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ACTIVE SOLAR ENERGY SYSTEM: A system designed to convert solar radiation into usable energy for space, water heating, or other uses. It requires a mechanical device, usually a pump or fan, to collect the sun's energy.
AGGREGATOR: An entity responsible for planning, scheduling, accounting, billing, and settlement for energy deliveries from the aggregator's portfolio of sellers and/or buyers. Aggregators seek to bring together customers or generators so they can buy or sell power in bulk, making a profit on the transaction.
AIR CONDITIONER: An assembly of equipment for air treatment consisting of a means for ventilation, air circulation, air cleaning, and heat transfer (either heating or cooling). The unit usually consists of an evaporator or cooling coil, and an electrically-driven compressor and condenser combination.
AIR POLLUTION: Unwanted particles, mist or gases put into the atmosphere as a result of motor vehicle exhaust, the operation of industrial facilities or other human activity.
AMBIENT AIR TEMPERATURE: Surrounding temperature, such as the outdoor air temperature around a building.
ALTERNATING CURRENT (AC): Flow of electricity that constantly changes direction between positive and negative sides. Almost all power produced by electric utilities in the United States moves in current that shifts direction at a rate of 60 times per second.
ALTERNATIVE FUELS: As defined by the National Energy Policy Act (EPAct) the fuels are methanol, denatured ethanol and other alcohols, separately or in mixtures of 85 percent by volume or more (or other percentage not less than 70 percent as determined by U.S. Department of Energy rule) with gasoline or other fuels; CNG; LNG; LPG; hydrogen; "coal-derived liquid fuels;" fuels "other than alcohols" derived from "biological materials;" electricity, or any other fuel determined to be "substantially not petroleum" and yielding "substantial energy security benefits and substantial environmental benefits."
ALTERNATIVE FUEL VEHICLE (AFV): Motor vehicles that run on fuels other than petroleum-based fuels. This excludes reformulated gasoline as an alternative fuel.
AMPERE (AMP): The unit of measure that tells how much electricity flows through a conductor. It is like using cubic feet per second to measure the flow of water. For example, a 1,200 watt, 120-volt hair dryer pulls 10 amperes of electric current (watts divided by volts).
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.
ANIMAL WASTE CONVERSION: Process of obtaining energy from animal wastes creating a type of biomass energy.
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.
ASH: Non-organic, non-flammable substance left over after combustible material has been completely burned.
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. Typically used as an input for opaque surfaces and windows in computer programs for calculating the energy performance of buildings.
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BALLAST: A device that provides starting voltage and limits the current during normal operation in electrical discharge lamps (such as fluorescent lamps).
BARREL: In the petroleum industry, a barrel is 42 U.S. gallons. One barrel of oil has an energy content of 6 million British thermal units (Btu). It takes one barrel of oil to make enough gasoline to drive an average car from Los Angeles to San Francisco and back (at 18 miles per gallon over the 700-mile round trip).
BARRELS PER DAY EQUIVALENT: A unit of measure that tells how much oil would have to be burned to produce the same amount of energy. For example, California's hydroelectric generation in 1983 was 58,000 barrels per day equivalent.
BATTERY: A device that stores energy and produces electric current by chemical action.
BIOCONVERSION: Processes that use plants or micro-organisms to change one form of energy into another. For example, an experimental process uses algae to convert solar energy into gas that could be used for fuel.
BIODIESEL: A biodegradable transportation fuel for use in diesel engines that is produced through the transesterfication of organically-derived oils or fats. It may be used either as a replacement for or as a component of diesel fuel.
BIOGAS: A mixture of methane and carbon dioxide produced by the bacterial decomposition of organic wastes and used as a 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. Bituminous coal is the most abundant coal in active U.S. mining regions. The heat content of bituminous coal consumed in the United States averages 24 million Btu per ton.
BLACKOUT: A power loss affecting many electricity consumers over a large geographical area for a significant period of time.
BOILER: A closed vessel in which water is converted to pressurized steam.
BOTTLED GAS: The liquefied petroleum gases propane and butane, contained under moderate pressure (about 125 pounds per square inch and 30 pounds per square inch respectively), in cylinders.
BREEDER: A nuclear reactor that produces more fuel than it consumes. The breeder, invented in the United States , is used as a power source in several European countries.
BRITISH THERMAL UNIT (Btu): The standard measure of heat energy. It takes one Btu to raise the temperature of one pound of water by one degree Fahrenheit at sea level. For example, it takes about 2,000 Btus to make a pot of coffee. One Btu is equivalent to 252 calories, 778 foot-pounds, 1055 joules, and 0.293 watt-hours.
BROKER: A retail agent who buys and sells power. The agent may also aggregate customers and arrange for transmission, firming and other ancillary services as needed.
BROWNOUT: A controlled power reduction in which the utility decreases the voltage on the power lines, so customers receive weaker electric current. Brownouts can be used if total power demand exceeds the maximum available supply. The typical household does not notice the difference.
BUNKER C FUEL OIL: A very heavy substance, left over after other fuels have been distilled from crude oil. Also called NO. 6 FUEL, it is used in power plants, ships and large heating installations. Bunker C fuel oil has high sulfur content, which causes air quality concerns when burned as fuel.
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CALORIE: One energy calorie is equivalent to 4.2 joules. Thus, it takes 500,000 calories of energy to boil a pot of coffee. One food calorie equals 1,000 energy calories.
CAPACITY: The maximum amount of electricity that a generating unit, power plant or utility can produce under specified conditions. Capacity is measured in megawatts and is also referred to as the nameplate rating.
CARBON DIOXIDE (CO 2): A colorless, odorless, non-poisonous gas that is a normal part of the air. Carbon dioxide, also called CO 2, is exhaled by humans and animals and is absorbed by green growing things and by the sea.
CARBON MONOXIDE (CO): A colorless, odorless, highly poisonous gas made up of carbon and oxygen molecules formed by the incomplete combustion of carbon or carbonaceous material, including gasoline. It is a major air pollutant on the basis of weight.
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.
CHEMICAL ENERGY: The energy generated when a chemical compound combusts, decomposes, or transforms to produce new compounds.
CIRCUIT: One complete run of a set of electric conductors from a power source to various electrical devices (appliances, lights, etc.) and back to the same power source.
COAL: Black or brown rock, formed under pressure from organic fossils in prehistoric times, that is mined and burned to produce heat energy.
COGENERATOR: Cogenerators use the waste heat created by one process, for example during manufacturing, to produce steam, which is used, in turn, to spin a turbine and generate electricity. (Also known as Combined Heat and Power [CHP] Plants)
COGENERATION: Cogeneration means the sequential use of energy for the production of electrical and useful thermal energy. The sequence can be thermal use followed by power production or the reverse, subject to the following standards: (a) At least 5 percent of the cogeneration project's total annual energy output shall be in the form of useful thermal energy. (b) Where useful thermal energy follows power production, the useful annual power output plus one-half the useful annual thermal energy output equals not less than 42.5 percent of any natural gas and oil energy input.
COKE: A porous solid left over after the incomplete burning of coal or of crude oil.
COMBINED CYCLE PLANT: An electric generating station that uses waste heat from its gas turbines to produce steam for conventional steam turbines. Also known as Cogenerator.
COMBUSTION: Burning - Rapid oxidation, with the release of energy in the form of heat and light.
COMFORT ZONE: The range of temperatures over which the majority of persons feel comfortable (neither too hot nor too cold).
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.
CONDUCTIVITY (k): The quantity of heat that will flow through one square foot of homogeneous material, one inch thick, in one hour, when there is a temperature difference of one degree Fahrenheit.
CONDUCTOR: A substance or medium that transmits heat, light, or sound.
CONSERVATION: Steps taken to cause less energy to be used than would otherwise be the case. These steps may involve improved efficiency, avoidance of waste, reduced consumption, etc. They may involve installing equipment (such as a computer to ensure efficient energy use), modifying equipment (such as making a boiler more efficient), adding insulation, changing behavior patterns, etc.
CONVECTION: Transferring heat by moving air, or transferring heat by means of upward motion of particles of liquid or gas heat from beneath.
COOLING DEGREE DAY: A unit of measure that indicates how heavy the air conditioning needs are under certain weather conditions.
COORDINATE SYSTEM: A system used to measure horizontal and vertical distances on a planimetric map. A coordinate system is usually defined by a map projection, a spheroid of reference, a datum, one or more standard parallels, a central meridian, and possible shifts in the x- and y- directions to locate x/y positions of a point, line, and area features in a coverage.
CORD: A measure of volume, 4 by 4 by 8 feet, used to define amounts of stacked wood available for use as fuel. Burned, a cord of wood produces about 5 million calories of energy.
CRUDE OIL: Petroleum as found in the earth, before it is refined into oil products. Crude oil is refined to produce petroleum products, including heating oils; gasoline, diesel and jet fuels; lubricants; asphalt; ethane, propane, and butane; and many other products used for their energy or chemical content.
CUBIC FOOT: The most common unit of measurement of natural gas volume. It equals the amount of gas required to fill a volume of one cubic foot under stated conditions of temperature, pressure and water vapor. One cubic foot of natural gas has an energy content of approximately 1,000 Btus. One hundred (100) cubic feet equals one therm (100 ft 3 = 1 therm).
CURIE: A measure of radioactivity.
CUBIC FEET PER MINUTE (CFM): A measure of flow rate.
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DATA MODEL: A formal method of arranging data to mimic the behavior of the real world entities they represent. Fully developed data models describe data types, integrity rules for the data types, and operations on the data types.
DATUM: A set of parameters and control points used to accurately define the three-dimensional shape of the Earth (e.g. as a spheroid). The corresponding datum is the basis for a planar coordinate system.
DAYLIGHTING: The use of sunlight to supplement or replace electric lighting.
DEGREE DAY: A unit, based upon temperature difference and time, used in estimating fuel consumption and specifying nominal annual heating load of a building. When the mean temperature is less than 65 degrees Fahrenheit the heating degree days are equal to the total number of hours that temperature is less than 65 degrees Fahrenheit for an entire year.
DEMAND SITE MANAGEMENT: Planning, implementation, and evaluation of utility-sponsored programs to influence the amount or timing of customers' energy use.
DEMAND: The level at which electricity or natural gas is delivered to users at a given point in time. Electric demand is expressed in kilowatts.
DEPARTMENT OF ENERGY (DOE): The federal department established by the Department of Energy Organization Act to consolidate the major federal energy functions into one cabinet-level department that would formulate a comprehensive, balanced national energy policy.
DEREGULATION: The elimination of regulation from a previously regulated industry or sector of an industry.
DESALINATION: The removal of salt from saline or sea water.
DIESEL OIL: Fuel for diesel engines obtained from the distillation of petroleum. It is composed chiefly of aliphatic hydrocarbons. Its volatility is similar to that of gas oil. Its efficiency is measured by cetane number.
DIGITAL ELEVATION MODEL (DEM): A topographic surface arranged in a data file as a set of regularly spaced x, y, z locations where z represents elevation.
DIRECT CURRENT (DC): Electricity that flows continuously in the same direction.
DISTILLATE FUEL OIL NO. 1 Diesel Fuel: A light distillate fuel oil that has distillation temperatures of 550 degrees Fahrenheit at the 90 percent point and meets the specifications defined in ASTM Specification D 975. It is used in high-speed diesel engines, such as those in city buses and similar vehicles.
DISTILLATE FUEL OIL NO. 2 Diesel Fuel: A fuel that has distillation temperatures of 500 degrees Fahrenheit at the 10 percent recovery point and 640 degrees Fahrenheit at the 90 percent recovery point and meets the specifications defined in ASTM Specification D 975. It is used in high-speed diesel engines, such as those in railroad locomotives, trucks, and automobiles. Low Sulfur Diesel Fuel: No. 2 diesel fuel that has a sulfur level no higher than 0.05 percent by weight. It is used primarily in motor vehicle diesel engines for on-highway use. High Sulfur Diesel Fuel: No. 2 diesel fuel that has a sulfur level above 0.05 percent by weight. Fuel oil (Heating Oil): A distillate fuel oil that has distillation temperatures of 400 degrees Fahrenheit at the 10 percent recovery point and 640 degrees Fahrenheit at the 90 percent recovery point and meets the specifications defined in ASTM Specification D 396. It is used in atomizing type burners for domestic heating or for moderate capacity commercial/industrial burner units.
DISTILLATE FUEL OIL NO. 4 No. 4 Fuel: A distillate fuel oil made by blending distillate fuel oil and residual fuel oil stocks. It conforms with ASTM Specification D 396 or Federal Specification VV-F-815C and is used extensively in industrial plants and in commercial burner installations that are not equipped with preheating facilities. It also includes No. 4 diesel fuel used for low- and medium-speed diesel engines and conforms to ASTM Specification D 975.
DISTILLATE FUEL OIL: A general classification for one of the petroleum fractions produced in conventional distillation operations. It includes diesel fuels and fuel oils. Products known as No. 1, No. 2, and No. 4 diesel fuel are used in on-highway diesel engines, such as those in trucks and automobiles, as well as off-highway engines, such as those in railroad locomotives and agricultural machinery. Products known as No. 1, No. 2, and No. 4 fuel oils are used primarily for space heating and electric power generation.
DISTRIBUTION: The delivery of electricity to the retail customer's home or business through low voltage distribution lines.
DISTRIBUTION SYSTEM: The substations, transformers and lines that convey electricity from high-power transmission lines to ultimate consumers.
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ELECTRIC UTILITY: Any person or state agency with a monopoly franchise (including any municipality), which sells electric energy to end-use customers; this term includes the Tennessee valley Authority, but does not include other Federal power marketing agency.
ELECTRICITY CONGESTION: A condition that occurs when insufficient transmission capacity is available to implement all of the desired transactions simultaneously.
ELECTRICITY DEMAND: The rate at which energy is delivered to loads and scheduling points by generation, transmission, and distribution facilities.
ENERGY EFFICIENCY: Using less energy/electricity to perform the same function or programs designed to use electricity more efficiently by doing the same with less. "Energy conservation" is a term which has also been used but it has the connotation of doing without in order to save energy rather than using less energy to do the some thing.
THE ENVIRONMENTAL PROTECTION AGENCY (EPA): A federal agency charged with protecting the environment.
ELECTRIC GENERATOR: A device that converts a heat, chemical or mechanical energy into electricity.
ELECTRICITY: A property of the basic particles of matter. A form of energy having magnetic, radiant and chemical effects. Electric current is created by a flow of charged particles (electrons).
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.
EMISSION STANDARD: The maximum amount of a pollutant legally permitted to be discharged from a single source.
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 BUDGET: A requirement in the Building Energy Efficiency Standards that a proposed building be designed to consume no more than a specified number of British thermal units (Btus) per year per square foot of conditioned floor area.
ENERGY RESERVES: The portion of total energy resources that is known and can be recovered with presently available technology at an affordable cost.
ENERGY RESOURCES: Everything that could be used by society as a source of energy.
ETHANOL (CH3CH2OH): A liquid that is produced chemically from ethylene or biologically from the fermentation of various sugars from carbohydrates found in agricultural crops and 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 percent concentration. Ethanol can also be used in higher concentration (E85) in vehicles optimized for its use. Also know as Ethyl Alcohol or Grain Alcohol.
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 percent by volume. ETBE is used as an oxygenate in some reformulated gasolines.
EXTRA HIGH VOLTAGE (EHV): Voltage levels higher than those normally used on transmission lines. Generally EHV is considered to be 345,000 volts or higher.
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FAHRENHEIT (F): A temperature scale in which the boiling point of water is 212 degrees and its freezing point is 32 degrees. To convert Fahrenheit to Celsius, subtract 32, multiply by 5, and divide the product by 9.
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.
FLAT PLATE: A device used to collect solar energy. It is a piece of metal painted black on the side facing the sun, to absorb the sun's heat.
FLUE GAS: Gas that is left over after fuel is burned and which is disposed of through a pipe or stack to the outer air.
FLUORESCENT: A tubular electric lamp that is coated on its inner surface with a phosphor and that contains mercury vapor whose bombardment by electrons from the cathode provides ultraviolet light which causes the phosphor to emit visible light either of a selected color or closely approximating daylight.
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.
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.
FUEL: A substance that can be used to produce heat or power.
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.
FUEL OIL: Petroleum products that are burned to produce heat or power.
FUEL ROD: A long slender tube that holds fissionable material (fuel) for nuclear reactor use. Fuel rods are assembled into bundles called fuel elements or assemblies, which are loaded individually into the reactor core.
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.
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GALLON: A unit of volume. A U.S. gallon has 231 cubic inches or 3.785 liters.
GAS: Gaseous fuel (usually natural gas) that is burned to produce heat energy. The word is also used colloquially to refer to gasoline.
GAS UTILITY: Any person engaged in, or authorized to engage in, distributing or transporting natural gas, including, but not limited to, any such person who is subject to the regulation of the Public Utilities Commission.
GASIFICATION: The process where biomass fuel is reacted with sub-stoichiometric quantities of air and oxygen usually under high pressure and temperature along with moisture to produce gas which contains hydrogen, methane, carbon monoxide, nitrogen, water and carbon dioxide. The gas can be burned directly in a boiler, or scrubbed and combusted in an engine-generator to produce electricity. The three types of gasification technologies available for biomass fuels are the fixed bed updraft, fixed bed downdraft and fluidized bed gasifies. Gasification is also the production of synthetic gas from coal.
GASOHOL: In the United States, gasohol (E10) refers to gasoline that contains 10 percent ethanol by volume. This term was used in the late 1970s and early 1980s but has been replaced in some areas of the country by terms such as E10, Super Unleaded Plus Ethanol, or Unleaded Plus.
GASOLINE: A light petroleum product obtained by refining oil, and used as motor vehicle fuel.
GASOLINE GRADES: The classification of gasoline by octane ratings. Each type of gasoline (conventional, oxygenated, and reformulated) is classified by three grades - Regular, Mid-grade, and Premium. In general, automotive octane requirements are lower at high altitudes. Therefore, in some areas of the United States , such as the Rocky Mountain States , the octane ratings for the gasoline grades may be 2 or more octane points lower. Regular gasoline: Gasoline having an antiknock index, i.e., octane rating, greater than or equal to 85 and less than 88. Mid-grade gasoline: Gasoline having an antiknock index, i.e., octane rating, greater than or equal to 88 and less than or equal to 90. Premium gasoline: Gasoline having an antiknock index, i.e., octane rating, greater than 90.
GENERATION COMPANY (GENCO): A regulated or non-regulated entity (depending upon the industry structure) that operates and maintains existing generating plants. The Genco may own the generation plants or interact with the short-term market on behalf of plant owners. In the context of restructuring the market for electricity, Genco is sometimes used to describe a specialized "marketer" for the generating plants formerly owned by a vertically-integrated utility.
GEOCODING: The process of finding the map coordinates of a location from an address.
GEOGRAPHIC COORDINATES: Values of latitude and longitude that define the position of a point on the Earth's surface.
GEOGRAPHIC DATA: Information about objects found on the Earth's surface, including their locations, shapes, and attributes. Geographic data can be in vector, raster, or tabular form.
GEOGRAPHIC INFORMATION SYSTEM (GIS): An organized collection of computer hardware, software, geographic data, and personnel designed to efficiently capture, store, update, manipulate, analyze, and display all forms of geographically referenced information.
GEOTHERMAL ENERGY: Hot water or steam extracted from geothermal reservoirs in the earth's crust. Water or steam extracted from geothermal reservoirs can be used for geothermal heat pumps, water heating, or electricity generation.
GEOTHERMAL GRADIENT: The change in the earth's temperature with depth. As one goes deeper, the earth becomes hotter.
GLOBAL WARMING: An increase in the near surface temperature of the Earth. Global warming has occurred in the distant past as the result of natural influences, but the term is today most often used to refer to the warming some scientists predict will occur as a result of increased emissions of greenhouse gases.
GIGAWATT (GW): One thousand megawatts (1,000 MW) or, one million kilowatts (1,000,000 kW) or one billion watts (1,000,000,000 watts) of electricity. One gigawatt is enough to supply the electric demand of about one million average homes.
GREENHOUSE EFFECT: The presence of trace atmospheric gases make the earth warmer than would direct sunlight alone. These gases (carbon dioxide [CO 2], methane [CH 4], nitrous oxide [N 2O], tropospheric ozone [O 3], and water vapor [H 2O]) allow visible light and ultraviolet light (shortwave radiation) to pass through the atmosphere and heat the earth's surface. This heat is re-radiated from the earth in form of infrared energy (longwave radiation). The greenhouse gases absorb part of that energy before it escapes into space. This process of trapping the longwave radiation is known as the greenhouse effect. Scientists estimate that without the greenhouse effect, the earth's surface would be roughly 54 degrees Fahrenheit colder than it is today -- too cold to support life as we know it.
GREENHOUSE GASES: Those gases, such as water vapor, carbon dioxide, nitrous oxide, methane, hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride, that are transparent to solar (short-wave) radiation but opaque to long-wave (infrared) radiation, thus preventing long-wave radiant energy from leaving Earth's atmosphere. The net effect is a trapping of absorbed radiation and a tendency to warm the planet's surface.
GRID: A system of interconnected power lines and generators that is managed so that the generators are dispatched as needed to meet the requirements of the customers connected to the grid at various points. Gridco is sometimes used to identify an independent company responsible for the operation of the grid.
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HEAT ENGINE: An engine that converts heat to mechanical energy.
HEAT GAIN: An increase in the amount of heat contained in a space, resulting from direct solar radiation, heat flow through walls, windows, and other building surfaces, and the heat given off by people, lights, equipment, and other sources.
HEAT LOSS: A decrease in the amount of heat contained in a space, resulting from heat flow through walls, windows, roof and other building surfaces and from exfiltration of warm air.
HEAT PUMP: An air-conditioning unit which is capable of heating by refrigeration, transferring heat from one (often cooler) medium to another (often warmer) medium, and which may or may not include a capability for cooling. This reverse-cycle air conditioner usually provides cooling in summer and heating in winter.
HEATING DEGREE DAY A unit that measure the space heating needs during a given period of time.
HEAVY WATER A type of hydrogen atom that may be used as fuel for fusion power plants. Also called deutrium, it is found in abundance in the seas.
HELIOCHEMICAL: Using solar radiation to cause chemical reactions.
HELIOTHERMAL: A process that uses the sun's rays to produce heat.
HERTZ: A unit of electromagnetic wave frequency that is equal to one cycle per second. -- It is named after Henrich R. Hertz.
HIGH VOLTAGE: High power transmission line service of 110 kilovolts(kv) to 765 kv which is used a primary service for industrial applications.
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).
HEATING VENTILATION AND AIR CONDITIONING (HVAC): A system that provides heating, ventilation and/or cooling within or associated with a building.
HYDROELECTRIC POWER: Electricity produced by falling water that turns a turbine generator. Also referred to as HYDRO.
HYDROGEN: A colorless, odorless, highly flammable gaseous element. It is the lightest of all gases and the most abundant element in the universe, occurring chiefly in combination with oxygen in water and also in acids, bases, alcohols, petroleum, and other hydrocarbons.
HYBRID VEHICLE: Usually a hybrid EV, a vehicle that employs a combustion engine system together with an electric propulsion system. Hybrid technologies expand the usable range of EVs beyond what an all-electric-vehicle can achieve with batteries only.
HYDROTHERMAL SYSTEMS: Underground reservoirs that produce either dry steam or a mixture of steam and water.
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INCANDESCENT LAMP: An electric lamp in which a filament is heated by an electric current until it emits visible light. Much of the energy is converted into heat; therefore, this class of lamp is a relatively inefficient source of light.
INSOLATION: The total amount of solar radiation (direct, diffuse, and reflected) striking a surface exposed to the sky.
INTERNAL COMBUSTION ENGINE: An engine in which fuel is burned inside the engine. A car's gasoline engine or rotary engine is an example of an internal combustion engine. It differs from engines having an external furnace, such as a steam engine.
INTERRUPTIBLE SERVICE: Electricity supplied under agreements that allow the supplier to curtail or stop service at times.
ION: An atom or group of atoms that is electrically charged.
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JOULE (J): 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.
KEROSENE: A light petroleum distillate that is used in space heaters, cook stoves, and water heaters and is suitable for use as a light source when burned in wick-fed lamps.
KILOVOLT (kv): One thousand volts (1,000). Distribution lines in residential areas usually are 12 kv (12,000 volts).
KILOWATT (kW): One thousand (1,000) watts. A unit of measure of the amount of electricity needed to operate given equipment. On a hot summer afternoon a typical home, with central air conditioning and other equipment in use, might have a demand of 4 kW each hour.
KILOWATT-HOUR (kWh): 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. In 1989, a typical household consumes 534 kWh in an average month.
KINETIC ENERGY: The energy (capacity for work) possessed by a body because of its motion.
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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.
LEGEND: The symbol key on a map to describe and explain a map's symbols.
LOAD CENTERS: A geographical area where large amounts of power are drawn by end-users.
LIGNITE: The lowest rank of coal, often referred to as brown coal, used almost exclusively as fuel for steam-electric power generation. It is brownish-black and has a high inherent moisture content, sometimes as high as 45. The heat content of lignite consumed in the United States averages 13 million Btu per ton. The texture of the original wood often is visible in lignite.
LIQUEFIED GASES: Gases that have been or can be changed into liquid form. These include butane, butylene, ethane, ethylene, propane and propylene.
LIQUEFIED NATURAL GAS (LNG): Natural gas that has been condensed to a liquid, typically by cryogenically cooling the gas to minus 327.2 degrees Fahrenheit.
LIQUEFIED PETROLEUM GAS (LPG): 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: The amount of electric power supplied to meet one or more end user's needs or an end-use device or an end-use customer that consumes power. Load should not be confused with demand, which is the measure of power that a load receives or requires.
LOAD MANAGEMENT: Steps taken to reduce power demand at peak load times or to shift some of it to off-peak times. This may be with reference to peak hours, peak days or peak seasons. The main affect on electric peaks is air-conditioning usage, which is therefore a prime target for load management efforts. Load management is achieved by persuading consumers to modify behavior or by using equipment that regulates some electric consumption.
LOW-E: A special coating that reduces the emissivity of a window assembly, thereby reducing the heat transfer through the assembly.
LUMEN: A measure of the amount of light available from a light source equivalent to the light emitted by one candle.
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MAP PROJECTION: A systematic conversion of locations on the Earth's surface from spherical to planar coordinates. Because the Earth is three-dimensional, some method must be used to depict a map in two dimensions. Some projections preserve shape; others preserve accuracy of area, distance, or direction.
MECHANICAL ENERGY: The sum of the kinetic energy and the potential energy of a system.
MEGAWATT (MW): One thousand kilowatts or one million watts. One megawatt is enough energy to power 1,000 average homes.
MEGAWATT HOUR (MWh): One thousand kilowatt-hours, or an amount of electricity that would supply the monthly power needs of a typical home having an electric hot water system.
METER: A device for measuring levels and volumes of a customer's gas and electricity use.
METHANE (CH 4): The simplest of hydrocarbons and the principal constituent of natural gas. Pure methane has a heating value of 1,012 Btu per standard cubic foot. Methane 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.
METHANOL (CH 3OH): A liquid formed by catalytically combining carbon monoxide (CO) with hydrogen (H 2) in a 1:2 ratio, under high temperature and pressure. Commercially it is typically made by steam reforming natural gas. Methanol is also formed in the destructive distillation of wood. (Also known as Methyl Alcohol, Wood Alcohol)
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.
MUNICIPAL SOLID WASTE: Locally collected garbage, which can be processed and burned to produce energy.
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NATURAL GAS: A gaseous mixture of hydrocarbon compounds, found in the earth, composed of methane, ethane, butane, propane and other gases.
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.
NITROGEN OXIDES (NO x): Oxides of nitrogen that are a chief component of air pollution that can be produced by the burning of fossil fuels.
NUCLEAR ENERGY: Power obtained by splitting heavy atoms (fission) or joining light atoms (fusion). A nuclear energy plant uses a controlled atomic chain reaction to produce heat. The heat is used to make steam run conventional turbine generators.
NUCLEAR REGULATORY COMMISSION (NRC): An independent federal agency that ensures that strict standards of public health and safety, environmental quality and national security are adhered to by individuals and organizations possessing and using radioactive materials. The NRC is the agency that is mandated with licensing and regulating nuclear power plants in the United States. It was formally established in 1975 after its predecessor, the Atomic Energy Commission, was abolished.
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OCEAN THERMAL GRADIENT (OTG): Temperature differences between deep and surface water. Deep water is likely to be 25 to 45 degrees Fahrenheit colder. The term also refers to experimental technology that could use the temperature differences as a means to produce energy.
OCTANE: A rating scale used to grade gasoline as to its antiknock properties. Also any of several isometric liquid paraffin hydrocarbons. 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.
ORGANIZATION OF PETROLEUM EXPORTING COUNTRIES (OPEC): Founded in 1960 for unify and coordinate petroleum polices of the members, its headquarters is in Vienna, Austria.
OUTAGE: An interruption of electric service that is temporary (minutes or hours) and affects a relatively small area (buildings or city blocks).
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 (O3): 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.
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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.
PARTS PER MILLION (PPM): The unit commonly used to represent the degree of pollutant concentration where the concentrations are small.
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).
PEAK LOAD OR PEAK DEMAND: The electric load that corresponds to a maximum level of electric demand in a specified time period. Peak periods during the day usually occur in the morning hours from 6 to 9 a.m. and during the afternoons from 4 to about 8 or 9 p.m. The afternoon peak demand periods are usually higher, and they are highest during summer months when air-conditioning use is the highest.
PETROLEUM: Oil as found it its natural state under the ground.
PHOTOCELL: A device that produces an electric reaction to visible radiant energy (light).
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.
PLANAR COORDINATE SYSTEM: A two-dimensional measurement system that defines locations on a map based on their distance from an origin (0,0) along two axes.
PLANIMETRIC MAP: A map that presents the horizontal, but not the vertical, positions of the features represented.
POTENTIAL ENERGY: The stored capacity for work of an object or a system. For example, the energy stored in a large rock that is ready to fall off a wall, or the energy in a pendulum at the top of its swing.
POWER PLANT: A central station generating facility that produces energy.
PROPANE: A gas that is both present in natural gas and refined from crude oil. It is used for heating, lighting and industrial applications.
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QUAD: One quadrillion (1015) British thermal units (Btus). An amount of energy equal to 170 million barrels of oil. Total U.S. consumption of all forms of energy is (in the 1990s) about 83 quads in an average year.
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.
RASTER DATA: A cellular data structure composed of rows and columns. Groups of cells represent features. The value of each cell represents the value of the feature. Image data is stored using this structure.
REACTOR: A device in which a controlled nuclear chain reaction can be maintained, producing heat energy.
RECOVERED ENERGY: Reused heat or energy that otherwise would be lost. For example, a combined cycle power plant recaptures some of its own waste heat and reuses it to make extra electric power.
REMOTE SENSING: Acquiring information about an object without contacting it physically. Methods include aerial photography, radar, and satellite imaging.
RENEWABLE ENERGY: Resources that constantly renew themselves or that are regarded as practically inexhaustible. These include solar, wind, geothermal, hydro and wood. Although particular geothermal formations can be depleted, the natural heat in the earth is a virtually inexhaustible reserve of potential energy. Renewable resources also include some experimental or less-developed sources such as tidal power, sea currents and ocean thermal gradients.
RENEWABLE RESOURCES: Renewable energy resources are naturally replenishable, but flow-limited. They are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Some (such as geothermal and biomass) may be stock-limited in that stocks are depleted by use, but on a time scale of decades, or perhaps centuries, they can be replenished. Renewable energy resources include biomass, hydro, geothermal, solar and wind. In the future they could also include the use of ocean thermal, wave, and tidal action technologies.
REPOSITORY: A place where things are stored.
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SEMI-CONDUCTOR: A solid crystalline substance, such as silicon, that has electrical conductivity greater than an insulator but less than a conductor.
SOLAR COLLECTOR: A device designed to receive solar radiation and convert it to thermal energy. Normally, a solar thermal collector includes a frame, glazing, and an absorber, together with appropriate insulation. The heat collected by the solar collector may be used immediately or stored for later use. Solar collectors are used for space heating; domestic hot water heating; and heating swimming pools, hot tubs, or spas.
SOLAR CELL: A photovoltaic cell that can convert light directly into electricity. A typical solar cell uses semiconductors made from silicon. .
SOLAR ENERGY: Heat and light radiated from the sun
SOLAR SATELLITE POWER: A proposed process of using satellites in geosynchronous orbit above the earth to capture solar energy with photovoltaic cells, convert it to microwave energy, beam the microwaves to earth where they would be received by large antennas, and changed from microwave into usable electricity.
SOLAR THERMAL POWER PLANT: A thermal power plant in which 75 percent or more of the total energy output is from solar energy and the use of backup fuels, such as oil, natural gas, and coal, does not, in the aggregate, exceed 25 percent of the total energy input of the facility during any calendar year period.
STEAM ELECTRIC PLANT: A power station in which steam is used to turn the turbines that generate electricity. The heat used to make the steam may come from burning fossil fuel, using a controlled nuclear reaction, concentrating the sun's energy, tapping the earth's natural heat or capturing industrial waste heat.
SUBSTATION: A facility that steps up or steps down the voltage in utility power lines. Voltage is stepped up where power is sent through long-distance transmission lines. it is stepped down where the power is to enter local distribution lines.
SULFUR: A yellowish nonmetallic element, sometimes known as "brimstone." It is present at various levels of concentration in many fossil fuels whose combustion releases sulfur compounds that are considered harmful to the environment. Some of the most commonly used fossil fuels are categorized according to their sulfur content, with lower sulfur fuels usually selling at a higher price.
SULFER DIOXIDE (SO 2) or SO x: A colorless, toxic and very irritating gas that is a byproduct of fossil fuel combustion. Other forms of sulfur oxides are sometimes called Sox.
SUPERCONDUCTOR: A synthetic material that has very low or no electrical resistance. Such experimental materials are being investigated in laboratories to see if they can be created at near room temperatures. If such a superconductor can be found, electrical transmission lines with no little or no resistance may be built, thus conserving energy usually lost in transmission. Superconductors could also have uses in computer chips, solid state devices and electrical motors or generators.
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TASK LIGHTING: Lighting designed specifically to illuminate one or more task locations, and generally confined to those locations.
THERM: One hundred thousand British thermal units (1 therm = 100,000 Btu).
THERMAL POWER PLANT: Any stationary or floating electrical generating facility using any source of thermal energy, with a generating capacity of 50 megawatts or more, and any facilities appurtenant thereto. Exploratory, development, and production wells, resource transmission lines, and other related facilities used in connection with a geothermal exploratory project or a geothermal field development project are not appurtenant facilities for the purposes of this division. Thermal power plant does not include any wind, hydroelectric, or solar photovoltaic electrical generating facility.
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 may be transformed in an isolated system, but its total is constant 2. Heat cannot be changed directly into work at constant temperature by a cyclic process 3. Heat capacity and entropy of every crystalline solid becomes zero at absolute zero (0 degrees Kelvin)
TIDAL POWER: Energy obtained by using the motion of the tides to run water turbines that drive electric generators.
TIGER: Acronym for Topologically Integrated Geographic Encoding and Referencing. A data format used by the U.S. Census Bureau to store street address ranges and census tract/block boundaries.
TOPOGRAPHIC MAPS: A map that displays both the horizontal and vertical positions of the features represented, using contours or other symbols to represent relief.
TURBINE: A machine in which the kinetic energy of a moving fluid or steam is converted into mechanical energy.
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URANIUM: A radioactive element, found in ores, of which atoms can be split to create energy.
VOLT: A unit of electromotive force. It is the amount of force required to drive a steady current of one ampere through a resistance of one ohm. Electrical systems of most homes and office have 120 volts.
VECTOR DATA: A coordinate-based data structure commonly used to represent linear map features. Attributes are associated with the feature (as opposed to raster which associates attributes with a grid cell).
VOLTAGE OF A CIRCUIT: The electric pressure of a circuit, measured in volts. Based on the maximum normal effective difference of potential between any two conductors of the circuit.
WATT: A unit of measure of electric power at a point in time, as capacity or demand. One watt of power maintained over time is equal to one joule per second. Some Christmas tree lights use one watt. The Watt is named after Scottish inventor James Watt and is capitalized when shortened to w and used with other abbreviations, as in kWh.
WATT-HOUR: One watt of power expended for one hour. One thousandth of a kilowatt-hour.
WEIR: A dam built to backup or direct the flow of water.
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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Glossary Terminology Sources:
- Getting to Know Arc View, ESRI Press