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Tribal Energy and Environmental Information Clearinghouse
Tribal Energy and Environmental Information Clearinghouse: Environmental resources for tribal energy development
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Glossary

Select a letter from the list below to view glossary terms, acronyms, and abbreviations.


A B C D E F G H I K L M N O P R S T U V W
AC
See Alternating current (AC).
AC power generation
See Alternating current (AC).
Access roads
Gravel or dirt roads (rarely paved) that provide overland access to transmission line and pipeline rights-of-way (ROWs) and facilities for construction, inspection, maintenance, and decommissioning. Access roads have an average distance of 5 miles or less, have a nominal width of 15 feet, and exist within the center of a nominal 25-foot-wide ROW.
Afforestation
Planting of new forests on lands that historically have not contained forests.
Aggregate
Mineral materials such as sand, gravel, crushed stone, or quarried rock used for construction purposes.
Agricultural residues
The plant parts, primarily stalks and leaves, not removed from the fields with the primary food or fiber product. Examples include corn stover (stalks, leaves, husks, and cobs), wheat straw, and rice straw.
Agricultural waste
Wastes from farming and livestock operations, including animal manure. Other examples include wheatstraw, corn stover, orchard pruning, rice hulls, and fruit pits.
AHPA
Archaeological and Historic Preservation Act.
Air Quality
Measure of the health-related and visual charactersistics of the air. Air quality standards are the prescribed level of constituents in the outside air that cannot be exceeded during a specific time in a specified area.
AIRFA
American Indian Religious Freedom Act.
Alcohol
An organic compound with a carbon bound to a hydroxyl group. Examples are methanol and ethanol.
Algae production
Cultivation of algae as a feedstock for biodiesel.
Alongshore
Parallel to and near the shoreline.
Alternating current (AC)
An electric current that reverses its direction at regularly recurring intervals.
Anaerobic digestion
Degradation of organic matter by microbes in the absence of oxygen to produce methane and carbon dioxide.
Ancillary facilities
Facilities other than principal components that are often required in an energy development, such as compressor stations, electrical substations, or storage facilities.
Anthropogenic
Human-made; produced as a result of human activities.
API
American Petroleum Institute.
Aquatic biota
Collective term describing the organisms living in and depending on the aquatic environment.
Aquifer
An underground bed or layer of earth, gravel, or porous stone that yields usable quantities of water to a well or spring.
ARPA
Archaeological Resources Protection Act.
Attenuator
A wave energy capture device with principal axis oriented parallel to the direction of the incoming wave that converts the energy due to the relative motion of the parts of the device as the wave passes along it.
Axial flow turbine
A turbine that typically has two or three blades mounted on a horizontal shaft to form a rotor; the kinetic motion of the water current creates lift on the blades causing the rotor to turn driving a mechanical generator. These turbines must be oriented in the direction of flow. There are shrouded and open rotor models.
Background-level noise
Noise in the environment (other than noise from the source of interest).
Baghouse
A chamber containing fabric filter bags that remove particles from furnace stack exhaust gases. Used to eliminate particles greater than 20 microns in diameter.
Ballast water
Water carried in special (ballast) tanks of ships and used to provide stability needed when carrying less than a full load of cargo and to keep the ship at the proper depth in the water. When the ship is loaded with cargo, the ballast water is released to surrounding waters; when the ship is empty, it takes on more water to keep it upright.
Barrage
A barrage is a dam placed across an inlet or estuary that allows a basin to fill during the incoming high tide and then water is directed through turbines during the outgoing tide.
Barrage system
A barrage or dam is typically used to convert tidal energy into electricity by forcing the water through turbines, activating a generator. Gates and turbines are installed along the dam. When the tides produce an adequate difference in the level of the water on opposite sides of the dam, the gates are opened. The water then flows through the turbines. The turbines turn an electric generator to produce electricity. A barrage facility operates like a hydroelectric dam and power plant.
Bathymetry
The measurement of depths of water in oceans, seas, and lakes; also information derived from such measurements. Topography of the ocean floor indicated by depth contours drawn at regular intervals.
Benthic
Living in or occurring at the bottom of a body of water.
Berm
A raised area with vertical or sloping sides.
Best Management Practices (BMPs)
A practice (or combination of practices) that is determined to provide the most effective, environmentally sound, and economically feasible means of managing an activity and mitigating its impacts.
BIA
Bureau of Indian Affairs, U.S. Department of the Interior.
Bilge water
A term used to describe the water that collects in the lowest compartment (bilge) of a ship, generally caused by seawater penetration.
Binary cycle
Binary geothermal systems that use extracted hot water or steam to heat a secondary fluid, which then drives a power turbine.
Binary-cycle power plant
A geothermal electricity generating plant employing a closed-loop heat exchange system, in which the heat of the geothermal fluid (the "primary fluid") is transferred to a lower-boiling-point fluid (the "secondary" or "working" fluid), which is then vaporized and used to drive a turbine/generator set.
Biodiesel
A biodegradable transportation fuel for use in diesel engines. Biodiesel is produced through the transesterification of organically derived oils or fats. It may be used either as a replacement for or as a component of diesel fuel.
Bioenergy
The production, conversion, and use of material directly or indirectly produced by photosynthesis (including organic waste) to manufacture fuels and substitutes for petrochemical and other energy-intensive products.
Biofuels
Liquid, solid, or gaseous fuel produced by the conversion of biomass. Examples include bioethanol from sugar cane or corn, charcoal or woodchips, and biogas from anaerobic decomposition of wastes.
Biogas
A combustible gas derived from decomposing biological waste under anaerobic conditions. Biogas normally consists of 50 to 60% methane.
Biomass
Any plant-derived organic matter. Biomass available for energy on a sustainable basis includes herbaceous and woody energy crops, agricultural food and feed crops, agricultural crop wastes and residues, wood wastes and residues, aquatic plants, and other waste materials, including some municipal wastes. Biomass is a very heterogeneous and chemically complex renewable resource.
Biomass energy
See Bioenergy.
Biomass feedstocks
Any material used as a fuel directly or converted to another form of fuel or energy product.
Biota
The living organisms in a given region.
Black liquor (pulping liquor)
A by-product of the paper production process that can be used as a source of energy. Alkaline spent liquor is removed from the digesters in the process of chemically pulping wood. After evaporation, the residual "black" liquor is burned as a fuel in a recovery furnace that permits the recovery of certain basic chemicals.
BLM
Bureau of Land Management, U.S. Department of the Interior.
BMPs
See: Best Management Practices (BMPs).
BOEMRE
Bureau of Ocean Energy Management, Regulation and Enforcement, U.S. Department of the Interior. This agency was formerly called the Minerals Management Service (MMS).
Bone dry (oven dry)
Having 0% moisture content. Wood heated in an oven at a constant temperature of 212 degrees F or above until its weight stabilizes is considered bone dry or oven dry.
boreal (reservoirs)
Related to northern regions.
Borehole
The circular hole made by drilling that extends from the surface to the gas resource to be recovered.
Borrow material
Earth materials such as sand and gravel.
Borrow pit
A pit or excavation area used for gathering earth materials (borrow) such as sand or gravel.
Bubble curtain
A device used during pile-driving without cofferdams that will surround the large-diameter piles and generate bubbles to attenuate peak underwater sound pressure levels, which may adversely affect fish and marine mammals.
Buoy
A float; especially a floating object moored to the bottom, to mark a channel, anchor, shoal rock, etc.
By-product
Material, other than the principal product, generated as a consequence of an industrial process or as a breakdown product in a living system.
CAA
Clean Air Act.
Capacity factor
The ratio of electricity generated, for the period of time considered, to the energy that could have been generated at continuous full-power operation during the same period.
Cap-and-trade
A system designed to limit and reduce carbon emissions. Cap-and-trade regulation creates a single market mechanism as opposed to a command-and-control approach that prescribes reductions on a source-by-source basis. Cap-and-trade regulation sets an overall limit on carbon emissions and allows entities subject to the system to comply by reducing emissions at their covered facilities and/or by purchasing emission allowances (or credits) from other entities that have reduced emissions beyond their compliance obligations.
Carbohydrates
Organic compounds made up of carbon, hydrogen, and oxygen and having approximately the formula CH2On. Carbohydrates include starches, cellulosics, and sugars.
Carbon (C)
An abundant non-metallic element (atomic number 6) that occurs in all organic compounds. It exists naturally in three forms (diamond, graphite, and amorphous). Diamond and graphite are pure forms of carbon. Carbon is a major component of coal, oil, and crude oil.
Carbon (offset) credits
Part of a tradable permit scheme. They provide a way to reduce greenhouse gas emissions by assigning them a monetary value. A credit gives the owner the right to emit one tonne of carbon dioxide
Carbon capture
To remove carbon dioxide from the atmosphere or prevent its emission into the atmosphere through storage.
Carbon capture and storage (CSS)
A technique for trapping carbon dioxide as it is emitted from large point sources, compressing it, and transporting it to a suitable storage site, where it is injected into the ground.
Carbon cycle
Term used to describe the flow of carbon in various forms such as carbon dioxide CO2 organic matter, and carbonates through the atmosphere, ocean, terrestrial biosphere, and lithosphere.
Carbon dioxide (CO2)
A colorless, odorless, nonpoisonous gas that occurs naturally as part of the earth's atmosphere. Carbon dioxide is a product of fossil fuel combustion, as well as other processes. It is considered a greenhouse gas because it traps heat radiated into the atmosphere. It is the reference gas against which other greenhouse gases are measured, and therefore, has a Global Warming Potential of 1.
carbon monoxide (CO)
A colorless, odorless gas that is toxic if breathed in high concentrations over an extended period. Carbon monoxide is a criteria air pollutant. One source of carbon monoxide is engine exhaust.
Carbon sequestration
The uptake and storage of carbon. Trees and plants, for example, absorb carbon dioxide, release the oxygen, and store the carbon. Fossil fuels were at one time biomass and continue to store carbon until burned.
Carbon sink
A pool (reservoir) that absorbs or takes up released carbon from another part of the carbon cycle. For example, if the net exchange between the biosphere and the atmosphere is toward the atmosphere, the biosphere is the source, and the atmosphere is the sink. Forests and oceans are large carbon sinks that partially offset greenhouse gas emissions by storing more carbon than they release.
Carbon source
A pool (reservoir) that releases carbon to another part of the carbon cycle.
Carbonless sources of energy
Technologies that generate energy without producing and emitting carbon dioxide into the atmosphere. Sources include solar power, wind power, geothermal energy, biomass energy, low-head hydropower, hydrokinetics (wave and tidal power), and nuclear power.
Casing
Steel pipe placed in an oil or gas well to prevent the hole from collapsing.
Catalyst
A substance that increases the rate of a chemical reaction without being consumed or produced by the reaction. Enzymes are catalysts for many biochemical reactions.
Catalytic fuels synthesis unit
A tank in which syngas is mixed with oil and a catalyst that converts the syngas into a mixture of alcohols or biofuel.
Cavitation
The formation and collapse of vapor- or gas-filled cavities that result from a sudden decrease and increase of pressure. Cavitation can cause mechanical damage to adjacent surfaces in meters, valves, pumps, and pipes at locations where flowing liquid encounters a restriction or change in direction.
CBM
Coal bed methane.
Cellulose
A carbohydrate that is the principal component of wood. It is made of linked glucose molecules that strengthen the cell walls of most plants.
Cellulosic biomass
That portion of plants that are composed of complex sugar polymers and complex polysaccharides.
CEQ
Council on Environmental Quality.
CERCLA
Comprehensive Environmental Response, Compensation, and Liability Act.
CERT
Council of Energy Resource Tribes.
CFL
Compact fluorescent bulb.
CFR
Code of Federal Regulations.
Char
The remains of solid biomass that has been incompletely combusted, such as charcoal if wood is incompletely burned.
Charcoal
Black, porous, carbonaceous material produced by the destructive distillation of wood and used as a fuel, filter, and absorbent. Charcoal is almost pure carbon, with about twice the energy content per unit mass as the original wood; therefore, it can burn at a much higher temperature than wood.
Check dam
A small dam constructed in a gully or other small water course to decrease the streamflow velocity, minimize channel erosion, promote deposition of sediment, and divert water from a channel.
Chipper
A machine that produces wood chips by knife action.
Chips
Small fragments of wood chopped or broken by mechanical equipment. Total tree chips include wood, bark, and foliage. Pulp chips or clean chips are free of bark and foliage.
Christmas trees
1) Drilling: The set of valves, spools and fittings connected to the top of a well to direct and control the flow of formation fluids from the well. 2) Well completions: An assembly of valves, spools, pressure gauges and chokes fitted to the wellhead of a completed well to control production.. “Christmas trees” are available in a wide range of sizes and configurations, such as low- or high-pressure capacity and single- or multiple-completion capacity.
Climate change
Refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). Climate change may result from natural factors, such as changes in the Sun’s intensity or slow changes in the Earth’s orbit around the Sun; natural processes within the climate system (such as changes in ocean circulation); human activities that change the atmosphere’s composition (through burning fossil fuels); and the land surface (for example, deforestation, reforestation, urbanization, desertification, etc.).
Closed system
A cooling system that exchanges heat with its surroundings by conduction and convection.
CO
See Carbon monoxide
CO2
See Carbon dioxide.
Coalbed methane
Coalbed methane is methane contained in coal seams, and is often referred to as virgin coalbed methane, or coal seam gas.
Combustion
A chemical process in which a substance (fuel) reacts rapidly with oxygen and gives off heat.
Combustion gases
The gases released from a combustion process.
Compressor
A machine used to boost natural gas pressure to move it through pipelines or other facilities.
Compressor station
A permanent facility housing one or more compressors.
Conductor
Metal wires, cables, and bus-bars used for carrying electric current. Conductors may be solid or stranded, that is, built up by an assembly of smaller solid conductors.
Convection
The heat transfer between a solid and a moving fluid.
Convective heat transfer
See Convection.
Corn ethanol production plant
See Ethanol production plant.
Corn stover
The refuse of a corn crop (e.g., stalks, leaves, husks, and cobs) after the grain is harvested.
Corona
The electrical breakdown of air into charged particles, caused by the electric field at the surface of conductors.
Corona discharge/noise
The 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 the voltage gradient exceeds a certain critical value, thereby producing light, audible noise (described as crackling or hissing), and ozone.
Criteria air pollutants
Six common air pollutants for which National Ambient Air Quality Standards (NAAQS) have been established by the U.S. Environmental Protection Agency under Title I of the Clean Air Act. They are sulfur dioxide, nitrogen oxides, carbon monoxide, ozone, particulate matter (PM2.5 and PM10), and lead. Standards were developed for these pollutants on the basis of scientific knowledge about their health effects.
Crude oil
A mixture of various hydrocarbon compounds and other materials, usually containing about 84% carbon, 14% hydrogen, 1–3% sulfur; and nitrogen, oxygen, heavy metals, and salts that total less than 1%. Crude oil is a nonrenewable source of energy (fossil fuel). Crude oil is measured in barrels (one barrel equals 42 gallons).
Crustal rock
Refers to rocks comprising the continental crust, which are typically granitic in composition.
Cryptobiotic soils
A biological soil crust composed of living cyanobacteria, green algae, brown algae, fungi, lichens, and/or mosses. Commonly found in arid regions around the world, cryptobiotic soils are important members of desert ecosystems and contribute to the well being of other plants by stabilizing sand and dirt, promoting moisture retention, and fixing atmospheric nitrogen.
Cultural Resources
The archaeological sites, historic structures and features, and traditional cultural properties of human occupation or use, including manufactured objects, such as tools or buildings. Cultural resources may also include objects, sites, or natural features significant to Native Americans.
Current
The movement of electricity through a conductor. It is measured in amperes.
CWA
Clean Water Act.
Cyclone separator
A device used to remove particulate matter suspended in exhaust gas.
CZMA
Coastal Zone Management Act
Danger trees
Trees located outside or inside the right-of-way that pose a threat to the operation of a transmission line.
DC
See Direct Current (DC).
DC power generation
See Direct Current (DC).
Decommissioning
All activities necessary to take out of service and dispose of a facility after its useful life.
Decomposer
An organism that gains energy by breaking down the final remains of living things. Predominantly bacteria and fungi, decomposers are important in freeing the last of minerals and nutrients from organics and recycling them back into the food web.
Decomposition (process)
The biochemical process by which biological materials are broken down into smaller particles, and eventually, into basic chemical compounds and elements.
Delineation well
A well drilled just outside of the proved area of an oil gas reservoir in an attempt to extend the known boundaries of the reservoir.
Dewatering
The removal or draining of water from an area. Removal or separation of a portion of the water in a sludge or slurry to dry the sludge so it can be handled and disposed of; removal or draining the water from a tank or trench.
Dextrose
A sugar found in plant and animal tissue and derived synthetically from starch.
Digester
An airtight vessel or enclosure in which bacteria decomposes biomass in the absence of oxygen to produce biogas.
Direct current (DC)
A steady current that flows in one direction only. The current from batteries is an example of direct current.
Direct use
Use of geothermal heat without first converting it to electricity, such as for space heating and cooling, food preparation, industrial processes, etc.
Directional drilling
The intentional deviation of a wellbore from vertical to reach subsurface areas off to one side from the surface drilling site.
Disposal well
A well into which produced water from other wells is injected into an underground formation for disposal. Disposal wells typically are subject to regulatory requirements to avoid the contamination of freshwater aquifers.
Dissolved solids
The total amount of dissolved material, organic and inorganic, contained in water or wastes.
Distillation
The process of separating the components of a liquid mixture according to their different boiling points.
Distributed generation
Refers to electricity provided by small, modular power generators (typically ranging in capacity from a few kilowatts to 50 megawatts) located at or near customer demand.
distributed low-head
The generation of small-scale low-head hydropower that is distributed by power lines in a local area. For example, individual farms, homes, or businesses may have their own low-head hydropower facility.
DOE
U.S. Department of Energy.
DOI
U.S. Department of the Interior.
Domestic waste
Solid wastes of the type routinely generated by households.
DOT
U.S. Department of Transportation.
Dredge
An apparatus used in the removal of substrate usually to deepen water passages.
Dredging
Underwater excavation activity or operation with the purpose of gathering up bottom sediments and disposing them at a different location. Sediment that has been dredged from the waterway is called dredged material or dredge spoil.
Drill rig
The mast, draw works, and attendant surface equipment of a drilling unit.
Drilling fluid
Fluid used to lubricate and cool the drill bit, to assist in lifting cuttings from the borehole, and to control pressures in the borehole.
Drilling mud
The circulating fluid used to bring cuttings out of the well bore, to cool the drill bit, and to provide hole stability and pressure control. Drilling mud includes a number of additives to maintain the mud at desired viscosities and weights. Some additives that may be used are caustic, toxic, or acidic.
Drivetrain
The mechanical connection between each of the major components of the wind turbine/generator. The drivetrain includes the blades and rotor hub and a mechanical transmission that converts the angular momentum from the rotating blades into power that is transmitted to the induction generator.
Dry steam
Very hot steam that does not occur with liquid.
Dry steam power plant
A geothermal electricity generating plant where steam (at temperatures greater than 455°F [235°C]) is piped directly from a geothermal reservoir to run turbines that power a generator.
DSIRE
Database of State Incentives for Renewables & Efficiency.
Dust abatement
The reduction or elimination of dust pollution.
Ebb tide
The period of tide between high water and the succeeding low water; a falling tide.
Ecological resources
Biota (fish, wildlife, and plants) and their habitats, which may be land, air, or water.
Effluent
The liquid or gas discharged after processing activities, usually containing residues from such use. Also discharge from a chemical reactor.
Electric and magnetic fields (EMF)
Fields that surround both large power lines that distribute power and the smaller electric lines in homes and appliances. Generated when charged particles (e.g., electrons) are accelerated. EMFs are typically generated by alternating current in electrical conductors. Also referred to as electromagnetic fields.
Electric current
The flow of electric charge. The preferred unit of measure is the ampere.
Electric power
The rate at which electricity does work — measured at a point in time, i.e., with no time dimension. The unit of measure for electric power is a watt. The maximum amount of electric power that a piece of electrical equipment can accommodate is the capacity or capability of that equipment.
Electrical power grid
A system of synchronized power providers and consumers connected by transmission and distribution lines and operated by one or more control centers.
Electricity
A form of energy characterized by the presence and motion of elementary charged particles generated by friction, induction, or chemical change.
electromagnetic fields (EMF)
Fields that surround both large power lines that distribute power and the smaller electric lines in homes and appliances. Generated when charged particles (e.g., electrons) are accelerated. EMFs are typically generated by alternating current in electrical conductors.
Electromagnetic interference (EMI)
Any electromagnetic disturbance that interrupts, obstructs, or otherwise degrades or limits the effective performance of electrical equipment. It is caused by the presence of electromagnetic radiation.
Electrostatic precipitator
A device that removes particulates from a gas stream by inducing a negative charge to the particles and collecting them on a positively charged or grounded plate.
Embayment
An indentation in the shoreline forming an open bay.
EMF
See Electric and Magnetic Fields (EMF).
EMI
See Electromagnetic Interference (EMI).
Emissions
Substances that are discharged into the air from industrial processes, vehicles, and living organisms. In the context of global climate change, they consist of important greenhouse gases (e.g., the release of carbon dioxide during fuel combustion).
Endangered species
Any species (plant or animal) that is in danger of extinction throughout all or a significant part of its range. Requirements for declaring a species endangered are found in the Endangered Species Act.
Energy
The capability of doing work; different forms of energy can be converted to other forms, but the total amount of energy remains the same.
Energy content
The amount of energy released when a given unit of fuel is combusted.
Energy crops
Crops grown specifically for their fuel value. These include food crops such as corn and sugarcane.
ENERGY STAR®
A government-backed program helping businesses and individuals protect the environment through superior energy efficiency.
Energy transmission
The process of moving electrical energy, a gas, or a liquid energy source from its point of generation or extraction to its point of distribution or consumption. Electrical energy is transmitted via transmission lines, while liquids and gases are transmitted through pipelines.
Enhanced Geothermal System (EGS)
An engineered reservoir that can extract economic amounts of heat from geothermal resources.
Environmental Impact Statement (EIS)
A document required of federal agencies by the National Environmental Policy Act (NEPA) for major proposals or legislation that will or could significantly affect the environment. It describes the positive and negative effects of the proposed and alternative actions.
Environmental justice
The fair treatment of people of all races, cultures, incomes, and educational levels with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies.
E.O.
Executive Order.
EPA
U.S. Environmental Protection Agency.
EPCRA
Emergency Planning & Community Right-to-Know Act.
Erosion
The movement of exposed soil caused by the action of rain, snowmelt, or wind.
ESA
Endangered Species Act.
Estuary
A transitional zone along the coastline where ocean saltwater mixes with freshwater from the land. A term used to describe the open area and distance across a bay or body of water in which wind can exert energy on waves to cause them to be higher and more forceful upon impact with shorelines.
Ethanol
(CH3CH2OH) A colorless, flammable liquid produced by fermentation of sugars. Ethanol is used as a fuel oxygenate.
Ethanol production plant
A plant that converts biomass to ethanol for use as an additive to gasoline. Ethanol is most often produced from corn or sugarcane by utilizing enzymes to convert starches to simple sugars and yeast to ferment the sugars into ethanol. Ethanol can also be produced from cellulose by a hydrolysis process requiring a pretreatment step to break down the hemicellulose and lignin that surround the cellulose in a protective sheath prior to the fermentation process. Examples of different types of ethanol production plants include those for corn ethanol, hydrolysis cellulosic ethanol, and gasification cellulosic ethanol. Ethanol can also be used for purposes other than a gasoline additive (e.g., alcohol).
Executive Order
A President’s declaration that has the force of law, usually based on existing statutory powers, and requiring no action by the Congress.
Exploratory well
A well that is drilled to evaluate the resources that may be present. In some cases it is used to evaluate the feasibility of sequestering carbon dioxide in the subsurface.
FAA
Federal Aviation Administration, U.S. Department of Transportation.
facility
Any building, structure, system, process, equipment, or activity that fulfills a specific purpose on a site.
Feedstock
Any material that can be converted to another form of fuel or energy product.
Feedstock plant
Raw material used in a processing plant. The most important feedstock for the European petrochemical industry is naphtha.
Fermentation
A biochemical reaction that breaks down complex organic molecules (such as carbohydrates) into simpler materials (such as ethanol, carbon dioxide, and water). Bacteria or yeasts can ferment sugars to ethanol.
Fetch
The unobstructed distance over water in which waves are generated by wind of relatively constant direction and speed. Wind fetch is a term used to describe the open area and distance across a bay or body of water in which wind can exert energy on waves to cause them to be higher and more forceful upon impact with shorelines.
Fiber optics
The transmission of light through optical fibers for communication or signaling.
FIFRA
Federal Insecticide, Fungicide, and Rodenticide Act.
Flare
Process that burns and evacuates unused gases.
Flash steam
Steam produced when the pressure on a geothermal liquid is reduced. Also called flashing.
flow
Volume of water passing a point in a given amount of time, expressed as cubic feet or cubic meters per second.
FLPMA
Federal Land Policy and Management Act.
Fluidized bed boiler
A large, refractory-lined vessel with an air distribution member or plate in the bottom, a hot gas outlet in or near the top, and some provisions for introducing fuel. The fluidized bed is formed by blowing air up through a layer of inert particles (such as sand or limestone) at a rate that causes the particles to go into suspension and continuous motion. The super-hot bed material increases combustion efficiency by its direct contact with the fuel.
Fluidized bed catalytic tar reformer
A unit where the syngas and vapor compounds are bubbled through a catalyst that converts any tars in the mixture to additional syngas.
Fly ash
Small particles of airborne ash produced by burning fossil fuels. Fly ash is expelled as noncombustible airborne emissions or recovered as a by-product for commercial use (e.g., as a replacement for Portland cement used in concrete).
Flyrock
The fragments of rock thrown and scattered during quarry or tunnel blasting.
Footprint
See Project footprint.
footprint, carbon
A measure of the amount of carbon dioxide emitted into the atmosphere. Typically measured in tons of CO2 emitted annually, one's carbon footprint is directly related to consumption of fossil fuels and of electricity from nonrenewable energy sources.
Forb
A broad-leafed flowering herb other than grass.
forebay
The part of a dam's reservoir that is immediately upstream of the powerhouse.
Formation
A rock/mineral deposit or structure covering an area with the same physical properties.
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.
FPPA
Farmland Protection and Policy Act.
Fraccing
(rhymes with “fracking”) A method of stimulating well production by increasing the permeability of the producing formation. Under extremely high hydraulic pressure, the fracturing fluid (water, oil, dilute hydrochloric acid, or other fluid) is pumped into the formation that parts or fractures it.
Fracturing
A method of stimulating oil or gas production by opening new flow channels in the formation surrounding a production well. It involves pumping of crude oil, diesel, water, or chemical into a reservoir with such force that the reservoir rock is broken and results in greater flow of oil or gas from the reservoir. Also known as hydraulic fracturing or fraccing.
Fugitive dust
Airborne particles emitted from any source (such as activities associated with construction, manufacturing, or transportation), other than through a controllable stack.
FWCA
Fish and Wildlife Coordination Act.
Gasification
A chemical or heat process to convert a solid fuel to a gaseous form.
Gasification cellulosic ethanol production plant
See Ethanol production plant.
Gathering
The movement of oil or gas from a production well to the treatment facility.
Gathering pipelines
Pipelines within a field that transport gas or oil from the well to a central production facility or to the point of sale.
Generator
A machine that converts mechanical energy into electrical energy. See also Induction generator.
Geologic sequestration
The collection and placement of carbon dioxide into suitable underground formations for storage.
Geological hazard
Extreme natural events in the crust of the earth that pose a threat to life and property. Earthquakes, volcanic eruptions, landslides, and tsunamis (tidal waves) are examples of geological hazards.
Geological resources
Material of value to humans that is extracted (or is extractable) from solid earth, including minerals, rocks, and metals.
Geology
The study of the materials, processes, environments, and history of the earth, including rocks and their formation and structure.
geomorphology
The study of the character and origin of landforms, such as mountains, valleys, etc.
Geothermal energy
The Earth's interior heat made available to man by extracting it from hot water or rocks.
Geothermal energy technology
Broadly defined as an activity, application, or device designed to harness energy from geothermal resources in order to perform useful work.
Geothermal gradient
The rate of temperature increase in the Earth as a function of depth. Temperature increases an average of 1° Fahrenheit for every 75 feet in descent.
Geothermal Heat Pump (GHP)
Device that takes advantage of the relatively constant temperature of the Earth's interior, using it as a source and sink of heat for both heating and cooling. When cooling, heat is extracted from the space and dissipated into the Earth; when heating, heat is extracted from the Earth and pumped into the space.
Geothermal reservoir
Underground storage of water trapped in porous rock capable of providing hydrothermal (hot water and steam) resources.
Geothermal resource
The natural heat of the earth that can be used for beneficial purposes when the heat is collected and transported to the surface. Typically found in underground reservoirs of hot water or steam created by heat from the Earth, but also exist in subsurface areas of dry hot rock.
Geyser
A spring that shoots jets of hot water and steam into the air.
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.
Glucose
(C6H12O6) A simple six-carbon sugar. A sweet, colorless sugar that is the most common sugar in nature and the sugar most commonly fermented to ethanol.
Glycerin
(C3H8O3) A liquid by-product of biodiesel production. Glycerin is used in the manufacture of dynamite, cosmetics, liquid soaps, inks, and lubricants.
Granitic
Medium- to coarse-textured, light-colored, intrusive igneous rock composed predominantly of felsic minerals (i.e., silicate minerals, like feldspar, that are enriched with lighter elements such as aluminum, sodium, and potassium).
Greenhouse Effect
Trapping and build-up of heat in the atmosphere (troposphere) near the Earth’s surface. Some of the heat flowing back toward space from the Earth's surface is absorbed by water vapor, carbon dioxide, ozone, and several other gases in the atmosphere and then reradiated back toward the Earth’s surface. If the atmospheric concentrations of these greenhouse gases rise, the average temperature of the lower atmosphere will gradually increase.
Greenhouse gas (GHG)
Any gas that absorbs infrared radiation (i.e., that traps heat) in the atmosphere. Natural and human-made greenhouse gases include, but are not limited to, water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), ozone (O3), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6).
Grid
See Electrical power grid.
Groundwater
The supply of water found beneath the earth's surface, usually in porous rock formations (aquifers), which may supply wells and springs. Generally, it refers to all water contained in the ground.
Guy wires
Wires or cables used to secure and stabilize support structures (e.g., wind turbines, meteorological towers, transmission towers, etc.).
Habitat
The place, including physical and biotic conditions, where a plant or animal lives.
Hammermill
A device consisting of a rotating head with free-swinging hammers that reduce chips or hogged fuel to a predetermined particle size through a perforated screen.
HAP
Hazardous air pollutant.
Haul out, hauling out
The place or the act of an animal crawling or pulling themselves out of the water and onto land, ice, or other object, such as a buoy
Hazardous material
Any material that poses a threat to human health and/or the environment. Hazardous materials are typically toxic, corrosive, ignitable, explosive, or chemically reactive.
Hazardous waste
Byproducts of society that can pose a substantial or potential hazard to human health or the environment when improperly managed. Possesses at least one of four characteristics (ignitability, corrosivity, reactivity, or toxicity), or appears on special U.S. Environmental Protection Agency lists.
Vertical change in elevation, expressed in either feet or meters, between the head water level and the tail water level.
head pond
A pond that is used to store water for a hydroelectric project.
Heat exchanger
A device for transferring thermal energy from one fluid to another.
Heat flow
Movement of heat from within the Earth to the surface, where it dissipates into the atmosphere, surface water, and space by radiation.
Hectare (ha)
An area equal to 2.47 acres. There are 100 hectares in 1 square kilometer.
Hemicellulose
Any of several polysaccharides found in plant cell walls that are more complex than a sugar and less complex than cellulose.
herbicides
Chemicals used to kill undesirable vegetation.
High tide
The maximum elevation reached by each rising tide.
Historic properties
Any prehistoric or historic sites, districts, buildings, structures, or objects included in or eligible for inclusion in the National Register of Historic Places maintained by the Secretary of the Interior. They include artifacts, records, and remains that are related to and located within such properties.
Historic trail
See National Historic Trails.
HMTA
Hazardous Materials Transportation Act.
Hogged fuel or hog fuel
Wood residues processed through a chipper or mill to produce coarse chips normally used for fuel. Bark, sawdust, plner shavings, wood chunks, dirt, and fines may be included.
Hopper
A funnel-shaped device used for transferring products.
Horizontal axis turbine
A turbine where the axis is oriented horizontally along the seafloor, parallel to the flow of the current.
Hot Dry Rock (HDR)
Subsurface geologic formation of abnormally high heat content that contains little or no water.
Hydraulic fracturing (Hydrofracturing)
Fracturing of rock at depth with fluid pressure. Hydraulic fracturing at depth may be accomplished by pumping water into a well at very high pressures. Under natural conditions, vapor pressure may rise high enough to cause fracturing in a process known as hydrothermal brecciation. See also Fracturing.
Hydrocarbons
A compound formed from carbon and hydrogen, e.g., oil and gas.
Hydrofracturing
See Hydraulic fracturing.
Hydrogen sulfide
(H2S) Colorless, toxic, and flammable gas emitted during organic decomposition. Also a by-product of oil refining and burning. Responsible for the foul odor of rotten eggs.
Hydrokinetic energy
Energy that can be captured from flowing water that occurs in rivers or ocean currents. This includes ocean wave energy, tidal energy, river-in-stream energy, and ocean current energy.
Hydrologic conduits
Channels for carrying water or other fluids, such as pipes and aqueducts.
Hydrology
The science that deals with the properties, distribution, and circulation of surface and subsurface water.
Hydrolysis cellulosic ethanol production plant
See Ethanol production plant.
hydropower
The use of water to power machinery or make electricity. Water moves constantly through a vast global cycle, evaporating from lakes and oceans, forming clouds, precipitating as rain or snow, then flowing back down to the ocean. The energy of this water cycle, which is driven by the sun, can be tapped to produce electricity or for mechanical tasks like grinding grain. Hydropower uses a fuel -- water -- that is not reduced or used up in the process. Because the water cycle is an endless, constantly recharging system, hydropower is considered a renewable energy resource.
hydropower facility, diversion
A diversion, sometimes called a "run-of-river" facility, channels a portion of a river through a canal or penstock. It may not require the use of a dam.
hydropower facility, impoundment
The most common type of hydroelectric power plant is an impoundment facility. An impoundment facility, typically a large hydropower system, uses a dam to store river water in a reservoir. Water released from the reservoir flows through a turbine, spinning it, which in turn activates a generator to produce electricity. The water may be released to meet changing electricity needs or to maintain a constant reservoir level.
hydropower facility, pumped storage
When the demand for electricity is low, a pumped storage facility stores energy by pumping water from a lower reservoir to an upper reservoir. During periods of high electrical demand, the water is released back to the lower reservoir to generate electricity.
Hydrothermal
Pertaining to hot water.
hypolimnion
The bottom and most dense layer of a stratified lake. It is typically the coldest layer in the summer and warmest in the winter. It is isolated from wind mixing and typically too dark for any appreciable plant photosynthesis to occur.
ICLEI
International Council for Local Environmental Initiatives.
ICOUP
See Intertribal Council on Energy Policy.
IEED
Office of Indian Energy and Economic Development, U.S. Department of the Interior.
Immobile herbicides
Herbicides that stay in place until they are eventually degraded.
Impermeable
Not permitting the passage of a fluid.
Impoundment
The accumulation of any form of water in a reservoir or other storage area.
Induction generator
(1) A generator that produces energy by the production of a magnetic field by the proximity of a electric charge. (2) A mechanical device that relies on Faraday's law of "electromagnetic induction" to generate electricity; the mechanical energy of a rotating metal shaft is used to "induce" an electromotive force in a coil of wires surrounding it that is capable of delivering an electric current when connected to a load. Induction generators are rugged and relatively cheap to build and operate, but are typically used to produce relatively small amounts of electrical power (on the order of hundreds of kilowatts). Induction generators are typically used in wind turbines where the rotating shaft receives its mechanical energy from the rotation of the wind-driven turbine blades.
Industrial waste
Materials discarded from industrial operations or derived from manufacturing processes.
Infrared radiation
Radiation emitted by the Earth's surface, the atmosphere, and clouds. It is also known as terrestrial or long-wave radiation. Infrared radiation has a distinctive range of wavelengths ("spectrum") longer than the wavelength of the red color in the visible part of the spectrum. The spectrum of infrared radiation is practically distinct from that of solar or short-wave radiation because of the difference in temperature between the Sun and the Earth-atmosphere system.
INGAA
Interstate Natural Gas Association of America.
Injection
The process of returning spent geothermal fluids to the subsurface. Sometimes referred to as reinjection.
Injection well
A well that is used to inject fluids into subsurface formations. Injection wells may be used for the disposal of produced water or to inject fluids (e.g., produced water, carbon dioxide, steam) into hydrocarbon producing formations to increase or maintain reservoir pressure or otherwise enhance the hydrocarbon recovery. An injection well can also be used to inject carbon dioxide into geologic formations that do not contain oil but that are otherwise well-suited for carbon sequestration.
Inlet
1) A short, narrow waterway connecting a smaller body of water with a large parent body of water; 2) An arm of the sea or other body of water, that is long compared to its width, and may extend a considerable distance inland; 3) A connecting passage between two bodies of water. Typically refers to tidal openings in barrier islands, but can also be applied to river mouths in tidal and non-tidal environments.
Installed capacity
Production capacity of a plant based either on its rated (nameplate) capacity or actual (practically determined) capacity.
Insulator
Something that does not allow electricity to flow through it easily. Glass and special rubber are good insulators. Insulators do not allow electricity to flow through them easily because the electrons in their atoms do not move easily from atom to atom.
intake
A structure that diverts water into a conduit leading to the power plant.
interim reclamation
Temporary reclamation initiated to stabilize disturbed surfaces on well pads, roads, and pipelines prior to final reclamation.
Intertribal Council on Utility Policy (ICOUP)
A non-profit organization providing a forum for discussion of utility development issues, including policy analysis and recommendations and technical workshops, with an emphasis on wind energy development.
Invasive plants
Any species, including noxious and exotic species, that is an aggressive colonizer and can out-compete indigenous species.
Invasive species
A species that is not native (or is alien) to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health (Executive Order 13112). It includes any species, including noxious and exotic species, that is an aggressive colonizer and can out-compete species native to the area.
Inverter
A device that converts direct current electricity to alternating current either for standalone systems or to supply power to an electricity grid.
ITEP
Institute for Tribal Environmental Professionals .
Kilogram (kg)
The base unit of mass in the International System, equal to 1,000 grams (2.2046 pounds)
Kilometer (km)
1,000 meters in length or approximatelly 0.62 mile.
Kilowatt (kW)
One thousand watts of electricity.
Land use
The way land is developed and used by humans.
Landfill gas
Gas that is generated by decomposition of organic material at landfill disposal sites. Landfill gas is approximately 50% methane.
Lava
Magma that reaches the Earth's surface and issues from volcanoes.
Laydown area
An area that has been cleared for the temporary storage of equipment and supplies. To ensure accessibility and safe maneuverability for transport and off-loading of vehicles, laydown areas are usually covered with rock and/or gravel.
Leaching
The process by which soluble substances are dissolved and transported down through the soil by recharge.
Lignin
An amorphous polymer that, together with cellulose, forms the cell walls of woody plants. Lignin acts as the bonding agent between cells.
Lignocellulose
Refers to plant materials made up primarily of lignin, cellulose, and hemicellulose.
Liquefaction
The process of converting biomass from a solid to a liquid or converting a gas to a liquid for use as a fuel. The conversion process is a chemical change that takes place at elevated temperatures and pressures, such as through heating, grinding, and blending with another liquid.
Liquid fuels
See Biofuels.
Liter (L)
Metric unit of volume equal to approximately 1.056 liquid quarts, 0.908 dry quart, or 0.264 gallon.
Lock
A structure adjacent to a dam or in a canal to allow passage of vessels from one water level to another. The lock consists of a chamber, with gates at either end, in which water is raised or lowered. Navigation locks and dams do not normally store flood waters.
Log
A systematic recording of data, as from the driller’s log, mud log, electrical well log, or radioactivity log. Many different logs may be run to obtain various characteristics of downhole formations.
Longwave radiation
The radiation emitted in the spectral wavelength greater than 4 micrometers, which corresponds to the radiation emitted from the Earth and the atmosphere. See also infrared radiation.
low head
Where the head water level at station intake and the tail water level at station discharge is 66 ft or less.
low-head hydropower plants
Small-scale hydropower facilities that can extract energy from small headwater dams.
Magma
Molten rock within the Earth, from which igneous rock is formed by cooling. Source of heat beneath the surface.
MBTA
Migratory Bird Treaty Act.
Mechanical-draft cooling tower
A closed-cycle cooling system whereby ambient air interacts with cooling water via large fans or other mechanical devices, thereby removing heat from the water by evaporation (evaporative cooling tower) or by conduction/convection (dry cooling tower).
Megajoule (MJ)
One million watts. A unit used for measuring large amounts of energy. "Mega" means 1 million; therefore, a megajoule is 1,000,000 joules. 1 megajoule is approximately equal to 238,846 calories or 0.27778 kW/hr.
Megawatt (MW)
One million watts of electricity.
Meteorological (monitoring) towers
A wind monitoring system that measures meteorological information such as wind speed, wind direction, and temperature at various heights above the ground. These data are used to evaluate the wind resource at a specific location.
Methane
A colorless, flammable, odorless hydrocarbon gas (CH4) that is the major component of natural gas. It is also an important source of hydrogen in various industrial processes. Methane is produced through anaerobic (without oxygen) decomposition of waste in landfills, animal digestion, decomposition of animal wastes, production and distribution of natural gas and petroleum, coal production, and incomplete fossil fuel combustion. Methane is a greenhouse gas with a global warming potential most recently estimated at 23 times that of carbon dioxide (CO2). See also Coal bed methane.
Methyl alcohol
(CH3OH) A light, volatile alcohol eligible for gasoline blending (also known as wood alcohol). Commercially, it is typically made by steam reforming natural gas. Also formed in the destructive distillation of wood.
Microalgae
Single-cell, photosynthetic organisms found in freshwater and seawater and capable of being harvested as an agricultural energy crop. Microalgae are known for their rapid growth and high energy content.
microhydropower facilities
A micro hydropower plant that has a capacity of up to 100 kilowatts (less than 100 kilowatt hours average per year).
Micrositing
A strategy that places facilities (such as wind turbines) in locations where maximum power production is possible throughout the year.
Mitigation
Actions taken to avoid, minimize, rectify, or compensate for any adverse environmental impact.
MJ
See Megajoule.
MMS
Minerals Management Service, U.S. Department of the Interior. In June 2010, this agency was renamed the Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE).
Moisture content (MC)
The weight of the water contained in wood, usually expressed as a percentage of weight, either oven-dry or as received.
Molecular sieve
A material containing tiny pores of a precise and uniform size that is used as an adsorbent for gases and liquids.
Mud
Mud is drilling fluid that consists mainly of a mixture of water, or oil distillate, and “heavy” minerals such as bentonite or barites.
Mud pot
A type of hot spring that contains boiling mud, typically sulfurous and often multicolored; tends to be associated with geysers and other hot springs in volcanic zones. Also known as painted pot or sulfur-mud pool.
Municipal solid waste
Waste material from households and businesses that is not regulated as hazardous. Any organic matter, including sewage, industrial, and commercial wastes, from municipal waste collection systems. Municipal waste does not include agricultural and wood wastes or residues.
NAAQS
See National Ambient Air Quality Standards.
Nacelle
The housing that protects the major components (e.g., generator and gear box) of a wind turbine. It is located behind the turbine blades.
NAGPRA
Native American Graves Protection and Repatriation Act.
National Ambient Air Quality Standards (NAAQS)
Standards established by the Clean Air Act, as amended. The primary NAAQS specify maximum outdoor air concentrations of criteria pollutants that would protect the public health within an adequate margin of safety. The secondary NAAQS specify maximum concentrations that would protect the public welfare from any known or anticipated adverse effects of a pollutant.
National Historic Preservation Act
Requires federal agencies to take into account the effects of their actions on historical and archaeological resources and consider opportunities to minimize their impacts.
National Historic Trail
These trails are designated by Congress under the National Trails System Act of 1968 and follow, as closely as possible, on federal land, the original trails or routes of travel with national historical significance.
National Register of Historic Places (NRHP)
A comprehensive list of districts, sites, buildings, structures, and objects that are significant in American history, architecture, archaeology, engineering, and culture. The National Register is administered by the National Park Service, which is part of the U.S. Department of the Interior.
Native American
A person culturally identified with a tribe that is indigenous to the United States.
Natural gas
Those hydrocarbons, other than oil and other than natural gas liquids, that occur naturally in the gaseous phase in the reservoir and are produced and recovered at the wellhead in gaseous form.
Natural gas compressor station
A facility that is used to compress natural gas in order to create additional pressure to increase the amount of gas a pipeline can hold, help move it through a pipeline, or to move it into or from storage.
Natural-draft cooling tower
A heat removal device used to transfer process waste heat to the atmosphere using the buoyancy of the exhaust air rising in a tall chimney-like structure to provide the draft.
Naturally Occurring Radioactive Materials (NORM)
Radioactive materials that are found in nature.
Near shore
The region seaward of the shore (from approximately the step at the base of the surf zone) extending offshore to the toe of the shore face. Nearshore is a general term to mean various areas of the coastal zone, ranging from the shoreline to the edge of the continental shelf.
NEPA
National Environmental Policy Act.
NESHAPs
National Emission Standards for Hazardous Air Pollutants.
NHPA
National Historic Preservation Act.
Nitrogen oxide (NOx)
A product of photochemical reactions of nitric oxide in ambient air; the major component of photochemical smog.
nitrogen oxides
The oxides of nitrogen, primarily nitrogen oxide (NO) and nitrogen dioxide (NO2), that are produced in the combustion of fossil fuels. Nitrogen dioxide emissions constitute an air pollution problem, because they contribute to acid deposition and the formation of atmospheric ozone. Nitrogen oxides are criteria air pollutants.
Nitrous oxide (N2O)
A powerful greenhouse gas with a global warming potential of 296 times that of carbon dioxide (CO2). Major sources of nitrous oxide include soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning.
NOAA
National Oceanic and Atmospheric Administration, U.S. Department of Commerce.
noise
Any sound that is undesirable because it interferes with speech and hearing, is intense enough to damage hearing, or is otherwise annoying (unwanted sound).
NORM
See Naturally Occurring Radioactive Materials (NORM).
NOx
See Nitrogen oxide.
noxious weeds
An annual, biennial, or perennial plant designated to be injurious to public health, the environment, public roads, crops, livestock, or other property.
NPDES
National Pollutant Discharge Elimination System.
NPS
National Park Service, U.S. Department of the Interior.
NRHP
See National Register of Historic Places (NRHP).
NSPS
New Source Performance Standards.
NSR
New Source Review.
NTEC
National Tribal Environmental Council .
NTOC
National Tribal Operations Committee.
NWCC
National Wind Coordinating Collaborative.
NWRSA
National Wildlife Refuge System Administration Act.
Occupational Safety & Health Administration (OSHA)
The federal agency that enforces workplace health and safety legislation, created by the Occupational Safety and Health Act of 1970.
Ocean wave energy
See wave energy.
Off-gas
The air or vapor that is released to the outside environment as a result of manufacturing operations or a treatment process.
Off-Highway Vehicle (OHV)
A class of vehicles that encompasses all-terrain vehicles (ATVs), off-highway motorcycles (OHMs), and off-road vehicles (ORVs) such as 4x4 trucks.
Offshore
That area which lies seaward of the coastline
OHV
Off-highway vehicle.
Oil and gas field
A natural accumulation of oil and gas in the subsurface. Oil and gas may be present in two or more reservoirs at different depths.
Once-through cooling
Water (fresh or saline) that is withdrawn from a river, stream, or other water body (man-made or natural), or a well, that is passed through a steam condenser one time, and then returned to the river or stream or water body some distance from the intake.
On-farm
Refers to a facility located on or adjacent to a farm that is the source of biomass.
Onshore
A direction landward from the sea.
Oscillating water column device
A partially submerged structure that encloses a column of air above a column of water; a collector funnels waves into the structure below the waterline, causing the water column to rise and fall; this alternately pressurizes and depressurizes the air column, pushing or pulling it through a turbine. There are shore-based and floating models.
OSH Act
Occupational Safety & Health Act regulations.
OSHA
Occupational Safety and Health Administration, U.S. Department of Labor.
Oven-dried wood
See Bone dry.
Overtopping device
A partially submerged structure; a collector funnels waves over the top of the structure into a reservoir; water runs back out to the sea from this reservoir through a turbine. There are shore-based and floating models.
PAHs
See Polycyclic aromatic hydrocarbons (PAHs).
Paleontological Resources
Fossilized remains, imprints, and traces of plants and animals preserved in rocks and sediments since some past geologic time.
Particulate matter (PM)
Fine solid or liquid particles, such as dust, soot, smoke, mist, fumes, or smog found in air or emissions. The size of the particulates is measured in micrometers (µm). One micrometer is 1 millionth of a meter or 0.000039 inch.
particulates
Solid particles and liquid droplets small enough to become airborne.
PCB
Polychlorinated biphenyl.
penstock
A closed conduit or pipe for conducting water to the powerhouse.
Perennial stream
A stream or reach of a stream that flows throughout the year.
Permeability
The capacity of a substance (such as rock) to transmit a fluid. The degree of permeability depends on the number, size, and shape of the pores and/or fractures in the rock and their interconnections. It is measured by the time it takes a fluid of standard viscosity to move a given distance.
Permeable host rock
Any porous rock comprising a viable geothermal reservoir. Permeability of the host rock is a measure of its ability to transmit a fluid (including both water and steam).
Permitted off-site disposal facility
A facility for disposing of hazardous waste that has met the requirements under Subtitle C of the Resource Conservation and Recovery Act.
pesticides
Substances or mixture thereof intended for preventing, destroying, repelling, or mitigating any pest. Also, any substance or mixture intended for use as a plant regulator, defoliant, or desiccant.
Petroleum
A broad category term that includes both crude oil and petroleum products, and is sometimes used interchangeably with the term ‘oil.’
Photobioreactor
A system that grows various plants especially algae, by providing efficient exposure to light, optimal temperatures, and pH levels.
Photosynthesis
A process used by many plants and bacteria to build carbohydrates from carbon dioxide and water, using energy derived from light. Photosynthesis is the key initial step in the growth of biomass and is depicted by the equation: CO2 + H2O + light + chlorophyll = (CH2O) + O2.
Pigging
See Pipeline Inspection Gauge Launch/Recovery (Pigging).
Pigs
Generic term signifying an independent, self-contained device, tool, or vehicle that is that is routinely introduced into pipelines to clean the inner wall of the pipe and monitor for critical conditions that could compromise the integrity or efficiency of the pipeline, such as cracks, corrosion, and pipe deformations. These tools are referred to as “pigs” because of the occasional squealing noises that can be heard as they travel through the pipeline.
Pile, pile driving
A long, heavy timber or section of concrete or metal that is driven or jetted into the earth or seabed to serve as a support or protection.
Pipeline
All parts of the physical facility through which liquids or gases, such as crude oil and natural gas, are moved, usually over long distances between a producing region and a local distribution system. There are three major types of pipelines used to transport hydrocarbons: crude oil, natural gas, and product pipelines. There are three components of a natural gas pipeline system: the gathering system, the interstate pipeline, and the distribution system.
Pipeline inspection gauge launch/recovery (Pigging) facilities
Facilities providing access to a pipeline for the purposes of cleaning and maintenance (pipelines are cleaned and monitored internally by devices known as "pigs" that travel through the pipeline). These facilities are usually smaller than pump or compressor stations and typically consist of one or more short sections of aboveground pipeline, valves, and other control equipment, and may include buildings (typically made of sheet metal), generators, storage areas, and a helipad. Pigging facilities are normally fenced and surfaced with gravel. Metering and regulating stations are placed periodically along the pipeline to allow pipeline companies to monitor and manage the natural gas in their pipes. They measure and track the flow of gas along the pipeline without impeding its movement.
Plug-flow system
A type of anaerobic digester that has a horizontal tank in which a constant volume of material is added, which forces material in the tank to move through the tank and be digested.
PM
See Particulate Matter (PM).
PM10
Particulate matter with a mean aerodynamic diameter of 10 micrometers (0.0004 in) or less. Particles smaller than this diameter can be deposited in the lungs. PM10 is one of the six criteria pollutants specified under Title I of the Clean Air Act.
PM2.5
Particulate matter with a mean aerodynamic diameter of 2.5 micrometers (0.0001 in.) or less.
Point absorber
Wave energy capture device, with principal dimension relatively small compared to the wavelength, that is able to capture energy from a wave front greater than the physical dimension of the device. There are floating and submerged models.
Polycyclic aromatic hydrocarbons (PAHs)
Any of a class of carcinogenic organic molecules that consist of three or more benzene rings and are commonly produced by fossil fuel combustion. Also called polynuclear aromatic hydrocarbons.
Porosity
The ratio of the aggregate volume of pore spaces in rock or soil to its total volume; usually stated as a percentage.
Power train
Interconnected mechanical devices that convert the kinetic energy of the ocean waves to electricity.
PPA
Pollution Prevention Act.
Produced water
Water brought to the surface through the borehole. Primary waste during production is produced water, which can comprise 98% of material brought to the surface. Conventional natural gas wells typically produce less water than oil wells. Produced water can become a significant waste stream during the production phase. Regulations govern the disposal of this waste stream; the majority of it is disposed of by underground injection either in disposal wells or, in mature producing fields, in enhanced oil recovery wells (i.e., wells through which produced water and other materials are injected into a producing formation in order to increase formation pressure and production). Substances found in high concentrations in produced water include chloride, sodium, calcium, magnesium, and potassium. Other contaminants can include polycyclic aromatic hydrocarbons (PAHs), lead, arsenic, barium, antimony, sulfur, zinc, and naturally occurring radioactive material (NORM). Other wastes include residual wastes that remain after separation of the oil and natural gas.
Production
Phase of commercial operation of an oil field. text Typical activities during the production phase include operation of wells and compressor or pump stations, waste management, and maintenance and replacement of facility components.
Production casing
Steel pipe installed in the borehole to isolate formations in the borehole and to eliminate communication among hydrocarbon-bearing zones and/or water aquifers and other mineral resources.
Production wells
A well used to retrieve petroleum or gas from an underground reservoir. In fields in which improved recovery techniques are being applied, it is the well through which oil is produced.
Project footprint
The land or water area covered by a project. This includes direct physical coverage (i.e., the area on which the project physically stands) and direct effects (i.e., the disturbances that may directly emanate from the project, such as noise).
Proppants
Substances such as sand or glass beads, that are pumped into the formation as part of the fracturing job. The proppants become wedged in the open fractures, leaving channels for oil to flow through into the well after the hydraulic fracture pressure is released. This process is often called a “frac job.” When high concentrations of acid are used, it may be called an “acid frac job.” See also Fracing.
PSD
Prevention of Significant Deterioration.
Pulping liquor
See Spent liquor.
Pump cavitation
See Cavitation.
Pump station
A facility containing centrifugal pumps used to maintain movement of product within oil pipelines.
Pyrolysis
The breaking apart of complex molecules by heating in the absence of oxygen, producing solid, liquid, and gaseous fuels.
RCRA
Resource Conservation and Recovery Act.
Recharge/recharging
The addition of water to an aquifer by natural infiltration (e.g., rainfall that seeps into the ground) or by artificial injection through wells.
Reclamation
Process of restoring surface environment to acceptable preexisting conditions. Reclamation (also referred to as restoration) includes surface contouring, equipment removal, pipeline plugging, revegetation, etc.
Red liquor
A by-product of wood cooking in the magnesium sulphite process that can be used as a source of energy.
Reforestation
Planting of forests on lands that previously contained forests but that had been converted to some other use.
Registries, registry systems
Electronic databases that track and record emissions and emission allowance holdings, retirements, cancellations, and transfers.
Renewable 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.
Reserve pit
An excavated pit that may be lined with plastic, which holds drill cuttings and waste mud.
Reservoir
A subsurface accumulation of liquid (e.g., crude oil, natural gas, steam) that can be recovered.
Residues
By-products from processing all forms of biomass that have significant energy potential. For example, making solid wood products and pulp from logs produces bark, shavings and sawdust, and spent pulping liquors. Because these residues are already collected at the point of processing, they can be convenient and relatively inexpensive sources of biomass for energy.
Revegetation
The reestablishment and development of self-sustaining plant cover. On disturbed sites, human assistance will speed natural processes by seedbed preparation, reseeding, and mulching.
Rig
A collective term to describe the equipment needed when drilling a well.
Right-of-way (ROW)
The land on which transmission lines and/or pipelines are located. The right-of-way is usually acquired in widths that vary with the kilovolt (kV) size of the transmission line, diameter of the pipeline, or number of collocated transmission lines and/or pipelines (e.g., they may range from as little as 25 to hundreds of feet wide). They provide a safety margin between the transmission line or pipeline and surrounding structures or vegetation. Some vegetation clearing is usually required within the ROW for safety and/or access. Vegetation favored within the ROW normally consists of species that are slow growing or that have low mature heights. Access roads may also be contained within portions of a ROW to provide convenient access for repair, maintenance, and inspection vehicles.
River in-stream energy systems
A series of devices placed directly in the flowing water of rivers that convert the movement of water into electrical energy.
ROWs
See Right-of-Way (ROW).
run-of-the-river (facility)
A low-head plant using the flow of a stream as it occurs, and having little or no reservoir capacity for storage.
Saccharification
A process in which liquefied starch is converted to dextrose (sugar).
Sacred landscapes
Natural places recognized by a cultural group as having spiritual or religious significance.
Salinity
A measure of the amount of salt and other mineral substances dissolved in water.
SCADA
Supervisory Control and Data Acquisition .
Scarifying
Loosening topsoil or breaking up the forest floor to improve conditions for seed germination or tree planting. Also refers to nicking or abrading the hard seed coat of some species to aid germination.
Scouring
Erosion of ocean seabed or shoreline, or a bed or bank of a river caused by tidal or river flow.
Scrubber
An air pollution control device that uses a liquid or solid to remove pollutants from a gas stream by adsorption or chemical reaction.
SDWA
Safe Drinking Water Act.
Secondary containment
An engineered system designed to contain accidental releases from containers storing liquids. Secondary containment devices typically are constructed of materials that are compatible with the materials being stored and are designed to contain at least the entire volume of stored material.
Sediment
Materials that sink to the bottom of a body of water, or materials that are deposited by wind, water, or glaciers.
Sedimentary rock
Rock formed at or near the earth’s surface from the consolidation of loose sediment that has accumulated in layers through deposition by water, wind, or ice, or deposited by organisms. Examples are sandstone and limestone.
Seismicity
Refers to the geographic and historical distribution of earthquakes.
Sensitive species
A plant or animal species listed by the state or federal government as threatened, endangered, or as a species of special concern. The list of sensitive species varies from state to state, and the same species can be considered sensitive in one state but not in another.
Shadow flicker
The visual, strobe-like effect that occurs when the rotating blades of wind turbines cast shadows.
Shield wires
Steel or aluminum-clad wires with a diameter of about 0.5 inch that are attached directly to the support tower (no insulation), providing a path for lightning to go directly to and through the towers to the ground straps at the base of the towers. They provide lightning protection for the conductors, other energized equipment, and even customer equipment.
SHPO
See State Historic Preservation Office(r) (SHPO).
Sink
In general, any process, activity, or mechanism that removes a greenhouse gas or a precursor of a greenhouse gas or aerosol from the atmosphere.
Site reclamation
Process of restoring surface environment to acceptable preexisting conditions. Reclamation (also referred to as restoration) includes surface contouring, equipment removal, pipeline plugging, revegetation, etc.
Slash
Unused and generally unmarketable accumulation of woody debris (such as that left on the land after timber or other forest products have been harvested), tree tops, limbs, bark, or windfalls.
slash (burning)
1) Any tree-tops, limbs, bark, abandoned forest products, windfalls, or other debris left on the land after timber or other forest products have been cut. 2) Of or being a form of agriculture in which an area of forest is cleared by cutting and burning and is then planted, usually for several seasons, before being left to return to forest.
Slope
The degree of inclination to the horizontal. (Usually expressed as a ratio, such as 1:25, indicating one unit rise in 25 units of horizontal distance; or in a decimal fraction (0.04).)
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.
Sluice gate
A mechanism for controlling the amount of water that passes through a manmade channel or dam.
Slurry
A liquid that has a very high level of suspended solids (usually from 2 to 30% by weight).
SO2
Sulfur dioxide.
Socioeconomics
The social and economic conditions in the study area.
SODAR
Sonic Detection and Ranging.
Soil horizon
A layer of soil that is nearly parallel to the land surface and is different from layers above and below.
Solar tubes
Light tubes or light pipes that are used for transporting or distributing natural or artificial light. In their application to daylighting, they are also often called sun pipes, solar pipes, solar light pipes, or daylight pipes.
Solid waste
All unwanted, abandoned, or discarded solid or semisolid material whether or not subject to decomposition, originating from any source.
Sour gas
A gas containing hydrogen sulfide, carbon dioxide, or mercaptans, all of which are extremely harmful.
SPCC
SPCCP Regulations (40 CFR Part 112).
SPCCP
Spill Prevention Control and Countermeasures Program.
Special status species
Special status species include both plant and animal species that are officially listed as threatened or endangered or are proposed or are candidates for listing as threatened or endangered under the provisions of the Endangered Species Act; also, those listed by a state in a category such as threatened or endangered, implying potential endangerment or extinction.
Spent liquor
The liquid residue left after an industrial process; can be a component of waste materials used as fuel. See also black liquor, red liquor, and sulfite liquor.
Staging area
A construction area located along the transmission line or pipeline where materials are received, stored, and shipped to the right-of-way. They are located adjacent to established roads with easy vehicle access. Diesel fuel, gasoline, lubricating oils, paints, herbicides, and blasting agents may be stored in these areas. Staging areas are generally located every 8 to 10 miles and vary in size from 1 to 3 acres. Disturbed areas that require minimal grading are usually selected.
Starch
A molecule composed of long chains of glucose molecules. Many plants store the energy produced in the phytosynthesis process in the form of starch.
State Historic Preservation Office(r) (SHPO)
The State office(r) charged with the identification and protection of prehistoric and historic resources in accordance with the National Historic Preservation Act.
Step-up transformer
Electrical device that changes the voltage of the electricity passing through it.
Stover
The dried stalks and leaves of a crop remaining after the grain has been harvested.
stream bank cutting
The side slopes of a channel between which the stream flow is normally confined.
Stringing
Laying out sections of pipe along the intended path of the pipeline.
Stripper/rectifier column
The section of a distillation column below the feed in which the condensate is progressively decreased in the fraction of a more volatile component by stripping. The portion of a distillation column above the feed tray in which rising vapor is enriched by interaction with a countercurrent falling stream of condensed vapor.
Submarine
Beneath the surface of the water; undersea.
Subsea cable
A cable designed for service underwater.
Subsidence
A sinking of part of the Earth's crust.
Substation
A facility that switches, changes, or regulates electric voltage. Substations vary in size and configuration but are often several acres in size. The area within a substation is normally unvegetated and surfaced with gravel. Substations are normally fenced and reached by a permanent access road. A substation generally contains a variety of structures, conductors, fencing, lighting, and other features that result in an industrial appearance. Transmission lines start from and end at a substation.
Sulfite liquor
End product of pulp and paper manufacturing processes that contains lignins and has a high moisture content; often reused in recovery boilers. Similar to black liquor.
Sulfur dioxide (SO2)
A naturally occuring gas consisting of sulfur and oxygen that causes acid rain. Burning fossil fuels, such as coal, releases SO2 into the atmosphere.
Surface water
Water on the earth’s surface that is directly exposed to the atmosphere, as distinguished from water in the ground (groundwater).
Surficial
Pertaining to or lying on the surface of the earth.
Surge tank
Storage tank used to regulate fluid levels, fluctuations in flow rate, temperature, and pressure.
SWEEP
Southwest Energy Efficiency Project.
Switchgrass
Switchgrass is the perennial herbaceous prairie grass native to the central North American Great Plains. It is considered a candidate for a cellulosic ethanol or other bioenergy feedstock as it has a high biomass yield per acre and is low maintenance. Switchgrass can be found in prairies, on roadsides, and in pastures.
SWRCA
Soil and Water Resources Conservation Act.
synchronous generator
An AC generator having a DC exciter. Synchronous generators are used as stand-alone generators for emergency power and can also be paralleled with other synchronous generators and the utility system.
Syngas
A synthetic gas produced through gasification of biomass. Syngas is a combination of hydrogen and carbon monoxide along with tars and other solids. Syngas is similar to natural gas and can be cleaned and conditioned to form a feedstock for production of methanol.
tailrace
The channel that carries water away from a dam.
TAPS
Trans-Alaska Pipeline System.
TEEIC
Tribal Energy and Environmental Information Clearinghouse.
TERA
Tribal Energy Resource Agreement.
Terawatt (TW)
A unit of power, equal to 1012 watts, or 1,000,000 megawatts. Abbreviated TW.
Terminators
Wave energy devices that extend perpendicular to the direction of wave travel and capture or reflect the power of the wave. These devices are typically onshore or nearshore; however, floating versions have been designed for offshore applications.
Terrestrial
Land-based, as opposed to water. Also, plants or animals living on land rather than in the water.
Terrestrial sequestration
The collection and storage of carbon dioxide by plants and the storage of carbon dioxide in soil.
The Geysers
A large geothermal steam field located north of San Francisco.
Thermal cracking
A refining process in which heat and pressure are used to break down, rearrange, or combine hydrocarbon molecules. Therma -cracking includes gas oil, visbreaking, fluid coking, delayed coking, and other thermal cracking processes (e.g., flexicoking).
Threatened species
Any species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. Requirements for declaring a species threatened are contained in the Endangered Species Act.
Tidal barrage
See barrage systems.
Tidal energy
Term used to describe the methods of creating energy from the movement of water due to the ocean tides, ocean waves, and currents in rivers.
Tidal range
The ebb and flow over land between mlw (mean low water) and mhw (mean high water) were tide is periodically present. (2) The difference in height between consecutive high and low (or higher high and lower low) waters.
Tidal turbine
Similar to a wind turbine, a tidal turbine converts the horizontal movement of the water from the incoming and outgoing tide into electricity. Tidal turbines can be placed wherever there is a reliable tidal flow and where there is minimal conflict with existing uses, e.g., ship traffic. Tidal turbines are arrayed underwater in rows, as in some wind farms.
Tide
The periodic rising and falling of water that results from gravitational attraction of the moon and sun acting on the rotating earth.
Toe-cutting
Lateral erosion of the “toe” or base of a streambank that causes the bank to collapse.
Tonne, ton
One U.S. ton (short ton) = 2,000 pounds. One Imperial ton (long ton or shipping ton) = 2,240 pounds. One metric tonne (tonne) = 1,000 kilograms (2,205 pounds). One oven-dry ton or tonne (ODT, sometimes termed bone-dry ton/tonne) is the amount of wood that weighs one ton/tonne at 0% moisture content. One green ton/tonne refers to the weight of undried (fresh) biomass material; moisture content must be specified if green weight is used as a fuel measure.
Topography
The configuration of the earth’s surface, including the shape, elevation, and position of its natural and manmade features.
Town gas
The purified crude gas remaining after removal of CO2. Town gas is a coal gas manufactured for domestic and industrial use.
Traditional cultural property
A property that is eligible for inclusion in the National Register of Historic Places because of its association with cultural practices or beliefs of a living community that (a) are rooted in that community's history, and (b) are important in maintaining the continuing cultural identity of the community.
Transesterification
A chemical process that reacts an alcohol with the triglycerides contained in vegetable oils and animal fats to produce biodiesel and glycerin.
Transformer
A device for transferring electric power from one circuit to another in an alternating current system. Transformers are also used to change voltage from one level to another.
Transmission grid
A system of power plants, transmission lines, and substations is referred to as a transmission grid.
Transmission line
A set of conductors insulators, support structures, and associated equipment used to move large quantities of electric power at high voltage, usually over long distances between substations. There are two major types of transmission lines: alternating current (AC) and direct current (DC). However, they have a variety of voltages (generally between 115 and 765 kV) and configurations, and they can be located either aboveground or underground.
Transmission system
Consists of electric transmission lines, towers, substations and other components for sending electricity to users.
Transmission towers
Support structures that keep the high-voltage conductors (power lines) separated from their surroundings and from each other. They can be open lattice metal structures or one or more wood or metal poles. Height can be over 150 feet with crossarms as much as 100 feet wide.
Trench/trenching
(1) In the context of energy transmission projects, a long, narrow ditch dug into the ground and embanked with its own soil, used to bury and protect a transmission line or pipeline. (2) In the context of hydropower, a long narrow submarine depression with relatively steep sides.
Tribal Energy Resource Agreement (TERA)
A TERA grants authority to a tribe to review and approve leases, business agreements, and rights-of-way for energy development on tribal lands.
Trust resources (on tribal lands)
Trust resources are interests in land, water, minerals, funds, or other assets or property that is held by the United States in trust for an Indian tribe or an individual Indian or which is held by an Indian tribe or Indian subject to a restriction on alienation imposed by the United States.
TSCA
Toxic Substances Control Act.
Tsunami
1) A long-period water wave caused by an underwater disturbance such as a volcanic eruption or earthquake. 2) A shallow water progressive wave, potentially catastrophic, caused by an underwater earthquake or volcano.
Turbidity
A measurement of the total suspended solids.
Turbine
A device in which a stream of water or gas turns a bladed wheel, converting the kinetic energy of the fluid flow into mechanical energy available from the turbine shaft. Turbines are considered the most economical means of turning large electrical generators. They are typically driven by steam, fuel vapor, water, or wind. Wind turbines can convert the energy in the wind into mechanical power that can be used for a variety of activities like grinding grain or pumping water. Wind turbines can also use generators to convert wind energy into electricity.
U.S. Environmental Protection Agency (U.S. EPA)
The independent federal agency, established in 1970, that regulates federal environmental matters and oversees the implementation of Federal environmental laws.
UIC
Underground injection control.
USACE
U.S. Army Corps of Engineers.
USC
United States Code.
USDA
U.S. Department of Agriculture.
USEPA
See U.S. Environmental Protection Agency (USEPA).
USFWS
U.S. Fish and Wildlife Service, U.S. Department of Agriculture.
USGS
U.S. Geological Survey, U.S. Department of the Interior.
UST
Underground storage tank.
Utility-scale energy generation facilities
These facilities generate large amounts of electricity that is transmitted from one location (wind farm) to many users through a transmission system, similar to the process at any other commercial power plant. At the utility scale, a wind farm, consists of many large wind turbines.
utility-scale low-head hydropower
Refers to plants (facilities) that distribute power to consumers via the transmission grid.
Vertical axis turbine
A turbine mounted in such a way that the axis is positioned perpendicular to the tidal stream and the ground.
Viewshed
The total landscape seen or potentially seen from all or a logical part of a travel route, use area, or water body.
Visual impact
Any modification in land forms, water bodies, or vegetation, or any introduction of structures, which negatively or positively affect the visual character or quality of a landscape.
Visual resources
Refers to all objects (manmade and natural, moving and stationary) and features such as landforms and water bodies that are visible on a landscape.
VOCs
See Volatile organic compounds.
Volatile organic compounds (VOCs)
A broad range of organic compounds that readily evaporate at normal temperatures and pressures. Examples include certain solvents, paint thinners, degreasers (benzene), chloroform, and methyl alcohol. Such compounds can react with other substances (primarily nitrogen oxides) to form ozone. They contribute significantly to photochemical smog production and certain health problems.
Volcanology
A branch of science that deals with volcanic phenomena.
waste management
The planning, coordination, and direction of functions related to generation, handling, treatment, storage, transportation, and disposal of waste. It also includes associated pollution prevention and surveillance and maintenance activities.
Waste production
Refers to food waste, animal manure, and municipal waste that can be used to produce biofuels and biogas.
Waste/wood waste
A category of biomass energy that includes black liquor, wood/wood waste liquids (red liquor, sludge wood, and spent sulfite liquor); wood/wood waste solids (peat, paper pellets, railroad ties, utility poles, etc.).
Wastewater
Water that typically contains less than a 1% concentration of organic hazardous waste materials.
Water vapor
The most abundant greenhouse gas, it is the water present in the atmosphere in gaseous form. Water vapor is an important part of the natural greenhouse effect. While humans are not significantly increasing its concentration, it contributes to the enhanced greenhouse effect because the warming influence of greenhouse gases leads to a positive water vapor feedback. In addition to its role as a natural greenhouse gas, water vapor plays an important role in regulating the temperature of the planet because clouds form when excess water vapor in the atmosphere condenses to form ice, water droplets, and precipitation.
Watershed
A topographically defined area drained by a river/stream or system of connecting rivers/streams such that all outflow is discharged through a single outlet. Also called a drainage area.
Watt (electric)
The electrical unit of power.
Wave energy
Energy derived from the movement of ocean waves.
Well or wellbore
The hole drilled from the surface to the gas-bearing formation, several of which may be developed from a single pad.
Well pad
Relatively flat work area (surface location) that is used for drilling a well or wells and producing from the well once it is completed.
Wellhead
Refers to the topmost point of a well and the structure built over it. Wellheads include control equipment such as outlets, valves, blowout preventers, casing heads, tubing heads and “Christmas trees.”
Wet scrubber
A vessel used for removing pollutants from a gas stream by means of a liquid spray, liquid jet, or liquid layer.
Wetlands
Areas that are soaked or flooded by surface or groundwater frequently enough or long enough to support plants, birds, animals, and aquatic life. Wetlands generally include swamps, marshes, bogs, estuaries, and other inland and coastal areas and are federally protected.
WGA
Western Governors' Association.
Wind energy
Air in motion. Winds are created by the uneven heating of the atmosphere by the sun in combination with the irregular surface of the earth and the earth’s rotation. These winds can be “harvested” using wind turbines and used to make electricity. The force of the wind makes the wind turbine blades spin, and the energy of this motion is converted into electricity by a generator. Wind energy is a free, renewable resource. Its use does not affect its future supply. Wind energy facilities convert energy from the motion of wind into electricity that is sent to energy consumers via electric transmission lines.
Wind farms
One or more wind turbines operating within a contiguous area for the purpose of generating electricity.
Wind power density
The method for rating wind energy, ranging from Class 1 (the lowest) to Class 7 (the highest). Wind power density of Class 3 or greater is generally considered adequate for utility-scale wind energy generation. The most economical sites for large wind farms have power density classes of Class 4 or higher.
Wind Power for Native Americans Program
Part of the Wind Powering America Program, that assists tribes in the evaluation and development of wind energy by providing technical assistance, including equipment loan programs, pilot project support, and other specific project assistance.
Wind resource areas (WRAs)
Areas where wind energy is available for use based on historical wind data, topographic features, and other parameters.
Wind shadow(ing)
The area behind an obstacle where air movement is not capable of moving material.
Wind turbines
Wind turbines can convert the energy in the wind into mechanical power that can be used for a variety of activities like grinding grain or pumping water. Wind turbines can also use generators to convert wind energy into electricity.
Winds for Schools Program
Part of the Wind Powering America Program, that supports the development of wind energy projects and educational programs at rural schools.
Wood
A solid lignocellulosic material naturally produced in trees and some shrubs, made of up to 40 to 50% cellulose, 20 to 30% hemicellulose, and 20 to 30% lignin.
Wood (forestry) residues
Includes tops, limbs, and other woody material not removed in forest harvesting operations in commercial hardwood and softwood stands, as well as woody material resulting from forest management operations such as precommercial thinnings and removal of dead and dying trees.
Woody crops
Trees grown in a forest or on plantations that are used primarily for burning to generate heat or electricity and can also be used for the production of biofuels.
WRAs
See Wind Resource Areas (WRAs).
WSR
Wild and Scenic Rivers Act.
WWEC
West-wide Energy Corridor.