Corona dischargeElectrical discharge accompanied by ionization of surrounding atmosphere around high-voltage transmission lines, occurring mostly under wet conditions.
Corona/corona noiseThe electrical breakdown of air into charged particles. The phenomenon appears as a bluish-purple glow on the surface of and adjacent to a conductor when…
Corporate average fuel economy (CAFE)(CAFE)Federal standards enacted in 1975 for fuel economy in motor vehicles. The average of city and highway fuel economy test results weighted by a manufacturer…
CorridorA strip of land through which one or more existing or potential facilities may be located.
Counterflow Heat ExchangerA heat exchanger in which two fluids flow in opposite directions for transfer heat energy from one to the other.
CounterpartyIn any financial contract, the persons or institutions entering the contract on the opposite sides of the transaction are called the counterparties.
CovenantsRules and restrictions governing the use of property.
coverNatural or manmade objects on the bottom of lakes, rivers, or impoundments, especially those that influence fish behavior.
crackingA reduction of molecular weight by breaking bonds, which may be done by thermal, catalytic, or hydrocracking.
CraterA steep-sided, usually circular depression formed by either explosion or collapse at a volcanic vent.
CrawlspaceThe unoccupied, and usually unfinished and unconditioned space between the floor, foundation walls, and the slab or ground of a building.
CreditCredit generally refers to the ability of a person or organization to borrow money, as well as the arrangements that are made for repaying the loan and…
Credit clearingA mechanism for settling mutual claims that shares among many parties the risk of a company failing to fulfill its contract.
Credit ratingYour credit rating is an independent statistical evaluation of your ability to repay debt based on your borrowing and repayment history.
Credit RiskA term used to describe the possibility of default on a loan by a borrower.
Credit ScoreA number, roughly between 300 and 800, that measures an individual's credit worthiness. The most well-known type of credit score is the FICOî score.
Creep (rate)Relatively slow movement along a fault. It is sometimes called "seismic creep" to distinguish it from the slumping of rock or soil on slopes (which is…
CreosoteA liquid byproduct of wood combustion (or distillation) that condenses on the internal surfaces of vents and chimneys, which if not removed regularly, can…
CrescentsQuarter-moon-shaped (hence crescent) artifacts that may have been in the form of blades, scrapers, or projectile points.
Criteria air pollutantsSix common air pollutants for which National Ambient Air Quality Standards (NAAQS) have been established by the U.S.
Critical Compression PressureThe highest possible pressure in a fuel-air mixture before spontaneous ignition occurs.
Critical habitatThe specific area within the geographical area occupied by the species at the time it is listed as endangered or threatened.
Critical habitat unit (CHU)(CHU)Under the Endangered Species Act, critical habitat is defined as "the specific areas within the geographic area occupied by a species on which are found…
Critical noticesPipeline issuances that provide information on conditions that affect natural gas scheduling or adversely affect scheduled gas flow.
Crop treeUsually a conifer tree grown to provide wood products.
Crucial winter rangeThe portion of the winter range to which a wildlife species is confined during periods of heaviest snow cover or that portion of the year-long range which…
CrustaceansAquatic animals with hard external skeletons and segmented limbs, belonging to the class Crustacea; include cladocerans, shrimp, crayfish, fairy shrimp…
Crustal spreading centerA linear zone in the Earth's crust whose opposite sides are moving away from one another.
CSPA type of tumor found in breast or prostate tissue. It is often large and bulky and grows quickly.
Cube LawIn reference to wind energy, for any given instant, the power available in the wind is proportional to the cube of the wind velocity; when wind speed…
Cubic Foot (of Natural Gas)A unit of volume equal to 1 cubic foot at a pressure base of 14.73 pounds standard per square inch absolute and a temperature base of 60 degrees…
CuestaAn elongated ridge formed by gently tilting sedimentary strata. The landform has a steep slope (escarpment or cliff) where the strata are exposed on their…
CullAny item of production picked out for rejection because it does not meet certain specifications.
Cull sectionA log cut from a tree that is rejected because of defects making it unsuitable for conventional forest products.
Cull treesLive saw-timber and pole-timber size trees which do not contain a merchantable sawlog due to poor form, quality, or undesirable species.
Cultural modificationAny human-caused change in the land form, water form, vegetation, or the addition of a structure which creates a visual contrast in the basic elements (e.
Cultural resourcesArchaeological sites, structures, or features; traditional use areas; and Native American sacred sites or special use areas that provide evidence of the…
Cumulative effectsEffects on the environment resulting from actions that are individually minor but that add up to a greater total effect as they take place over a period…
Cumulative impactsThe impacts assessed in an environmental impact statement that could potentially result from incremental impacts of the action when added to other past…
Current (Electrical)The flow of electrical energy (electricity) in a conductor, measured in amperes.
Current DollarsThe value or purchasing power of a dollar that has not been reduced to a common basis of constant purchasing power, but instead reflects anticipated…
Curtailable loadElectricity deliveries that are subject to interruption by the grid operator.
Customer ChargeAn amount to be paid for energy periodically by a customer without regard to demand or energy consumption.
Customer ClassCategories of energy consumers, as defined by consumption or demand levels, patterns, and conditions, and generally included residential, commercial…
Cut-and-fillThe process of earth grading by excavating part of a higher area and using the excavated material for fill to raise the surface of an adjacent lower area.
Cut-In-SpeedThe lowest wind speed at which a wind turbine begins producing usable power.
Cut-Out-SpeedThe highest wind speed at which a wind turbine stops producing power.
CyanobacteriaBlue-green algae, prokaryotic, photosynthetic organisms that generally have a blue-green tint and lack chloroplasts.
CycleIn alternating current, the current goes from zero potential or voltage to a maximum in one direction, back to zero, and then to a maximum potential or…
Cycling LossesThe loss of heat as the water circulates through a water heater tank and inlet and outlet pipes.
Cyclone BurnerA furnace/combustion chamber in which finely ground fuel is blown in spirals in the combustion chamber to maximize combustion efficiency.
Cyclone separatorA device used to remove particulate matter suspended in exhaust gases.
Czochralski ProcessA method of growing large size, high quality semiconductor crystal by slowly lifting a seed crystal from a molten bath of the material under careful…
Daily (or Next-Day) IndexesPublished (Platts, NGI, Dow Jones, SNL, ICE, NGW) price indices for commodities (gas or electricity) to be delivered the next day based on transactions…
Daily DealsUsually transactions done on a day for delivery or settlement or both, the next day.
DamA structure for impeding and controlling the flow of water in a water course, and which increases the water elevation to create the hydraulic head.
DamperA movable plate used to control air flow; in a wood stove or fireplace, used to control the amount and direction of air going to the fire.
Darrius (Wind) MachineA type of vertical-axis wind machine that has long, thin blades in the shape of loops connected to the top and bottom of the axle; often called an…
Day-ahead marketsForward markets for electricity to be supplied the following day. This market closes with acceptance by the independent system operator, power exchange…
Day-night average noise levelTwenty-four-hour average noise level, obtained after the addition of a 10-dB penalty for environmental noise occurring from 10 p.m. to 7 a.m.
DaylightingThe use of direct, diffuse, or reflected sunlight to provide supplemental lighting for building interiors.
Daytime mean rural background levelDaytime (7 a.m. to 10 p.m.) average sound level in the rural environment, from all sources other than a particular noise that is of interest.
Decibel (dB)(dB)A standard unit for measuring the loudness or intensity of sound. In general, a sound doubles in loudness with every increase of 10 decibels.
Decibel, A-weighted (dBA)(dBA)A measurement of sound approximating the sensitivity of the human ear and used to characterize the intensity or loudness of a sound.
DeciduousPlants that shed their leaves annually. Not evergreen.
Decision noticeThe written record of a federal agency decision after an environmental assessment.
DeclinationThe angular position of the sun at solar noon with respect to the plane of the equator.
Declining Block RateAn electricity supplier rate structure in which the per unit price of electricity decreases as the amount of energy increases.
DecommissioningThe process of removing a power plant, apparatus, equipment, building, or facility from operation.
DecompositionThe process of breaking down organic material; reduction of the net energy level and change in physical and chemical composition of organic material.
DecouplingA regulatory design that breaks the link between utility revenues and energy sales to encourage utility investment in conservation.
Deed RestrictionA legally binding restriction on the use, activity, and/or limitation of property rights, recorded at the registry of deeds.
Deep DischargeDischarging a battery to 20 percent or less of its full charge capacity.
Deep-cycle batteryA battery with large plates that can withstand many discharges to a low state of charge.
Degree DayA unit for measuring the extent that the outdoor daily average temperature (the mean of the maximum and minimum daily dry-bulb temperatures) falls below…
Degree HourThe product of 1 hour, and usually the number of degrees Fahrenheit the hourly mean temperature is above a base point (usually 65 degrees Fahrenheit)…
DehumidifierA device that cools air by removing moisture from it.
dehydrationA condition caused by the loss of too much water from the body. Severe diarrhea or vomiting can cause dehydration.
dehydrogenationA chemical reaction in which hydrogen is removed from a compound.
Delivery Point(s)An industry-designated location at which delivery may be made in fulfillment of contract terms.
DeltaThe relationship between an option's price and the price of the underlying stock or futures contract is called its delta.
DemandForm PCT/IPEA/401, filed with an International Preliminary Examining Authority, demanding that an international application shall be the subject of an…
Demand (Tankless) Water HeaterA type of water heater that has no storage tank thus eliminating storage tank stand-by losses.