Glossary

Legend

Access
Acid mine drainage
Acid rain
Acquisition (foreign crude oil)
Acquisition (minerals)
Acquisition costs, mineral rights
Active power
Active solar
Actual peak reduction
Afforestation
AGA
Agglomerating character
Aggregator
Alternating current (AC)
American Indian Coal Lease
AMI
Amorphous silicon
Ampere
Amp-Hours
AMR
Anaerobic decomposition
Anaerobic lagoon
Angle of Incidence
ANSI
Anthracite
Anthropogenic
Antireflection Coating
API
API gravity
Apparent consumption, (coal)
Apparent consumption, natural gas (international)
Apparent power
Appliance Energy Efficiency Ratings
Aromatics
Array
Asbestos
Ash
ASTM
Auger mine
Auxiliary generator
Average daily production
Average mine price
Average Open Market Sales Price (coal)
Average Recovery Percentage (coal)
Average revenue per kilowatthour
Aviation gasoline (finished)
Backup generator
Backup power
Barrel
Barrels per stream day
Base gas
Base load
Base load capacity
Base load plant
Base rate
Benzene (C6H6)
Biodiesel
Biofuels
Biogenic emissions
Biomass
Biomass gas
Biomass waste
Biomass-based diesel fuel
Bituminous coal
Black lung benefits
Blast furnace
Block-rate structure
BOE
Boiler
Bone coal
Bottled gas, LPG, or propane
Bottom ash
British Thermal Unit (Btu)
Broker
BTX
Bunker fuels
Buy-back oil
Cannel coal
Capability
Capacity charge
Capacity factor
Captive coal
Carbon black
Carbon budget
Carbon cycle
Carbon intensity
Carbon output rate
Carbon sequestration
Carbon sink
Carbon stocks
Catalytic converter
Catalytic cracking
Catalytic hydrocracking
Catalytic hydrotreating
Catalytic reforming
Ccf
Central Power Plant
Central Receiver Solar Power Plants
Chained dollars
Chlorofluorocarbon (CFC)
CHP
Christmas tree
Circuit
Circuit Breaker
Climate change
Closed Coupled
CNG
CO nonattainment area
Coal
Coal bed
Coal bed degasification
Coal Blending
Coal briquets
Coal carbonized
Coal chemicals
Coal Classification
Coal financial reporting regions
Coal fines
Coal gas
Coal gasification
Coal liquefaction
Coal mine
Coal mining productivity
Coal production
Coal rank
Cofiring
Cogeneration
Coke (coal)
Coke (petroleum)
Coke Battery
Coking
Coloumb
Combustion
Combustion chamber
Conservation
Crude oil
Crude oil qualities
Crude oil refinery input
Cull wood
Current
Current (electric)
Cycle/reactor history
Cycling (natural gas)
Dam
Decentralized Energy System
Deforestation
Demurrage
Denaturant
Denatured
Densified biomass fuel
Depleted resources
Deregulation
Desulfurization
Diesel fuel
Distributed Energy
Diversity
Divestiture
Dry natural gas production
Efficacy
EIA
Electric industry reregulation
Electric industry restructuring
Electric non-utility
Electric power
Electric power grid
Electric power industry
Electric power plant
Electric power sector
Electric power system
Electric rate
Electric system loss
Electric utility
Emission
Emissions
Emissions coefficient
Energy
Energy Efficiency
Energy Factor (EF)
Energy information
Energy Information Administration (EIA)
Energy Policy Act of 1992 (EPACT)
Enriched uranium
Environmental impact statement
Environmental restoration
Environmental restrictions
EPACT
Estimated Recoverable Reserves (coal)
Extraction loss
Fabricated fuel
Federal coal lease
Federal Energy Regulatory Commission (FERC)
Federal Power Act
Finished leaded gasoline
Fission
Flexicoking
Flue gas desulfurization
Flux material
Fossil fuel
Foundry
Fractionation
Fuel cell
Gas well
Gas well productivity
Gasification
Gate station
Generation
Geothermal energy
Geothermal plant
Gigawatt (GW)
Gigawatt-electric (GWe)
Gigawatthour (GWh)
Gilsonite
Glazing
Global climate change
Global warming
Global warming potential (GWP)
Green Energy
Green pricing
Greenhouse effect
Greenhouse gases
Grid
Hybrid transmission line
Hydroelectric power
Hydrogen
IEA
Indian coal lease
Intergovernmental Panel on Climate Change (IPCC)
Investor Owned Utility (IOU)
Isotopes
Jet fuel
Joint Implementation (JI)
Joule (J)
Kerogen
Kerosene-type jet fuel
Kilowatt (kW)
Kilowatt-electric (kWe)
Kilowatthour (kWh)
Kilowatt-hour (kWh)
Langley
Leachate
Lead acid battery
Leaded gasoline
Leading edge
Lease and plant fuel
Light water reactor (LWR)
Line loss
Liquefied natural gas (LNG)
Load
Load Forecast
LPG
LRG
Lumen
Lumen
Marine freight
Mcf
Megavoltamperes (MVA)
Megawatt (MW)
Megawatt electric (MWe)
Megawatt-hour
Megawatthour (MWh)
Module
National Defense Authorization Act
National Electrical Code (NEC)
Natural gas
Natural Gas Liquids (NGL)
Natural Gas Policy Act of 1978 (NGPA)
Natural uranium
Net Energy Production (or Net Energy Balance)
Net Metering
Non-Renewable Energy
Nuclear electric power (nuclear power)
Nuclear Energy
Nuclear fuel
Nuclear reactor
Ocean Acidification
Ocean energy systems
Octane
Off-Grid Electric
Off-Peak
Offsystem (natural gas)
Ohm
Oil reservoir
Oil shale
Oil well
Oil well (casing head) gas
Old field
Old reservoir
On-Peak
On-Site Generation
Organization for Economic Cooperation and Development (OECD)
Organization of Petroleum Exporting Countries (OPEC)
Outage
Ozone
Passive Solar Design
Photovoltaic (PV)
Photovoltaic and solar thermal energy (as usedat electric utilities)
Photovoltaic cell (PVC)
Plutonium (Pu)
Power Purchase Agreement (PPA)
Preliminary permit (hydroelectric power)
Public Utility Holding Company Act of 1935 (PUHCA)
Public Utility Regulatory Policies Act of 1978
Public Utility Regulatory PoliciesAct (PURPA) of 1978
Radiant Barrier
Radioactive waste
Radioactivity
Renewable Energy
Renewable Energy Certificates (REC)
Renewable energy resources
Restructuring
Shale
Shrinkage
Sludge
Solar Cell
Solar energy
Solar Gain
Solar Lease
Solar Panel
Solar Power Purchase Agreement (PPA)
Stand-alone
Steam turbine
Storage hydroelectric plant
Storage site
Strategic Petroleum Reserve (SPR)
Subsidy
Tar sands
Therm
Thermal Energy
Tidal Power
Tilt Angle
Tracking Solar Array
Transmission line
Transmission network
Transmitting utility
Turbine
Uranium (U)
Uranium concentrate
Uranium deposit
Uranium Mill Tailings Radiation Control Act (UMTRA) of 1978
Uranium ore
Utility
Value (of shipments)
Voltage
Wafer
Watt (W)
Watthour (Wh)
Wattmeter
Weir
Wind energy
Wind turbine
Access

The customer's legal right as stipulated in his or her contract to utilize energy systems as a method of transferring energy to a home or business. (Source: Choose Energy )

Acid mine drainage

This refers to water pollution that results when sulfur-bearing minerals associated with coal are exposed to air and water and form sulfuric acid and ferrous sulfate. The ferrous sulfate can further react to form ferric hydroxide, or yellow boy, a yellow-orange iron precipitate found in streams and rivers polluted by acid mine drainage. (Source: EIA)

Acid rain

Also called acid precipitation or acid deposition, acid rain is precipitation containing harmful amounts of nitric and sulfuric acids formed primarily by sulfur dioxide and nitrogen oxides released into the atmosphere when fossil fuels are burned. It can be wet precipitation (rain, snow, or fog) or dry precipitation (absorbed gaseous and particulate matter, aerosol particles or dust). Acid rain has a pH below 5.6. Normal rain has a pH of about 5.6, which is slightly acidic. The term pH is a measure of acidity or alkalinity and ranges from 0 to 14. A pH measurement of 7 is regarded as neutral. Measurements below 7 indicate increased acidity, while those above indicate increased alkalinity. (Source: EIA)

Acquisition (foreign crude oil)

All transfers of ownership of foreign crude oil to a firm, irrespective of the terms of that transfer. Acquisitions thus include all purchases and exchange receipts as well as any and all foreign crude acquired under reciprocal buy-sell agreements or acquired as a result of a buy-back or other preferential agreement with a host government. (Source: EIA)

Acquisition (minerals)

The procurement of the legal right to explore for and produce discovered minerals, if any, within a specific area; that legal right may be obtained by mineral lease, concession, or purchase of land and mineral rights or of mineral rights alone. (Source: EIA)

Acquisition costs, mineral rights

Direct and indirect costs incurred to acquire legal rights to extract natural resources. Direct costs include costs incurred to obtain options to lease or purchase mineral rights and costs incurred for the actual leasing (e.g., lease bonuses) or purchasing of the rights. Indirect costs include such costs as brokers' commissions and expenses; abstract and recording fees; filing and patenting fees; and costs for legal examination of title and documents. (Source: EIA)

Active power

The component of electric power that performs work, typically measured in kilowatts (kW) or megawatts(MW). Also known as "real power." The terms "active" or "real" are used to modify the base term "power" to differentiate it from Reactive Power. See Power, Reactive Power, Apparent Power (Source: EIA)

Active solar

As an energy source, energy from the sun collected and stored using mechanical pumps or fans to circulate heat-laden fluids or air between solar collectors and a building. (Source: EIA)

Actual peak reduction

The actual reduction in annual peak load (measured in kilowatts) achieved by customers that participate in a utility demand-side management (DSM) program. It reflects the changes in the demand for electricity resulting from a utility DSM program that is in effect at the same time the utility experiences its annual peak load, as opposed to the installed peak load reduction capability (i.e., potential peak reduction). It should account for the regular cycling of energy efficient units during the period of annual peak load. (Source: EIA)

Afforestation

Planting of new forests on lands that have not been recently forested. (Source: EIA)

AGA

American Gas Association (Source: EIA)

Agglomerating character

Agglomeration describes the caking properties of coal. Agglomerating character is determined by examination and testing of the residue when a small powdered sample is heated to 950 degrees Centigrade under specific conditions. If the sample is "agglomerating," the residue will be coherent, show swelling or cell structure, and be capable of supporting a 500-gram weight without pulverizing. (Source: EIA)

Aggregator

A broker who acts on behalf of a group of customers to negotiate a bulk energy rate from an energy supplier. (Source: Choose Energy)

Alternating current (AC)

An electric current that reverses its direction at regularly recurring intervals. (Source: EIA)

American Indian Coal Lease

A lease granted to a mining company to produce coal from land held in trust by the United States for Native Americans, Native American tribes, and Alaska Natives in exchange for royalties and other revenues. (Source: EIA)

AMI

Advanced Metering Infrastructure is a term denoting electricity meters that measure and record usage data at a minimum, in hourly intervals, and provide usage data to both consumers and energy companies at least once daily. (Source: EIA)

Amorphous silicon

An alloy of silica and hydrogen, with a disordered, noncrystalline internal atomic arrangement, that can be deposited in thin-film layers (a few micrometers in thickness) by a number of deposition methods to produce thin-film photovoltaic cells on glass, metal, or plastic substrates. (Source: EIA)

Ampere

The unit of measurement of electrical current produced in a circuit by 1 volt acting through a resistance of 1 Ohm. (Source: EIA)

Amp-Hours

The measure of the flow of current over one hour. (Source: Choose Energy)

AMR

Automated Meter Reading is a term denoting electricity meters that collect data for billing purposes only and transmit this data one way, usually from the customer to the distribution utility. (Source: EIA)

Anaerobic decomposition

Decomposition in the absence of oxygen, as in an anaerobic lagoon or digester, which produces CO2 and CH4. (Source: EIA)

Anaerobic lagoon

A liquid-based organic waste management installation characterized by waste residing in water at a depth of at least 6 feet for periods of 30 to 200 days. (Source: EIA)

Angle of Incidence

The angle between the direct impact of the sun’s rays and the surface of the solar panel. To get the maximum amount of solar energy, you want the panel to be perpendicular to the sun’s rays. Your solar installer will angle the solar panels to get the maximum amount of energy efficiency. (Source: Choose Energy)

ANSI

American National Standards Institute (Source: EIA)

Anthracite

The highest rank of coal; used primarily for residential and commercial space heating. It is a hard, brittle, and black lustrous coal, often referred to as hard coal, containing a high percentage of fixed carbon and a low percentage of volatile matter. The moisture content of fresh-mined anthracite generally is less than 15 percent. The heat content of anthracite ranges from 22 to 28 million Btu per ton on a moist, mineral-matter-free basis. The heat content of anthracite coal consumed in the United States averages 25 million Btu per ton, on the as-received basis (i.e., containing both inherent moisture and mineral matter). Note (Source: EIA)

Anthropogenic

Made or generated by a human or caused by human activity. The term is used in the context of global climate change to refer to gaseous emissions that are the result of human activities, as well as other potentially climate-altering activities, such as deforestation. (Source: EIA)

Antireflection Coating

A material applied to the surface of a solar panel that reduces light reflection to increase light transmission. (Source: Choose Energy)

API

The American Petroleum Institute, a trade association. (Source: EIA)

API gravity

American Petroleum Institute measure of specific gravity of crude oil or condensate in degrees. An arbitrary scale expressing the gravity or density of liquid petroleum products. The measuring scale is calibrated in terms of degrees API; it is calculated as follows (Source: EIA)

Apparent consumption, (coal)

Coal production plus imports of coal, coke, and briquets minus exports of coal, coke, and briquets plus or minus stock changes. Note (Source: EIA)

Apparent consumption, natural gas (international)

The total of an individual nation's dry natural gas production plus imports less exports. (Source: EIA)

Apparent power

The product of the voltage (in volts) and the current (in amperes). It comprises both active and reactive power. It is measured in "volt-amperes" and often expressed in "kilovolt-amperes" (kVA) or "megavolt-amperes" (MVA). See Power, Reactive Power, Real Power. (Source: EIA)

Appliance Energy Efficiency Ratings

A ratings system established by the U.S. Department of Energy to determine how efficiently appliances convert energy sources to useful energy. (Source: Choose Energy)

Aromatics

Hydrocarbons characterized by unsaturated ring structures of carbon atoms. Commercial petroleum aromatics are benzene, toluene, and xylene (BTX). (Source: EIA)

Array

Several solar panels that are connected together in a single system. (Source: Choose Energy)

Asbestos

A group of naturally occurring minerals that separate into long, thin fibers. Asbestos was used for many years to insulate and fireproof buildings. In the 1989 CBECS, information on asbestos in buildings was collected (Section R of the Buildings Questionnaire) for the U.S. Environmental Protection Agency (EPA). Asbestos treatment methods include removal, encapsulation or sealing, and enclosure behind a permanent barrier. (Source: EIA)

Ash

Impurities consisting of silica, iron, alumina, and other noncombustible matter that are contained in coal. Ash increases the weight of coal, adds to the cost of handling, and can affect its burning characteristics Ash content is measured as a percent by weight of coal on an "as received" or a "dry" (moisture-free, usually part of a laboratory analysis) basis. (Source: EIA)

ASTM

American Society for Testing and Materials (Source: EIA)

Auger mine

A surface mine in which the coal bed is removed by means of a large diameter drill. Usually operated only when the overburden becomes too thick for economical strip mining. (Source: EIA)

Auxiliary generator

A generator at the electric plant site that provides power for the operation of the electrical generating equipment itself, including related demands such as plant lighting, during periods when the electric plant is not operating and power is unavailable from the grid. A black start generator used to start main central station generators is considered to be an auxiliary generator. (Source: EIA)

Average daily production

The ratio of the total production at a mining operation to the total number of production days worked at the operation. (Source: EIA)

Average mine price

The ratio of the total value of the coal produced at the mine to the total production tonnage. (Source: EIA)

Average Open Market Sales Price (coal)

The ratio, for a specified time period, of the total value of the open market sales of coal produced at the mine to the value of the total open market sales tonnage. (Source: EIA)

Average Recovery Percentage (coal)

The percentage of coal that can be recovered from known coal reserves at reporting mines, weight averaged for all mines in the reported geographic area. (Source: EIA)

Average revenue per kilowatthour

The average revenue per kilowatthour of electricity sold by sector (residential, commercial, industrial, or other) and geographic area (State, Census division, and national) is calculated by dividing the total monthly revenue by the corresponding total monthly sales for each sector and geographic area. (Source: EIA)

Aviation gasoline (finished)

A complex mixture of relatively volatile hydrocarbons with or without small quantities of additives, blended to form a fuel suitable for use in aviation reciprocating engines. Fuel specifications are provided in ASTM Specification D 910 and Military Specification MIL-G-5572. Note (Source: EIA)

Backup generator

A generator that is used only for test purposes, or in the event of an emergency, such as a shortage of power needed to meet customer load requirements. (Source: EIA)

Backup power

Electric energy supplied by a utility to replace power and energy lost during an unscheduled equipment outage. (Source: EIA)

Barrel

A unit of volume equal to 42 U.S. gallons. (Source: EIA)

Barrels per stream day

The maximum number of barrels of input that a distillation facility can process within a 24-hour period when running at full capacity under optimal crude and product slate conditions with no allowance for downtime. (Source: EIA)

Base gas

The quantity of natural gas needed to maintain adequate reservoir pressures and deliverability rates throughout the withdrawal season. Base gas usually is not withdrawn and remains in the reservoir. All natural gas native to a depleted reservoir is included in the base gas volume. (Source: EIA)

Base load
Base load capacity

The generating equipment normally operated to serve loads on an around-the-clock basis. (Source: EIA)

Base load plant

A plant, usually housing high-efficiency steam-electric units, which is normally operated to take all or part of the minimum load of a system, and which consequently produces electricity at an essentially constant rate and runs continuously. These units are operated to maximize system mechanical and thermal efficiency and minimize system operating costs. (Source: EIA)

Base rate

A fixed kilowatthour charge for electricity consumed that is independent of other charges and/or adjustments. (Source: EIA)

Benzene (C6H6)

An aromatic hydrocarbon present in small proportion in some crude oils and made commercially from petroleum by the catalytic reforming of naphthenes in petroleum naphtha. Also made from coal in the manufacture of coke. Used as a solvent in the manufacture of detergents, synthetic fibers, petrochemicals, and as a component of high-octane gasoline. (Source: EIA)

Biodiesel

A fuel typically made from soybean, canola, or other vegetable oils; animal fats; and recycled grease. It can serve as a substitute for petroleum-derived diesel or distillate fuel. For EIA reporting, it is a fuel composed of mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats, designated B100, and meeting the requirements of ASTM (American Society for Testing materials) D 6751. (Source: EIA)

Biofuels

Liquid fuels and blending components produced from biomass feedstocks, used primarily for transportation. (Source: EIA)

Biogenic emissions

Emissions that are naturally occurring and are not significantly affected by human actions or activity. (Source: EIA)

Biomass

Organic nonfossil material of biological origin constituting a renewable energy source. (Source: EIA)

Biomass gas

A medium Btu gas containing methane and carbon dioxide, resulting from the action of microorganisms on organic materials such as a landfill. (Source: EIA)

Biomass waste

Organic non-fossil material of biological origin that is a byproduct or a discarded product. Biomass waste includes municipal solid waste from biogenic sources, landfill gas, sludge waste, agricultural crop byproducts, straw, and other biomass solids, liquids, and gases; but excludes wood and wood-derived fuels (including black liquor), biofuels feedstock, biodiesel, and fuel ethanol. Note (Source: EIA)

Biomass-based diesel fuel

Biodiesel and other renewable diesel fuel or diesel fuel blending components derived from biomass, but excluding renewable diesel fuel coprocessed with petroleum feedstocks. (Source: EIA)

Bituminous coal

A dense coal, usually black, sometimes dark brown, often with well-defined bands of bright and dull material, used primarily as fuel in steam-electric power generation, with substantial quantities also used for heat and power applications in manufacturing and to make coke. Bituminous coal is the most abundant coal in active U.S. mining regions. Its moisture content usually is less than 20 percent. The heat content of bituminous coal ranges from 21 to 30 million Btu per ton on a moist, mineral-matter-free basis. The heat content of bituminous coal consumed in the United States averages 24 million Btu per ton, on the as-received basis (i.e., containing both inherent moisture and mineral matter). (Source: EIA)

Black lung benefits

In the content of the coal operation statement of income, this term refers to all payments, including taxes, made by the company attributable to Black Lung. (Source: EIA)

Blast furnace

A furnace in which solid fuel (coke) is burned with an air blast to smelt ore. (Source: EIA)

Block-rate structure

An electric rates schedule with a provision for charging a different unit cost for various increasing blocks of demand for energy. A reduced rate may be charged on succeeding blocks. (Source: EIA)

BOE

Barrels of Oil Equivalent (used internationally) (Source: EIA)

Boiler

A device for generating steam for power, processing, or heating purposes; or hot water for heating purposes or hot water supply. Heat from an external combustion source is transmitted to a fluid contained within the tubes found in the boiler shell. This fluid is delivered to an end-use at a desired pressure, temperature, and quality. (Source: EIA)

Bone coal

Coal with a high ash content; it is dull in appearance, hard, and compact. (Source: EIA)

Bottled gas, LPG, or propane

Any fuel gas supplied to a building in liquid form, such as liquefied petroleum gas, propane, or butane. It is usually delivered by tank truck and stored near the building in a tank or cylinder until used. (Source: EIA)

Bottom ash

Residue mainly from the coal burning process that falls to the bottom of the boiler for removal and disposal. (Source: EIA)

British Thermal Unit (Btu)

A universal measure of energy consumption equal to the amount of energy needed to heat one pound of water by one degree Fahrenheit. (Source: Choose Energy)

Broker

A company that facilitates the sale and/or purchase of electricity between businesses and energy suppliers. (Source: Choose Energy)

BTX

The acronym for the commercial petroleum aromatics-- benzene, toluene, and xylene. (Source: EIA)

Bunker fuels

Fuel supplied to ships and aircraft, both domestic and foreign, consisting primarily of residual and distillate fuel oil for ships and kerosene-based jet fuel for aircraft. The term "international bunker fuels" is used to denote the consumption of fuel for international transport activities. Note (Source: EIA)

Buy-back oil

Crude oil acquired from a host government whereby a portion of the government's ownership interest in the crude oil produced in that country may or should be purchased by the producing firm. (Source: EIA)

Cannel coal

A compact, tough variety of coal, originating from organic spore residues, that is non-caking, contains a high percentage of volatile matter, ignites easily, and burns with a luminous smoky flame. (Source: EIA)

Capability

The maximum load an electrical apparatus can accommodate for a specific period of time without exceeding approved temperature and stress limits. (Source: Choose Energy)

Capacity charge

An element in a two-part pricing method used in capacity transactions (energy charge is the other element). The capacity charge, sometimes called Demand Charge, is assessed on the amount of capacity being purchased. (Source: EIA)

Capacity factor

The ratio of the electrical energy produced by a generating unit for the period of time considered to the electrical energy that could have been produced at continuous full power operation during the same period. (Source: EIA)

Captive coal

Coal produced to satisfy the needs of the mine owner, or of a parent, subsidiary, or other affiliate of the mine owner (for example, steel companies and electricity generators), rather than for open market sale. (Source: EIA)

Carbon black

An amorphous form of carbon, produced commercially by thermal or oxidative decomposition of hydrocarbons and used principally in rubber goods, pigments, and printer's ink. (Source: EIA)

Carbon budget

The balance of the exchanges (incomes and losses) of carbon between carbon sinks (e.g., atmosphere and biosphere) in the carbon cycle. Also see Carbon cycle and Carbon sink. (Source: EIA)

Carbon cycle

All carbon sinks and exchanges of carbon from one sink to another by various chemical, physical, geological, and biological processes. Also see Carbon sink. (Source: EIA)

Carbon intensity

The amount of carbon by weight emitted per unit of energy consumed. A common measure of carbon intensity is weight of carbon per British thermal unit (Btu) of energy. When there is only one fossil fuel under consideration, the carbon intensity and the emissions coefficient are identical. When there are several fuels, carbon intensity is based on their combined emissions coefficients weighted by their energy consumption levels. Also see Emissions coefficient and Carbon output rate. (Source: EIA)

Carbon output rate

The amount of carbon by weight per kilowatthour of electricity produced. (Source: EIA)

Carbon sequestration

The fixation of atmospheric carbon dioxide in a carbon sink through biological or physical processes. (Source: EIA)

Carbon sink

A reservoir that absorbs or takes up released carbon from another part of the carbon cycle. The four sinks, which are regions of the Earth within which carbon behaves in a systematic manner, are the atmosphere, terrestrial biosphere (usually including freshwater systems), oceans, and sediments (including fossil fuels). (Source: EIA)

Carbon stocks

The quantity of carbon stored in biological and physical systems including (Source: EIA)

Catalytic converter

A device containing a catalyst for converting automobile exhaust into mostly harmless products. (Source: EIA)

Catalytic cracking

The refining process of breaking down the larger, heavier, and more complex hydrocarbon molecules into simpler and lighter molecules. Catalytic cracking is accomplished by the use of a catalytic agent and is an effective process for increasing the yield of gasoline from crude oil. Catalytic cracking processes fresh feeds and recycled feeds. (Source: EIA)

Catalytic hydrocracking

A refining process that uses hydrogen and catalysts with relatively low temperatures and high pressures for converting middle boiling or residual material to high octane gasoline, reformer charge stock, jet fuel, and /or high grade fuel oil. The process uses one or more catalysts, depending on product output, and can handle high sulfur feed stocks without prior desulfurization. (Source: EIA)

Catalytic hydrotreating

A refining process for treating petroleum fractions from atmospheric or vacuum distillation units (e.g., naphthas, middle distillates, reformer feeds, residual fuel oil, and heavy gas oil) and other petroleum (e.g., cat cracked naphtha,coker naphtha, gas oil, etc.) in the presence of catalysts and substantial quantities of hydrogen. Hydrotreating includes desulfurization, removal of substances (e.g., nitrogen compounds) that deactivate catalysts, conversion of olefins to paraffins to reduce gum formation in gasoline, and other processes to upgrade the quality of the fractions. (Source: EIA)

Catalytic reforming

A refining process using controlled heat and pressure with catalysts to rearrange certain hydrocarbon molecules, there by converting paraffinic and naphthenic type hydrocarbons (e.g., low octane gasoline boiling range fractions) into petrochemical feedstocks and higher octane stocks suitable for blending into finished gasoline. Catalytic reforming is reported in two categories. They are (Source: EIA)

Ccf

A unit of volume equal to 100 cubic feet, used by some utilities to measure natural gas. (Source: Choose Energy)

Central Power Plant

A large plant that generates power for distribution to multiple utilities and customers. (Source: Choose Energy)

Central Receiver Solar Power Plants

Also known as “power towers,” these plants use fields of tracking mirrors to reflect the sun’s rays to a single thermal receiver. This super-powered solar energy from a common thermal receiver produces high-temperature thermal energy that heats molten nitrate salts. The salts are then used to create steam that is then sent on to a steam turbine-generator, producing useful electricity. (Source: Choose Energy)

Chained dollars

A measure used to express real prices. Real prices are those that have been adjusted to remove the effect of changes in the purchasing power of the dollar; they usually reflect buying power relative to a reference year. Prior to 1996, real prices were expressed in constant dollars, a measure based on the weights of goods and services in a single year, usually a recent year. In 1996, the U.S. Department of Commerce introduced the chained-dollar measure. The new measure is based on the average weights of goods and services in successive pairs of years. It is "chained" because the second year in each pair, with its weights, becomes the first year of the next pair. The advantage of using the chained-dollar measure is that it is more closely related to any given period covered and is therefore subject to less distortion over time. (Source: EIA)

Chlorofluorocarbon (CFC)

Any of various compounds consisting of carbon, hydrogen, chlorine, and flourine used as refrigerants. CFCs are now thought to be harmful to the earth's atmosphere. (Source: EIA)

CHP

Combined Heat and Power (Source: EIA)

Christmas tree

The valves and fittings installed at the top of a gas or oil well to control and direct the flow of well fluids. (Source: EIA)

Circuit

A conductor or a system of conductors through which electric current flows. (Source: EIA)

Circuit Breaker

A device used to protect electrical equipment by breaking the electrical circuit if the circuit experiences an overload. For example, if you have several high-energy products such as hair dryers and space heaters plugged into the same circuit, the circuit breaker will turn off electricity to protect the items from frying. (Source: Choose Energy)

Climate change

A term used to refer to all forms of climatic inconsistency, but especially to significant change from one prevailing climatic condition to another. In some cases, "climate change" has been used synonymously with the term "global warming"; scientists, however, tend to use the term in a wider sense inclusive of natural changes in climate, including climatic cooling. (Source: EIA)

Closed Coupled

A system in which the fuel production equipment is either in close proximity or connected to the equipment using the fuel. (Source: Choose Energy)

CNG

Compressed Natural Gas (Source: EIA)

CO nonattainment area

Areas with carbon monoxide design values of 9.5 parts per million or more, generally based on data for 1988 and 1989. (Source: EIA)

Coal

A readily combustible black or brownish-black rock whose composition, including inherent moisture, consists of more than 50 percent by weight and more than 70 percent by volume of carbonaceous material. It is formed from plant remains that have been compacted, hardened, chemically altered, and metamorphosed by heat and pressure over geologic time. (Source: EIA)

Coal bed

A bed or stratum of coal. Also called a coal seam. (Source: EIA)

Coal bed degasification

This refers to the removal of methane or coal bed gas from a coal mine before or during mining. (Source: EIA)

Coal Blending

The process of combining two or more coals with different characteristics to obtain coal with a certain quality, such as low sulfur content. (Source: EIA)

Coal briquets

Anthracite, bituminous, and lignite briquets comprise the secondary solid fuels manufactured from coal by a process in which the coal is partly dried, warmed to expel excess moisture, and then compressed into briquets, usually without the use of a binding substance. In the reduction of briquets to coal equivalent, different conversion factors are applied according to their origin from hard coal, peat, brown coal, or lignite. (Source: EIA)

Coal carbonized

The amount of coal decomposed into solid coke and gaseous products by heating in a coke oven in a limited air supply or in the absence of air. (Source: EIA)

Coal chemicals

Coal chemicals are obtained from the gases and vapor recovered from the manufacturing of coke. Generally, crude tar, ammonia, crude light oil, and gas are the basic products recovered. They are refined or processed to yield a variety of chemical materials. (Source: EIA)

Coal Classification

In the United States, coals are classified by rank progressively from lignite (least carbonaceous) to anthracite (most carbonaceous) based on the proximate analyses of various properties (fixed carbon, volatile matter, heating value, and agglomerating character), following methods prescribed by the American Society for Testing and Materials. The International Coal Classification of the Economic Commission for Europe recognizes two broad categories of coal, “brown coal” and “hard coal.” In terms of U.S. coal classification, the international classification of brown coal includes lignite and lower-ranked subbituminous coal, whereas hard coal includes all higher rank coals. See Coal Rank. (Source: EIA)

Coal financial reporting regions

A geographic classification of areas with coal resources which is used for financial reporting of coal statistics. (Source: EIA)

Coal fines

Coal with a maximum particle size usually less than one-sixteenth inch and rarely above one-eighth inch. (Source: EIA)

Coal gas

Substitute natural gas produced synthetically by the chemical reduction of coal at a coal gasification facility. (Source: EIA)

Coal gasification

The process of converting coal into gas. The basic process involves crushing coal to a powder, which is then heated in the presence of steam and oxygen to produce a gas. The gas is then refined to reduce sulfur and other impurities. The gas can be used as a fuel or processed further and concentrated into chemical or liquid fuel. (Source: EIA)

Coal liquefaction

A chemical process that converts coal into clean-burning liquid hydrocarbons, such as synthetic crude oil and methanol. (Source: EIA)

Coal mine

An industrial operation for extracting coal from the ground. Mines include earth-moving and excavating operations and usually incorporate activities related to the processing (cleaning and crushing or sizing) and transporting of coal (such as loading the coal into a rail car) to the end user. (Source: EIA)

Coal mining productivity

Coal mining productivity is calculated by dividing total coal production by the total direct labor hours worked by all mine employees. (Source: EIA)

Coal production

The sum of sales, mine consumption, issues to miners, and issues to coke, briquetting, and other ancillary plants at mines. Production data include quantities extracted from surface and underground mines, and normally exclude wastes removed at mines or associated reparation plants. (Source: EIA)

Coal rank

The classification of coals according to their degree of progressive alteration from lignite to anthracite. In the United States, the standard ranks of coal include lignite, subbituminous coal, bituminous coal, and anthracite and are based on fixed carbon, volatile matter, heating value, and agglomerating (or caking) properties. (Source: EIA)

Cofiring

The process of burning natural gas in conjunction with another fuel to reduce air pollutants. (Source: EIA)

Cogeneration

The production of electrical energy and another form of useful energy (such as heat or steam) through the sequential use of energy. (Source: EIA)

Coke (coal)

A solid carbonaceous residue derived from low-ash, low-sulfur bituminous coal from which the volatile constituents are driven off by baking in an oven at temperatures as high as 2,000 degrees Fahrenheit so that the fixed carbon and residual ash are fused together. Coke is used as a fuel and as a reducing agent in smelting iron ore in a blast furnace. Coke from coal is grey, hard, and porous and has a heating value of 24.8 million Btu per ton. (Source: EIA)

Coke (petroleum)

A residue high in carbon content and low in hydrogen that is the final product of thermal decomposition in the condensation process in cracking. This product is reported as marketable coke or catalyst coke. The conversion is 5 barrels (of 42 U.S. gallons each) per short ton. (Source: EIA)

Coke Battery

A series of coke ovens stacked in rows into which coal is loaded and processed into coke. (Source: EIA)

Coking

Thermal refining processes used to produce fuel gas, gasoline blendstocks, distillates, and petroleum coke from the heavier products of atmospheric and vacuum distillation. Includes (Source: EIA)

Coloumb

A unit of electrical charge – a coloumb is the charge transported by a constant current of one ampere per second. (Source: Choose Energy)

Combustion

Chemical oxidation accompanied by the generation of light and heat. (Source: EIA)

Combustion chamber

An enclosed vessel in which chemical oxidation of fuel occurs. (Source: EIA)

Conservation

A reduction in energy consumption that corresponds with a reduction in service demand. Service demand can include buildings-sector end uses such as lighting, refrigeration, and heating; industrial processes; or vehicle transportation. Unlike energy efficiency, which is typically a technological measure, conservation is better associated with behavior. Examples of conservation include adjusting the thermostat to reduce the output of a heating unit, using occupancy sensors that turn off lights or appliances, and car-pooling. (Source: EIA)

Crude oil

A mixture of hydrocarbons that exists in liquid phase in natural underground reservoirs and remains liquid at atmospheric pressure after passing through surface separating facilities. Depending upon the characteristics of the crude stream, it may also include 1. Small amounts of hydrocarbons that exist in gaseous phase in natural underground reservoirs but are liquid at atmospheric pressure after being recovered from oil well (casing head) gas in lease separators and are subsequently comingled with the crude stream without being separately measured. Lease condensate recovered as a liquid from natural gas wells in lease or field separation facilities and later mixed into the crude stream is also included; 2. Small amounts of nonhydrocarbons produced with the oil, such as sulfur and various metals; 3. Drip gases, and liquid hydrocarbons produced from tar sands, oil sands, gilsonite, and oil shale. (Source: EIA)

Crude oil qualities

Refers to two properties of crude oil, the sulfur content, and API gravity, which affect processing complexity and product characteristics. (Source: EIA)

Crude oil refinery input

The total crude oil put into processing units at refineries. (Source: EIA)

Cull wood

Wood logs, chips, or wood products that are burned. (Source: EIA)

Current

The flow of electricity through a conductor. Current is measured in amperes. (Source: Choose Energy)

Current (electric)

A flow of electrons in an electrical conductor. The strength or rate of movement of the electricity is measured in amperes. (Source: EIA)

Cycle/reactor history

A group of assemblies that have been irradiated in the same cycles in an individual reactor and are said to have the same cycle/reactor history. (Source: EIA)

Cycling (natural gas)

The practice of producing natural gas for the extraction of natural gas liquids, returning the dry residue to the producing reservoir to maintain reservoir pressure and increase the ultimate recovery of natural gas liquids. The reinjected gas is produced for disposition after cycling operations are completed. (Source: EIA)

Dam

A physical barrier constructed across a river or waterway to control the flow of or raise the level of water. The purpose of construction may be for flood control, irrigation needs, hydroelectric power production, and/or recreation usage. (Source: EIA)

Decentralized Energy System

Energy systems that supply individual or group energy loads. (Source: Choose Energy)

Deforestation

The net removal of trees from forested land. (Source: EIA)

Demurrage

The charge paid to the vessel owner or operator for detention of a vessel at the port(s) beyond the time allowed, usually 72 hours, for loading and unloading. (Source: EIA)

Denaturant

Petroleum, typically pentanes plus or conventional motor gasoline, added to fuel ethanol to make it unfit for human consumption. Fuel ethanol is denatured, usually prior to transport from the ethanol production facility, by adding 2 to 5 volume percent denaturant. See Fuel Ethanol, and Fuel Ethanol Minus Denaturant. (Source: EIA)

Denatured

Fuel ethanol that is rendered unfit for human consumption by the addition of a petroleum denaturant, typically pentanes plus or conventional motor gasoline. Fuel ethanol is usually denatured prior to transport from the ethanol production facility, by adding 2- to 5-volume-percent denaturant. (Source: EIA)

Densified biomass fuel

Raw biomass, primarily wood, that has been condensed into a homogenously sized, energy-dense product, such as wood pellets, intended for use as fuel. It is mainly used for residential and commercial space heating and electricity generation. (Source: EIA)

Depleted resources

Resources that have been mined; include coal recovered, coal lost in mining, and coal reclassified as subeconomic because of mining. (Source: EIA)

Deregulation

In short, deregulation means that you now have a choice in who you purchase your electricity and natural gas from. In other words, you can shop around for the energy plan that’s right for you. (Source: Choose Energy)

Desulfurization

The removal of sulfur, as from molten metals, petroleum oil, or flue gases. (Source: EIA)

Diesel fuel

A fuel composed of distillates obtained in petroleum refining operation or blends of such distillates with residual oil used in motor vehicles. The boiling point and specific gravity are higher for diesel fuels than for gasoline. (Source: EIA)

Distributed Energy

A term that describes an electricity system in which power is produced at many small sites across the grid rather than at a single large site, such as a power plant. Distributed energy, such as home solar, puts the production of electricity closer to its point of consumption, improving efficiency. (Source: Choose Energy)

Diversity

The electric utility system's load is made up of many individual loads that make demands upon the system usually at different times of the day. The individual loads within the customer classes follow similar usage patterns, but these classes of service place different demands upon the facilities and the system grid. The service requirements of one electrical system can differ from another by time-of-day usage, facility usage, and/or demands placed upon the system grid. (Source: EIA)

Divestiture

The stripping off of one utility function from the others by selling (spinning-off) or in some other way changing the ownership of the assets related to that function. Stripping off is most commonly associated with spinning-off generation assets so they are no longer owned by the shareholders that own the transmission and distribution assets. (Source: EIA)

Dry natural gas production

The process of producing consumer-grade natural gas. Natural gas withdrawn from reservoirs is reduced by volumes used at the production (lease) site and by processing losses. Volumes used at the production site include (1) the volume returned to reservoirs in cycling, repressuring of oil reservoirs, and conservation operations; and (2) gas vented and flared. Processing losses include (1) nonhydrocarbon gases (e.g., water vapor, carbon dioxide, helium, hydrogen sulfide, and nitrogen) removed from the gas stream; and (2) gas converted to liquid form, such as lease condensate and plant liquids. Volumes of dry gas withdrawn from gas storage reservoirs are not considered part of production. Dry natural gas production equals marketed production less extraction loss. (Source: EIA)

Efficacy

The amount of useful energy delivered per unit of energy input. One example is the visible light output relative to power input. (Source: Choose Energy)

EIA

The Energy Information Administration. An independent agency within the U.S. Department of Energy that develops surveys, collects energy data, and analyzes and models energy issues. The Agency must meet the requests of Congress, other elements within the Department of Energy, Federal Energy Regulatory Commission, the Executive Branch, its own independent needs, and assist the general public, or other interest groups, without taking a policy position. See more information about EIA at http (Source: EIA)

Electric industry reregulation

The design and implementation of regulatory practices to be applied to the remaining traditional utilities after the electric power industry has been restructured. Reregulation applies to those entities that continue to exhibit characteristics of a natural monopoly. Reregulation could employ the same or different regulatory practices as those used before restructuring. (Source: EIA)

Electric industry restructuring

The process of replacing a monopolistic system of electric utility suppliers with competing sellers, allowing individual retail customers to choose their supplier but still receive delivery over the power lines of the local utility. It includes the reconfiguration of vertically-integrated electric utilities. (Source: EIA)

Electric non-utility

Any entity that generates, transmits, or sells electricity, or sells or trades electricity services and products, where costs are not established and recovered by regulatory authority. Examples of these entities include, but are not limited to, independent power producers, power marketers and aggregators (both wholesale and retail), merchant transmission service providers, self-generation entities, and cogeneration firms with Qualifying Facility Status. (Source: EIA)

Electric power

The rate at which electric energy is transferred. Electric power is measured by capacity and is commonly expressed in megawatts (MW). (Source: EIA)

Electric power grid

A system of synchronized power providers and consumers connected by transmission and distribution lines and operated by one or more control centers. In the continental United States, the electric power grid consists of three systems the Eastern Interconnect, the Western Interconnect, and the Texas Interconnect. In Alaska and Hawaii, several systems encompass areas smaller than the State (e.g., the interconnect serving Anchorage, Fairbanks, and the Kenai Peninsula; individual islands). (Source: EIA)

Electric power industry

Stationary and mobile generating units that are connected to the electric power grid and can generate electricity. The electric power industry includes the "electric power sector" (utility generators and independent power producers) and industrial and commercial power generators, including combined-heat-and-power producers, but excludes units at single-family dwellings. (Source: EIA)

Electric power plant

A station containing prime movers, electric generators, and auxiliary equipment for converting mechanical, chemical, and/or fission energy into electric energy. (Source: EIA)

Electric power sector

An energy-consuming sector that consists of electricity only and combined heat and power(CHP) plants whose primary business is to sell electricity, or electricity and heat, to the public--i.e., North American Industry Classification System 22 plants. See also Combined heat and power (CHP) plant and Electricity only plant. (Source: EIA)

Electric power system

An individual electric power entity--a company; an electric cooperative; a public electric supply corporation as the Tennessee Valley Authority; a similar Federal department or agency such as the Bonneville Power Administration; the Bureau of Reclamation or the Corps of Engineers; a municipally owned electric department offering service to the public; or an electric public utility district (a "PUD"); also a jointly owned electric supply project such as the Keystone. (Source: EIA)

Electric rate

The price set for a specified amount and type of electricity by class of service in an electric rate schedule or sales contract. (Source: EIA)

Electric system loss

Total energy loss from all causes for an electric utility. (Source: EIA)

Electric utility

A corporation, person, agency, authority, or other legal entity or instrumentality aligned with distribution facilities for delivery of electric energy for use primarily by the public. Included are investor-owned electric utilities, municipal and State utilities, Federal electric utilities, and rural electric cooperatives. A few entities that are tariff based and corporately aligned with companies that own distribution facilities are also included. (Source: EIA)

Emission

A substance (often a pollutant) emitted from a system because of a process. (Source: Choose Energy)

Emissions

Anthropogenic releases of gases to the atmosphere. In the context of global climate change, they consist of radiatively important greenhouse gases (e.g., the release of carbon dioxide during fuel combustion). (Source: EIA)

Emissions coefficient

A unique value for scaling emissions to activity data in terms of a standard rate of emissions per unit of activity (e.g., pounds of carbon dioxide emitted per Btu of fossil fuel consumed). (Source: EIA)

Energy

The capacity for doing work as measured by the capability of doing work (potential energy) or the conversion of this capability to motion (kinetic energy). Energy has several forms, some of which are easily convertible and can be changed to another form useful for work. Most of the world's convertible energy comes from fossil fuels that are burned to produce heat that is then used as a transfer medium to mechanical or other means in order to accomplish tasks. Electrical energy is usually measured in kilowatthours, while heat energy is usually measured in British thermal units (Btu). (Source: EIA)

Energy Efficiency

A way of managing how much energy we use. Something is energy efficient if it can perform the same task with less energy, like a compact fluorescent bulb, which produces the same amount of light as an incandescent bulb, but uses one-third to one-fifth as much energy. (Source: Choose Energy)

Energy Factor (EF)

The measure of overall efficiency of a variety of appliances (i.e. water heaters, dishwashers, clothes washers and dryers). (Source: Choose Energy)

Energy information

Includes (A) all information in whatever form on fuel reserves, extraction, and energy resources (including petrochemical feedstocks) wherever located; production, distribution, and consumption of energy and fuels wherever carried on; and (B) matters relating to energy and fuels, such as corporate structure and proprietary relationships, costs, prices, capital investment, and assets, and other matters directly related there to, wherever they exist. (Source: EIA)

Energy Information Administration (EIA)

An independent agency within the U.S. Department of Energy that develops surveys, collects energy data, and does analytical and modeling analyses of energy issues. The Agency must satisfy the requests of Congress, other elements within the Department of Energy, Federal Energy Regulatory Commission, the Executive Branch, its own independent needs, and assist the general public, or other interest groups, without taking a policy position. (Source: EIA)

Energy Policy Act of 1992 (EPACT)

This legislation creates a new class of power generators, exempt wholesale generators, that are exempt from the provisions of the Public Holding Company Act of 1935 and grants the authority to the Federal Energy Regulatory Commission to order and condition access by eligible parties to the interconnected transmission grid. (Source: EIA)

Enriched uranium

Uranium in which the U-235 isotope concentration has been increased to greater than the 0.711 percent U-235 (by weight) present in natural uranium. (Source: EIA)

Environmental impact statement

A report that documents the information required to evaluate the environmental impact of a project. It informs decision makers and the public of the reasonable alternatives that would avoid or minimize adverse impacts or enhance the quality of the environment. (Source: EIA)

Environmental restoration

Although usually described as "cleanup," this function encompasses a wide range of activities, such as stabilizing contaminated soil; treating groundwater; decommissioning process buildings, nuclear reactors, chemical separations plants, and many other facilities; and exhuming sludge and buried drums of waste. (Source: EIA)

Environmental restrictions

In reference to coal accessibility, land-use restrictions that constrain, postpone, or prohibit mining in order to protect environmental resources of an area; for example, surface- or ground water quality, air quality affected by mining, or plants or animals or their habitats. (Source: EIA)

EPACT

Energy Policy Act of 1992 (Source: EIA)

Estimated Recoverable Reserves (coal)

An estimate of coal reserves, based on a demonstrated reserve base, adjusted for assumed accessibility and recovery factors, and does not include any specific economic feasibility criteria. (Source: EIA)

Extraction loss

The extraction of gas plant liquids constituents such as ethane, propane, normal butane, isobutane, and natural gasoline. Usually reported in barrels or gallons, but may be reported in cubic feet for purposes of comparison with dry natural gas volumes. See Natural gas plant liquids (NGPL) production. (Source: EIA)

Fabricated fuel

Fuel assemblies composed of an array of fuel rods loaded with pellets of enriched uranium dioxide. (Source: EIA)

Federal coal lease

A lease granted to a mining company to produce coal from land owned and administered by the Federal Government in exchange for royalties and other revenues. (Source: EIA)

Federal Energy Regulatory Commission (FERC)

The Federal agency with jurisdiction over interstate electricity sales, wholesale electric rates, hydroelectric licensing, natural gas pricing, oil pipeline rates, and gas pipeline certification. FERC is an independent regulatory agency within the Department of Energy and is the successor to the Federal Power Commission. (Source: EIA)

Federal Power Act

Enacted in 1920, and amended in1935, the Act consists of three parts. The first part incorporated the Federal Water Power Act administered by the former Federal Power Commission, whose activities were confined almost entirely to licensing non-Federal hydroelectric projects. Parts II and III were added with the passage of the Public Utility Act. These parts extended the Act's jurisdiction to include regulating the interstate transmission of electrical energy and rates for its sale as wholesale in interstate commerce. The Federal Energy Regulatory Commission is now charged with the administration of this law. (Source: EIA)

Finished leaded gasoline

Contains more than 0.05 gram of lead per gallon or more than 0.005 gram of phosphorus per gallon. Premium and regular grades are included, depending on the octane rating. Includes leaded gasohol. Blendstock is excluded until blending has been completed. Alcohol that is to be used in the blending of gasohol is also excluded. (Source: EIA)

Fission

The process whereby an atomic nucleus of appropriate type, after capturing a neutron, splits into (generally) two nuclei of lighter elements, with the release of substantial amounts of energy and two or more neutrons. (Source: EIA)

Flexicoking

A thermal cracking process which converts heavy hydrocarbons such as crude oil, tar sands bitumen, and distillation residues into light hydrocarbons. Feed stocks can be any pumpable hydrocarbons including those containing high concentrations of sulfur and metals. (Source: EIA)

Flue gas desulfurization

Equipment used to remove sulfur oxides from the combustion gases of a boiler plant before discharge to the atmosphere. Also referred to as scrubbers. Chemicals such as lime are used as scrubbing media. (Source: EIA)

Flux material

A substance used to promote fusion, e.g., of metals or minerals. (Source: EIA)

Fossil fuel

An energy source formed in the Earth's crust from decayed organic material. The common fossil fuels are petroleum, coal, and natural gas. (Source: EIA)

Foundry

An operation where metal castings are produced, using coke as a fuel. (Source: EIA)

Fractionation

The process by which saturated hydrocarbons are removed from natural gas and separated into distinct products, or "fractions," such as propane, butane, and ethane. (Source: EIA)

Fuel cell

A device capable of generating an electrical current by converting the chemical energy of a fuel (e.g., hydrogen) directly into electrical energy. Fuel cells differ from conventional electrical cells in that the active materials such as fuel and oxygen are not contained within the cell but are supplied from outside. It does not contain an intermediate heat cycle, as do most other electrical generation techniques. (Source: EIA)

Gas well

A well completed for production of natural gas from one or more gas zones or reservoirs. Such wells contain no completions for the production of crude oil. (Source: EIA)

Gas well productivity

Derived annually by dividing gross natural gas withdrawals from gas wells by the number of producing gas wells on December 31 and then dividing the quotient by the number of days in the year. (Source: EIA)

Gasification

A method for converting coal, petroleum, biomass, wastes, or other carbon-containing materials into a gas that can be burned to generate power or processed into chemicals and fuels. (Source: EIA)

Gate station

Location where the pressure of natural gas being transferred from the transmission system to the distribution system is lowered for transport through small diameter, low pressure pipelines. (Source: EIA)

Generation

The process of producing electric energy by transforming other forms of energy; also, the amount of electric energy produced, expressed in kilowatthours. (Source: EIA)

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. (Source: EIA)

Geothermal plant

A plant in which the prime mover is a steam turbine. The turbine is driven either by steam produced from hot water or by natural steam that derives its energy from heat found in rock. (Source: EIA)

Gigawatt (GW)

One billion watts or one thousand megawatts. (Source: EIA)

Gigawatt-electric (GWe)

One billion watts of electric capacity. (Source: EIA)

Gigawatthour (GWh)

One billion watthours. (Source: EIA)

Gilsonite

Trademark name for uintaite (or uintahite), a black, brilliantly lustrous natural variety of asphalt found in parts of Utah and western Colorado. (Source: EIA)

Glazing

Transparent material used to admit light while reducing heat loss. Used on windows, skylights, greenhouses and more. (Source: Choose Energy)

Global climate change

See Climate change . (Source: EIA)

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 anthropogenic emissions of greenhouse gases. (Source: EIA)

Global warming potential (GWP)

An index used to compare the relative radiative forcing of different gases without directly calculating the changes in atmospheric concentrations. GWPs are calculated as the ratio of the radiative forcing that would result from the emission of one kilogram of a greenhouse gas to that from the emission of one kilogram of carbon dioxide over a fixed period of time, such as 100 years. (Source: EIA)

Green Energy

Green energy refers to environmentally friendly energy that is generated from sustainable or renewable sources such as solar, wind, water, or geothermal power. (Source: Choose Energy)

Green pricing

In the case of renewable electricity, green pricing represents a market solution to the various problems associated with regulatory valuation of the nonmarket benefits of renewables. Green pricing programs allow electricity customers to express their willingness to pay for renewable energy development through direct payments on their monthly utility bills. (Source: EIA)

Greenhouse effect

The result of water vapor, carbon dioxide, and other atmospheric gases trapping radiant (infrared) energy, thereby keeping the earth's surface warmer than it would otherwise be. Greenhouse gases within the lower levels of the atmosphere trap this radiation, which would otherwise escape into space, and subsequent re-radiation of some of this energy back to the Earth maintains higher surface temperatures than would occur if the gases were absent. (Source: EIA)

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. (Source: EIA)

Grid

The layout of an electrical distribution system. See electric power grid. (Source: EIA)

Hybrid transmission line

A double-circuit line that has one alternating current and one direct circuit. The AC circuit usually serves local loads along the line. (Source: EIA)

Hydroelectric power

The use of flowing water to produce electrical energy. (Source: EIA)

Hydrogen

The lightest of all gases, occurring chiefly in combination with oxygen in water; exists also in acids, bases, alcohols, petroleum, and other hydrocarbons. (Source: EIA)

IEA

International Energy Agency (Source: EIA)

Indian coal lease

A lease granted to a mining company to produce coal from Indian lands in exchange for royalties and other revenues; obtained by direct negotiation with Indian tribal authorities, but subject to approval and administration by the U.S. Department of the Interior. (Source: EIA)

Intergovernmental Panel on Climate Change (IPCC)

A panel established jointly in 1988 by the World Meteorological Organization and the United Nations Environment Program to assess the scientific information relating to climate change and to formulate realistic response strategies. (Source: EIA)

Investor Owned Utility (IOU)

A provider owned by stockholders or investors. Sometimes called a private power provider, it contrasts public power providers owned by government agencies or cooperatives. (Source: Choose Energy)

Isotopes

Forms of the same chemical element that differ only by the number of neutrons in their nucleus. Most elements have more than one naturally occurring isotope. Many isotopes have been produced in reactors and scientific laboratories. (Source: EIA)

Jet fuel

A refined petroleum product used in jet aircraft engines. It includes kerosene-type jet fuel and naphtha-type jet fuel. (Source: EIA)

Joint Implementation (JI)

Agreements made between two or more nations under the auspices of the Framework Convention on Climate Change (FCCC) whereby a developed country can receive "emissions reduction units" when it helps to finance projects that reduce net emissions in another developed country (including countries with economies in transition). (Source: EIA)

Joule (J)

The meter-kilogram-second unit of work or energy, equal to the work done by a force of one newton when its point of application moves through a distance of one meter in the direction of the force; equivalent to 107 ergs and one watt-second. (Source: EIA)

Kerogen

Naturally occurring solid organic matter in sedimentary rock that is insoluble in organic solvents. Kerogen originates from algae, plankton, and plant material from aquatic and terrestrial environments. Under the right conditions of pressure, temperature, and time, kerogen can form oil and natural gas. (Source: EIA)

Kerosene-type jet fuel

A kerosene-based product having a maximum distillation temperature of 400 degrees Fahrenheit at the 10-percent recovery point and a final maximum boiling point of 572 degrees Fahrenheit and meeting ASTM Specification D 1655and Military Specifications MIL-T-5624P and MIL-T-83133D (Grades JP-5and JP-8). It is used for commercial and military turbo jet and turbo prop aircraft engines. (Source: EIA)

Kilowatt (kW)

One thousand watts. (Source: EIA)

Kilowatt-electric (kWe)

One thousand watts of electric capacity. (Source: EIA)

Kilowatthour (kWh)

A measure of electricity defined as a unit of work or energy, measured as 1 kilowatt (1,000watts) of power expended for 1 hour. One kWh is equivalent to 3,412 Btu. (Source: EIA)

Kilowatt-hour (kWh)

This is the unit of electricity that providers use to determine the rate they charge for electricity use. A kilowatt-hour refers to an amount of electrical power (measured in kilowatts) used over a given time (measured in hours). For example, if you ran an air conditioner with a power-level requirement of one kilowatt for an hour, you would use a single kilowatt-hour. Likewise, if you used a computer with a power-level requirement of 120 watts for eight hours, you would also use a single kilowatt-hour. (Source: Choose Energy)

Langley

A unit or measure of solar radiation; 1 calorie per square centimeter or 3.69 Btu per square foot. (Source: EIA)

Leachate

The liquid that has percolated through the soil or other medium. (Source: EIA)

Lead acid battery

An electrochemical battery that uses lead and lead oxide for electrodes and sulfuric acid for the electrolyte. (Source: EIA)

Leaded gasoline

A fuel that contains more than0.05 gram of lead per gallon or more than 0.005 gram of phosphorus per gallon. (Source: EIA)

Leading edge

In reference to a wind energy conversion system, the area of a turbine blade surface that first comes into contact with the wind. (Source: EIA)

Lease and plant fuel

Natural gas used in well, field, and lease operations (such as gas used in drilling operations, heaters, dehydrators, and field compressors) and as fuel in natural gas processing plants. (Source: EIA)

Light water reactor (LWR)

A nuclear reactor that uses water as the primary coolant and moderator, with slightly enriched uranium as fuel. (Source: EIA)

Line loss

Electric energy lost because of the transmission of electricity. Much of the loss is thermal in nature. (Source: EIA)

Liquefied natural gas (LNG)

Natural gas (primarily methane) that has been liquefied by reducing its temperature to -260 degrees Fahrenheit at atmospheric pressure. (Source: EIA)

Load

Load refers to the total amount electrical power being used over a given period of time. (Source: Choose Energy)

Load Forecast

The estimate of power need for a future period of time. (Source: Choose Energy)

LPG

See Liquefied Petroleum Gases. (Source: EIA)

LRG

See Liquefied Refinery Gases. (Source: EIA)

Lumen

A unit of luminous flux represents the amount of light emitted that is visible to the human eye. In the International System of Units, it is the amount of light a one candela source emits over a square radian angle. It is used in measuring and comparing the amount of light visible to the human eye produced by lamps such as light-emitting diodes, compact fluorescent lights, and incandescent bulbs. (Source: Need to know)

Lumen

A unit of luminous flux represents the amount of light emitted that is visible to the human eye. In the International System of Units, it is the amount of light a one candela source emits over a square radian angle. It is used in measuring and comparing the amount of light visible to the human eye produced by lamps such as light-emitting diodes, compact fluorescent lights, and incandescent bulbs. (Source: Need to know)

Marine freight

Freight transported over rivers, canals, the Great Lakes, and domestic ocean waterways. (Source: EIA)

Mcf

An Mcf is a unit of volume equal to 1,000 cubic feet, used by some utilities to measure natural gas. (Source: Choose Energy)

Megavoltamperes (MVA)

Millions of voltamperes, which are a measure of apparent power. (See definition for apparent power.) (Source: EIA)

Megawatt (MW)

One million watts of electricity. (Source: EIA)

Megawatt electric (MWe)

One million watts of electric capacity. (Source: EIA)

Megawatt-hour

A megawatt-hour is equal to 1,000 kilowatt-hours or 1,000,000 watt-hours. (Source: Choose Energy)

Megawatthour (MWh)

One thousand kilowatt-hours or 1million watt-hours. (Source: EIA)

Module

A module is a collection of solar photovoltaic cells connected together in a single panel. (Source: Choose Energy)

National Defense Authorization Act

The federal law, enacted in 1994 and amended in 1995, that required the Secretary of Energy to prepare the Baseline Report. (Source: EIA)

National Electrical Code (NEC)

The set of regulations for the U.S. to ensure electrical systems are designed and installed safely. (Source: Choose Energy)

Natural gas

A gaseous mixture of hydrocarbon compounds, the primary one being methane. (Source: EIA)

Natural Gas Liquids (NGL)

A group of hydrocarbons including ethane, propane, normal butane, isobutane, and natural gasoline. Generally include natural gas plant liquids and all liquefied refinery gases except olefins. (Source: EIA)

Natural Gas Policy Act of 1978 (NGPA)

Signed into law on November 9, 1978, the NGPA is a framework for the regulation of most facets of the natural gas industry. (Source: EIA)

Natural uranium

Uranium with the U-235 isotope present at a concentration of 0.711 percent (by weight), that is, uranium with its isotopic content exactly as it is found in nature. (Source: EIA)

Net Energy Production (or Net Energy Balance)

The net energy production is the amount of useful energy a system produces, minus the amount of energy required to produce the fuel. (Source: Choose Energy)

Net Metering

Net metering is a process that allows consumers with home solar panels to sell any excess energy produced back to the utility company. If your home solar panels produce more energy than you use, that excess energy can also be rolled over to next month’s bill. (Source: Choose Energy)

Non-Renewable Energy

Energy sources that cannot be replaced, remaining in finite amounts in the environment. Fossil fuels like coal, natural gas and crude oil are non-renewable energy sources. (Source: Choose Energy)

Nuclear electric power (nuclear power)

Electricity generated by the use of the thermal energy released from the fission of nuclear fuel in a reactor. (Source: EIA)

Nuclear Energy

Energy created by splitting radioactive atoms like uranium. Nuclear energy produces the problem of radioactive waste, which is extremely difficult to dispose of responsibly. (Source: Choose Energy)

Nuclear fuel

Fissionable materials that have been enriched to such a composition that, when placed in a nuclear reactor, will support a self-sustaining fission chain reaction, producing heat in a controlled manner for process use. (Source: EIA)

Nuclear reactor

An apparatus in which a nuclear fission chain reaction can be initiated, controlled, and sustained at a specific rate. A reactor includes fuel (fissionable material), moderating material to control the rate of fission, a heavy-walled pressure vessel to house reactor components, shielding to protect personnel, a system to conduct heat away from the reactor, and instrumentation for monitoring and controlling the reactor's systems. (Source: EIA)

Ocean Acidification

The process by which the hydronium ion concentration increases in the ocean, measured as decreasing pH. One source of ocean acidification is the dissolution of carbon dioxide, which forms carbonic acid with water and then dissociates into hydronium and bicarbonate. Lower pH impacts ocean life, including their soft and hard materials, and also human-built structures in the ocean, such as vessels. (Source: Need to know)

Ocean energy systems

Energy conversion technologies that harness the energy in tides, waves, and thermal gradients in the oceans. (Source: EIA)

Octane

A flammable liquid hydrocarbon found in petroleum. Used as a standard to measure the anti-knock properties of motor fuel. (Source: EIA)

Off-Grid Electric

An off-grid electric system is a stand-alone energy system that works independently from the main electrical power grid. (Source: Choose Energy)

Off-Peak

A period of low energy demand. (Source: Choose Energy)

Offsystem (natural gas)

Natural gas that is transported to the end user by the company making final delivery of the gas to the end user. The end user purchases the gas from another company, such as a producer or marketer, not from the delivering company (typically a local distribution company or a pipeline company). (Source: EIA)

Ohm

A measure of the electrical resistance of a material equal to the resistance of a circuit in which the potential difference of 1 volt produces a current of 1 ampere. (Source: EIA)

Oil reservoir

An underground pool of liquid consisting of hydrocarbons, sulfur, oxygen, and nitrogen trapped within a geological formation and protected from evaporation by the overlying mineral strata. (Source: EIA)

Oil shale

A sedimentary rock containing kerogen, a solid organic material. (Source: EIA)

Oil well

A well completed for the production of crude oil from at least one oil zone or reservoir. (Source: EIA)

Oil well (casing head) gas

Associated and dissolved gas produced along with crude oil from oil completions. (Source: EIA)

Old field

A field discovered prior to the report year. (Source: EIA)

Old reservoir

A reservoir discovered prior to the report year. (Source: EIA)

On-Peak

A period of high energy demand. (Source: Choose Energy)

On-Site Generation

Energy generated at the site of where most to all of it will be used. (Source: Choose Energy)

Organization for Economic Cooperation and Development (OECD)

An international organization helping governments tackle the economic, social and governance challenges of a globalized economy. Its membership comprises about 30 member countries. With active relationships with some 70 other countries, non-governmental organizations (NGOs) and civil society, it has a global reach. For details about the organization, visit http (Source: EIA)

Organization of Petroleum Exporting Countries (OPEC)

An intergovernmental organization whose stated objective is to "coordinate and unify the petroleum policies of member countries." It was created at the Baghdad Conference on September 10-14, 1960. Current members (with years of membership) include (Source: EIA)

Outage

A stoppage of the electric power supply. (Source: Choose Energy)

Ozone

A molecule made up of three atoms of oxygen. Occurs naturally in the stratosphere and provides a protective layer shielding the Earth from harmful ultraviolet radiation. In the troposphere, it is a chemical oxidant, a greenhouse gas, and a major component of photochemical smog. (Source: EIA)

Passive Solar Design

A structure designed with specific elements that heat and cool the structure, without the use of mechanical equipment. Some passive solar design features include building orientation, window sizing and consideration of local climate. (Source: Choose Energy)

Photovoltaic (PV)

Photovoltaic refers to a method of converting solar energy into electricity. Solar panels are frequently referred to as photovoltaic panels or cells. (Source: Choose Energy)

Photovoltaic and solar thermal energy (as usedat electric utilities)

Energy radiated by the sun as electromagnetic waves (electromagnetic radiation) that is converted at electric utilities into electricity by means of solar (photovoltaic) cells or concentrating (focusing) collectors. (Source: EIA)

Photovoltaic cell (PVC)

An electronic device consisting of layers of semiconductor materials fabricated to form a junction (adjacent layers of materials with different electronic characteristics) and electrical contacts and being capable of converting incident light directly into electricity (direct current). (Source: EIA)

Plutonium (Pu)

A heavy, fissionable, radioactive, metallic element (atomic number 94) that occurs naturally in trace amounts. It can also result as a byproduct of the fission reaction in a uranium-fuel nuclear reactor and can be recovered for future use. (Source: EIA)

Power Purchase Agreement (PPA)

A contract that defines the terms between an electricity generator (the seller) and one looking to purchase electricity, typically a utility or an independent energy supplier). (Source: Choose Energy)

Preliminary permit (hydroelectric power)

A single site permit granted by the FERC (Federal Energy Regulatory Commission), which gives the recipient priority over anyone else to apply for a hydroelectric license. The preliminary permit enables the recipient to prepare a license application and conduct various studies for economic feasibility and environmental impacts. The period for a preliminary permit may extend to 3 years. (Source: EIA)

Public Utility Holding Company Act of 1935 (PUHCA)

This act prohibits acquisition of any wholesale or retail electric business through a holding company unless that business forms part of an integrated public utility system when combined with the utility's other electric business. The legislation also restricts ownership of an electric business by non-utility corporations. (Source: EIA)

Public Utility Regulatory Policies Act of 1978

The Public Utility Regulatory Policies Act of1978, passed by the U.S. Congress. This statute requires States to implement utility conservation programs and create special markets for co-generators and small producers who meet certain standards, including the requirement that States set the prices and quantities of power the utilities must buy from such facilities. (Source: EIA)

Public Utility Regulatory PoliciesAct (PURPA) of 1978

One part of the National Energy Act, PURPA contains measures designed to encourage the conservation of energy, more efficient use of resources, and equitable rates. Principal among these were suggested retail rate reforms and new incentives for production of electricity by cogenerators and users of renewable resources. The Commission has primary authority for implementing several key PURPA programs. (Source: EIA)

Radiant Barrier

A reflective foil sheeting that displays low radiant energy transmission and can even block radiant heat transfer. Radiant barriers are usually installed in attics to reduce the amount of heat that flows through the roof to the living space. (Source: Choose Energy)

Radioactive waste

Materials left over from making nuclear energy. Radioactive waste can destroy living organisms if it is not stored safely. (Source: EIA)

Radioactivity

The spontaneous emission of radiation from the nucleus of an atom. Radionuclides lose particles and energy through this process. (Source: EIA)

Renewable Energy

Renewable energy refers to energy that is generated from renewable sources, like wind, geothermal and solar power. (Source: Choose Energy)

Renewable Energy Certificates (REC)

Also known as a Renewable Energy Credit, a REC represents one megawatt hour (mWh) of energy generated from a renewable source, such as solar or wind. By purchasing the REC from someone who has generated renewable energy and fed it into the grid, consumers can offset their own fossil-fuel generated electricity. In effect, RECs allows consumers to certify that a portion of their energy came from a renewable source. (Source: Choose Energy)

Renewable energy resources

Energy resources that are naturally replenishing but flow-limited. They are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Renewable energy resources include biomass, hydro, geothermal, solar, wind, ocean thermal, wave action, and tidal action. (Source: EIA)

Restructuring

The Public Utility Holding Company Act of 1935 changed the structure of the electrical power industry by taking away certain territories’ utility monopoly and allowing open competition between power suppliers for the areas’ customers. (Source: Choose Energy)

Shale

A very fine-grained, clastic sedimentary rock that forms when mud, silt, and clay-size mineral particles are consolidated and compacted into relatively impermeable layers. Shale is characterized by a finely laminated or stratified structure and is the most abundant sedimentary rock. Shale can contain varying amounts of organic matter, so it has the potential to become a hydrocarbon source rock. The pore size of shale reservoirs ranges from nanometers to micrometers. Hydrocarbons in some shale reservoirs can be extracted using hydraulic fracturing. (Source: EIA)

Shrinkage

The volume of natural gas that is transformed into liquid products during processing, primarily at natural gas liquids processing plants. (Source: EIA)

Sludge

A dense, slushy, liquid-to-semifluid product that accumulates as an end result of an industrial or technological process designed to purify a substance. Industrial sludges are produced from the processing of energy-related raw materials, chemical products, water, mined ores, sewerage, and other natural and man-made products. Sludges can also form from natural processes, such as the run off produced by rain fall, and accumulate on the bottom of bogs, streams, lakes, and tidelands. (Source: EIA)

Solar Cell

The photovoltaic device that converts sunlight into electricity. Multiple solar cells are combined within a solar panel in order to generate a sufficient amount of electricity. (Source: Choose Energy)

Solar energy

The radiant energy of the sun, which can be converted into other forms of energy, such as heat or electricity. (Source: EIA)

Solar Gain

The amount of solar energy a building absorbs from various entry points. Solar energy can pass through windows, conduct through the exterior to the interior or even be absorbed through materials within the building. (Source: Choose Energy)

Solar Lease

A financing method for home solar installation. It refers to an agreement in which a homeowner pays a monthly fee for use of the solar panels. Solar leases typically last for between 15-25 years. The advantage of a solar lease is that you don’t have to pay any upfront costs to go solar. (Source: Choose Energy)

Solar Panel

A collection of solar cells mounted within a frame for use in a solar PV system installation. (Source: Choose Energy)

Solar Power Purchase Agreement (PPA)

A financing method for home solar installation. It refers to an agreement in which a homeowner has a solar system installed at little to no cost. In return, the homeowner agrees to purchase the power provided by the solar installation – typically at rates well-below the market price. (Source: Choose Energy)

Stand-alone

A solar system that is not connected to the power grid. Stand-alone systems only provide electricity when they are receiving energy from the sun. Some stand-alone systems are connected to a battery bank for storing electricity generated. (Source: Choose Energy)

Steam turbine

A device that converts high-pressure steam, produced in a boiler, into mechanical energy that can then be used to produce electricity by forcing blades in a cylinder to rotate and turn a generator shaft. (Source: EIA)

Storage hydroelectric plant

A hydroelectric plant with reservoir storage capacity for power use. (Source: EIA)

Storage site

Spent nuclear fuel storage pool or dry cask storage facility, usually located at the reactor site, as licensed by (or proposed to be licensed by) the Nuclear Regulatory Commission (NRC). (Source: EIA)

Strategic Petroleum Reserve (SPR)

Petroleum stocks maintained by the Federal Government for use during periods of major supply interruption. (Source: EIA)

Subsidy

A government action towards the energy sector that lowers energy production costs, raises prices for energy producers or lowers energy prices for consumers. (Source: Choose Energy)

Tar sands

Naturally occurring bitumen-impregnated sands that yield mixtures of liquid hydrocarbon and that require further processing other than mechanical blending before becoming finished petroleum products. (Source: EIA)

Therm

A unit of heat used to measure natural gas volume. It is equivalent to the energy produced by one Ccf, or 100 cubic feet of natural gas. (Source: Choose Energy)

Thermal Energy

Energy produced from heat energy. (Source: Choose Energy)

Tidal Power

Energy harnessed from the rise and fall of ocean tides. The water is captured during peak tidal flow at a tidal power plant and is directed through a hydroelectric turbine. (Source: Choose Energy)

Tilt Angle

The angle between a solar array and the surface it’s mounted onto. This is different from the Angle of Incidence, which refers to the angle between a solar array and the sun’s rays. (Source: Choose Energy)

Tracking Solar Array

Advanced solar panel array that follows the path of the sun to capture the maximum possible daily solar energy. (Source: Choose Energy)

Transmission line

A set of conductors, insulators, supporting structures, and associated equipment used to move large quantities of power at high voltage, usually over long distances between a generating or receiving point and major substations or delivery points. (Source: EIA)

Transmission network

A system of transmission or distribution lines so cross-connected and operated as to permit multiple power supply to any principal point. (Source: EIA)

Transmitting utility

A regulated entity which owns and may construct and maintain wires used to transmit wholesale power. It may or may not handle the power dispatch and coordination functions. It is regulated to provide non-discriminatory connections, comparable service, and cost recovery. (Source: EIA)

Turbine

A machine for generating rotary mechanical power from the energy of a stream of fluid (such as water, steam, or hot gas). Turbines convert the kinetic energy of fluids to mechanical energy through the principles of impulse and reaction, or a mixture of the two. (Source: EIA)

Uranium (U)

A heavy, naturally radioactive, metallic element (atomic number 92). Its two principally occurring isotopes are uranium-235 and uranium-238. Uranium-235 is indispensable to the nuclear industry because it is the only isotope existing in nature, to any appreciable extent, that is fissionable by thermal neutrons. Uranium-238 is also important because it absorbs neutrons to produce a radioactive isotope that subsequently decays to the isotope plutonium-239, which also is fissionable by thermal neutrons. (Source: EIA)

Uranium concentrate

A yellow or brown powder obtained by the milling of uranium ore, processing of in situ leach mining solutions, or as a byproduct of phosphoric acid production. (Source: EIA)

Uranium deposit

A discrete concentration of uranium mineralization that is of possible economic interest. (Source: EIA)

Uranium Mill Tailings Radiation Control Act (UMTRA) of 1978

The act that directed the Department of Energy to provide for stabilization and control of the uranium mill tailings from in active sites in a safe and environmentally sound manner to minimize radiation health hazards to the public. It authorized the Department to undertake remedial actions at 24 designated inactive uranium-processing sites and at an estimated 5,048 vicinity properties. (Source: EIA)

Uranium ore

Rock containing uranium mineralization in concentrations that can be mined economically, typically one to four pounds of U3O8 per ton or 0.05 percent to 0.2 percent U3O8. (Source: EIA)

Utility

This refers to the company that generates and delivers electricity to your home or business. Even if you purchase your energy supply from another company, the utility is still responsible for reliably delivering that energy to your home or business. (Source: Choose Energy)

Value (of shipments)

The value received for the complete systems at the company's net billing price, freight-on-board factory, including charges for cooperative advertising and warranties. This does not include excise taxes, freight or transportation charges, or installation charges. (Source: EIA)

Voltage

The difference in electrical potential between any two conductors or between a conductor and ground. It is a measure of the electric energy per electron that electrons can acquire and/or give up as they move between the two conductors. (Source: EIA)

Wafer

A thin sheet of semiconductor (photovoltaic material) made by cutting it from a single crystal or ingot. (Source: EIA)

Watt (W)

The unit of electrical power equal to one ampere under a pressure of one volt. A Watt is equal to 1/746 horse power. (Source: EIA)

Watthour (Wh)

The electrical energy unit of measure equal to one watt of power supplied to, or taken from, an electric circuit steadily for one hour. (Source: EIA)

Wattmeter

A device for measuring power consumption. (Source: EIA)

Weir

A dam in a waterway over which water flows and that serves to raise the water level or to direct or regulate flow. (Source: EIA)

Wind energy

Kinetic energy present in wind motion that can be converted to mechanical energy for driving pumps, mills, and electric power generators. (Source: EIA)

Wind turbine

Wind energy conversion device that produces electricity; typically three blades rotating about a horizontal axis and positioned up-wind of the supporting tower. (Source: EIA)