# Alernative Fuels Data Center's Glossary

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·· A ·
Additives Chemicals added to fuel in very small quantities to improve   and maintain fuel quality.  Detergents and corrosion inhibitors are examples of gasoline additives.

Air Quality Management District (AQMD) A term used principally in California to describe administrative     districts organized to control air pollution.  Nationwide, AQMDs are parallel to the areas designated   for classification against the National Ambient Air   Quality Standards(NAAQS).  Generally, AQMDs and their   national parallel encompass multiple jurisdictions and   closely   follow the definition of Consolidated Metropolitan   Statistical Areas and Metropolitan Statistical Areas.

Air Toxics Toxic air pollutants defined under Title II of the CAA, including   benzene, formaldehyde, acetaldehyde, 1-3 butadiene and polycyclic organic matter (POM).  Benzene is a   constituent of motor vehicle exhaust, evaporative and refueling emissions. The other compounds are exhaust pollutants.

Alcohols Organic compounds that are distinguished from hydrocarbons by the inclusion of a hydroxyl group. The two simplest alcohols are methanol and ethanol.

Aldehydes A class of organic compounds derived by removing the hydrogen atoms from an alcohol.  Aldehydes can be produced from the oxidation of an alcohol.

Alternative Fuel As defined pursuant to the EPACT, methanol, denatured ethanol and other alcohols, separately or in mixtures of 85% by volume or more with gasoline or other fuels, CNG, LNG, LPG, hydrogen, �coal-derived liquid fuels,� fuels �other than alcohols� derived from �biological materials,� electricity, neat biodiesel, or any other fuel determined to be �substantially not petroleum� and yielding �substantial energy security benefits and substantial environmental benefits.�

Alternative Fuels Data Center (AFDC) A program sponsored by DOE and managed by the National Renewable Energy Laboratory to collect data and information on all types of Alternative Fuels and AFVs across the country.

Alternative Fuels Utilization Program (AFUP) A program managed by DOE with the goals of improving national energy security by displacing imported oil, improving air quality by development and widespread use of alternative fuels for transportation and increasing the production of AFVs.

Alternative Motor Fuels Act of 1988 (AMFA) Public Law 100-494.  Encourages the development, production and demonstration of alternative motor fuels and AFVs.

Alternative-Fuel Provider A fuel provider (or any affiliate or business unit under its control) is an alternative-fuel provider if its principal business is producing, storing, refining, processing, transporting, distributing, importing or selling (at wholesale or retail) any alternative fuel (other than electricity); or generating, transmitting, importing, or selling (at wholesale and retail) electricity; or if that fuel provider produces, imports, or produces and imports (in combination), an average of 50,000 barrels per day of petroleum and 30% (a substantial portion) or more of its gross annual revenues are derived from producing alternative fuels.

Alternative-Fuel Vehicle (AFV) As defined by the Energy Policy Act, any dedicated, flexible-fueled, or dual-fueled vehicle designed to operate on at least one alternative fuel.

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·American Society for Testing and Materials (ASTM) A non-profit organization that provides a management system to develop published technical information. ASTM standards, test methods, specifications and procedures are recognized as definitive guidelines for motor fuel quality as well as a broad range of other products and procedures.

Anhydrous Describes a compound that does not contain any water.  Ethanol produced for fuel use is often referred to as anhydrous ethanol, as it has had almost all water removed.

Aromatics Hydrocarbons based on the ringed six-carbon benzene series or related organic groups. Benzene, Toluene and Xylene are the principal aromatics, commonly referred to as the BTX group. They represent one of the heaviest fractions in gasoline.

· B ·
BTX Industry term referring to the group of aromatic hydrocarbonsbenzene, toluene and xylene (see aromatics).

Balance of Payments The dollar amount difference between a country�s exports and imports.  In the United States, large oil imports are one of the main causes of the negative balance of payments with the rest of the world.

Benzene A six-carbon aromatic; common gasoline component identified as being toxic.  Benzene is a known carcinogen.

Bi-fuel Vehicle A vehicle with two separate fuel systems designed to run on either an alternative fuel, or gasoline or diesel, using only one fuel at a time. Bi-fuel vehicles are referred to as �dual-fuel� vehicles in the CAA and EPACT.

Biochemical Conversion The use of enzymes and catalysts to change biological substances chemically to produce energy products.  For example, the digestion of organic wastes or sewage by microorganisms to produce methane is a biochemical process.

Biodiesel A biodegradable transportation fuel for use in diesel engines that is produced through transesterification of organically derived oils or fats. Biodiesel is used as a component of diesel fuel.  In the future it may be used as a replacement for diesel.

Biomass Renewable organic matter such as agricultural crops, crop-waste residues, wood, animal and municipal waste, aquatic plants; fungal growth, etc., used for the production of energy.

British Thermal Unit (Btu) A standard unit for measuring heat energy.  One Btu represents the amount of heat required to raise one pound of water one degree Fahrenheit (at sea level).

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·Butane A gas, easily liquefied, recovered from natural gas. Used as a low-volatility component of motor gasoline, processed further for a high-octane gasoline component, used in LPG for domestic and industrial applications and used as a raw material for petrochemical synthesis.

Butyl Alcohol Alcohol derived from butane that is used in organic synthesis and as a solvent.

· C ·
California Air Resources Board (CARB) The state agency that regulates the air quality in California.  Air quality regulations established by CARB are often stricter than those set by the federal government.

California Low-Emission Vehicle Program State requirement for automakers to produce vehicles with fewer emissions than current U.S. Department of Environmental Protection Agency's (EPA) standards.  The four categories of California Low-Emission Vehicle Program standards from least to most stringent are transitional low emission vehicles (TLEVs), low emission vehicles (LEV), ultra low emission vehicles (ULEV), and zero emission vehicles (ZEV).

California Pilot Program Federal program, administered by EPA under the Clean Air Act, which sets lower emission standards (relative to cars in the general U.S. market) for a set number of new passenger cars and light trucks sold in California. Beginning in 1996, the program will require the sale of 150,000 clean vehicles in the state, increasing in 1999 to 300,000 annually.  California must mandate availability of any fuel necessary to operate clean fuel vehicles.

Carbon Dioxide (CO2 ) A product of combustion that has become an environmental concern in recent years.  CO2 does not directly impair human health but is a �greenhouse gas� that traps the earth�s heat and contributes to the potential for global warming.

Carbon Monoxide (CO) A colorless, odorless gas produced by the incomplete combustion of fuels with a limited oxygen supply, as in automobile engines.  CO is poisonous if inhaled, entering the bloodstream through the lungs and forming carboxyhemoglobin, a compound that inhibits the blood�s capacity to carry oxygen to organs and tissues.  CO can impair exercise capacity, visual perception, manual dexterity and learning functions.

Carbon Sequestration The absorption and storage of CO2 from the atmosphere by the roots and leaves of plants; the carbon builds up as organic matter in the soil.

Carcinogens Chemicals and other substances known to cause cancer.

Catalyst A substance whose presence changes the rate of chemical reaction without itself undergoing permanent change in its composition.  Catalysts may be accelerators or retarders.  Most inorganic catalysts are powdered metals and metal oxides, chiefly used in the petroleum, vehicle and heavy chemical industries.

Certification of Higher-learning in Alternative Motorfuels Program (CHAMP) A national program established by DOE to implement Section   411 of the Energy Policy Act of 1992.

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·Cetane Ignition performance rating of diesel fuel.  Diesel equivalent to gasoline octane.

Clean Air Act (CAA) Signed into law in 1963, then amended in 1970, and again in 1990. (See Clean Air Act Amendments of 1990)  Includes emissions standard for mobile and stationary sources.  Enforced by the U.S. Environmental Protection Agency.

Clean Air Act Amendments of 1990 (CAAA)The original Clean Air Act (CAA) was signed in 1963.  The   law sets emission standards for stationary sources (e.g.,   factories and power plants).  The CAA was amended   several times, most recently in 1990 (Public Law 101-549).    The Amendments of 1970 introduced motor vehicle emission   standards (e.g., automobiles and trucks).  Criteria   pollutants included lead, ozone, CO, SO2, NOx, and   particulate matter (PM), as well as air toxins.  The CAA   include reformulated gasoline (RFG) and oxygenated gasoline   provisions.  The RFG provision requires use of RFG   all year in certain areas.  The oxygenated gasoline   provision requires use of oxygenated gasoline during certain   months, when CO and ozone pollution is most serious.    The regulations also require certain fleet operators   to use clean fuel vehicles in 22 cities.

Clean Cities Program A voluntary program established and administered by DOE to increase AFV market penetration, particularly in more polluted urban areas.  Clean Cities chapters are recognized by DOE as having successfully established a sulf-sustaining environment for AFVs.  Specific chapters may include federal, state, and local government agencies, vehicle manufacturers and suppliers, fleet managers, utilities, local distribution companies, and other stakeholders.  The first international entities joined the program in 1995.

Clean Diesel An evolving definition of diesel fuel with lower emission specifications, which strictly limit sulfur content to 0.05 weight %; in California, aromatics content is further limited to 10 volume % (for large refiners).

Clean Fuel CAA (as amended in 1990) specification that identifies RFG and alternative fuels as clean fuel.

Clean Fuel Vehicle (CFV) Any vehicle certified by EPA as meeting certain federal emissions standards.  The three categories of federal CFV standards from least to most stringent are LEV, ULEV, and ZEV.  The ILEV standard is voluntary and does not need to be adopted by states as part of the Clean-Fuel Fleet Program.  CFVs are eligible for two federal programs, the California Pilot Program and the Clean-Fuel Fleet Program.  CFV exhaust emissions standards for light-duty vehicles and light-duty trucks are numerically similar to those of CARB�s California Low-Emission Vehicle Program. (See Appendix A for a listing of CARB�s tailpipe emissions standards for passenger cars and light-duty trucks 0-3750 LVW.)

Clean-Fuel Fleet Program Federal program requiring fleet purchase of Clean-Fuel Vehicles beginning in 1988.

Closed-Loop Carburetion System in which the fuel/air ratio in the engine is carefully controlled to optimize emissions performance.  A closed-loop system uses a fuel metering correction signal to optimize fuel metering.

Co-solvents Heavier molecular weight alcohols used with methanol to improve water tolerance and reduce other negative characteristics of gasoline/alcohol blends.  Tertiary butyl alcohol (TBA) was used commercially as a co-solvent for methanol/gasoline blends during the 1980s.

Compressed Natural Gas (CNG) Natural gas that has been compressed under high pressures, typically between 2000 and 3600 psi, held in a container.   The gas expands when released for use as a fuel.

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·Compression Ignition The form of ignition that initiates combustion in a diesel engine.  The rapid compression of air within the cylinders generates the heat required to ignite the fuel as it is injected.

Congestion Mitigation and Air Quality Improvement (CMAQ) Program A federal grant program established by the Intermodal Surface Transportation Act of 1991 that allocates funds to states to help themsimultaneously expand or initiate transportation services while improving air quality.  CMAQ funds may be used to support alternative-fuel andalternative-fuel vehicle programs.

Consolidated Metropolitan Statistical Area (CMSA) As used in the Clean Air Act (CAA) and the Energy Policy Act (EPACT), geographical areas defined by the Bureau of Census that includes cities or combinations of multiple cities with large population concentrations.  The Metropolitan Statistical Area (MSA) refers to geographical areas that generally include one city with a smaller population concentration.  For certain programs (e.g., oxygenated gasoline), the CAA adds definitions employed by the Office of Management and Budget.  For all EPACT mandates for AFVs and for the CAA Clean-Fuel Vehicle Program, use of the terms CMSA and MSA are delimited to areas with a 1980 population of 250,000 or more, as determined by the Bureau of the Census.

Converted or Conversion Vehicle A vehicle originally designed to operate on gasoline or diesel that has been modified or altered to run on an alternative fuel.

Cooperative Research and Development Agreement (CRADA)Federal and private joint research and development program that is used to further technology commercialization.

Corporate Average Fuel Economy (CAFE) (P.L. 94-163) Law passed in 1975 that set federal fuel economy standards.  The CAFE values are an average of city and highway fuel economy test results weighted by a manufacturer for either its car or truck fleet.

Corrosion Inhibitors Additives used to inhibit corrosion in the fuel system (e.g., rust).

Cryogenic Storage Extreme low-temperature storage.

· D ·
Dedicated Natural Gas Vehicle A vehicle that operates only on natural gas.  Such a vehicle is incapable of running on any other fuel.

Dedicated Vehicle Operates solely on one fuel.  Generally, dedicated vehicles provide superior emissions and performance results because their design has been optimized for operation on only one fuel.

Denatured Alcohol Ethanol that contains a small amount of a toxic substance, such as methanol or gasoline, which cannot be removed easily by chemical or physical means.  Alcohols intended for industrial use must be denatured to avoid federal alcoholic beverage tax.

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·Department of Energy See U.S. Department of Energy (DOE).

Detergent Additives used to inhibit deposit formation in the fuel and intake systems in automobiles.

Distillation Curve The percentages of gasoline that evaporate at various temperatures.  The distillation curve is an important indicator for fuel standards such as volatility (vaporization).

Domestic Fuel As defined by the Energy Policy Act, Section 301,domestic fuel is derived from resources within the United States, its possessions and commonwealths, and Canada and Mexico (the two nations in a free-trade agreement with the U.S.).

Dual-Fuel VehicleVehicle designed to operate on a combination   of an alternative fuel and a conventional fuel.   This includes a) vehicles using a mixture of gasoline or   diesel and an alternative fuel in one fuel tank, commonly   called flexible-fueled vehicles; and b) vehicles capable   of operating either on an alternative fuel, a conventional   fuel or both, simultaneously using two fuel   systems commonly called bi-fuel vehicles.

· E ·
E10 (Gasohol) Ethanol mixture containing 93% ethanol, 5% methanol and 2%kerosene, by volume.

E85 Ethanol/gasoline mixture containing 85% denatured ethanol and 15% gasoline, by volume.

E93 Ethanol mixture containing 93% ethanol, 5% methanol and   2% kerosene, by volume.

E95Ethanol/gasoline mixture containing   95% denatured ethanol and 5% gasoline, by   volume.

Electric Vehicle A vehicle powered by electricity, generally provided by batteries.  EVs qualify in the zero emission vehicle (ZEV) category for emissions.

Electricity Electric current used as a power source.  Electricity can be generated from a variety of feedstocks including oil, coal, nuclear, hydro, natural gas, wind, and solar.  In electric vehicles, onboard rechargeable batteries power an electric motor.

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·Emission Standards Limits or ranges established for pollution levels emitted by vehicles as well as stationary sources.  The first standards were established under the 1963 Clean Air Act.  Emissions limits are imposed on four classes of vehicles; automobiles, light-duty trucks, heavy-duty gasoline trucks, and heavy-duty diesel trucks.

Energy Policy Act of 1992 (EPACT) (P.L. 102-486) A broad-ranging act signed into law on Oct. 24, 1992.  Titles III, IV, V, XV and XIX of EPACT deal with alternative transportation fuels.  EPACT accelerates the purchase requirements for AFVs by the federal fleet, proposes eliminating the cap on CAFE credits that manufacturers can earn by producing dual and flexible fuel vehicles and requires fleets in large urban areas to purchase AFVs.  Establishes tax incentives for purchasing AFVs, converting conventional gasoline vehicles to operate on alternative fuels and installing refueling or recharging facilities by the private sector.

Environmental Protection Agency See U.S. Environmental Protection Agency (EPA)

Ester An organic compound formed by reacting an acid with an alcohol, always resulting in the elimination of water.

Ethane (C2H6) A colorless hydrocarbon gas of slight odor having a gross heating value of 1,773 BTUs per cubic foot.  It is a normal constituent of natural gas.

Ethanol (also known as Ethyl Alcohol, Grain Alcohol, CH         3 CH 2 OH) Can be produced chemically from ethylene or biologically from the fermentation of various sugars from carbohydrates found in agricultural crops and cellulosic residues from crops or wood.  Used in the United States as a gasoline octane enhancer and oxygenate, it increases octane 2.5 to 3.0 numbers at 10% concentration.  Ethanol also can be used in higher concentration in alternative-fuel vehicles optimized for its use.

Ether A class of organic compounds containing an oxygen atom linked to two organic groups.

Etherification Oxygenation of an olefin by methanol or ethanol. For example, MTBE is formed from the chemical reaction of isobutylene and methanol.

Ethyl Alcohol See Ethanol.

Ethyl Ester A fatty ester formed when organically derived oils are combined with ethanol in the presence of a catalyst.  After water washing, vacuum drying and filtration, the resulting ethyl ester has characteristics similar to petroleum-based diesel motor fuels.

Ethyl Tertiary Butyl Ether (ETBE) An aliphatic ether similar to MTBE.  This fuel oxygenate is manufactured by reacting isobutylene with ethanol.  Having high octane and low volatility characteristics, ETBE can be added to gasoline up to a level of approximately 17% by volume.  ETBE is not yet commercially available.

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·Evaporative Emissions Hydrocarbon vapors that escape from a fuel storage tank or a vehicle fuel tank or vehicle fuel system.

· F ·
Flexible-Fuel Vehicle Vehicles with a common fuel tank designed to run on varying blends of unleaded gasoline with either ethanol or methanol.

Fuel Cell An electrochemical engine with no moving parts that converts the chemical energy of a fuel, such as hydrogen, and an oxidant, such as oxygen, directly to electricity.  The principal components of a fuel cell are catalytically activated electrodes for the fuel (anode) and the oxidant (cathode) and an electrolyte to conduct ions between the two electrodes.

· G ·
Gasoline Gallon Equivalent (gge) A unit for measuring alternative fuels so that they can be compared with gasoline on an energy equivalent basis.  This is required because the different fuels have different energy densities.

Global Warming The theoretical escalation of global temperatures caused by the increase of greenhouse gas emissions in the lower atmosphere.

Greenhouse Effect A warming of the earth and its atmosphere as a result of the thermal trapping of incoming solar radiation by CO2, water vapor, methane, nitrous oxide, chlorofluorocarbons, and other gases, both natural and man-made.

Gross Vehicle Weight (gvw) Maximum weight of a vehicle, including payload.

· H ·
Heavy-Duty Vehicle According to EPA, a heavy-duty vehicle is any vehicle weighing 8,500 lb gvw or more.  In California, vehicles weighing more than 14,000 lb gvw are classified as heavy-duty vehicles.

· I ·
Inherently Low Emission Vehicle (ILEV) FEDERAL ONLY.  Describes vehicle meeting EPA's CFV ILEV standards.  Tailpipe standards may be HC LEV with ULEV NOx, ULEV or ZEV and includes the additional requirement that evaporative emissions be 2 grams per test over the test procedure and 5 grams per test without the use of any auxiliary emission control devices.  ILEVs will be dedicated AFVs in most cases.  Dual-fuel vehicles will be considered ILEVs only if both fuels meet the standard. (Very low-volatility gasoline may also meet the standard.)  ILEVs are exempt from certain transportation control measures, including high-occupancy vehicle (HOV) lane restrictions.  The standard is voluntary and need not be adopted by states.

Intermodal Surface Transportation Efficiency Act of 1991   (ISTEA)An omnibus act that further integrates the national intermodal surface transportation system and authorizes funds for highway construction, highway safety programs, and mass transit programs.  ISTEA seeks a national intermodal surface transportation system that is economical, energy efficient, and environmentally sound.  Section 1008 of the ISTEA establishes the Congestion Mitigation and Air Quality Improvement Program which can provide funds to support alternative-fuel and alternative-fuel vehicle programs.

· L ·
LNG to CNG Station A station, supplied with LNG, that pumps and vaporizes the liquid supply to vehicles as CNG fuel, generally at the correct pressure and temperature (i.e., the temperature effect of compression is factored into the design).

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·LNG vehicle A vehicle that uses LNG as its fuel.

Lead see Tetraethyl Lead.

Light-Duty Vehicles According to the EPA, a light-duty vehicle is any vehicle weighing 8,500 lb gvw or less.  In California, vehicles weighing less than 6,000 lb gvw are classified as light-duty vehicles.

Liquefied Natural Gas (LNG) Natural gas that has been condensed to a liquid typically by cryogenically cooling the gas.

Liquefied Petroleum Gas (LPG) A mixture of hydrocarbons found in natural gas and produced from crude oil, used principally as a feedstock for the chemical industry, home heating fuel, and motor vehicle fuel.  Also known by the principal constituent propane.

Liter (L) A metric measurement used to calculate the volume displacement of an engine.  One liter is equal to 1,000 cubic centimeters or 61 cubic inches.

Low-Emission Vehicle (LEV) Describes vehicle meeting either EPA�s CFV or LEV standards or CARB�s California Low Emission VehicleProgram LEV standards.  LEVs produce fewer emissions than TLEVs.

Lubricity Capacity to reduce friction.

· M ·
M100 100% (neat) methanol.

M85 85% methanol and 15% unleaded gasoline by volume, used as a motor fuel in FFVs.

Medium-Duty Vehicle A truck, van, or specialized vehicle weighing between 8,500 and 14,000 lb.

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·Methane (CH4) The simplest of the hydrocarbons and the principal constituent of natural gas.  Pure methane has a heating value of 1,012 Btu per standard cubic foot.

Methanol (also known as Methyl Alcohol, Wood Alcohol, CH3, OH) A liquid fuel formed by catalytically combining CO with hydrogen in a 1 to 2 ratio under high temperature and pressure.  Commercially, it is typically manufactured by steam reforming natural gas.  Also formed in the destructive distillation of wood.

Methyl Alcohol See Methanol.

Methyl Ester A fatty ester formed when organically derived oils are combined with methanol in the presence of a catalyst.  Methyl Ester has characteristics similar to petroleum-based diesel motor fuels.

Methyl Tertiary Butyl Ether (MTBE) An ether manufactured by reacting methanol and isobutylene.  The resulting ether has high octane and low volatility.  MTBE is a fuel oxygenate and is permitted in unleaded gasoline up to a level of 15% by volume.

Mobile Source Emissions Emissions resulting from the operations of any type of motor vehicle.

Motor Octane The octane as tested in a single-cylinder octane test engine at more severe operating conditions.  Motor Octane Number (MON) affects high-speed and part-throttle knock and performance under load, passing, climbing and other operating conditions.  Motor octane is represented by the designation M in the (R+M)/2 equation and is the lower of the two numbers.

· N ·
National Ambient Air Quality Standards (NAAQS) Ambient standards for air pollutants specifically regulated   under the CAA.  These pollutants include ozone, CO,   NO2, lead, PM, and SOx.

National Automotive Technical Education Foundation A consortium of automotive education experts which has established a steering committee to administer the CHAMP certification process at educational institutions.

National Low-Emission Vehicle (NLEV) ProgramThis program creates voluntary requirements which automakers can adopt in lieu of compliance with other vehicle emission control measures. The National LEV program was developed through an unprecedented cooperative effort by the Ozone Transport Commission (OTC) states, auto manufacturers, environmentalists, fuel providers, EPA and other interested parties. Starting in the northeastern states in model year 1999, and nationally in model year 2001, new light duty vehicles and light, light-duty trucks will meet tailpipe emission standards that are more stringent than EPA can mandate prior to model year 2004.  The NLEV program will result in substantial reductions in non-methane organic gases (NMOG) and oxides of nitrogen (NOx) which contribute to unhealthy levels of smog in  many areas across the country.  For more details related to the NLEV Program see EPA's web site at: http;//www.epa.gov/oms/lev-nlev.htm

Natural Gas A mixture of gaseous hydrocarbons, primarily methane, occurring naturally in the earth and used principally as a fuel.

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·Natural Gas Distribution System This term generally applies to mains, services, and equipment that carry or control the supply of natural gas from a point of local supply, up to and including the sales meter.

Natural Gas Transmission System Pipelines installed for the purpose of transmitting natural gas from a source or sources of supply to one or more distribution centers.

Near Neat Fuel Fuel that is virtually free from admixture or dilution.

Neat Alcohol Fuel Straight or 100% alcohol (not blended with gasoline), usually in the form of either ethanol or methanol.

Neat Fuel Fuel that is free from admixture or dilution with other   fuels.

Non-Attainment Area A region, determined by population density in accordance     with the U.S. Census Bureau, which exceeds minimum   acceptable   NAAQS for one or more "criteria pollutants"   (see   Clear Air Act Amendments).  Such areas are required     to seek modifications to their State Implementation   Plans,   setting forth a reasonable timetable using   EPA-approved   means to achieve attainment of NAAQS for   these criteria   pollutants by a certain date.  Under   the CAA, if   a non-attainment area fails to attain NAAQS,   EPA may superimpose   a Federal Implementation Plan   with stricter requirements   or impose fines, constructions   bans, cutoffs   in federal grant revenues, and   so forth, until the area   achieves the applicable NAAQS.

Non-Methane Organic Gases (NMOG) The sum of non-oxygenatedand oxygenated hydrocarbons exclusive of methane contained in a gas sample as measured in accordance with California�s non-methane organic gas test procedure.

Non-Road Vehicle (off-road vehicle) A vehicle that does not travel streets, roads, or highways.  Such vehicles include construction vehicles, locomotives, forklifts, tractors, golf carts, and so forth.

· O ·
OEM Original Equipment Manufacturer.

Octane Enhancer Any substance such as MTBE, ETBE, toluene andxylene that is added to gasoline to increase octane and reduce engineknock.

Octane Rating (Octane Number) A measure of a fuel�s resistance to self ignition, hence a measure as well of the antiknock properties of the fuel.

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·Office of Mobile Sources Division of EPA that proposes, promulgates and enforces regulations to control emissions of NAAQS pollutants and precursors from motor fuels and vehicles.

Onboard Refueling Vapor Recovery (ORVR) System required on vehicles beginning in 1998 to control refueling emissions.

Open-Loop Fuel Control System in which the air/fuel mixture is preset by design with no feedback correction signal to optimize fuel metering.

Original Equipment Manufacturer (OEM) The original manufacturer of a vehicle or engine.

Oxides of Nitrogen (NOx) Regulated air pollutants, primarily NO and NO2 but including other substances in minute concentrations.  Under the high pressure and temperature conditions in an engine, nitrogen and oxygen atoms in the air react to form various NOx.  Like hydrocarbons, NOx are precursors to the formation of smog.  They also contribute to the formation of acid rain.

Oxygenate A term used in the petroleum industry to denote fuel additives containing hydrogen, carbon and oxygen in their molecular structure.  Includes ethers such as MTBE and ETBE and alcohols such as ethanol and methanol.

Oxygenated Fuels Fuels blended with an additive, usually methyl tertiary butyl ether (MTBE) or ethanol to increase oxygen content, allowing more thorough combustion for reduced carbon monoxide emissions.

Oxygenated Gasoline Gasoline containing an oxygenate such as ethanol or MTBE.  The increased oxygen content promotes more complete combustion, thereby reducing tailpipe emissions of CO.

Ozone Tropospheric ozone (smog) is formed when volatile organic compounds (VOCs), oxygen and NOx react in the presence of sunlight(not to be confused with stratospheric ozone, which is found in the upper atmosphere and protects the earth from the sun�s ultraviolet rays).  Though beneficial in the upper atmosphere, at ground level, ozone is a respiratory irritant and considered a pollutant.

Ozone Transport Region (OTR) The Clean Air Act Amendments of 1990 enable EPA to establish   Ozone Transport Regions to reduce the likelihood   ozone and its precursors will be carried from one area   to another, lowering air quality in the downwind location.    The first such region consists of the states of Connecticut,   Delaware, Maine, Maryland, Massachusetts, New   Hampshire, New Jersey, New York, Pennsylvania, Rhode   Island, Vermont, and the District of Columbia.

· P ·
Paraffins Group of saturated aliphatic hydrocarbons, including methane, ethane, propane and butane and noted by the suffix �-ane�.

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·Particulate Matter (PM) A generic term for a broad class of chemically and physically diverse substances that exist as discrete particles (liquid droplets or solids) over a wide range of sizes.  A NAAQS pollutant.

Particulate Trap Diesel vehicle emission control device that traps and incinerates diesel particulate emissions after they are exhausted from the engine but before they are expelled into the atmosphere.

Petroleum Fuel Gasoline and diesel fuel.

Phase Separation The phenomenon of a separation of a liquid or vapor into two or more physically distinct and mechanically separable portions or layers.

Portable Fueling System A system designed to deliver natural gas to fueling stations.  Such systems are usually configured as tube trailers and are mobile. Fuel delivery usually occurs via over-the-road vehicles.

Pounds Per Square Inch (psi) A unit of measure for pressure.

Private Fleet A fleet of vehicles owned by a non-government entity.

Propane (C3H8) A gas whose molecules are composed of three carbon and eight hydrogen atoms.  Propane is present in most natural gas in the United States, and is also refined from crude petroleum.  Propane contains about 2,500 BTUs per standard cubic foot.  Propane is the principal constituent in Liquified Petroleum Gas (LPG).

Public Fueling Station Refers to fueling station that is accessible to the general public.

Pump Octane The octane as posted on retail gasoline dispensers as (R+M)/2; same as Antiknock Index.

· R ·
Reactivity Adjustment Factor (RAF) An NMOG adjustment used in the certification of vehicles to the California emission standards to reflect reduced ozone forming potential of a fuel, especially alternative fuels.

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·Reformulated Gasoline (RFG) Gasolines that have had their compositions and/or characteristics altered to reduce vehicular emissions of pollutants, particularly pursuant to EPA regulations under the CAA.

Refueling Emissions VOC vapors that escape from the vehicle fuel tank during refueling.  Storage II pump controls and onboard refueling vapor recovery systems (ORVR) are intended to control these emissions.

Reid Vapor Pressure (RVP) A standard measurement of a liquid�s vapor pressure in psi at 100 degrees Fahrenheit.  It is an indication of the propensity of the liquid to evaporate.

Research Octane Number (RON) The octane as tested in a single-cylinder octane test engine operated under less severe operating conditions.  RON affects low to medium-speed knock and engine run-on.  Research Octane is presented by the designation R in the (R+M)/2 equation and is the higher of the two numbers.

Retrofit To change a vehicle or engine after its original purchase, usually by adding equipment such as conversion systems.

· S ·
Smog A visible haze caused primarily by particulate matter and   ozone. Ozone is formed by the reaction of hydrocarbons and NOx in the atmosphere.

Spark Ignition Engine Internal combustion engine in which the charge is ignited electrically (e.g., with a spark plug).

State Implementation Plan (SIP) Plan that a state must submit to EPA under the CAA to demonstrate compliance to NAAQS.

Super Ultra-Low-Emission Vehicle (SULEV) Describes California medium-duty vehicle that produces fewer emissions that an ULEV.  There is no federal equivalent and therefore qualifies as a ULEV under CFF.

· T ·
Tax Incentives In general, a means of employing the tax code to stimulate investment in or development of a socially desirable economic objective without direct expenditure from the budget of a given unit of government.  Such incentives can take the form of tax exemptions or credits.

Tertiary Amyl Ethyl Ether (TAEE) An ether based on reactive C5 olefins and ethanol.

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·Tertiary Amyl Methyl Ether (TAME) An ether based on reactive C5 olefins and methanol.

Tetraethyl Lead or Lead An octane enhancer.  One gram of lead increases the octane of one gallon of gasoline about 6 numbers.  The EPA has phased down the use of lead in gasoline as it has been determined to be a health hazard.  Lead has been prohibited in highway vehicle gasoline since January 1, 1996.

Therm A unit of heating value equivalent to 100,000 British Thermal Units (BTUs).

Toluene Basic aromatic compound derived from petroleum and used to increase octane.  The most common hydrocarbon purchased for use in increasing octane.

Toxic Emission Any pollutant emitted from a source that can negatively affect human health or the environment.

Toxic Substance A generic term referring to a harmful substance or group of substances.  Typically, these substances are especially harmful to health, such as those considered under EPA's hazardous substance program.  Technically, any compound that has the potential to produce adverse health effects is considered a toxic substance.

Transesterification A process in which organically-derived oils or fats are combined with alcohol (ethanol or methanol) in the presence of a catalyst to form esters (ethyl or methyl ester).

Transitional Low-Emission Vehicle (TLEV) Describes vehicle meeting either EPA�s CFV TLEV standards or CARB�s California Low-Emission Vehicle Program TLEV standards.  TLEVs produce fewer emissions than federal Tier 1 vehicles.  TLEVs are eligible for the federal California Pilot Program but not eligible for the Clean-Fuel Fleet Program.

Transportation Control Measures (TCM) Restrictions imposed by state or local governments to limit use or access by vehicles during certain times or subject to specific operating requirements, e.g., high-occupancy vehicle (HOV) lanes.

· U ·
U.S. Department of Energy (DOE) A department of the federal government, established by the Carter Administration in 1977, to consolidate energy-oriented programs and agencies.  The DOE mission includes the coordination and management of energy conservation, supply, information dissemination, regulation, research, development and demonstration.  The Department includes the Office of Transportation Technologies.

U.S. Environmental Protection Agency (EPA) A government agency, established by the Nixon Administration in 1970, responsible for the protection of the environment and public health.  EPA seeks to reduce air, water and land pollution and pollution from solid waste, radiation, pesticides and toxic substances.  EPA also controls emissions from motor vehicles, fuels and fuel additives.

**·A·B·C·D·E·F·G·H·I·J·L·M·N·O·P·R·S·T·U·V·W·Y·Z·Ultra-Low-Emission Vehicle (ULEV) Describes vehicle meeting either EPA�s CFV ULEV standards or CARB�s California Low-Emission Vehicle Program ULEV standards.  ULEVs produce fewer emissions than LEVs.  Fleets who purchase CFV ULEVs may earn credits under the Clean-Fuel Fleet Vehicle Program.  Manufacturers that sell CFV ULEVs may earn credits under the federal California Pilot Program.

· V ·
Vapor Pressure or Volatility The tendency of a liquid to pass into the vapor state at a given temperature.  With automotive fuels, volatility is determined by measuring RVP.

Vehicle Conversion Retrofitting a vehicle engine to run on an alternative fuel.

Volatile Organic Compound (VOC) Reactive gas released during combustion or evaporation of fuel and regulated by EPA.  VOCs react with NOx in the presence of sunlight and form ozone.

· W ·
Wood Alcohol See Methanol.

· X ·
Xylene An aromatic hydrocarbon derived from petroleum and used to increase octane.  Highly valued as a petrochemical feedstock.  Xylene is highly photochemically reactive and, as a constituent of tailpipe emissions, is a contributor to smog formation.********************************