ALTERNATIVE FUELS - WHAT ARE THEY?

GOAL:
To understand that there are optional types of fuel available.

OBJECTIVES:
The students will learn:

1. the most important alternative fuels available,
2. the characteristics of each alternative fuel,
3. the sources of each alternative fuel.

LESSON/INFORMATION:
Petroleum, specifically oil, is virtually the single source of transportation energy. "Oil provides 42 percent of America's energy and 97 percent of its transportation fuels."

"Transportation sources account for 67 percent of carbon monoxide emissions nationwide." "The transportation sector accounted for about one-third of the nation's CO2 emissions in 1988 and about 8 percent of global CO2 emissions - close to 1.7 billion tons." (Union of Concerned Scientists, pg. 1.) "With the Earth's known usable oil reserves expected to be depleted by 2040, oil is becoming harder to extract and the process is inflicting damage on the environment. As the U.S. supply dwindles (it is expected to run out by 2020), more oil will be imported from foreign sources..." (Earth Day, page 1.) From these quotes, it is obvious that America and the world needs to move toward other than standard gasoline as sources of transportation energy.

Many alternative fuels are proposed. Some are presently available. A few are in the experimental stage. Others are in theoretical research and development. Three barriers -an artificially repressed gasoline price, the lack of coordination between fuel and vehicle manufacturers, and a fuel distribution and taxation infrastructure - are most often cited as the reasons for the slow evolution of alternative fuels. Alternative fuels that are presently available and could be widely distributed are: reformulated gasoline, compressed natural gas (CNG), Methanol, Ethanol, and liquified petroleum gas (LPG). Related guides with specific details are found in the following guides: CNG - An Alternative Fuel, Ethanol - An Alternative Fuel, LPG - An Alternative Fuel, and Methanol - An Alternative Fuel.

Hydrogen, as a transportation fuel, demonstrates much promise. However, this alternative fuel requires additional research and development before it can feasibly be introduced as a viable alternative to gasoline. Hydrogen, as an automotive fuel, is in the early stages of experimentation and development. Future hydrogen powered vehicles may produce tailpipe emissions that approach zero. Hydrogen is plentiful and can yield high energy levels. Selected comparable properties of various fuels are shown below in Table 1.

Table 1
SELECTED PROPERTIES OF PRESENTLY AVAILABLE FUELS.
Physical
State		 Gasoline
Liquid		 Liquified
Petroleum
Gas		 Compressed
Natural
Gas		 Methanol
Liquid		 Ethanol
Liquid
Net Energy
Content
BTU/lb		 18,700
19,100		 19,800 21,300a 8,600 11,500
Octane
Number Range
(R + M) ÷ 2		 87 - 93 104b 120b 99 100
Sulfur Content
(W + %)		 0.02 - 0.045 Negc Negc None None
a - Pure Methane
b - Octane ratings above 100 are correlated with given concentration of tetraethyl lead in 150-octane
c - Natural sulfur content very low but measurable.
Source: Steering A New Course: Transportation, Energy, and the Environment, pages 75, 76.

Measuring a fuel's relative potential energy can easily be done by defining that fuel's Btu content. A Btu is defined as the amount of heat necessary to raise one (1) pound of water, one (1) degree Fahrenheit.

Gasoline and LPG are derived from oil or from natural gas production while CNG comes from natural gas. Both oil and natural gas are fossil fuels. The finite reserves of oil are far less than those of natural gas. Farm crops and waste-by-products are the usual sources for methanol and ethanol. The primary CNG component, methane, also may be produced from these sources.

From an environmental standpoint, the sulphur content affects the level of tailpipe acids produced as an exhaust by-product. These acids significantly contribute to "acid rain." Acid rain affects plant life, animals, and humans. Environmentalists are deeply concerned over increased exposure and concentrations of automobile-produced, exhaust-oriented, tailpipe emissions.

An engine fuel's "antiknock" or octane rating is important to an engine's performance and to the power yield curve. Gasoline has a relatively low octane number, thus compression ratios must be moderated resulting in a lower power yield per cubic inch displacement. Gasoline may be refined to higher octane levels; however, more fuel stocks are needed. Greater waste by-products result as a part of this refining process. Other additives such as tetraethyl lead, phosphorus, and boron were formally used to raise octane ratings. They are no longer used as they damage catalytic converters and are environmentally detrimental. Additionally, exhaust by-products that contain lead are thought to cause some forms of retardation in small children. Tailpipe emissions produced from gasoline yield significant amounts of benzene, a known carcinogen. Other additives, such as MTBE, are being studied to determine if they are carcinogenic.

ACTIVITY:
Use the chart on the following page for this activity.

1. Using car owner's manuals from various current models, determine what type of fuels other than gasoline may be used.

2. Determine if required conversion systems for other types of fuel are available in your area.

3. For each vehicle or conversion system found, determine for each, the cost-extra or associated new vehicle cost; cost (materials and labor) to install each after- market system.

Alternative Fuel Vehicles
Type of Vehicle Type of System Fuel System
Make,
Model,
etc.		 Type of
Fuel(s)
possible		 Factory
Installed		 Locally
Installed		 Cost
(Materials
and Labor)		 Maintenance Operational
Characteristics		 Available Fuel
Stations Locally




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INFORMATION CHECK
Directions: Indicate whether the statements below are true or false. If the statement is false, explain why it is false.

1. ________ CNG is made from oil-based stock.

2. ________ LPG is made from natural gas.

3. ________ Gasoline without octane boosters has a lower octane rating than any of the alternative fuels (LPG, CNG, Ethanol, Methanol).

4. ________ Alternative fuels contain less sulphur than does gasoline.

5. ________ Gasoline powered engines produce benzene by-product pollutants, which are known to be carcinogenic.

TEACHERS NOTES:
This activity guide should be performed before any other alternative fuel activity guides.

ANSWERS TO INFORMATION CHECK:
1. False. CNG is manufactured from natural gas stocks. CNG may also be manufactured from methane derived from agricultural products.

2. False. LPG is made from oil stocks. Propane and butane are by-products of other oil refining processes including the production of gasoline.

3. True.

4. True.

5. True.

REFERENCES:
New Transportation Fuels, Reference: American Petroleum Institute, page 1, Washington, D.C.-1991. Special Issue Department, Public Affairs Group.

The Automobile. Earth Day, 1990, Fact Sheet, Stanford, CA 1990.

Gordon, Deborah, Steering A New Course: Transportation, Energy, and the Environment. A Report by the Union of Concerned Scientists, Cambridge, MA 1991.

Motor - Vehicle Fuel Efficiency and Global Warming. Union of Concerned Scientists Briefing Paper: Cambridge, MA. 1991.

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