks; for medium-duty trucks (8,501 to 26,000 lbs. GVW), the

conventional-fuel vehicles were acquired for less than the dedicated propane vehicles; and for heavy-duty trucks (more

than 26,000 lbs. GVW), the costs to acquire conventional-fuel vehicles were significantly higher than the costs to acquire

propane vehicles. On average, for all vehicle types, the acquisition costs for conventional-fuel vehicles ($35,802) tended

to be 73 percent higher than the cost to acquire propane vehicles ($20,736) (Figure 3.5.8). The majority of this

difference can be attributed to the difference between acquisition costs for propane vehicles and for conventional-fuel

heavy-duty vehicles. The differences for the other vehicle types are not nearly that great. The large difference in the

heavy-duty vehicle category cannot be explained without further information, but one possible explanation is that the

heavy-duty propane vehicles tend to be just slightly more than 26,000 lbs. GVW, whereas the conventional-fuel heavyduty vehicles are very large vehicles weighing substantially more than 26,000 lbs. This explanation would be consistent

with the finding that the acquisition costs for heavy-duty propane vehicles tend to be very close to the acquisition costs

for medium-duty propane vehicles.
Conventional-Fuel Dedicated Propane Multifuel Propane

Vehicle Type

$0

$10,000

$20,000

$30,000

$40,000

Acquisition Cost

Conversion Cost

Source: Energy Information Administration, Office of Energy Markets and End Use, Form 

EIA-885, Propane Provider Fleet Survey.

Energy Information Administration/Describing Current and

Potential Markets for Alternative-Fuel Vehicles 3-19

Figure 3.5.8. Propane Provider Fleet Vehicle Acquisition

and Conversion Costs

The cost to convert vehicles from a

conventional fuel to an alternative fuel was

fairly stable over the various vehicle types,

ranging from around $1,200 to just under

$1,800. The most costly conversion

appeared to be the conversion of a large

passenger car ($1,783) to a dedicated AFV,

and the least expensive conversion tended

to be that of medium-duty trucks to

multifuel vehicles ($1,150). Conversion to

a dedicated AFV tended to cost slightly

more than conversion to a multifuel vehicle,

with the difference averaging $100 to $150

(Figure 3.5.8).

One of the many benefits of AFV’s

promoted by the industry is that they are

more economical to maintain because the

engines tend to have fewer moving parts

and the fuels burn cleaner. The data from the Propane Provider Fleet Survey seem to confirm this. The respondents

report that the maintenance costs for their propane vehicles are less than for their conventional-fuel vehicles across all

vehicle types. The difference between the two types of vehicles is slightly greater for dedicated vehicles (5.7 percent)

than for multifuel vehicles (4.4 percent).
Energy Information Administration/Describing Current and

Potential Markets for Alternative-Fuel Vehicles 3-49

3.7 Data Quality

Propane Provider Fleet Survey

Unlike the Electric Utility Fleet Survey and the Natural Gas Supplier Fleet Survey, the Propane Provider Fleet Survey

was conducted as a sample survey and, therefore, the data collected are subject to sampling and nonsampling error.

However, the sampling error will affect only portions of the data collected. The data that were collected from the top

35 providers, but not the 100 sampled companies, are not subject to sampling error because that part of the survey was

a census.

Nonsampling Error

Nonsampling errors are errors of the survey process and include both random errors and systematic errors or biases. The

magnitudes of nonsampling biases cannot be estimated from the sample data. Thus, avoidance of systematic biases is

a primary objective of all stages of survey design. Subsequent to conducting a survey, problems of unit nonresponse and

item nonresponse need to be addressed. The treatment of these types of errors in the Propane Provider Fleet Survey are

discussed below.

Unit Nonresponse

Unit nonresponse is the type of nonresponse that occurs when no data are available for a survey respondent. Most unit

nonresponse occurs when a respondent is unavailable or refuses to cooperate. There was one instance of unit

nonresponse in the top 35 providers portion of the Propane Provider Fleet Survey that was accounted for using a simple

weight adjustment. One respondent among the top 35 providers was also a respondent to the Natural Gas Supplier Fleet

Survey. In order to prevent duplication of the data collection and to reduce burden on the respondent, that particular

provider was released from the Propane Provider Fleet Survey. The remaining 33 responding providers were given a

weight of 34/33 = 1.03 to account for the nonresponding provider. Within the sample portion of the survey, there was

100 percent response.

Imputation for Item Nonresponse

There were three variables on the Propane Provider Fleet Survey that required imputation due to item nonresponse.

Those variables were fuel storage capacity, vehicle fuel consumption, and vehicle miles traveled (VMT). For fuel

storage capacity, the hot-deck procedure was used to impute for missing responses. In hot-decking, when a certain

response is missing for a given respondent, another respondent, called a donor, is randomly chosen to furnish its reported

value for that missing item. The donated value is then assigned to the nonrespondent company.

Due to the complex nature of consumption and miles-traveled data, it was determined that the hot-deck procedure would

not be adequate. Therefore, missing responses for consumption and miles traveled were derived using nonmissing data

items for the nonrespondent companies along with data from outside sources. The outside data used were average fuel

economies (in miles per unit of fuel) for each fuel and each vehicle type. For those companies that did not report

consumption data, but did report VMT, the missing consumption data were imputed by dividing the reported VMT by

the appropriate fuel economy estimate.

If a respondent did not report either consumption or VMT, a more complicated derivation was necessary. First, an

average VMT per vehicle was computed from all reported values for each fuel and vehicle type. Consumption was then

imputed as gallons per vehicle by dividing the appropriate average VMT per vehicle by the appropriate fuel economy

estimate. There were two respondents who were unable to report the consumption data by vehicle type, but were able

to provide the total consumption of each fuel. For these two respondents, the consumption was first imputed as

described; the ratio was adjusted using the reported total consumption. The ratio was computed by dividing the reported
Sh

2 ' ji

(Yi & Yi)

2

nh & 1

F ' jh (

N & n

n

) Nh Sh

2

RSE ' ( F

Y

) ( 100

Energy Information Administration/Describing Current and

3-50 Potential Markets for Alternative-Fuel Vehicles

total consumption by the sum (over all vehicle types) of imputed consumption. Once the consumption was imputed,

those newly imputed data were used to impute VMT by multiplying the imputed consumption by the appropriate fuel

economy estimate.

Sampling Error

The random differences between the survey estimate and the true population value that occur because of the particular

sample that was selected are known as sampling errors. The average sampling error, averaged over all possible samples,

should be zero. Although the sampling error is nonzero and unknown for the particular sample chosen, the sample design

permits sampling errors to be estimated. The typical magnitude of the sampling error is measured by the “standard error”

of the estimate. Standard errors in this report are given as percents of their estimated values, that is, as relative standard

errors (RSE’s).

For a given survey statistic, Y, the relative standard error, RSE(Y) is computed as follows:

where,

n = total sample size

n = sample size in stratum h h

N = total population size, and

N = population size in stratum h. h

For this survey, there were four strata representing the four Census regions. The propane provider frame, omitting the

top 35 providers, was separated into these four strata before the sample of 100 companies was selected. The top 35

providers did not contribute to sampling error because they were in the sample with certainty. However, for determining

RSE’s, the contribution of the top 35 providers was kept in the denominator. RSE’s for applicable tables are included

in the “3.6 Detailed Tables” section.

Electric Utility Fleet Survey

Because the Electric Utility Fleet Survey was conducted as a census survey, the data collected are not subject to sampling

error. However, as with all surveys, non-sampling errors can occur. These types of errors cannot be estimated using

sample data. No adjustments for either unit or item nonresponse were performed on the data collected in the Electric

Utility Fleet Survey.

Natural Gas Suppliers Fleet

Because the Natural Gas Supplier Fleet Survey was conducted as a census survey, the data collected are not subject to

sampling error. However, as with all surveys, non-sampling errors can occur. These types of errors cannot be estimated

using sample data.