This list is an ongoing process. It will be added to as, well, as I decide to add things. I may also try to make it a more useable format at some point. If you have a better definition, or a new term to add, feel free to email me! [email protected]

• ABSORPTANCE - The ratio of the radiation absorbed by a surface to the total energy falling on that surface described as a percentage.
• AFRAMAX TANKER - A tanker of 75,000 to 115,000 dwt.
• AFUE (Annual Fuel Utilization Efficiency) - A measure of heating efficiency, in consistent units, determined by applying the federal test method for furnaces. This value is intended to represent the ratio of heat transferred to the conditioned space by the fuel energy supplied over one year.
• ANGLE OF INCIDENCE - The angle that the sun's rays make with a line perpendicular to a surface. The angle of incidence determines the percentage of direct sunshine intercepted by a surface.
• ANSI - American National Standards Institute is the national organization that coordinates development and maintenance of consensus standards and sets rules for fairness in their development. ANSI also represents the USA in developing international standards.
• ANTHRACITE - Hard coal, found deep in the earth. It burns very hot, with little flame. It usually has a heating value of 12,000-15,000 British thermal units (Btus) per pound.
• ASHRAE - Acronym for American Society of Heating, Refrigerating and Air- Conditioning Engineers.
• ATOM - The smallest unit of an element consisting of a dense positively charged nucleus (of protons and neutrons) orbited by negatively charged electrons.
• AZIMUTH - The angular distance between true south and the point on the horizon directly below the sun.
• BARREL OF OIL - Historically, actual barrels containing 42 US Gallons. One barrel of oil has an energy content of 6 million British thermal units. We have long since stopped transporting oil in barrels, but the unit of measurement � 42 gallons � still exists. ( http://en.wikipedia.org/wiki/Barrel)
• BARRELS PER DAY EQUIVALENT (BPD-Equivalent) - A unit of measure that tells how much oil would have to be burned to produce the same amount of energy.
• BASE LOAD - The lowest level of power production needs during a season or year.
• BATTERY - A device that stores energy and produces electric current by chemical action.
• BIODIESEL - A biodegradable transportation fuel for use in diesel engines that is produced through the transesterification of organically- derived oils or fats. It may be used either as a replacement for or as a component of diesel fuel.
• BIOMASS - Energy resources derived from organic matter. These include wood, agricultural waste and other living-cell material that can be burned to produce heat energy. They also include algae, sewage and other organic substances that may be used to make energy through chemical processes.
• BITUMINOUS COAL - Soft coal containing large amounts of carbon. It has a luminous flame and produces a great deal of smoke.
• BTU (British Thermal Unit) - A measurement of the amount of heat energy in a substance. The amount of heat necessary to raise 1 pound of water one degree F. About equal to a kitchen match.
• BUNKERS - Heavy fuel oil used to power a ship's engines.
• CAPACITY FACTOR - The ratio of the actual output of a power plant as compared to it�s output if it had operated at full nameplate capacity. The percentage of nameplate generation capacity that is actually available. (http://en.wikipedia.org/wiki/Capacity_factor)
• CELSIUS - A temperature scale based on the freezing (0 degrees) and boiling (100 degrees) points of water. Abbreviated as C in second and subsequent references in text. Formerly known as Centigrade. To convert Celsius to Fahrenheit, multiply the number by 9, divide by 5, and add 32.
• COAL - Black or brown rock, formed under pressure from organic fossils in prehistoric times, that is mined and burned to produce heat energy.
• COMBINED CYCLE PLANT - An electric generating station that uses waste heat from its gas turbines to produce steam for conventional steam turbines.
• COMPRESSED NATURAL GAS (CNG) - Natural gas that has been compressed under high pressure, typically between 2,000 and 3,600 pounds per square inch, held in a container. The gas expands when released for use as a fuel.
• CONDUCTION - The transfer of heat energy through a material (solid, liquid or gas) by the motion of adjacent atoms and molecules without gross displacement of the particles.
• CONVECTION - Transferring heat by moving air, or transferring heat by means of upward motion of particles of liquid or gas heat from beneath.
• CFM (cubic feet per minute) - A measure of flow rate.
• CURIE - A measure of radioactivity.
• DEMAND - The rate at which energy is delivered to loads and scheduling points by generation, transmission or distribution facilities.
• DENSITY - The mass of a unit volume of a substance.
• DISTRIBUTED GENERATION - A distributed generation system involves small amounts of generation located on a utility's distribution system for the purpose of meeting local (substation level) peak loads and/or displacing the need to build additional (or upgrade) local distribution lines.
• DRAFT - Vertical distance between the waterline and the vessel's keel.
• DWT (Deadweight tonne) - The maximum weight of cargo and supplies that can be carried by a ship, expressed in long tons (2,240 lbs).
• EER (Energy Efficiency Ratio) - The ratio of cooling capacity of an air conditioning unit in Btus per hour to the total electrical input in watts under specified test conditions.
• EFFICIENCY - The ratio of the useful energy delivered by a dynamic system (such as a machine, engine, or motor) to the energy supplied to it over the same period or cycle of operation.
• ELECTROLYSIS - Breaking a chemical compound down into its elements by passing a direct current through it. Electrolysis of water, for example, produces hydrogen and oxygen.
• ELECTROMAGNETIC FIELDS (EMF) - Ordinary every day use of electricity produces magnetic and electric fields. These 60 Hertz fields (fields that go back and forth 60 times a second) are associated with electrical appliances, power lines and wiring in buildings.
• ENERGY - The capacity for doing work. Forms of energy include: thermal, mechanical, electrical and chemical. Energy may be transformed from one form into another.
• ENERGY RESERVES - The portion of total energy resources that is known and can be recovered with presently available technology at an affordable cost.
• FISSION - A release of energy caused by the splitting of an atom's nucleus. This is the energy process used in conventional nuclear power plants to make the heat needed to run steam electric turbines.
• FISSIONABLE MATERIAL - A substance whose atoms can be split by slow neutrons. Uranium-235, plutonium-239 and uranium-233 are fissionable materials.
• FLARE GAS - Unwanted natural gas that is disposed of by burning as it is released from an oil field. Known as Flaring Off
• FOSSIL FUEL - Oil, coal, natural gas or their by-products. Fuel that was formed in the earth in prehistoric times from remains of living-cell organisms.
• FOOTCANDLE - A unit of illuminance on a surface that is one foot from a uniform point source of light of one candle and is equal to one lumen per square foot.
• FUEL CELL - A device or 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 into 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, thus producing electricity. http://en.wikipedia.org/wiki/Fuel_cell
• FUSION ENERGY - A power source, now under development, based on the release of energy that occurs when atoms are combined under the most extreme heat and pressure. It is the energy process of the sun and the stars.
• GEOTHERMAL ENERGY - Natural heat from within the earth, captured for production of electric power, space heating or industrial steam.
• GEOTHERMAL STEAM - Steam drawn from deep within the earth.
• GROSS TON (Shipping) - Unit of 100 cubic feet or 2.831 cubic meters used in arriving at the calculation of gross tonnage.
• HEAT ENGINE - An engine that converts heat to mechanical energy.
• HEATING VALUE - The amount of heat produced by the complete combustion of a given amount of fuel
• HIGH-SULFUR COAL - Coal whose weight is more than one percent sulfur.
• HORSEPOWER (HP) - A unit for measuring the rate of doing work. One horsepower equals about three-fourths of a kilowatt (745.7 watts).
• HYDRAULIC FRACTURING (Fracking) - A common technique used to stimulate the production of oil and natural gas - Normally in shale rock. A liquid is injected into the ground to create fractures that extend from the well bore into the rock.
  http://en.wikipedia.org/wiki/Hydraulic_fracturing - http://www.earthworksaction.org/FracingDetails.cfm
• HYDROELECTRIC POWER - Electricity produced by falling water that turns a turbine generator. Also referred to as HYDRO.
• INCANDESCENT LAMP - An electric lamp in which a filament is heated by an electric current until it emits visible light.
• INSOLATION - The total amount of solar radiation (direct, diffuse, and reflected) striking a surface exposed to the sky.
• ION - An atom or group of atoms that is electrically charged.
• ISO - INDEPENDENT SYSTEM OPERATOR. A neutral operator responsible for maintaining instantaneous balance of the grid system
• JOULE - A unit of work or energy equal to the amount of work done when the point of application of force of 1 newton is displaced 1 meter in the direction of the force. It takes 1,055 joules to equal a British thermal unit. It takes about 1 million joules to make a pot of coffee.
• KILOWATT - 1000 watts - A measurement of the rate at which work is done.
• KILOWATT-HOUR (kWh) - 1000 watt hours.The most commonly-used unit of measure telling the amount of electricity consumed over time. It means one kilowatt of electricity supplied for one hour. A measure of the amount of energy
• KNOT - A measure of the speed of a vessel. 1 knot = 1 nautical mile per hour, = 1,85 km/h = 1,15 miles per hour
• LANDFILL GAS - Gas generated by the natural degrading and decomposition of municipal solid waste by anaerobic microorganisms in sanitary landfills. The gases produced, carbon dioxide and methane, can be collected by a series of low-level pressure wells and can be processed into a medium Btu gas that can be burned to generate steam or electricity.
• LATENT HEAT - A change in the heat content that occurs without a corresponding change in temperature, usually accompanied by a change of state (as from liquid to vapor during evaporation).
• LIGNITE - Brownish black coal having qualities in between those of bituminous coal and peat. The texture of the original wood often is visible in lignite.
• LIQUEFACTION - The process of making synthetic liquid fuel from coal. The term also is used to mean a method for making large amounts of gasoline and heating oil from petroleum.
• LIQUEFIED GASES - Gases that have been or can be changed into liquid form. These include butane, butylene, ethane, ethylene, propane and propylene.
• LNG (LIQUEFIED NATURAL GAS) - Natural gas that has been condensed to a liquid, typically by cryogenically cooling the gas to minus 260 degrees Fahrenheit (below zero).
• LPG (LIQUEFIED PETROLEUM GAS) - A mixture of gaseous hydrocarbons, mainly propane and butane that change into liquid form under moderate pressure. LPG or propane is commonly used as a fuel for rural homes for space and water heating, as a fuel for barbecues and recreational vehicles, and as a transportation fuel. It is normally created as a by-product of petroleum refining and from natural gas production.
• LOAD FACTOR - A percent telling the difference between the amount of electricity a consumer used during a given time span and the amount that would have been used if the usage had stayed at the consumer's highest demand level during the whole time. The term also is used to mean the percentage of capacity of an energy facility - such as power plant or gas pipeline - that is utilized in a given period of time.
• LOW-SULFUR COAL - Coal having one percent or less of sulfur by weight.
• LOW-SULFUR OIL - Oil having one percent or less of sulfur by weight.
• LUMEN - A measure of the amount of light available from a light source equivalent to the light emitted by one candle.
• LUX - A unit of illumination equal to the direct illumination on a surface that is everywhere one meter from a uniform point source of one candle; a unit of illumination that is equal to one lumen per square meter. Also see footcandle.
• M85 - A blend of 85 percent methanol and 15 percent unleaded regular gasoline, used as a motor fuel.
• M100 - 100 percent (neat) methanol used as a motor fuel in dedicated methanol vehicles, such as some heavy-duty truck engines.
• MAGNETO HYDRO DYNAMICS (MHD) - A means of producing electricity directly by moving liquids or gases through a magnetic field.
• MARSH GAS - A common term for gas that bubbles to the surface of the water in a marsh or swamp. It is colorless, odorless and can be explosive.
• MCF - One thousand cubic feet or natural gas, having an energy value of one million Btu.
• MEGAWATT - 1 Million (1,000,000) watts.
• MEGAWATT-HOUR - 1 Million (1,000,000) watt hours � A measure of the amount of energy.
• METHANE - A light hydrocarbon that is the main component of natural gas and marsh gas. It is the product of the anaerobic decomposition of organic matter, enteric fermentation in animals and is one of the greenhouse gases. Chemical formula is CH4.
• METHANOL (also known as Methyl Alcohol, Wood Alcohol, CH3OH) - A liquid formed by catalytically combining carbon monoxide (CO) with hydrogen (H2) in a 1:2 ratio, under high temperature and pressure. Commercially it is typically made by steam reforming natural gas. Also formed in the destructive distillation of wood.
• METHYL TERTIARY BUTYL ETHER (MTBE) - An ether manufactured by reacting methanol and isobutylene. The resulting ether has a high octane and low volatility. MTBE is a fuel oxygenate and is permitted in unleaded gasoline up to a level of 15 percent. It is one of the primary ingredients in reformulated gasolines.
• MTBE (METHYL TERTIARY-BUTYL ETHER) - A clean- burning oxygenate with high octane and low volatility added to unleaded gasoline to reduce carbon monoxide emissions.
• NAMEPLATE CAPACITY - The rated output of a generator. Maximum output.
• NAMEPLATE CAPACITY - The total manufacturer-rated capacities of equipment such as turbines, generators, condensers, transformers, and other system components.
• NATURAL GAS - Hydrocarbon gas found in the earth, composed of methane, ethane, butane, propane and other gases.
• NGV (NATURAL GAS VEHICLE) - vehicles that are powered by compressed or liquefied natural gas.
• NEUTRON - An uncharged particle found in the nucleus of every atom except that of hydrogen.
• NEWTON - A unit of force. The amount of force it takes to accelerate one kilogram at one meter per second per second.
• NOx - Oxides of nitrogen that are a chief component of air pollution that can be produced by the burning of fossil fuels. Also called nitrogen oxides.
• OCTANE - A rating scale used to grade gasoline as to its antiknock properties. Also any of several isometric liquid paraffin hydrocarbons, C8H18. Normal octane is a colorless liquid found in petroleum boiling at 124.6 degrees Celsius.
• OCTANE RATING - A measure of a gasoline's resistance to exploding too early in the engine cycle, which causes knocking. The higher the rating, the lower the chance of premature ignition.
• OHM - A unit of measure of electrical resistance. One volt can produce a current of one ampere through a resistance of one ohm.
• OIL SHALE - A type of rock containing organic matter that produces large amounts of oil when heated to high temperatures.
• OPEC - Acronym for Organization of Petroleum Exporting Countries founded in 1960 for unify and coordinate petroleum polices of the members. Headquarters is in Vienna, Austria.
• OXYGENATE - A term used in the petroleum industry to denote octane components containing hydrogen, carbon and oxygen in their molecular structure. Includes ethers such as MTBE and ETBE and alcohols such as ethanol or methanol. The oxygenate is a prime ingredient in reformulated gasoline. The increased oxygen content given by oxygenates promotes more complete combustion, thereby reducing tailpipe emissions.
• OZONE - A kind of oxygen that has three atoms per molecule instead of the usual two. Ozone is a poisonous gas, but the ozone layer in the upper atmosphere shields life on earth from deadly ultraviolet radiation from space. The molecule contains three oxygen atoms (O3).
• PADD (PETROLEUM ADMINISTRATION FOR DEFENSE DISTRICTS) - The United States is divided by the U.S. Department of Energy into five PADD regions for planning purposes.
• PARTICULATE MATTER (PM) - Unburned fuel particles that form smoke or soot and stick to lung tissue when inhaled. A chief component of exhaust emissions from heavy-duty diesel engines.
• PANAMAX - A vessel of approximately 50,000 to 80,000 dwt, of maximum lenght, breadth and draft capable of passing fully loaded through the Panama Canal.
• PASSIVE SOLAR ENERGY - Use of the sun to help meet a building's energy needs by means of architectural design (such as arrangement of windows) and materials (such as floors that store heat, or other thermal mass).
• PEAKER - A nickname for a power generating station that is normally used to produce extra electricity during peak load times.
• PEAK LOAD - The highest electrical demand within a particular period of time. Daily electric peaks on weekdays occur in late afternoon and early evening. Annual peaks occur on hot summer days.
• PEAK LOAD POWER PLANT - A power generating station that is normally used to produce extra electricity during peak load times.
• PEAKING UNIT - A power generator used by a utility to produce extra electricity during peak load times.
• PETROLEUM COKE (often abbreviated Pet coke or petcoke) - A carbonaceous solid derived from oil refinery coker units or other cracking processes. It is mostly solid carbon, and is used as such in manufacturing. When burned it produces extremely high heat, so it is also used in various heat furnaces (such as forges, and metal refining) in place of coal coke.
• PHOTOSYNTHESIS - A process by which green plants change carbon dioxide into oxygen and organic materials. The energy for this process comes from sunlight.
• PHOTOVOLTAIC CELL - A semiconductor that converts light directly into electricity
• PROPANE - A gas that is both present in natural gas and refined from crude oil. It is used for heating, lighting and industrial applications. See also LPG.
• QUAD - One quadrillion (1,000,000,000,000,000) British thermal units (Btus). An amount of energy equal to 170 million barrels of oil.
• RAD - A unit of measure of absorbed radiation. Acronym for radiation absorbed dose. One rad equals 100 ergs of radiation energy per gram of absorbing material.
• RADIANT ENERGY - Energy transferred by the exchange of electromagnetic waves from a hot or warm object to one that is cold or cooler. Direct contact with the object is not necessary for the heat transfer to occur.
• RADIATION - The flow of energy across open space via electromagnetic waves such as light. Passage of heat from one object to another without warming the air space in between.
• RANKINE CYCLE - The steam-Rankine cycle employing steam turbines has been the mainstay of utility thermal electric power generation for many years. The cycle, as developed over the years uses superheat, reheat and regeneration. Modern steam Rankine systems operate at a cycle top temperature of about 1,073 degrees Celsius with efficiencies of about 40 percent.
• REFINERY - A facility that separates crude oil into varied oil products. The refinery uses progressive temperature changes to separate by vaporizing the chemical components of crude oil that have different boiling points. These are distilled into usable products such as gasoline, fuel oil, lubricants and kerosene.
• REID VAPOR PRESSURE (RVP) - A standard measurement of a liquid's vapor pressure in pounds per square inch at 100 degrees Fahrenheit. It is an indication of the propensity of the liquid to evaporate
• RETORTING - The heating of oil shale to get the oil out from it.
• SEER (Seasonal Energy Efficiency Ratio) - The total cooling output of a central air conditioning unit in Btus during its normal usage period for cooling divided by the total electrical energy input in watt-hours during the same period, as determined using specified federal test procedures.
• SHALE GAS - Natural gas produced from shale. http://en.wikipedia.org/wiki/Shale_gas
• SOLAR CELL - A photovoltaic cell that can convert light directly into electricity. A typical solar cell uses semiconductors made from silicon.
• SOLAR COLLECTOR - A component of an active or passive solar system that absorbs solar radiation to heat a transfer medium which, in turn, supplies heat energy to the space or water heating system.
• SOLAR ENERGY - Heat and light radiated from the sun.
• SOLAR IRRADIATION - The amount of radiation, both direct and diffuse, that can be received at any given location.
• SOLAR RADIATION - Electromagnetic radiation emitted by the sun.
• SPECIFIC HEAT - In English units, the quantity of heat, in Btu, needed to raise the temperature of one pound of material one degree Fahrenheit.
• STILL GAS (refinery gas) - Any form or mixture of gases produced in refineries by distillation, cracking, reforming, and other processes. This gas mixture includes methane, ethane, ethylene, normal butane, butylene, propane, propylene, etc. Still gas is used as a fuel for the refinery, and as a feedstock for making petrochemicals.
• STIRLING ENGINE - An external combustion engine that converts heat into useable mechanical energy (shaftwork) by the heating (expanding) and cooling (contracting) of a captive gas such as helium or hydrogen.
• SUEZMAX - A vessel of approximately 130,000 to 160,000 dwt, of maximum lenght, breadth and draft capable of passing fully loaded through the Suez Canal.
• SYNFUEL - Synthetic gas or synthetic oil. Fuel that is artificially made as contrasted to that which is found in nature. Synthetic gas made from coal is considered to be more economical and easier to produce than synthetic oil. When natural gas supplies in the earth are being depleted, it is expected that synthetic gas will be able to be used widely as a substitute fuel.
• SYNGAS - Synthetic gas made from coal.
• TAR SANDS - Sedimentary rocks containing heavy oil that cannot be extracted by conventional petroleum recovery methods
• TAME (TERTIARY AMYL METHYL ETHER) - An oxygenate that can be used in reformulated gasoline. It is an ether based on reactive C5 olefins and methanol.
• TARIFF - A document, approved by the responsible regulatory agency,listing the terms and conditions, including a schedule of prices, under which utility services will be provided.
• THERM - One hundred thousand (100,000) British thermal units (1 therm = 100,000 Btu).
• THERMODYNAMICS - A study of the transformation of energy into other manifested forms and of their practical applications. The three laws of thermodynamics are:
  • 1. Law of Conservation of Energy -- Energy can neither be created nor destroyed. It can only change forms. In any process in an isolated system, the total energy remains the same. Energy may be transformed in an isolated system, but its total is constant
  • 2. Entropy -- energy systems have a tendency to increase their entropy rather than decrease it. IE: Heat can spontaneously flow from a higher-temperature region to a lower-temperature region, but not the other way around. Heat cannot be changed directly into work at constant temperature by a cyclic process
  • 3. As temperature approaches absolute zero, the entropy of a system approaches a constant minimum. IE: Heat capacity and entropy of every crystalline solid becomes zero at absolute zero (0 degrees Kelvin)
• TON OF COOLING - A useful cooling effect equal to 12,000 Btu hours. Originally, how much heat could be absorbed by a one ton block of ice.
• TONNE - A metric tonne of 1,000 kilograms or 2,240 pounds.
• TRANSMITTANCE - The time rate of heat flow per unit area under steady conditions from the air (or other fluid) on the warm side of a barrier to the air (or fluid) on the cool side, per unit temperature difference between the two sides.
• WATT - A measurement of the rate at which work is done. One watt is equal to 1 joule (J) of energy per second. ( http://en.wikipedia.org/wiki/Watt)
• WATT-HOUR - A measure of an amount of energy. One watt of power expended for one hour

Here is another glossary from the EIA (Energy Information Administration): http://www.eia.doe.gov/glossary