Energy terms starting with P

255 terms

Photovoltaic (PV) array An interconnected system of PV modules that function as a single electricity-producing unit.
Photovoltaic (PV) cell The smallest semiconductor element within a PV module that converts incident sunlight into electrical energy (direct current voltage and current).
Photovoltaic (PV) facility A solar energy facility that uses photovoltaic cells to produce electricity and that includes all components, such as the PV system, power conditioning…
Photovoltaic (PV) module An assembly of solar cells (flat-plate type) or receiver(s) and optics (concentrator type) and ancillary parts, such as interconnects and terminals…
Photovoltaic (PV) panel A collection of modules, either flat-plate or concentrator type, mechanically fastened, electrically interconnected, and designed to provide a…
Photovoltaic (PV) power plant See Photovoltaic (PV) facility
Photovoltaic (PV) receiver An assembly of one or more PV cells that accepts concentrated sunlight and incorporates means for thermal and electric energy removal.
Photovoltaic (PV) system See Photovoltaic (PV) facility
Photovoltaic (PV; Solar) Array A group of solar photovoltaic modules connected together.
Photovoltaic (Solar) Cell Treated semiconductor material that converts solar irradiance to electricity.
Photovoltaic (Solar) Module or Panel A solar photovoltaic product that generally consists of groups of PV cells electrically connected together to produce a specified power output under…
Photovoltaic (Solar) System A complete PV power system composed of the module (or array), and balance-of-system (BOS) components including the array supports, electrical…
Photovoltaic Device A solid-state electrical device that converts light directly into direct current electricity of voltage-current characteristics that are a function of the…
Photovoltaic Peak Watt see Peak Watt.
Photovoltaic-Thermal (PV/T) Systems A solar energy system that produces electricity with a PV module, and collects thermal energy from the module for heating.
Photovoltaics (PV) Technologies that utilize semiconducting materials that convert sunlight directly into electricity.
Phreatic vegetation Vegetation supported by groundwater below the land surface.
Phreatophytes Any plant, typically living in the desert, that obtains its water from long taproots that reach the water table.
Physical basis Describes a physical natural gas purchase for the following month where the price is tied to the closing price of the expiring Nymex futures contract.
Physical Vapor Deposition A method of depositing thin semiconductor photovoltaic) films. With this method, physical processes, such as thermal evaporation or bombardment of ions…
Physiography The physical geography of an area or the description of its physical features.
Phytoplankton Small, often single-celled plants that live suspended in bodies of water.
Pictograph A design drawn in pigment upon an unprepared or ground rock surface.
Piezometer A nonpumping well, generally of small diameter, for measuring the elevation of a water table.
Piling unmerchantable material (PUM) A logging contract requirement to remove and pile unmerchantable woody material of a specified size.
Pilot scale The size of a system between the small laboratory model size (bench scale) and a full-size system.
Pitch Control A method of controlling a wind turbine's speed by varying the orientation, or pitch, of the blades, and thereby altering its aerodynamics and efficiency.
Pithouse A semi-subterranean dwelling with an excavated floor and earthen superstructure supported by posts and beams.
Pivotal supplier A power supplier whose capacity must be used to meet peak demand and whose capacity exceeds the market’s supply margin.
Placer An alluvial deposit of sand and gravel containing valuable minerals. (nps geo)
Placer mining That form of mining in which the surficial detritus is washed for gold or other valuable minerals.
Placer mining claim Minerals are loose on the ground or in a streambed.
Plains An extensive area that ranges from level to gently sloping or undulating.
Plan A benefit your employer, union or other group sponsor provides to you to pay for your health care services.
Planetary boundary layer turbulence structure In the Earth's atmosphere, the planetary boundary layer is the air layer near the ground that is affected by diurnal heat, moisture, or momentum transfer…
Plankton (planktonic) The aggregate of small plant and animal organisms that float or drift in fresh or salt water.
Planned Unit Development (PUD) A real estate project in which individuals hold title to a residential lot and home while the common facilities are owned and maintained by a homeowners'…
Planning The process of setting development goals and policy, gathering and evaluating information, and developing alternatives for future actions based on the…
Plant association A grouping of plant species, or a plant community, that recurs across the landscape.
Plant factor The capacity factor of an entire generating facility including all available generating units. (See also capacity factor)
Playa Flat areas that contain seasonal or year-to-year shallow lakes that often evaporate, leaving minerals behind.
Playa lake Ephemeral lakes formed in the lowest part of a closed (internally drained) basin in an arid region.
Pleistocene The oldest epoch of the Quaternary period, ranging from 2.6 million to 10,000 years ago.
Plenum The space between a hanging ceiling and the floor above or roof; usually contains HVAC ducts, electrical wiring, fire suppression system piping, etc.
Plot A forest area defined by its condition.
Plug Flow Digester A type of anaerobic digester that has a horizontal tank in which a constant volume of material is added and forces material in the tank to move through…
Plume A visible or measurable discharge of a contaminant from a given point of origin.
Plume downwash Downward movement of plumes immediately to the lee of flow obstacles such as buildings, bluffs, or smokestacks, caused by wake turbulence or lee cavity…
Plume model A computer model used to calculate air pollutant concentrations at receptor locations.
Pluton A body of igneous rock that solidified below the Earth's surface.
Plutonic Pertaining to a class of igneous rocks that have solidified far below the Earth's surface.
Pluvial lake A lake formed during episodes of heavy precipitation or glacial melting, such as during the Pleistocene, and may either be extinct or remain as a remnant…
PM10 Particulate that is less than 10 microns in diameter. These particulates are present in the smoke created by burning wood.
PM2.5 Particulate that is less than 2.5 microns in diameter.
Point light source A light source that has no visible surface area, and appears as a point, such as a star.
Point of diversion A specifically named place where water is removed from a body of water. The location of a surface water or groundwater extraction associated with a water…
Point source (emissions) A stationary location or fixed facility from which pollutants are discharged; any single identifiable source of pollution; e.g.
Point-Contact Cell A high efficiency silicon photovoltaic concentrator cell that employs light trapping techniques and point-diffused contacts on the rear surface for…
Polishing treatment The final sewage treatment process to further reduce BOD5, suspended solids, and other pollutants.
Polycrystalline A semiconductor (photovoltaic) material composed of variously oriented, small, individual crystals.
Polyethylene A registered trademark for plastic sheeting material that can be used as a vapor retarder. This plastic is used to make grocery bags.
polymer (PAH-lih-mer) A molecule made up of small identical molecules called monomers. The monomers are joined together in a repeating pattern.
polysaccharide (PAH-lee-SA-kuh-ride) A large carbohydrate molecule. It contains many small sugar molecules that are joined chemically. Also called glycan.
Polystyrene (See Foam Insulation)
Porous Media A solid that contains pores; normally, it refers to interconnected pores that can transmit the flow of fluids.
Portfolio Standard The requirement that an electric power provider generate or purchase a specified percentage of the power it supplies/sells from renewable energy…
Positive Energy Balance When producing a fuel takes less energy than the amount of energy the fuel provides.
Post-aeration The introduction of oxygen into waste water to further reduce BOD and COD after secondary or advanced treatment.
Potable water Water that is suitable for drinking, as defined by local health officials.
Potential Energy Energy available due to position.
Potential Fossil Yield Classification (PFYC) Initially developed by the U.S. Forest Service and the Region 2 Paleo Initiative in May 1996, the PFYC system provides baseline guidance for assessing the…
Potentially Active Fault See Fault, potentially active
Pound Pound mass (sometimes abbreviated lb(m)). A unit of mass equal to 0.454 kilograms.
Pound force (sometimes abbreviated lb(f)) A force which will accelerate one pound mass at a rate of 32.2 ft/second(2).
Pound of Steam One pound of water in vapor phase; is NOT steam pressure, which is expressed as pounds per square inch (psi).
Pound Per Square Inch Absolute (psia) A unit of pressure [hydraulic (liquid) or pneumatic (gas)] that does not include atmospheric pressure.
Power Authority to do. One has the power to do something if he is of legal age. Also, used as "powers," the term refers to authority granted by one person to…
Power (Output) Curve A plot of a wind energy conversion device's power output versus wind speed.
Power (Solar) Tower A term used to describe solar thermal, central receiver, power systems, where an array of reflectors focus sunlight onto a central receiver and absorber…
Power block Portion of the facility at which electrical power is generated.
Power Coefficient The ratio of power produced by a wind energy conversion device to the power in a reference area of the free windstream.
Power Conditioning The process of modifying the characteristics of electrical power (for e.g., inverting dc to ac).
Power conditioning system (PCS) In solar energy facilities, the collection of electrical equipment that converts direct current (DC) from a photovoltaic array to alternating current (AC)…
Power Density The amount of power per unit area of a free windstream.
Power Factor (PF) The ratio of actual power being used in a circuit, expressed in watts or kilowatts, to the power that is apparently being drawn from a power source…
Power Generation Mix The proportion of electricity distributed by a power provider that is generated from available sources such as coal, natural gas, petroleum, nuclear…
Power marketer A business entity engaged in buying and selling electricity. Power marketers do not usually own generating or transmission facilities.
Power production capacity The amount of power that a facility can produce under ideal operating conditions. See also Battery capacity
Power Provider A company or other organizational unit that sells and distributes electrical power (e.g.
Power purchase agreement Guarantees a market for power produced by an independent power producer and the price at which it is sold to a purchaser.
Power tower A type of CSP technology composed of many large, sun-tracking mirrors (heliostats) that focus sunlight on a receiver at the top of a centrally located…
Power tower system See Power tower
Power Transmission Line An electrical conductor/cable that carries electricity from a generator to other locations for distribution.
Power, electrical A unit of electrical energy, usually expressed in watts (W), kilowatts (kW), or megawatts (MW). One watt equals 3.14 Btu per hour.
Precambrian The oldest and largest division of geologic time, between the consolidation of the Earth's crust and the beginning of the Cambrian period.
Precommercial thinning Thinning for timber stand improvement purposes, generally in young, densely stocked stands.
Preheater (Solar) A solar heating system that preheats water or air that is then heated more by another heating appliance.
Prehistoric The time period before the appearance of written records. In the New World this generally refers to indigenous, precontact societies.
Prehistoric resources Refers to any material remains, structures, and items used or modified by people before Euro-Americans established a presence in the region.
Prescribed fires Application of fire (by planned or unplanned ignitions) to fuels in either their natural or modified states, under specified conditions, to allow the fire…