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DSE Energy Glossary
| Ga | See gallium. |
| Gaas | See gallium arsenide. |
| Gale | Winds that can be classified as |
| Gallium (Ga) | A chemical element, metallic in nature, used in making certain kinds of solar cells and semiconductor devices. |
| Gallium Arsenide (Gaas) | A crystalline, high-efficiency compound used to make certain types of solar cells and semiconductor material. |
| Gallon | A unit of volume. A U.S. gallon has 231 cubic inches or 3.785 liters. |
| Gas | Gaseous fuel (usually natural gas) that is burned to produce heat energy. The word also is used, colloquially, to refer to gasoline. |
| Gas Synthesis | A method producing synthetic gas from coal. Also called the FISCHER-TROPSCH PROCESS. |
| Gasohol | In the United States, gasohol (E10) refers to gasoline that contains 10 percent ethanol by volume. This term was used in the late 1970s and early 1980s but has been replaced in some areas of the country by terms such as E-10, Super Unleaded Plus Ethanol, or Unleaded Plus. |
| Gasoline | A light petroleum product obtained by refining oil, and used as motor vehicle fuel. |
| Gassing | Gaseous by-products when charging a battery, e.g. Hydrogen from a lead acid battery. |
| Gassing Current | The portion of charge current that goes into electrolytical production of hydrogen and oxygen from the electrolytic liquid. This current increases with increasing voltage and temperature. |
| Gearbox | A protective casing for a system of gears. |
| Gel-Type Battery | A Lead-Acid battery in which the electrolyte is immobilized in a gel. |
| General Lighting | Lighting designed to provide a substantially uniform level of illumination throughout an area, exclusive of any provision for special visual tasks or decorative effects. |
| Generating Plant | A location where certain fuels (coal, natural gas, or nuclear) or hydropower are converted to electrical power. |
| Generating Station | A power plant. |
| Generation Company (Genco) | A regulated or non-regulated entity (depending upon the industry structure) that operates and maintains existing generating plants. The Genco may own the generation plants or interact with the short term market on behalf of plant owners. In the context of restructuring the market for electricity, Genco is sometimes used to describe a specialized "marketer" for the generating plants formerly owned by a vertically-integrated utility. |
| Generation Dispatch And Control | Aggregating and dispatching (sending off to some location) generation from various generating facilities, providing backups and reliability services. Ancillary services include the provision of reactive power, frequency control, and load following.(Also see "Power Pool" and "Poolco" below.) |
| Generator | A device for converting mechanical energy to electrical energy. |
| Geothermal (Ground Source) Heat Pump | a space heating/cooling system which moves heat from and to the earth, as opposed to making heat using a fuel source. Geothermal heat pumps take advantage of the almost constant temperature just a few feet underground |
| Geothermal Element | an element of a county general plan consisting of a statement of geothermal development policies, including a diagram or diagrams and text setting forth objectives, principles, standards, and plan proposals, including a discussion of environmental damages and identification of sensitive environmental areas, including unique wildlife habitat, scenic, residential, and recreational areas, adopted pursuant to Section 65303 of the Government Code. GEOTHERMAL ENERGY |
| Geothermal Energy | can be used to generate electricity, heat water and heat and cool buildings. |
| Geothermal Gradient | The change in the earth’s temperature with depth. As one goes deeper, the earth becomes hotter. |
| Geothermal Heat Pump | A type of heat pump that uses the ground, ground water, or ponds as a heat source and heat sink, rather than outside air. Compare to HEAT PUMP. |
| Geothermal Phenomena | an observable event at the surface, whose occurrence is the result of the Earth’s internal heat; includes volcanoes, geysers, hot springs, mud pots and fumaroles. |
| Geothermal Power Plant | a facility which uses geothermal steam or heat to drive turbine-generators to produce electricity. Three different types make use of the various temperature ranges of geothermal resources |
| Geothermal Reservoir | a large volume of underground hot water and steam in porous and fractured hot rock. The hot water in geothermal reservoirs occupies only 2 to 5% of the volume of rock, but if the reservoir is large enough and hot enough, it can be a powerful source of energy. Geothermal reservoirs are sometimes overlain by a layer of impermeable rock. While geothermal reservoirs usually have surface manifestations such as hot springs or fumaroles, some do not. |
| Geothermal Resource | the natural heat, hot water, and steam within the Earth |
| Geothermal Steam | Steam drawn from deep within the earth. |
| Geothermal Water | water heated by the natural heat inside the Earth. |
| Geyser | a natural hot spring that sends up a fountain of water and steam into the air; some geysers "spout" at regular intervals and some are unpredictable. |
| Gigawatt | One billion watts. |
| Gigawatt (GW) | A measurement of power equal to a thousand million Watts. |
| Gigawatt-Hour (Gwh) | A measurement of energy. One Gigawatt-hour is equal to one Gigawatt being used for a period of one hour, or one Megawatt being used for 1000 hours. |
| Gin Pole | Either of two different types of devices used with wind generator towers. With a tilt-up tower, it describes the lever that helps tilt the tower up. With a fixed tower, it describes a temporary crane used to raise tower sections or the wind generator. |
| Glazing | A covering of transparent or translucent material (typically glass or plastic) used for admitting light. |
| Global Climate Change | Gradual changing of global climates due to buildup of carbon dioxide and other greenhouse gases in the earth’s atmosphere. Carbon dioxide produced by burning fossil fuels has reached levels greater than what can be absorbed by green plants and the seas. |
| Global Warming | A term used to describe the increase in average global temperatures due to the greenhouse effect. |
| Global Warming/ Greenhouse Effect |
the trapping of heat in the atmosphere. Incoming solar radiation goes through the atmosphere to the Earth’s surface, but outgoing radiation (heat) is absorbed by water vapor, carbon dioxide, and ozone in the atmosphere. At certain levels this is beneficial because it keeps the planet warm enough for life as we know it. However, an increase in the normal amount of carbon dioxide and other gases may contribute to a human-caused warming trend that could have serious effects on global climate, the global ecosystem, and food supplies. |
| Glycol (Propylene Glycol) | An antifreeze, heat transfer fluid that is circulated through closed loop solar hot water collectors. |
| Governing | Limiting the output of a device. In respect to small wind generators, governing normally happens through furling. |
| Governor | A device that assists in the control of the speed of the blade rotation. It can be built into the blades 😉 |
| Gpm | Gallons per minute. |
| Green Credit | Green credits are a new way to purchase renewable electric generation that divides the generation into two separate products the commodity energy and the renewable attributes. The green credit represents the renewable attributes of a single megawatt of renewable energy. |
| Green Power | A popular term for energy produced from renewable energy resources. |
| Greenfield | A site on which no prior wind resource has been identified. |
| Greenhouse Effect | The heating effect resulting from long wave radiation trapped by greenhouse gases that have been produced from natural and human sources. |
| Greenhouse Effect (Relating To Buildings) | The characteristic tendency of some transparent materials (such as glass) to transmit radiation with relatively short wavelengths (such as sunlight) and block radiation of longer wavelengths (such as heat). This tendency leads to a heat build-up within the space enclosed by such a material. |
| Greenhouse Gases | Gases such as water vapor, carbon dioxide, methane, and low-level ozone that are transparent to solar radiation, but opaque to long wave radiation. These gases contribute to the greenhouse effect. |
| Grid | An electrical utility distribution network. |
| Grid (Also “Power Grid” And “Utility Grid”) | A common term referring to an electricity transmission and distribution system. |
| Grid Lines | Metallic contacts fused to the surface of a solar cell to provide a low resistance path for electrons to flow out to the cell interconnect wires. |
| Grid-Connected | An energy producing system connected to the utility transmission grid. Also called Grid tied. |
| Grid-Connected System | A solar electric or photovoltaic (PV) system in which the PV array acts like a central generating plant, supplying power to the grid. |
| Grid-Interactive System | Same as grid-connected system. |
| Grid-Tie System | A renewable energy system that is connected to the utility grid, selling excess energy back to the utility. Also called a utility-interactive system. |
| Gross Area | The area of a surface including areas not belonging to that surface (such as windows and doors in a wall). |
| Gross National Product (Gnp) | The total market value of the goods and services produced by a nation before deduction or depreciation charges and other allowance for capital consumption and is widely used as a measure of economic activity. |
| Ground | A connection from an electrical circuit to the earth. |
| Ground Fault | Unwanted current path to ground. |
| Ground Loop | An undesirable feedback condition caused by two or more circuits sharing a common electrical line. |
| Ground Mount | A peice of equipment upon which solar or wind modules are mounted. |
| Ground Rod (Electrode) | A metal rod (typically 5/8 inch diameter) that is driven into the earth (typically 8 feet deep) and is electrically connected to the negative conductor and/or any metal parts, wiring enclosures, or conduit of an electrical circuit. |
| Gust | A sudden brief increase in the speed of the wind. |
| Guy Wires | Steel cables that support a tower. |
DSE Energy Glossary
| Fan Coil | A component of a heating, ventilation and air conditioning (HVAC) system containing a fan and heating or cooling coil, used to distribute heated or cooled air. |
| Farad | The farad is the SI unit of the capacitance of an electrical system, that is, its capacity to store electricity. It is a rather large unit as defined and is more often used as a microfarad. It is named after the English chemist and physicist Michael Faraday (1791-1867). |
| Fault | a crack or break in the Earth’s crust along which movement has occurred, often resulting in earthquakes. |
| Favonius | The Latin word for the West Wind in Roman mythology. |
| Feathering | In wind generators, this refers to an adjustment of the blades so that they catch less wind. This can prevent damage to the machine in high winds. |
| Federal Emergency Management Agency (Fema) | The federal agency in charge of disaster recovery in locations that have been declared disaster areas by a state’s Governor and the President of the United States. |
| Federal Energy Regulatory Commission (Ferc) | An independent regulatory commission within the U.S. Department of Energy that has jurisdiction over energy producers that sell or transport fuels for resale in interstate commerce; the authority to set oil and gas pipeline transportation rates and to set the value of oil and gas pipelines for ratemaking purposes; and regulates wholesale electric rates and hydroelectric plant licenses. |
| Fenestration | In simplest terms, windows or glass doors. Technically fenestration is described as any transparent or translucent material plus any sash, frame, mullion or divider. This includes windows, sliding glass doors, French doors, skylights, curtain walls and garden windows. |
| Fermi Level | Energy level at which the probability of finding an electron is one-half. In a metal, the Fermi level is very near the top of the filled levels in the partially filled valence band. In a semiconductor, the Fermi level is in the band gap. |
| Fill Factor | On an I-V (current-voltage) curve characterizing the output of a solar cell or module, the ratio of the maximum power to the product of the open-circuit voltage and the short-circuit current. The higher the fill factor (FF) the "squarer" the shape of the I-V curve. |
| Finish Charge | The final stage of battery charging, when the battery is charged at a slow rate over a long period of time. |
| Firm Energy | Power supplies that are guaranteed to be delivered under terms defined by contract. |
| Fission | A release of energy caused by the splitting of an atom’s nucleus. This is the energy process used in conventional nuclear power plants to make the heat needed to run steam electric turbines. |
| Fissionable Material | A substance whose atoms can be split by slow neutrons. Uranium-235, plutonium-239 and uranium-233 are fissionable materials. |
| Fixed Tilt Array | A photovoltaic array set in at a fixed angle with respect to horizontal. |
| Flagging | Noticeable deformation of trees from prevailing winds. Flagging is an indication of an effective wind site. Lack of flagging is not necessarily an indication of a poor wind site. |
| Flare Gas | Unwanted natural gas that is disposed of by burning as it is released from an oil field. |
| Flat Plate | A device used to collect solar energy. It is a piece of metal painted black on the side facing the sun, to absorb the sun’s heat. |
| Flat Plate Collector | A solar thermal collector that converts the sun’s radiation into heat on a flat surface. Does not use reflecting surfaces or lens arrangements to concentrate the sun’s energy. |
| Flat-Plate Array | A photovoltaic (PV) array that consists of non-concentrating PV modules. |
| Flat-Plate Module | An arrangement of photovoltaic cells or material mounted on a rigid flat surface with the cells exposed freely to incoming sunlight. |
| Flat-Plate Photovoltaics (Pv) | A PV array or module that consists of nonconcentrating elements. Flat-plate arrays and modules use direct and diffuse sunlight, but if the array is fixed in position, some portion of the direct sunlight is lost because of oblique sun-angles in relation to the array. |
| Flat-Plate PV | A solar PV array or module that does not contain concentrating devices and so responds to both direct and diffuse sunlight. |
| Flexible Fuel Vehicle (Ffv) | a vehicle that can operate on either alcohol fuels (methanol or ethanol) or regular unleaded gasoline or any combination of the two from the same tank. |
| Float Charge | A battery charge current that is equal to, or slightly greater than, the self-discharge rate. |
| Float Life | The number of years that a battery can keep its stated capacity when it is kept at float charge. |
| Float Service | A battery operation in which the battery is normally connected to an external current source; for instance, a battery charger that supplies the battery load under normal conditions, while also providing enough energy input to the battery to make up for its internal losses, thus keeping the battery always at full charge and ready for service. |
| Float-Zone Process | A method of growing a large-size, high-quality crystal whereby coils heat a polycrystalline ingot placed atop a single-crystal seed. As the coils are slowly raised the molten interface beneath the coils becomes single crystal. |
| Flooded Cell Battery | A form of rechargeable battery where the plates are completely immersed in a liquid electrolyte. Most cars use flooded-cell batteries. Flooded cell batteries are the most commonly used type for independent and remote area power supplies. |
| Flow | In hydro-electric terms, flow refers to the quantity of water supplied to a water source or exiting a nozzle per unit of time. Commonly measured in gallons per minute. |
| Flue Gas | Gas that is left over after fuel is burned and which is disposed of through a pipe or stack to the outer air. |
| Fluidized Bed Combustion | A process for burning powdered coal that is poured in a liquid-like stream with air or gases. The process reduces sulfur dioxide emissions from coal combustion. |
| Fluorescent Lamp | A tubular electric lamp that is coated on its inner surface with a phosphor and that contains mercury vapor whose bombardment by electrons from the cathode provides ultraviolet light which causes the phosphor to emit visible light either of a selected color or closely approximating daylight. |
| Fluorescent Light | A form of lighting that uses long thin tubes of glass which contain mercury vapor and various phosphor powders (chemicals based on phosphorus) to produce white light. Generally considered to be the most efficient form of home lighting. |
| Fluorescent Lights | Lights where the source of light is produced by gas that glows when connected to electricity. Fluorescent light bulbs have a very long life – between 8000 and 20,000 hours. They use up to 75 percent less power than regular light bulbs. |
| Fluorocarbon Gases | Propellants used in aerosol products and refrigerants that are believed to be causing depletion of the earth’s ozone shield. See CFCs. |
| Foehn | Any warm, dry wind that blows down the leeward side of a mountain range, particularly the hot, dry winds that move down from snow-clad mountains through Alpine valleys. |
| Footcandle | A unit of illuminance on a surface that is one foot from a uniform point source of light of one candle and is equal to one lumen per square foot. |
| Forced Air Unit (Fau) | A central furnace equipped with a fan or blower that provides the primary means for circulation of air. |
| Fossil Fuel | Oil, coal, natural gas or their by-products. Fuel that was formed in the earth in prehistoric times from remains of living-cell organisms. |
| Fossil Fuels | Fuels formed in the ground from the decayed remains of dead plants and animals. It takes millions of years to form fossil fuels. Oil, natural gas, and coal are fossil fuels. |
| Fracture | a crack in the Earth’s crust along which no movement has occurred. |
| Framing Effects | The effect of framing (wood or metal studs, joists, beams, etc.) on the overall U-value of a wall, roof, floor, window or other building surface. Framing generally increases the U-Value and decreases the R-Value of insulated surfaces. |
| Framing Percentage | The area of actual framing in an envelope assembly divided by the overall area of the envelope assembly. This percentage is used to calculate the overall U-value of an assembly. |
| Francis Turbine | A type of reaction hydro-turbine used in low to medium heads. It consists of fixed vanes on a shaft. Water flows down through the vanes and out sideways. |
| Freestanding Tower | A wind generator tower with no guy wires. This can be either a lattice tower or a monopole. Freestanding towers are the most expensive type of tower, requiring large excavations and large amounts of concrete. |
| Frequency | The number of cycles or repetitions per unit time of a complete waveform, in electrical applications usually expressed in cycles per second or Hertz (Hz). Electrical equipment in the United States requires 60 Hz, in Europe 50Hz. |
| Frequency Regulation | This indicates the variability in the output frequency. Some loads will switch off or not operate properly if frequency variations exceed 1%. |
| Fresnel Lens | An optical device that focuses light like a magnifying glass; concentric rings are faced at slightly different angles so that light falling on any ring is focused to the same point. |
| Friagem | Like a “norther,” a winter wind that sweeps across the southern United States and then out over the Gulf of Mexico, only a friagem blows northward from the South Pole into South America. |
| Friction Loss | Lost energy due to friction. 1 In hydro systems, pipe sized too small can lead to serious friction losses. 2 In any belt drive system, there will be some losses due to friction. |
| Fuel | Any material that can be consumed to make energy. |
| Fuel Cell | A device in which a fuel, such as hydrogen gas, is combined with oxygen to produce electricity, water, and heat. |
| Fuel Gas | Synthetic gas used for heating or cooling. It has less energy content than pipeline-quality gas. |
| Fuel Oil | Petroleum products that are burned to produce heat or power. |
| Fuel Reprocessing (Nuclear) | The means for obtaining usable, fissionable material from spent reactor fuel. |
| Fuel Rod (Nuclear) | A long slender tube that holds fissionable material (fuel) for nuclear reactor use. Fuel rods are assembled into bundles called fuel elements or assemblies, which are loaded individually into the reactor core. |
| Fuel Security | See Energy Security. |
| Full Sun | The amount of power density in sunlight received at the earth’s surface at noon on a clear day (about 1,000 Watts/square meter). |
| Fumarole | a small hole or vent in the Earth’s surface, found near volcanic areas, from which steam or gases shoot out. |
| Funnel Cloud | A rotating, cone-shaped column of air extending downward from the base of a thunderstorm, but not in contact with the ground. (When it reaches the ground, it is called a tornado.) |
| Furling | Reducing a wind generator’s swept area to protect it from high winds. Common furling methods are to tilt the rotor (blades) up or sideways out of the wind, or to feather (twist) the blades to degrade the airfoil. |
| Fuse | A safety device with a metal wire or strip that melts when the current gets too strong, cutting off the flow of the electrical current. |
| Fusion Energy | A power source, now under development, based on the release of energy that occurs when atoms are combined under the most extreme heat and pressure. It is the energy process of the sun and the stars. |
DSE Energy Glossary
| Earth | Refers to physically connecting a part of an electrical system to the ground, done as a safety measure, by means of a conductor embedded in suitable soil. Synonymous with “ground.” |
| Earth-Leakage Circuit Breaker (ELCB) | A device used to prevent electrical shock hazards in mains voltage power systems, including independent power systems. Also known as residual current devices (RCD’s). |
| Earthquake | the vibration or movement of the ground caused by a sudden shift along faults (cracks) in the earth’s crust; most earthquakes occur at the places where tectonic plates edges meet. |
| Ecology | The study of interrelationships of animals and plants to one another and to their environment. |
| Economic Efficiency | A term that refers to the optimal production and consumption of goods and services. This generally occurs when prices of products and services reflect their marginal costs. Economic efficiency gains can be achieved through cost reduction, but it is better to think of the concept as actions that promote an increase in overall net value (which includes, but is not limited to, cost reductions). |
| Economies Of Sale | Economies of scale exist where the industry exhibits decreasing average long-run costs with size. |
| Economizer Air | A ducting arrangement and automatic control system that allows a heating, ventilation and air conditioning (HVAC) system to supply up to 100 percent outside air to satisfy cooling demands, even if additional mechanical cooling is required. |
| Economizer Water | A system which uses either direct evaporative cooling, or a secondary evaporatively cooled water loop and cooling coil to satisfy cooling loads, even if additional mechanical cooling is required. |
| Economy Energy (Electricity Utility) | Electricity purchased by one utility from another to take the place of electricity that would have cost more to produce on the utility’s own system. |
| Ecosystem | The interacting system of biological community and its nonliving environment. |
| Edge-Defined Film-Fed Growth (Efg) | A method for making sheets of polycrystalline silicon for photovoltaic devices in which molten silicon is drawn upward by capillary action through a mold. |
| Edison, Thomas Alva | The "father" of the American energy industry, Thomas Edison was an American inventor who was born in 1847 and died in 1931. He patented a total of 1,093 inventions |
| EEI | Edison Electric Institute. An association of electric companies formed in 1933 "to exchange information on industry developments and to act as an advocate for utilities on subjects of national interest." |
| EER | (Energy Efficiency Ratio) the ratio of cooling capacity of an air conditioning unit in Btus per hour to the total electrical input in watts under specified test conditions. |
| EER (Energy Efficiency Ratio) | The ratio of cooling capacity of an air conditioning unit in Btus per hour to the total electrical input in watts under specified test conditions. |
| Efficacy, Lighting | The ratio of light from a lamp to the electrical power consumed, including ballast losses, expressed as lumens per watt. |
| Efficiency | Found in electrical energy. It is the amount of a utility’s power generation process that is efficiently used to produce power. However some power can be lost in the transmission process. |
| Efficiency (PV Modules) | The ratio of power output of a photovoltaic cell to the incident power from the sun or simulated sun sources under specified standard insolation conditions. A solar cell that converts 1/10 of the sun’s energy that strikes its surface to electricity has an efficiency of 10 percent. |
| Electric Circuit | Path followed by electrons from a power source (generator or battery) through an external line (including devices that use the electricity) and returning through another line to the source. |
| Electric Current | The rate at which electrons flow through an electrical conductor, usually measured in amperes (amps). |
| Electric Generator | A device that converts a heat, chemical or mechanical energy into electricity. |
| Electric Radiant Heating | A heating system in which electric resistance is used to produce heat which radiates to nearby surfaces. There is no fan component to a radiant heating system. |
| Electric Resistance Heater | A device that produces heat through electric resistance. For example, an electric current is run through a wire coil with a relatively high electric resistance, thereby converting the electric energy into heat which can be transferred to the space by fans. |
| Electric Utility | Any person or state agency with a monopoly franchise (including any municipality), which sells electric energy to end-use customers; this term includes the Tennessee valley Authority, but does not include other Federal power marketing agency (from EPAct). |
| Electrical Energy | energy of electric charges or electric currents. |
| Electrical Grid | An integrated system of electricity distribution, usually covering a large area. |
| Electrical Potential | Same as VOLTAGE. |
| Electricity | The movement of electrons (a sub-atomic particle), produced by a voltage, through a conductor. |
| Electricity Generation | The process of producing electricity by transforming other forms or sources of energy into electrical energy. Electricity is measured in kilowatt hours (kWh). |
| Electrochemical Cell | A device containing two conducting electrodes, one positive and the other negative, made of dissimilar materials (usually metals) that are immersed in a chemical solution (electrolyte) that transmits positive ions from the negative to the positive electrode and thus forms an electrical charge. One or more cells constitute a battery. |
| Electrode | An electrically conductive material, forming part of an electrical device, often used to lead current into or out of a liquid or gas. In a battery, the electrodes are also known as plates. |
| Electrodeposition | Electrolytic process in which a metal is deposited at the cathode from a solution of its ions. |
| Electrolysis | The production of chemical energy by passing an electric current through a liquid called an electrolyte. |
| Electrolyte | The medium that provides ionic transport between the electrodes of a battery. All common batteries contain an electrolyte, such as the sulfuric acid used in lead-acid batteries. |
| Electromagnet | A magnet created from wire coils that produces a magnetic field when electricity flows through the coils |
| Electromagnetic | Objects made magnetic by an electric current. |
| Electromagnetic Fields (Emf) | Ordinary every day use of electricity produces magnetic and electric fields. These 60 Hertz fields (fields that go back and forth 60 times a second) are associated with electrical appliances, power lines and wiring in buildings. |
| Electromagnetic Radiation (Emr) | Magnetic radiation produced by a changing electrical current, such as alternating current (AC). |
| Electron | A negatively charged particle. The movement of electrons in an electrical conductor constitutes an electric current. |
| Electron Volt (Ev) | The amount of kinetic energy gained by an electron when accelerated through an electric potential difference of 1 Volt; equivalent to 1.603 x 10^-19; a unit of energy or work. |
| Element | A substance consisting entirely of atoms of the same atomic number. |
| Elephanta | The violent windstorms that occur at the beginning and the end of the monsoon season in India. |
| Elevation | 1) The height above sea level (altitude); 2) A geometrical projection, such as a building, on a plane perpendicular to the horizon. |
| Embodied Energy | The energy consumed by all of the processes associated with the production of a material. This includes the energy required in mining, transport, manufacturing, administration, use, disposal, etc. |
| Emergency Core Cooling System (Eccs) | Equipment designed to cool the core of a nuclear reactor in the event of a complete loss of the coolant. |
| Emission | A substance or pollutant emitted as a result of a process. |
| Emission Standard | The maximum amount of a pollutant legally permitted to be discharged from a single source. |
| Emissivity | The property of emitting radiation; possessed by all materials to a varying extent. |
| Emittance | The emissivity of a material, expressed as a fraction. Emittance values range from 0.05 for brightly polished metals to 0.96 for flat black paint. |
| Energy | Power consumed multiplied by the duration of use. For example, 1000 Watts used for four hours is 4000 Watt hours. |
| Energy Audit | A survey that shows how much energy used in a home, which helps find ways to use less energy. |
| Energy Budget | A requirement in the Building Energy Efficiency Standards that a proposed building be designed to consume no more than a specified number of British thermal units (Btus) per year per square foot of conditioned floor area. |
| Energy Charge | The amount of money owed by an electric customer for kilowatt-hours consumed. |
| Energy Consumption | The amount of energy consumed in the form in which it is acquired by the user. The term excludes electrical generation and distribution losses. |
| Energy Contribution Potential | Recombination occurring in the emitter region of a photovoltaic cell. |
| Energy Conversion | The Changing Of Energy From One Form To Another. One Of The Many Examples Are Heat Energy Being Converted Into Mechanical Energy, And Then Mechanical Energy Into Electrical Energy, As Is Done In Steam-Driven Electric Power Plants. |
| Energy Density | A ratio of a battery or cell’s capacity to either its volume or weight. Volumetric energy density is expressed in watt-hours per cubic inch. Weight energy density is expressed in watt-hours per pound. |
| Energy Efficiency | the measure of the amount of energy which any technology can convert to useful work; technology with a higher energy efficiency will require less energy to do the same amount of work. |
| Energy Levels | The energy represented by an electron in the band model of a substance. |
| Energy Management System | A control system (often computerized) designed to regulate the energy consumption of a building by controlling the operation of energy consuming systems, such as the heating, ventilation and air conditioning (HVAC), lighting and water heating systems. |
| Energy Payback Time | The time required for any energy producing system or device to produce as much energy as was required in its manufacture. For solar electric panels, this is normally in the range 6-36 months. |
| Energy Reserves | The portion of total energy resources that is known and can be recovered with presently available technology at an affordable cost. |
| Energy Resource | a source of useable power which can be drawn on when needed. Energy resources are often classified as renewable or non-renewable. |
| Energy Resources | Everything that could be used by society as a source of energy. |
| Energy Security/Fuel Security | policy that considers the risk of dependence on fuel sources located in remote and unstable regions of the world and the benefits of domestic and diverse fuel sources. |
| Energy Storage | The process of storing or converting energy from one form to another for later use. An example of a storage device is a battery. |
| Energy/Fuel Diversity | policy that encourages the development of energy technologies to diversify energy supply sources, thus reducing reliance on conventional (petroleum) fuels; applies to all energy sectors. |
| Engine | A machine that converts energy into mechanical force or motion. Sources of energy include heat, chemical reaction, potential energy of elevated water, etc. |
| Enthalpy | The quantity of heat necessary to raise the temperature of a substance from one point to a higher temperature. The quantity of heat includes both latent and sensible. |
| Entitlement | Electric energy or generating capacity that a utility has a right to access under power exchange or sales agreements. |
| Environment | All the natural and living things around us. The earth, air, weather, plants, and animals all make up our environment. |
| Environmental Protection Agency (EPA) |
Federal government agency that makes and enforces standards for pollution control; designed to protect the environment. |
| Epact | The Environmental Protection Agency. A federal agency charged with protecting the environment. |
| EPACT | The Energy Policy Act of 1992 addresses a wide variety of energy issues. The legislation creates a new class of power generators, exempt wholesale generators (EWGs), that are exempt from the provisions of the Public Utilities Holding Company Act of 1935 and grants the authority to FERC to order and condition access by eligible parties to the interconnected transmission grid. |
| Epitaxial Growth | The growth of one crystal on the surface of another crystal. The growth of the deposited crystal is oriented by the lattice structure of the original crystal. |
| Equalization | The process of restoring all cells in a battery to an equal state-of-charge. For lead-acid batteries, this is a charging process designed to bring all cells to 100 percent state-of-charge. |
| Equalization Charge | The process of mixing the electrolyte in batteries by periodically overcharging the batteries for a short time. |
| Equalizing Charge | A continuation of normal battery charging, at a voltage level slightly higher than the normal end-of-charge voltage, in order to provide cell equalization within a battery. |
| Equinox | The two times of the year when the sun crosses the equator and night and day are of equal length; usually occurs on March 21st (spring equinox) and September 23 (fall equinox). |
| Equinox (Spring & Fall) | The time when the sun crosses the plane of the earth’s equator, making night and day of equal length all over the earth, occurring about March 21st and September 21st. |
| Eruption | the explosive discharge of material such as molten rock and gases, or hot water (as from volcanoes or geysers). |
| Esco (Efficiency Service Company) | A company that offers to reduce a client’s electricity consumption with the cost savings being split with the client. |
| Ethanol (Also Know As Ethyl Alcohol Or Grain Alcohol, Ch3ch2oh) |
a liquid that is produced chemically from ethylene or biologically from the fermentation of various sugars from carbohydrates found in agricultural crops and cellulosic residues from crops or wood. Used in the United States as a gasoline octane enhancer and oxygenate, it increases octane 2.5 to 3.0 numbers at 10 percent concentration. Ethanol can also be used in higher concentration (E85) in vehicles optimized for its use. |
| Ethyl Tertiary Butyl Ether (Etbe) | an aliphatic ether similar to MTBE. This fuel oxygenate is manufactured by reacting isobutylene with ethanol. Having high octane and low volatility characteristics, ETBE can be added to gasoline up to a level of approximately 17 percent by volume. ETBE is used as an oxygenate in some reformulated gasolines. |
| Ethylene | A colorless gas that burns and is an oil refinery product. |
| Eurus | The East Wind in Greek mythology. (The same word is used in Latin.) |
| EV (Electric Vehicle) | a vehicle powered by electricity, usually provided by batteries but may also be provided by photovoltaic (solar) cells or a fuel cell. |
| EVA (Ethylene Vinyl Acetate) | An encapsulant used between the glass cover and the solar cells in PV modules. It is durable, transparent, resistant to corrosion, and flame retardant. |
| Evaporation | The process of a liquid changing its state into a gas when heat is added. In the most common occurrence on earth, water evaporation requires 970 btus per pound (pint). |
| Evaporative Cooling | Cooling by exchange of latent heat from water sprays, jets of water, or wetted material. |
| Exchange (Electric Utility) | Agreements between utilities providing for purchase, sale and trading of power. Usually relates to capacity (kilowatts) but sometimes energy (kilowatt-hours). |
| Exempt Wholesale Generator (Ewg) | Created under the 1992 Energy Policy Act, these wholesale generators are exempt from certain financial and legal restrictions stipulated in the Public Utilities Holding Company Act of 1935. |
| Exfiltration | Air flow outward through a wall, building envelope, etc. |
| Exhaust | Air removed deliberately from a space, by a fan or other means, usually to remove contaminants from a location near their source. |
| Exports (Electric Utility) | Power capacity or energy that a utility is required by contract to supply outside of its own service area and not covered by general rate schedules. |
| Extra High Voltage (Ehv) | Voltage levels higher than those normally used on transmission lines. Generally EHV is considered to be 345,000 volts or higher. |
| Extrinsic Semiconductor | The product of doping a pure semiconductor. |
DSE Energy Glossary
| Dangling Bonds | A chemical bond associated with an atom on the surface layer of a crystal. The bond does not join with another atom of the crystal, but extends in the direction of exterior of the surface. |
| Day-Ahead Market | The forward market for energy and ancillary services to be supplied during the settlement period of a particular trading day that is conducted by the ISO, the PX, and other Scheduling Coordinators. This market closes with the ISO’s acceptance of the final day-ahead schedule. |
| Day-Ahead Schedule | Day-ahead Schedule A schedule prepared by a Scheduling Coordinator or the ISO before the beginning of a trading day. This schedule indicates the levels of generation and demand scheduled for each settlement period of that trading day. |
| Daylighting | The placement of windows and skylights to provide natural interior lighting and to reduce daytime electrical demand. |
| Daylighting Control | A control system that varies the light output of an electric lighting system in response to variations in available daylight. |
| Daylighting Systems | provide light during the day, significantly reducing the cost of, and heat gain from, electric lighting. |
| Days Of Autonomy | The number of consecutive days that a stand-alone renewable energy system will meet a defined load without additional energy input. |
| Days Of Storage | The number of consecutive days the stand-alone system will meet a defined load without solar energy input. This term is related to system availability. |
| DC (Direct Current) | Direct current. A one-way flow of electrons. Typical sources of direct current are solar-electric cells, rectifiers, and direct current generators. To be used for typical 120 volt or 220 volt household appliances, DC must be converted to AC (alternating current). |
| DC Motor, Brushless | High-technology motor used in centrifugal-type DC submersible pumps and other applications. The motor is filled with oil to keep water out. An electronic system is used to precisely alternate the current, causing the motor to spin. |
| DC Motor, Brush-Type | The traditional DC motor, in which small carbon blocks called “brushes” conduct current into the spinning portion of the motor. They are used in many applications, including DC surface pumps and also in DC submersible diaphragm pumps. Brushes naturally wear down after years of use, and may be replaced. |
| DC Motor, Permanent Magnet | A variable speed motor that uses permanent magnets instead of wound coils. Reduced voltage (in low sun) produces proportionally reduced speed, and causes no harm to the motor. |
| DC-To-DC Converter | Electronic circuit to convert direct current voltages (e.g., photovoltaic module voltage) into other levels (e.g., load voltage). Can be part of a maximum power point tracker. |
| Dealer | A Retailer of PV products and/or PV Systems |
| Deep Cycle Battery | A battery designed to regularly discharge 80% of its capacity before recharging. |
| Deep Discharge | Discharging a battery to less than 20% of it’s capacity. |
| Deep-Cycle Battery | A battery designed to regularly discharge 50 to 80 percent of its capacity before recharging. |
| Degree Day | A quantitative index reflecting demand for energy to heat or cool buildings. Heating and cooling degree days show the difference between the mean daily temperature and a 65°F base. The higher the heating degree days at any location, the colder the winter. The higher the cooling degree days at any location, the hotter the summer. |
| Dehydrate | to free from moisture in order to preserve; to dry fruits, vegetables or lumber, for instance. A factory in in Nevada, for example uses geothermal heat to dehydrate onions and garlic for restaurants. |
| Deintegration | (See disaggregation) |
| Delta T | A difference in temperature. Often used in the context of the difference between the design indoor temperature and the outdoor temperature. |
| Demand | The rate at which energy is delivered to loads and scheduling points by generation, transmission or distribution facilities. |
| Demand Bid | Demand Bid A bid into the PX indicating a quantity of energy or an ancillary service that an eligible customer is willing to purchase and, if relevant, the maximum price that the customer is willing to pay. |
| Demand Side Management (DSM) | Planning, implementation, and evaluation of utility-sponsored programs to influence the amount or timing of customers’ energy use. |
| Demonstration | The application and integration of a new product or service into an existing or new system. Most commonly, demonstration involves the construction and operation of a new electric technology interconnected with the electric utility system to demonstrate how it interacts with the system. This includes the impacts the technology may have on the system and the impacts that the larger utility system might have on the functioning of the technology. |
| Dendrite | A slender threadlike spike of pure crystalline material, such as silicon. |
| Dendritic Web Technique | A method for making sheets of polycrystalline silicon in which silicon dendrites are slowly withdrawn from a melt of silicon whereupon a web of silicon forms between the dendrites and solidifies as it rises from the melt and cools. |
| Density | the amount of mass in a given volume of something. Two objects can be the same size, but have different densities because one of the objects has more mass "packed" into the same amount of space. Objects are smaller when they are cold, larger when hot. |
| Depletable Energy Sources | 1) electricity purchased from a public utility 2) energy obtained from burning coal, oil, natural gas or liquefied petroleum gases. |
| Depletion Zone | Same as cell barrier. The term derives from the fact that this microscopically thin region is depleted of charge carriers (free electrons and hole). |
| Depth Of Discharge (DOD) | the amount of energy withdrawn from a battery or cell expressed as a percentage of its rated capacity. |
| Deregulation | The process of changing policies and laws of regulation in order to increase competition among suppliers of commodities and services. The Energy Policy Act initiated deregulation of the electric power industry in 1992. |
| Derivatives | A specialized security or contract that has no intrinsic overall value, but whose value is based on an underlying security or factor as an index. A generic term that, in the energy field, may include options, futures, forwards, etc. |
| Design Month | The month in which the combination of insolation and load requires the maximum energy from the array. |
| DHW | Domestic hot water |
| Diesel Oil | Fuel for diesel engines obtained from the distillation of petroleum. It is composed chiefly of aliphatic hydrocarbons. Its volatility is similar to that of gas oil. Its efficiency is measured by cetane number. |
| Differential Controller | An electronic switch that turns off or on based on the difference between two temperatures. In a solar hot water system, the controller measures the temperature at the collector and compares it to the water temperature in a storage tank to turn the pump on or off. |
| Diffuse Insolation | Incident sunlight received indirectly because of scattering due to clouds, fog, particulates, or other obstructions in the atmosphere. The other component of sunlight is Direct. |
| Diffuse Radiation | Radiation received from the sun after reflection and scattering by the clouds, fog, haze, dust or other substances in the atmosphere, and the ground. |
| Diffusion Furnace | Furnace used to make junctions in semiconductors by diffusing dopant atoms into the surface of the material. |
| Diffusion Length | The mean distance a free electron or hole moves before recombining with another hole or electron. |
| Digital Multimeter (Dmm) | A device with multiple electrical measurement capabilities, such as voltage, amperage, resistance, etc., commonly usable for both AC and DC circuits. It has a digital display. |
| Diode | A semiconductor device that allows electrical current in only one direction. |
| Diodes | A rectifier that consists of a semi conducting crystal with two terminals and that is analogous in use to an electron tube diode. |
| Direct Access | The ability of a retail customer to purchase commodity electricity directly from the wholesale market rather than through a local distribution utility. (See also Retail Competition) |
| Direct Beam Radiation | Radiation received by direct solar rays. Measured by a pyrheliometer with a solar aperture of 5.7° to transcribe the solar disc. |
| Direct Current | A type of electricity transmission and distribution by which electricity flows in one direction through the conductor. Usually the electricity is a relatively low voltage and high current. Direct current is abbreviated as DC. |
| Direct Current (DC) | Current where the flow of electrons never changes direction. |
| Direct Energy Conversion | Production of electricity from an energy source without transferring the energy to a working fluid or steam. For example, photovoltaic cells transform light directly into electricity. Direct conversion systems have no moving parts and usually produce direct current. |
| Direct Expansion | (refrigeration) |
| Direct Gain | In passive solar heating, a direct gain system relies on the sunshine to directly hit the substance or mass being heated. Direct gain systems used today usually rely on a layer(s) of glass to assist in holding the heat within a space where the heat is desirable. |
| Direct Insolation | Sunlight falling directly upon a collector. Opposite of diffuse insolation. |
| Direct Radiation | Light that has traveled in a straight path from the sun (also referred to as beam radiation). An object in the path of direct radiation casts a shadow on a clear day. |
| Direct Solar Gain | Solar energy collected from the sun (as heat) in a building through windows, walls, skylights, etc. |
| Direct Use | use of geothermal water and it’s heat to grow fish, dry vegetable, fruit and wood products, heat greenhouses and city buildings, or provide hot water for spas. |
| Directly Conditioned Space | See conditioned space, directly. |
| Disaggregation | The functional separation of the vertically integrated utility into smaller, individually owned business units (i.e., generation, dispatch/control, transmission, distribution). The terms "deintegration," "disintegration" and "delamination" are sometimes used to mean the same thing. (See also "Divestiture.") |
| Discharge | Withdrawal of electrical energy from a battery. |
| Discharge Factor | A number equivalent to the time in hours during which a battery is discharged at constant current usually expressed as a percentage of the total battery capacity, i.e., C/5 indicates a discharge factor of 5 hours. |
| Discharge Rate | The rate, usually expressed in amperes or time, at which electrical current is taken from the battery. |
| Disconnect | Switch gear used to connect or disconnect components in a photovoltaic system. |
| Dispatch | The operating control of an integrated electric system to: Assign generation to specific generating plants and other sources of supply to effect the most reliable and economical supply as the total of the significant area loads rises or falls. Control operations and maintenance of high-voltage lines, substations and equipment, including administration of safety procedures. Operate the interconnection. Schedule energy transactions with other interconnected electric utilities. |
| Dispatchability | The ability of a generating unit or other source of electric power to vary output. |
| Dispatchable Power | Energy output that can be planned on and typically provides a continuous power output. Solar power and Wind power in not dispatchable without configuration with out some other power or storage mechanism. Hydrocarbon based power plants or nuclear plants are dispatchable. |
| Dissolved Gas | Natural gas that can be developed for commercial use, and which is found mixed with oil in naturally occurring underground formations. |
| Distributed Energy Resources (Der) | A variety of small, modular power-generating technologies that can be combined with energy management and storage systems and used to improve the operation of the electricity delivery system, whether or not those technologies are connected to an electricity grid. |
| Distributed Generation | A popular term for localized or on-site power generation. |
| Distributed Power | Generic term for any power supply located near the point where the power is used. Opposite of central power. See stand-alone systems. |
| Distributed Systems | Systems that are installed at or near the location where the electricity is used, as opposed to central systems that supply electricity to grids. A residential photovoltaic system is a distributed system. |
| Distribution | The process of distributing electricity. Distribution usually refers to the portion of power lines between a utility’s power pole and transformer and a customer’s point of connection. |
| Distribution Network | The overall network formed by the Distribution System. |
| Distribution System | The poles, wires, cables, substations and other equipment required to transport electricity energy from the transmission system to people’s homes. |
| Distribution System (Electric Utility) | The substations, transformers and lines that convey electricity from high-power transmission lines to ultimate consumers. See GRID. |
| Distribution Utility (Disco) | The regulated electric utility entity that constructs and maintains the distribution wires connecting the transmission grid to the final customer. The Disco can also perform other services such as aggregating customers, purchasing power supply and transmission services for customers, billing customers and reimbursing suppliers, and offering other regulated or non-regulated energy services to retail customers. The "wires" and "customer service" functions provided by a distribution utility could be split so that two totally separate entities are used to supply these two types of distribution services. |
| Distributor | Using means a wholesaler of PV products |
| District Heating System | a heating system that provides heat to a large number of buildings all from a central facility. In geothermal district heating systems, one or more wells can serve entire districts. |
| Divestiture | The stripping off of one utility function from the others by selling (spinning-off) or in some other way changing the ownership of the assets related to that function. Most commonly associated with spinning-off generation assets so they are no longer owned by the shareholders that own the transmission and distribution assets. (See also "Disaggregation.") |
| DOE | The federal department established by the Department of Energy Organization Act to consolidate the major federal energy functions into one cabinet-level department that would formulate a comprehensive, balanced national energy policy. DOE’s main headquarters are in Washington, D.C. |
| Doldrums | A narrow, virtually windless zone near the Equator, created as heated air rises upward, leaving the ocean’s surface calm and glassy. |
| Donor | In a photovoltaic device, an n-type dopant, such as phosphorus, that puts an additional electron into an energy level very near the conduction band; this electron is easily exited into the conduction band where it increases the electrical conductivity over than of an undoped semiconductor. |
| Donor Level | The level that donates conduction electrons to the system. |
| Dopant | A chemical element (impurity) added in small amounts to an otherwise pure semiconductor material to modify the electrical properties of the material. An n-dopant introduces more electrons. A p-dopant creates electron vacancies (holes). |
| Doping | The addition of dopants to a semiconductor. |
| Dose | The amount of ionizing radiation energy absorbed per unit mass of irradiated material at a specific location, such as a part of a human body. |
| Double Glazing | Windows having two sheets of glass with an airspace between. |
| Downburst | A severe localized downdraft from a thunderstorm. Also called a microburst. |
| Downstream | A term used in the petroleum industry referring to the refining, transportation and marketing side of the business. |
| Downtime | Time when the photovoltaic system cannot provide power for the load. Usually expressed in hours per year or that percentage. |
| Downwind | In relation to a wind turbine, the direction away from the source of wind. A downwind turbine has its blades on the downwind side of the tower. |
| Downwind Wind Turbine | A horizontal axis wind turbine in which the rotor is downwind of the tower. |
| Draft Tube | A tube added to the outfall of a hydro turbine to increase energy production by taking advantage of the drop in the tailrace. |
| Drainback System | A solar hot water system that only fills the collector when the temperature differential is appropriate. The water that is circulated through the collectors is stored in a reservoir. Draining the collectors provides freeze protection. |
| Draindown System | A solar hot water system that uses a special draindown valve that redirects the collector fluid and drains it down when the collector system pump is not operating. These systems have been prone to failure and are not recommended. |
| Dry Bulb Temperature | A measure of the sensible temperature of air. |
| Dry Cell | A cell (battery) with a captive electrolyte. A primary battery that cannot be recharged. |
| Dry Cell Battery | A battery that uses a solid paste as an electrolyte. |
| Dry Hole | A drilled well that does not yield gas and/or oil quantities or condition to support commercial production; also applied to gas that has been produced and from which liquid components have been removed. |
| Dual-Duct System | A central plant heating , ventilation and air conditioning (HVAC ) system that produces conditioned air at two temperatures and humidity levels. The air is then supplied through two independent duct systems to the points of usage where mixing occurs. |
| Dual-Paned (Double-Glazed) | Two panes of glass or other transparent material, separated by a space. |
| Duct | A passageway made of sheet metal or other suitable material used for conveying air or other gas at relatively low pressures. |
| Dump | Excess hydropower that cannot be stored or conserved. Also know as SPILL ENERGY. |
| Dump Load | A device to which the wind generators power flows when the batteries are too full to accept more charge, sometimes an electric heating element is used. |
| Dust Devil | A small whirlwind, of a usually short duration, that swirls dust, debris, and sand to great heights. |
| Duty Cycle | The fraction of time a device or load actually uses energy in a unit of time. For example, a load that uses energy for 5 seconds out of every 10 seconds has a 50 percent duty cycle. |
| Duty Rating | The amount of time an inverter (power conditioning unit) can produce at full rated power. |
| Dynamic/Shunt Braking | Dissipating the kinetic energy of rotation either as heat in a braking resistor or bulb, or in a direct short circuit. |
| Dynamo | The first type of large generator developed for a power plant. |
Research & Reference Materials
| Biochemicals For The Automotive Industry: Schlegel Corporation, a manufacturer of automotive components, replaced methylene chloride with a biochemical cleaning system. Learn how they saved $72,000 in combined purchase, disposal and regulatory costs. |
| Biochemicals For The Printing Industry: new link — Bolger Publications switched from using petroleum-based press wash to a vegetable-based product, resulting in a safer work environment and financial savings. To learn more about Bolger’s case study and the use of biochemicals in the printing industry. |
| Clackamas High School: Take a tour of this LEED Silver school project at the Boora Architects web site. |
| Dsire (Database Of State Incentives For Renewable Energy) : displays the results of a survey of state financial incentives, programs, and regulatory policies designed to promote renewable energy technologies. |
| Ecovillages: A residential community in Loudoun County, Virginia committed to sustainable development. |
| Environmental Showcase Home: Greens the desert and saves "green" with a $30/month energy bill. |
| Fighting Climate Change One House At A Time: Mike & Catherine Tidwell’s story. With a healthy sense of responsibility and a small loan from the bank, Mike and Catherine Tidwell set about reducing their carbon footprint by rethinking how their house uses energy. On their way they have shown that Americans of modest means can achieve enormous reductions in greenhouse gas emissions. |
| Fog And The Namibian Beetle Provide Water In The Desert: A good example of biomimetics: Effective fog harvesting. |
| Four Times Square, Ny: An ecologically responsible office tower located in the heart of Manhattan. Highlighted High Performance Features |
| Greenhome Project: Habitat for Humanity’s Washington DC affiliate |
| Inland Technology Inc: Biochemical Cleaning Solvents: Boeing Aerospace Corporation cleans its airplane parts with a plant-based terpene cleaning solvent in place of petroleum-based solvents. / (added 09/2005) |
| Nw Federal Credit Union: This facility incorporates many wonderful examples of sustainability accentuated by beautiful views of downtown Seattle and Mt. Rainer. |
| Red Feather Development Group: brings volunteers and tribal members together to learn strawbale building methods. / (added 09/2005) |
| Short Rotation Woody Crops Program: Suny Albany: / (added 09/2005) |
| The Tofte Project: An interactive website describing the earth-friendly remodeling of a 50-year-old summer cabin in the town of Tofte on the North Shore of Lake Superior. |
Links to Online Energy Calculators
| A Performance Calculator For Grid-Connected Pv Systems V1: |
| A Performance Calculator For Grid-Connected Pv Systems V2: / (added 09/2005) |
| BTU Calculator: Version 1 is the original PVWATTS. The user chooses a state from a map or a text list, and then the city of interest. The calculations may be done using the default system parameters, or the user may specify the PV system size, local electric costs, whether a fixed or tracking PV array, and the PV array tilt and azimuth angles. PVWATTS calculates monthly and annual energy production in kWh and monthly savings in dollars. The user may also choose to output hourly AC power data, which can saved to a text file. Version 1 can be run for Guam or Puerto Rico as well as the 50 states. |
| Business Energy Analyzer : |
| Calculate Your Solar Energy Needs: How big of a stove do you need? |
| Calenergy.Org: The Business Energy Analzyer is designed to provide a comprehensive analysis of energy use in your business along with customized energy efficiency improvement recommendations. The calculator prepares a report, based on information submitted by the user, showing investments with greatest savings and those with the fastest payback on investment. Information on multiple buildings may be stored and updated for use in future analyses. |
| Canadian Small Wind Energy Calculator: Solar Mike’s Web Site SolarScript© PV System Design On-Line Calculator v2.4 |
| Carbon Dioxide Calculator: Many state electrical utilities have implemented programs where operators of photovoltaic systems connected to the electrical power grid can sell power to the utility operator. PVWATTS calculates electrical energy produced by a grid-connected photovoltaic system. |
| Carbon Dioxide Calculator : is a Web site developed to help you determine the cost and benefits of installing solar or wind energy on your home or building. The Web site also features a database of contractors to help you select an experienced building professional. Developed under funding from the California Energy Commission’s Renewable Energy Consumer Education grant program. |
| Carboncounter : is a Web-based calculator developed for the Canadian Wind Energy Association (CANWEA). This online wind calculator helps consumers determine the cost and benefits of installing small wind energy systems for their home, farm or building. |
| Climate Change Calculator – American Forests: This CO2 calculator, based on the ChoCO2 studies of GEIC (the Global Environment Information Centre in Tokyo), calculates CO2 emissions from everyday Japanese electrical appliances and automobiles based on energy consumption figures. By marking the appliances you use and filling out the required information, you can get a quick idea of how you can impact on the environment through your lifestyle. |
| Co2 Calculator : Carboncounter.org is an individual carbon dioxide emissions calculator generated by The Climate Trust, a pioneering non-profit organization that invests in high-quality projects that reduce or avoid greenhouse gas emissions, and Mercy Corps, an international relief and development agency. |
| Co2 Reduction Calculator: This tool prepared for the Canadian government calculates personal greenhouse gas emissions and lists mitigation strategies. Using a graphical example of a Canadian community, the user answers a series of questions on home heating and cooling, appliances, transportation and recreation activities. The calculator estimates personal CO2 emissions, offers suggestions for reducing emissions, and shows reductions achieved for those actions. The reporting function provides a graphical emissions breakdown for each feature. Available online or as a downloadable file. |
| Co2 Reduction Calculator : Calculates tons of carbon dioxide emitted by your household this year, and number of trees that would need to be planted to offset those emissions. / (added 09/2005) |
| Energy Advisor / Home Energy Saver : This calculator estimates the time and cost required to phase out CO2 production with a range of renewable energy technologies and carbon sinks. / (added 09/2005) |
| Energy Conversion Calculator: This calculator estimates the time and cost required to phase out CO2 production with a range of renewable energy technologies and carbon sinks. / (added 09/2005) |
| Energy To Carbon Dioxide Converter : The emissions calculator tabulates a user’s aggregate monthly emissions of seven air pollutants (in pounds) from electricity and natural gas consumption, airplane trips, and vehicle miles traveled (auto or sport utility vehicle/truck) and compare them with average national emissions. Emissions profiles may be saved and updated monthly to track performance. The site also offers suggestions on reducing emissions. / (added 09/2005) |
| Energy To Carbon Dioxide Converter From National Energy Foundation: new link — The Home Energy Saver is designed to help you identify the best ways to save energy in your home, and find the resources to make the savings happen. The Home Energy Saver asks for a detailed description of your home, and then quickly computes energy use on-line. Results are provided in dollars, kilowatt-hours and CO2 emissions for your house and the most energy efficient house. By changing one or more features, you can estimate how much energy and money you can save and how much pollution you can prevent by improving your home’s energy efficiency. In addition, the Home Energy Saver’s "Making it Happen" and Energy Librarian" modules connect users to an expanding array of "how-to" information resources throughout the Internet. |
| Energy To Carbon Dioxide Converter From National Energy Foundation : energy converter |
| Energy Usage Worksheet: Converts emissions from electricity consumption and transportation activities to equivalent amounts and provides information on ways U.K. households can reduce their energy consumption. |
| Findsolar.Org: A Worksheet to help you figure out what you energy needs are. |
| Greenhouse Gas Equivalencies Calculator – US Ctc Gateway : Calculates the emissions savings from using Australian energy star equipment. Results list savings in kilowatt-hours, coal needed to provide this energy, kilograms CO2, and equivalent car travel. |
| Home Analyzer : This site provided by the US Environmental Projection Agency can be used to calculate a household’s greenhouse gas emissions, as well as the impact of measures implemented to reduce these. |
| How Much Does Your Vehicle Pollute? : new link — Determines your auto’s carbon dioxide, sulfur dioxide, and nitrogen oxide emissions. Will calculate values specific to your mileage, or typical for the year and make of your auto. Includes additional information explaining the significance of the result and what can be done to lower emissions. |
| Hydrogen Equivilant Calculator: This utility will assist you in referencing Hydrogen equivalents at standard temperature and pressure. |
| Iowa Solar Calculator: |
| Kerychip – Photovoltaic Software : Free Download – photovoltaic sizing calculations programs -Device construction, development of analogue and digitals circuits, print and schematic design -Development of micro controller solutions -Data acquisitions – analog and digital signal |
| Lishines.Org: is a Web site developed for Long Island, NY to help you determine the cost and benefits of installing solar on your home or building. The Web site also features a database of contractors to help you select an experienced building professional. This Web site was initially developed in 2003 under funding from RELI & the DOE Million Solar Roofs grant program. In July, 2005 Energy Matters LLC licensed content to RELI, who now administers and maintains the site / (added 09/2005) |
| Lmno Engineering : new link — Have calculators for fluid flow and formula information, good for hydro calculations or water pumping applications (things like friction loss through pipes, etc.). |
| Personal Co2 Calculation: A worksheet to determine yearly direct personal carbon dioxide emissions. Results include yearly personal carbon dioxide emissions and a per capita comparison chart to other industrialized countries. Suggestions on reducing emissions while saving money are also provided. / (added 09/2005) |
| Power Profiler : The Power Profiler helps users determine the specific air emissions impacts of electricity used to power their home or business using actual monthly energy use information (provided by the user), average monthly use, or default values for monthly residential and commercial electricity use. |
| Safe Climate’s Calculator: The SafeClimate carbon footprint calculator allows you to determine carbon dioxide emissions from major sources: home energy consumption and transportation by car and plane. |
| See The Safeclimate Carbon Dioxide Footprint Calculator Description In The Individuals Section, Above : |
| The Co2 Calculator : Calculates CO2 emissions from everyday Japanese electrical appliances and automobiles based on energy consumption figures. / (added 09/2005) |
| Travel Matters Emissions Calculators : TravelMatters! is a new website from the Center for Neighborhood Technology that provides a trio of resources – interactive emissions calculators, online emissions maps, and a wealth of educational content – that emphasize the relationship between more efficient transit systems and lower greenhouse gas emissions. TM’s Emissions Calculator allows users to conceptualize how much carbon dioxide they emit due to their travel decisions. The site also offers transportation emissions by county for all contiguous states. |
| Units Units Units: How to convert them / (added 09/2005) |
| Water Consumption Calculator: |
DSE Energy Glossary
| Cadmium (Cd) | A chemical element used in making certain types of solar cells and batteries. |
| Cadmium Telluride (Cdte) | A polycrystalline thin-film photovoltaic material. |
| Caldera | a bowl-shaped landform, created either by a huge volcanic explosion (which destroys the top of a volcano) or by the collapse of a volcano’s top. |
| Call-Back | A provision included in some power sale contracts that lets the supplier stop delivery when the power is needed to meet certain other obligations. |
| Calorie | One energy calorie is equivalent to 4.2 joules. Thus, it takes 500,000 calories of energy to boil a pot of coffee. One food calorie equals 1,000 energy calories. |
| Calorie (Energy Calorie | small "c" |
| Capacitance | An electrical effect in AC circuits that results in amperage peaking before voltage. |
| Capacitor | An electronic component used for the temporary storage of electricity, as well for removing unwanted noise in circuits. A capacitor will block Direct Current but will pass Alternating Current. |
| Capacity | See Battery Capacity. |
| Capacity (C) | See battery capacity. |
| Capacity Factor | The ratio of the average load on (or power output of) an electricity generating unit or system to the capacity rating of the unit or system over a specified period of time. |
| Capacity Release | A secondary market for capacity that is contracted by a customer which is not using all of its capacity. |
| Captive Customer | A customer who does not have realistic alternatives to buying power from the local utility, even if that customer had the legal right to buy from competitors. |
| Captive Electrolyte Battery | A battery having an immobilized electrolyte (gelled or absorbed in a material). |
| Carbon Dioxide | A colorless, odorless, non-poisonous gas that is a normal part of the air. Carbon dioxide, also called CO2, is exhaled by humans and animals and is absorbed by green growing things and by the sea. |
| Carbon Dioxide (Co2) | A colorless, odorless noncombustible gas present in the atmosphere. It is formed by the combustion of carbon and carbon compounds (such as fossil fuels and biomass), by respiration, which is a slow combustion in animals and plants, and by the gradual oxidation of organic matter in the soil. |
| Carbon Monoxide (Co) | A colorless, odorless but poisonous combustible gas. Carbon monoxide is produced in the incomplete combustion of carbon and carbon compounds, for example, fossil fuels like coal and petroleum. |
| Carcinogens | Potential cancer-causing agents in the environment. They include among others: industrial chemical compounds found in food additives, pesticides and fertilizers, drugs, toy, household cleaners, toiletries and paints. Naturally occurring ultraviolet solar radiation is also a carcinogen. |
| Catalytic Cracking | A refinery process that converts a high-boiling range fraction of petroleum (gas oil) to gasoline, olefin feed for alkylation, distillate, fuel oil and fuel gas by use of a catalyst and heat. |
| Cathode | The negative pole or electrode of an electrolytic cell, vacuum tube, etc., where electrons enter (current leaves) the system; the opposite of an anode. |
| Cathodic Protection | A method of preventing oxidation (rusting) of exposed metal structures, such as bridges and pipelines, by imposing between the structure and the ground a small electrical voltage that opposes the flow of electrons and that is greater than the voltage present during oxidation. |
| Caulking | Material used to make an air-tight seal by filling in cracks, such as those around windows and doors. |
| Cd | see cadmium. |
| CdTe | see cadmium telluride. |
| Cell | The basic unit of a PV module or battery. The most basic unit that contains the necessary materials, such as electrodes and electrolyte in a battery, to produce electricity. |
| CELL (Battery) | A single unit of an electro-chemical device capable of producing an electrical current by converting chemical energy into electrical energy. The cell is the basic unit used to store energy in the battery. The cell contains an anode, a cathode, and the electrolyte. A battery usually consists of several cells electrically connected together to produce higher voltages. (Sometimes the terms cell and battery are used interchangeably). |
| CELL (Solar) | The smallest, basic photovoltaic device that generates electricity when exposed to light. |
| Cell Barrier | A very thin region of static electric charge along the interface of the positive and negative layers in a photovoltaic cell. The barrier inhibits the movement of electrons from one layer to the other, so that higher-energy electrons from one side diffuse preferentially through it in one direction, creating a current and thus a voltage across the cell. Also called depletion zone or space charge. |
| Cell Efficiency | The ratio of the electrical energy produced by a photovoltaic cell (under full sun conditions or 1 kw/m2) to the energy from sunlight falling upon the photovoltaic cell. |
| Cell Junction | The area of immediate contact between two layers (positive and negative) of a photovoltaic cell. The junction lies at the center of the cell barrier or depletion zone. |
| Celsius | A temperature scale based on the freezing (0 degrees) and boiling (100 degrees) points of water. Abbreviated as C in second and subsequent references in text. Formerly known as Centigrade. To convert Celsius to Fahrenheit, multiply the number by 9, divide by 5, and add 32. For example: 10 degrees Celsius x 9 = 90; 90 / 5 = 18; 18 + 32 = 50 degrees Fahrenheit. |
| Central Power Plant | A large power plant that generates power for distribution to multiple customers. |
| CFCS (Chlorofluorocarbons Or Chlorinated Fluorocarbons) |
A family of artificially produced chemicals receiving much attention for their role in stratospheric ozone depletion. On a per molecule basis, these chemicals are several thousand times more effective as greenhouse gases than carbon dioxide. Since they were introduced in the mid-1930s, CFCs have been used as refrigerants, solvents and in the production of foam material. The 1987 Montreal protocol on CFCs seeks to reduce their production by one-half by the year 1998. |
| CFM (Cubic Feet Per Minute) | A measure of flow rate. CURIE |
| Charge | Electricity produced by a surplus (position) or shortage (negative) of electrons in an object. |
| Charge Carrier | A free and mobile conduction electron or hole in a semiconductor. |
| Charge Controller | A component of a photovoltaic system that controls the flow of current to and from the battery to protect it from over-charge and over-discharge. The charge controller may also indicate the system operational status. |
| Charge Factor | A number corresponding to the time (in hours) for which a battery can be charged at a constant current without damaging it. Usually expressed as a function of battery capacity, e.g. C/10 indicates a charge factor of 10 hours. Related to Charge Rate. |
| Charge Rate | A measure of the current used to charge a battery as a proportion of its capacity. |
| Chemical Energy | The energy liberated in a chemical reaction, as in the combustion of fuels. |
| Chemical Vapor Deposition (Cvd) | A method of depositing thin semiconductor films used to make certain types of photovoltaic devices. With this method, a substrate is exposed to one or more vaporized compounds, one or more of which contain desirable constituents. A chemical reaction is initiated, at or near the substrate surface, to produce the desired material that will condense on the substrate. |
| Chiller | A device that cools water, usually to between 40 and 50 degrees Fahrenheit for eventual use in cooling air. |
| Chinook | A warm, dry wind that originates with moist wind from the Pacific Ocean and releases its moisture as precipitation over the Rocky Mountains. The air is then compressed and heated as it descends over the frozen plains of the northwestern United States and Canada, often melting several inches of snow in a matter of hours. This leads some people to call these winds snow eaters. |
| Circuit | A group of electrical components that make a complete electrical path, providing some function. |
| Circuit Breaker | A device used to interrupt or break an electrical circuit when an overload condition exists. Circuit breakers are used to protect electrical equipment from potential damage. |
| Clean Fuel Vehicle | is frequently incorrectly used interchangeably with "alternative fuel vehicle." Generally, refers to vehicles that use low-emission, clean-burning fuels. Public Resources Code Section 25326 defines clean fuels, for purposes of the section only, as fuels designated by ARB for use in LEVs, ULEVs or ZEVs and include, but are not limited to, electricity, ethanol, hydrogen, liquefied petroleum gas, methanol, natural gas, and reformulated gasoline. |
| Cleavage Of Lateral Epitaxial Films For Transfer (CLEFT) |
A process for making inexpensive Gallium Arsenide (gaas) photovoltaic cells in which a thin film of gaas is grown atop a thick, single-crystal gaas (or other suitable material) substrate and then is cleaved from the substrate and incorporated into a cell, allowing the substrate to be reused to grow more thin-film gaas. |
| Clerestory | A wall with windows that is between two different (roof) levels. The windows are used to provide natural light into a building. |
| Climate | The prevailing or average weather conditions of a geographic region. |
| Climate Zone | A geographical area is the state that has particular weather patterns. These zones are used to determine the type of building standards that are required by law. |
| Closed Loop System | A solar hot water system of which no part is vented to the atmosphere or fed with fresh liquid. The system liquid, usually some form of antifreeze solution, is recirculated. Closed loop solar systems are also known as glycol systems and indirect systems. |
| Cloud Enhancement | The increase in solar intensity caused by reflected irradiance from nearby clouds. |
| Clunkers | also known as gross-polluting or super- emitting vehicles, i.e., vehicles that emit far in excess of the emission standards by which the vehicle was certified when it was new. |
| Coal | Black or brown rock, formed under pressure from organic fossils in prehistoric times, that is mined and burned to produce heat energy. |
| Coal Conversion | Changing coal into synthetic gas or liquid fuels. See GASIFICATION. |
| Coal Oil | Oil that can be obtained by distilling bituminous coal. |
| Coal Seam | A mass of coal, occurring naturally at a particular location, that can be commercially mined. |
| Coal Slurry Pipeline | A pipe system that transports pulverized coal suspended in water. |
| Cob Construction | A traditional building technique using hand formed lumps of earth mixed with sand and straw. |
| Cogeneration | The joint production of electricity and useful heat at a single facility, resulting in more efficient use of the thermal energy. |
| Cogenerator | Cogenerators use the waste heat created by one process, for example during manufacturing, to produce steam which is used, in turn, to spin a turbine and generate electricity. Cogenerators may also be QFs. |
| Coke | A porous solid left over after the incomplete burning of coal or of crude oil. |
| Coke Oven Gas | Gas given off by coke ovens. Coke oven gas is interchangeable with goal gas. |
| Collector Loop | The plumbing loop in a solar hot water system that includes the solar collectors. The collectors heat the fluid in the collector, and the heated fluid can be used directly (if water) or the heat can be exchanged to a potable water loop. |
| Combined Collector | A photovoltaic device or module that provides useful heat energy in addition to electricity. |
| Combined Cycle Plant | An electric generating station that uses waste heat from its gas turbines to produce steam for conventional steam turbines. |
| Combined Hydronic Space/Water Heating | a system in which both space heating and domestic water heating are provided by the same water heater(s). |
| Combiner Box | A box where wires from individual PV modules or strings are combined into larger wires to run to the battery bank. Can also contain overcurrent protection devices. |
| Combustion | the burning of gas, liquid, or solid, in which the fuel is oxidized, producing heat and often light. |
| Combustion Burning | Rapid oxidation, with the release of energy in the form of heat and light. |
| Comfort Conditioning | The process of treating air to simultaneously control its temperature, humidity, cleanliness, and distribution to meet the comfort requirements of the occupants of the conditioned space. |
| Comfort Zone | The range of temperatures over which the majority of persons feel comfortable (neither too hot nor too cold). |
| Commercialization | Programs or activities that increase the value or decrease the cost of integrating new products or services into the electricity sector. (See "Sustained Orderly Development.") |
| Compact Fluorescent Light (Cfl) | A smaller version of standard fluorescent lamps that can directly replace incandescent lights. Cfls use 65 to 80 percent less energy, while producing the same lumens. |
| Competitive Transmission Charge | A non-bypassable charge that customers pay to a utility for the recovery of its stranded costs. |
| Compressed Natural Gas (Cng) | natural gas that has been compressed under high pressure, typically between 2,000 and 3,600 pounds per square inch, held in a container. The gas expands when released for use as a fuel. |
| Concentrating Solar Power (CSP) systems | concentrate the sun�s energy using reflective devices, such as troughs or mirror panels, to produce heat that is used for industrial processes or to generate electricity. |
| Concentrator | A photovoltaic module, which includes optical components such as lenses (Fresnel lens) to direct and concentrate sunlight onto a solar cell of smaller area. Most concentrator arrays must directly face or track the sun. They can increase the power flux of sunlight hundreds of times. |
| Condensate | Liquid fuel obtained by burning gas or vapor produced from oil and gas wells. |
| Condense | to change from a gas to drops of liquid. Water-cooled geothermal power plants use cooling towers to cool the used steam and condense it back to water for injection back to the edge of the reservoir. In binary power plants, an organic liquid is first vaporized (with heat from geothermal water) to drive a turbine, then cooled and condensed back to a liquid and recycled again and again in a closed loop. |
| Condenser | A heat exchanger in which the refrigerant, compressed to a hot gas, is condensed to liquid by rejecting heat. |
| Conditioned Space, Directly | An enclosed space that is provided with heating equipment that has a capacity exceeding 10 Btus/(hr-ft2), or with cooling equipment that has a capacity exceeding 10 Btus/(hr-ft2). An exception is if the heating and cooling equipment is designed and thermostatically controlled to maintain a process environment temperature less than 65 degrees Fahrenheit or greater than 85 degrees Fahrenheit for the whole space the equipment serves |
| Conductance | The quantity of heat, in Btu’s, that will flow through one square foot of material in one hour, when there is a 1 degree F temperature difference between both surfaces. Conductance values are given for a specific thickness of material, not per inch thickness. |
| Conduction | Heat transfer from a hot object to a colder object through direct contact. |
| Conduction Band (Or Conduction Level) | An energy band in a semiconductor in which electrons can move freely in a solid, producing a net transport of charge. |
| Conductivity (K) | The quantity of heat that will flow through one square foot of homogeneous material, one inch thick, in one hour, when there is a temperature difference of one degree Fahrenheit between its surfaces. |
| Conductor | A material with relatively low resistance through which electricity will readily flow�wires, cables, busbars. The most common conductors are copper and aluminum. |
| Conduit | A pipe or elongated box used to house and protect electrical cables. |
| Congestion | A condition that occurs when insufficient transfer capacity is available to implement all of the preferred schedules simultaneously. |
| Congestion Management | Alleviation of congestion by the ISO. |
| Conservation | Steps taken to cause less energy to be used than would otherwise be the case. These steps may involve improved efficiency, avoidance of waste, reduced consumption, etc. They may involve installing equipment (such as a computer to ensure efficient energy use), modifying equipment (such as making a boiler more efficient), adding insulation, changing behavior patterns, etc. |
| Constant-Speed Wind Turbines | Wind turbines that operate at a constant RPM (rotor revolutions per minute). They are designed for optimal energy capture at a specific rotor diameter and at a particular wind speed. |
| Contact Resistance | The resistance between metallic contacts and the semiconductor. |
| Continental Drift | the theory that the continents have drifted apart when a supercontinent, Pangaea, broke apart. See Plate Tectonics. |
| Continental Shelf | The portion of the sea bottom that slopes gradually from the edge of a continent. Usually defined as areas where water is less than 200 meters or 600 feet deep. |
| Contingency Planning | The Energy Commission’s strategy to respond to impending energy emergencies such as curtailment or shortage of fuel or power because of natural disasters or the result of human or political causes, or a clear threat to public health, safety or welfare. |
| Continuous Output Rating | The maximum amount of power an inverter may deliver to a load (or loads) for a sustained period of time. |
| Contract Path | The most direct physical transmission tie between two interconnected entities. When utility systems interchange power, the transfer is presumed to take place across the "contract path," notwithstanding the electrical fact that power flow in the network will distribute in accordance with network flow conditions. This term can also mean to arrange for power transfer between systems. (See also Parallel path flow) |
| Contracts For Differences (Cfd) | A type of bilateral contract where the electric generation seller is paid a fixed amount over time which is a combination of the short-term market price and an adjustment with the purchaser for the difference. For example, a generator may sell a distribution company power for ten years at 6-cents/kilowatt-hour (kWh). That power is bid into Poolco at some low /kWh value (to ensure it is always taken). The seller then gets the market clearing price from the pool and the purchaser pays the producer the difference between the Poolco selling price and 6-cents/kWh (or vice versa if the pool price should go above the contract price). |
| Control Area | An electric power system, or a combination of electric power systems, to which a common automatic generation control (AGC) is applied to match the power output of generating units within the area to demand. |
| Convection | 1Heat transfer by the movement of fluid (usually air or water). 2 Heat transfer through either the natural or forced movement of air |
| Convection Currents | the currents caused by hot air or fluid rising and falling. Hot air or fluid expands and is therefore less dense than its cooler surroundings, thus it rises; as it cools it contracts, becomes more dense and sinks down creating something of a rolling motion. These motions are thought to be party of the dynamic geologic processes that drive the movement of crustal plates. See Plate Tectonics |
| Conventional Fuel | The fossil fuels |
| Conventional Gas | Natural gas occurring in nature, as opposed to synthetic gas. |
| Conversion | device or kit by which a conventional fuel vehicle is changed to an alternative fuel vehicle. |
| Conversion Efficiency | The ratio of the electrical energy generated by a solar PV cell to the solar energy impacting the cell. Also see: photovoltaic (conversion) efficiency |
| Conversion Fuel Factor | A number stating units of one system in corresponding values of another system. |
| Converted Vehicle | a vehicle originally designed to operate on gasoline that has been modified or altered to run on an alternative fuel. |
| Converter | An electronic device for DC power that steps up voltage and steps down current proportionally (or vice-versa). |
| Cooling Capacity, Latent | Available refrigerating capacity of an air conditioning unit for removing latent heat from the space to be conditioned. |
| Cooling Capacity, Sensible | Available refrigerating capacity of an air conditioning unit for removing sensible heat from the space to be conditioned. |
| Cooling Capacity, Total | Available refrigerating capacity of an air conditioner for removing sensible heat and latent heat from the space to be conditioned. |
| Cooling Degree Day | A unit of measure that indicates how heavy the air conditioning needs are under certain weather conditions. |
| Cooling Load | The rate at which heat must be extracted from a space in order to maintain the desired temperature within the space. |
| Cooling Load Temperature Difference (Cltd) | A value used in cooling load calculations for the effective temperature difference (delta T) across a wall or ceiling, which accounts for the effect of radiant heat as well as the temperature difference. |
| Cooling Tower | A device for evaporatively cooling water by contact with air. |
| Co-Op | This is the commonly used term for a rural electric cooperative. Rural electric cooperatives generate and purchase wholesale power, arrange for the transmission of that power, and then distribute the power to serve the demand of rural customers. Co-ops typically become involved in ancillary services such as energy conservation, load management and other demand-side management programs in order to serve their customers at least cost. |
| Cooperative (Electric Utility) | A joint venture organized by consumers to make electric utility service available in their area. |
| Copper Indium Diselenide (Cuinse2, Or CIS) | A polycrystalline thin-film photovoltaic material (sometimes incorporating gallium (CIGS) and/or sulfur). |
| Core (Outer And Inner) | the extremely hot center of the Earth. The outer core is probably molten rock and is located about 3,200 miles (5,100) kilometers down from the earth�s surface; the inner core may be solid iron and is found a the very center of the Earth- about 4,000 miles (6,400 kilometers) down. |
| Corporate Average Fuel Economy (Cafe) | A sales-weighted average fuel mileage calculation, in terms of miles per gallon, based on city and highway fuel economy measurements performed as part of the federal emissions test procedures. CAFE requirements were instituted by the Energy Policy and Conservation Act of 1975 (89 Statute. 902) and modified by the Automobile Fuel Efficiency Act of 1980 (94 Statute. 1821). For major manufacturers, CAFE levels in 1996 are 27.5 miles per gallon for light-duty automobiles. CAFE standards also apply to some light trucks. The Alternative Motor Fuels Act of 1988 allows for an adjusted calculation of the fuel economy of vehicles that can use alternative fuels, including fuel-flexible and dual-fuel vehicles. |
| Cross-Flow Turbine | A turbine where the flow of water is at right angles to the axis of rotation of the turbine. Crystalline silicon |
| Crude Oil | Petroleum as found in the earth, before it is refined into oil products. Also called CRUDE. |
| Crude Oil Stocks | Stocks held at refineries and at pipeline terminals. Does not include stocks held on leases (storage facilities adjacent to the wells). |
| Crust | the solid outermost layer of the Earth, mostly consisting of rock, and ranging from 3 |
| Crystalline Silicon | A type of photovoltaic cell made from a slice of single-crystal silicon or polycrystalline silicon. |
| Cubic Foot | The most common unit of measurement of natural gas volume. It equals the amount of gas required to fill a volume of one cubic foot under stated conditions of temperature, pressure and water vapor. One cubic foot of natural gas has an energy content of approximately 1,000 Btus. One hundred (100) cubic feet equals one therm (100 ft3 = 1 therm). |
| Cultivate | to grow and tend (plants or crops), farm. |
| Current | Is the flow of electrons. Water flowing in a pipe is similar to electric current. You need voltage to make the current flow, just like water pressure is needed to make the water flow. It’s impossible to see an electric current, but it’s there � and is used to run everything from a light to your CD player. Also see: Ampere |
| Current At Maximum Power (Imp) | The current at which maximum power is available from a module. |
| Cutoff Voltage | Electrical equipment setting for the voltage level at which a battery is considered to be empty, and the discharge process is terminated. Most commonly found in inverters and charge controllers that include a feature for low voltage disconnection. |
| Cut-Off Voltage | The voltage levels at which the charge controller (regulator) disconnects the PV array from the battery, or the load from the battery. |
| Cycle | In alternating current electricity, the current flows in one direction from zero to a maximum voltage, then goes back down to zero, then to a maximum voltage in the opposite direction. This comprises one cycle. The number of complete cycles per second determines the current frequency. In the United States the standard for alternating current is 60 cycles. |
| Cycle Life | Number of charge-discharge cycles a battery can perform under specified conditions before it fails to meet its specified performance (e.g. Capacity decreases to 80% of nominal capacity). |
| Cyclone | Air spinning inward toward centers of low air pressure. Cyclones spin counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. |
| Czochralski Process | A method of growing large size, high quality semiconductor crystal by slowly lifting a seed crystal from a molten bath of the material under careful cooling conditions. |
DSE Energy Glossary
| Balance Of System | Represents all components and costs other than the photovoltaic modules/array. It includes design costs, land, site preparation, system installation, support structures, power conditioning, operation and maintenance costs, indirect storage, and related costs. |
| Balance Of System (BOS) | Parts or components of a photovoltaic system other than the photovoltaic array or other generating equipment. |
| Balanced Schedule | A Scheduling Coordinator’s schedule is balanced when generation, adjusted for transmission losses, equals demand. |
| Ballast | A circuit used to condition and stabilize an electric current, for example, in a fluorescent light. |
| Balneology | using hot spring mineral water for therapy. This is perhaps the oldest use of natural geothermal waters. |
| Band Gap | In a semiconductor, the energy difference between the highest valence band and the lowest conduction band. |
| Band Gap Energy (Eg) | The amount of energy (in electron volts) required to free an outer shell electron from its orbit about the nucleus to a free state, and thus promote it from the valence to the conduction level. |
| Barrel | In the petroleum industry, a barrel is 42 U.S. gallons. One barrel of oil has an energy content of 6 million British thermal units. It takes one barrel of oil to make enough gasoline to drive an average car from Los Angeles to San Francisco and back (at 18 miles per gallon over the 700-mile round trip). |
| Barrels Per Day Equivalent (Bpd-Equivalent) | A unit of measure that tells how much oil would have to be burned to produce the same amount of energy. |
| Barrier Energy | The energy given up by an electron in penetrating the cell barrier; a measure of the electrostatic potential of the barrier. |
| Base Load | The lowest level of power production needs during a season or year. |
| Base Load Unit | A power generating facility that is intended to run constantly at near capacity levels, as much of the time as possible. |
| Base Rate | That portion of the total electric or gas rate covering the general costs of doing business unrelated to fuel expenses. |
| Baseline Forecast | A prediction of future energy needs which does not take into account the likely effects of new conservation programs that have not yet been started. |
| Batch Solar Hot Water Heater | The simplest of solar hot water systems. A tank of water within a glass-covered insulated enclosure aimed at the sun. Water is heated in the tank and then flows to the load or an auxiliary water heater. |
| Battery | A single electric cell, or group of connected cells, that produces a direct electric current. |
| Battery Available Capacity | The total maximum charge, expressed in ampere-hours, that can be withdrawn from a cell or battery under a specific set of operating conditions including discharge rate, temperature, initial state of charge, age, and cut-off voltage. |
| Battery Bank | A group of batteries which stores excess electrical energy for later use. |
| Battery Capacity | The maximum total electrical charge, expressed in ampere-hours, which a battery can deliver to a load under a specific set of conditions. |
| Battery Cell | An individual unit of a battery that can store electrical energy and is capable of furnishing a current to an external load. For lead-acid batteries the voltage of a cell (fully charged) is about 2.2 volts dc. A battery may consist of a number of cells. |
| Battery Charger | A device used to charge a battery by converting (usually) mains voltage AC to a DC voltage suitable for the battery. Chargers often incorporate some form of regulator to prevent overcharging and damage to the battery. |
| Battery Cycle Life | The number of times a battery can be discharged and charged before it fails. |
| Battery Energy Capacity | The total energy available, expressed in watt-hours (kilowatt-hours), which can be withdrawn from a fully charged cell or battery. The energy capacity of a given cell varies with temperature, rate, age, and cut-off voltage. This term is more common to system designers than it is to the battery industry where capacity usually refers to ampere-hours. |
| Battery Energy Storage | Energy storage using electrochemical batteries. The three main applications for battery energy storage systems include spinning reserve at generating stations, load leveling at substations, and peak shaving on the customer side of the meter. |
| Battery Life | The period during which a cell or battery is capable of operating above a specified capacity or efficiency performance level. With lead-acid batteries, end-of-life is generally considered when a fully charged cell can deliver only 80 percent of its rated capacity. Beyond this state of aging, deterioration and loss of capacity begins to accelerate rapidly. Life may be measured in cycles or years, depending on the type of service for which the cell or battery is intended. |
| Battery Self Discharge | Energy loss by a battery not under load. |
| Battery Self-Discharge | Energy loss by a battery that is not under load. |
| Battery State Of Charge (SOC) | The charge status as a percentage of full charge |
| Benzene | A type of colorless liquid hydrocarbon that can be used as a motor fuel. Its chemical symbol is C6H6. |
| Betz Limit | The theoretical maximum energy that a wind generator can extract from the wind—59.6 percent. |
| Bi-Fuel Vehicle | A vehicle with two separate fuel systems designed to run on either fuel, using only one fuel at a time. These systems are advantageous for drivers who do not always have access to an alternative fuel refueling station. Bi-fuel systems are usually used in light-duty vehicles. One of the two fuels is typically an alternative fuel. |
| Bi-Gas | A process being developed as a means of making synthetic gas from coal. The synthetic gas would be intended to substitute for natural gas in meeting industrial and home energy needs. |
| Bilateral Contract | A two-party agreement for the purchase and the sale of energy products and services. |
| Bioconversion | Processes that use plants or micro-organisms to change one form of energy into another. For example, an experimental process uses algae to convert solar energy into gas that could be used for fuel. |
| Biodiesel | a biodegradable transportation fuel for use in diesel engines that is produced through the transesterfication of organically- derived oils or fats. It may be used either as a replacement for or as a component of diesel fuel. |
| Bioenergy | the energy from biomass (organic matter)—can be used directly for heat or to power a generator to produce electricity. Biomass can also be chemically converted into a fuel oil or liquid fuels. |
| Biofuels (Biomass Fuels) | Biomass converted directly to energy or converted to liquid or gaseous fuels, such as ethanol methane, and hydrogen. |
| Biomass | Any organic matter available on a renewable basis, including agricultural crops, wastes, and residues; wood, wood wastes, and residues; animal wastes and municipal wastes; and aquatic plants. |
| Biosphere | The zone at and adjacent to the earth’s surface where all life exists; all living organisms of the earth. |
| Bipv | Building Integrated Photovoltaics. As the name suggests, this is where PV modules are integrated in to the building construction materials as on integrated unit. |
| BIPV (Building-Integrated Photovoltaics) | A term for the design and integration of photovoltaic (PV) technology into the building envelope, typically replacing conventional building materials. This integration may be in vertical facades, replacing view glass, spandrel glass, or other facade material; into semitransparent skylight systems; into roofing systems, replacing traditional roofing materials; into shading "eyebrows" over windows; or other building envelope systems. |
| Bituminous Coal | Soft coal containing large amounts of carbon. It has a luminous flame and produces a great deal of smoke. |
| Blackout | The total loss of electric power supplied by the electric company. |
| Blade | The energy capturing, aerodynamically designed part of a wind turbine, which interacts directly with the wind. |
| Blocking Diode | A diode used to prevent current flow in an undesirable direction e.g. From the rest of the PV array to a failed module or from the battery to the PV array when current generation is low. |
| Boiler | A closed vessel in which water is converted to pressurized steam. |
| Boiling Point | temperature at which a single substance, such as water, changes from a liquid to a gas (steam) under normal atmospheric pressure. The boiling point at which water transitions to steam is 212°F (100°C). Some liquids boil at a lower temperature than water – a principle utilized in binary power plants. Boiling point is also affected by pressure. The greater the pressure, the higher the boiling point. This principle is put to work in geothermal (flash) power plants when superheated (hotter than boiling) geothermal water is brought up wells. The hot water flashes to steam when the pressure is released as it reaches the surface. This phenomenon also occurs naturally, resulting in such features as geysers. |
| Boiling Water Reactor | (BWR) A nuclear power unit in which water used as a coolant is allowed to boil at the core. The resulting steam may be used to drive electric turbines. |
| Bora | A cold wind that blows from the north or northeast across the lands around the Adriatic Sea. This wind is named after Boreas. |
| Boreas | The North Wind in Greek mythology. (“Aquilo” in Latin.) |
| Boron (B) | The chemical element commonly used as the dopant in photovoltaic device or cell material. |
| Bottled Gas | The liquified petroleum gases propane and butane, contained under moderate pressure (about 125 pounds per square inch and 30 pounds per square inch respectively), in cylinders. |
| Bottoming Cycle | A means to increase the thermal efficiency of a steam electric generating system by converting some waste heat from the condenser into electricity rather than discharging all of it into the environment. |
| Boule | A sausage-shaped, synthetic single-crystal mass grown in a special furnace, pulled and turned at a rate necessary to maintain the single-crystal structure during growth. |
| Brake | Device for stopping a wind turbine. This can be an electric brake that shorts the output of the turbine (dynamic braking), or a mechanical brake that physically stops the rotation, as with a brake drum and shoe. |
| Breaker | A manually operable switching device that also automatically opens a circuit in the event of overcurrent. |
| Breeder | A nuclear reactor that produces more fuel than it consumes. The breeder, invented in the United States, is used as a power source in several European countries. |
| Breeze | Wind classified as light, gentle, moderate, fresh, or strong. To see the corresponding wind speeds for each of these, look at the Beaufort Scale above. |
| British Thermal Unit (Btu) | The amount of heat energy required to raise one pound of water from a temperature of 60 degrees F to 61 degrees F at one atmosphere pressure. One Watt hour equals 3,413 BTU. |
| Broker | A retail agent who buys and sells power. The agent may also aggregate customers and arrange for transmission, firming and other ancillary services as needed. |
| Brownout | A temporary reduction of voltage supplied by the electric company. Typically causes lights to dim. |
| BTU (British Thermal Unit) | Measurement of heat energy. 1 BTU is the amount of energy it require to heat 1 pound of water from 60 to 61 degrees Fahrenheit. 1W = 3413BTU. |
| Building Envelope | The assembly of exterior partitions of a building which enclose conditioned spaces, through which thermal energy may be transferred to or from the exterior, unconditioned spaces, or the ground |
| Bulk Charge | The initial phase of battery charging, when the largest amount of energy is put into the battery. |
| Bulk Power Supply | Often this term is used interchangeably with wholesale power supply. In broader terms, it refers to the aggregate of electric generating plants, transmission lines, and related-equipment. The term may refer to those facilities within one electric utility, or within a group of utilities in which the transmission lines are interconnected. |
| Busbar | In electric utility operations, a busbar is a conductor that serves as a common connection for two or more circuits. It may be in the form of metal bars or high-tension cables. |
| Buss | An electrical connection component that can accept multiple cables or wires. Also bus, bus bar, or busbar |
| Buster | A sudden and violent cold wind that blows across Australia from the south. In parts of Australia it is referred to as a “southerly buster” or a “brickfielder.” |
| Butane | A hydrocarbon gas found in the earth along with natural gas and oil. Butane turns into a liquid when put under pressure. It is sold as bottled gas. It is used to run heaters, stoves and motors, and to help make petrochemicals. |
| Buy Through | An agreement between utility and customer to import power when the customer’s service would otherwise be interrupted. |
| Buyer | An entity that purchases electrical energy or services from the Power Exchange (PX) or through a bilateral contract on behalf of end-use customers. |
| Bypass Diode | A diode connected across one or more solar cells in a photovoltaic module such that the diode will conduct if the call(s) change polarity. |
DSE Energy Glossary
| Term | Definition |
| Absorbed Glass Mat (AGM) Batteries | Employ a micro-fibrous silica glass mat envelope to immobilize their electrolyte. This makes them non-spillable and gives them a lower self-discharge rate than conventional flooded lead-acid batteries. |
| Absorber | 1) In a photovoltaic device, the material that readily absorbs photons to generate charge carriers (free electrons or holes). 2) The absorber is that part of a solar thermal collector that receives the incident radiant energy and transforms it into heat energy. |
| Absorbers | Dark coloured objects that soak up heat in solar collectors. |
| Absorptance | The ratio of the radiation absorbed by a surface to the total energy falling on that surface described as a percentage. |
| Absorption Coefficient | The factor by which photons are absorbed as they travel a unit distance through a material. |
| AC (Alternating Current) | A type of electrical current, the direction of which is reversed at regular intervals or cycles. Alternating current is abbreviated as AC. |
| Acceptor | An element (like boron) that is missing outer shell electrons to be used in solar panel construction. |
| Access Charge | A charge paid by all market participants withdrawing energy from the ISO controlled grid. The access charge will recover the portion of a utility’s transmission revenue requirement not recovered through the variable usage charge. |
| Acid Rain | Precipitation that has become acidic as the result of chemical reactions. Sulfur dioxide emissions from fossil fuel burning power plants react with the water, oxygen, and other chemicals in the air to cause acid rain. |
| Activated Shelf Life | The period of time, at a specified temperature, that a charged battery can be stored before its capacity falls to an unusable level. |
| Activation Voltage(S) | The voltage(s) at which a charge controller will take action to protect the batteries. |
| Active Solar Energy System | Solar radiation used by special equipment to provide space heating, hot water or electricity. |
| Active Solar Heater | A water or space heating system that moves heated air or water using pumps or fans. |
| Active Solar Thermal System | A system that traps the sun’s energy with solar collectors and uses an electromechanical subsystem to move that energy to its point of intended use for water heating, space heating, pool heating, industrial process heat, electrical generation and space cooling. |
| Addition | An alteration to an existing building that increases conditioned space. |
| Adjustable Set Point | A feature allowing the user to adjust the voltage levels at which a charge controller will become active. |
| Adjustment Bid | A bid that is used by the ISO to adjust supply or demand when congestion is anticipated. |
| Adverse Hydro | Water conditions limiting the production of hydroelectric power. In years having below-normal levels of rain and snow, and in seasons having less-than-usual runoff from mountain snowpack, there is then less water available for hydro energy production. |
| Aeolus | The god of the winds in Greek mythology. |
| After-Market | broad term that applies to any change after the original purchase, such as adding equipment not a part of the original purchase. As applied to alternative fuel vehicles, it refers to conversion devices or kits for conventional fuel vehicles. |
| Aggregator | An entity responsible for planning, scheduling, accounting, billing, and settlement for energy deliveries from the aggregator’s portfolio of sellers and/or buyers. Aggregators seek to bring together customers or generators so they can buy or sell power in bulk, making a profit on the transaction. |
| AGM (Adsorbed Glass Mat) | a newer type of battery construction that uses saturated adsorbant glass mats rather than gelled or liquid electrolyte. AGM batteries are typically more expensive than flooded (liquid), but offer enhanced reliability. |
| Agriculture | the growing (farming) of plants, flowers, trees, grains, and other crops. Greenhouses can be heated with hot water from geothermal reservoirs. In some places pipes of hot water are buried under the soil. Geothermal heat is also used to dry crops. |
| AIC | See amperage interrupt capability. |
| Air | The mixture of gases that surrounds the earth and forms its atmosphere. Air is composed primarily of oxygen and nitrogen. |
| Air Change | The replacement of a quantity of air in a space within a given period of time, typically expressed as air changes per hour. If a building has one air change per hour, this is equivalent to all of the air in the building being replaced in a one-hour period. |
| Air Conditioner | An assembly of equipment for air treatment consisting of a means for ventilation, air circulation, air cleaning, and heat transfer (either heating or cooling). The unit usually consists of an evaporator or cooling coil, and an electrically-driven compressor and condenser combination. |
| Air Film | A layer of still air adjacent to a surface which provides some thermal resistance. |
| Air Film Coefficient | A measure of the heat transfer through an air film. [See ASHRAE Table 1, ASHRAE Handbook, 1985 Fundamentals] |
| Air Mass | The length of the path of solar radiation through the atmosphere. E.g. Air mass of 1 means the sun is overhead (goes trough 1 atmosphere). |
| Air Pollution | Air with contaminants in it that prevent the air from dispersing as it normally would, and interfere with biological processes. |
| Air-To-Air Heat Exchanger | A device with separate air chambers that transfers heat between the conditioned air being exhausted and the outside air being supplied to a building. |
| Alcohol Fuels | A class of liquid chemicals that have certain combinations of hydrogen, carbon and oxygen, and that are capable of being used as fuel. |
| Alteration | Any change or modification to a building’s construction. [See Addition]. |
| Alternating Current | An electric current that reverses directions at regular intervals (typically 60 times a second); abbreviated "AC." This current found in homes. |
| Alternating Current (Ac) | An electrical current in which the direction of electron flow reverses periodically, usually many times per second. Most U.S. household electrical systems use AC current rated at 120 volts and 60 cycles per second. |
| Alternative (Transportation) Fuels | as defined by the National Energy Policy Act (EPAct) the fuels are: methanol, denatured ethanol and other alcohols, separately or in mixtures of 85 percent by volume or more (or other percentage not less than 70 percent as determined by U.S. Department of Energy rule) with gasoline or other fuels; CNG; LNG; LPG; hydrogen; "coal-derived liquid fuels;" fuels "other than alcohols" derived from "biological materials;" electricity, or any other fuel determined to be "substantially not petroleum" and yielding "substantial energy security benefits and substantial environmental benefits." |
| Alternative Energy Sources | See RENEWABLE ENERGY. |
| Alternative Fuel Vehicle (Afv) | motor vehicles that run on fuels other than petroleum-based fuels. As defined by the National Energy Policy Act (EPAct), this excludes reformulated gasoline as an alternative fuel. |
| Alternative Fuels | A popular term for “non-conventional”transportation fuels like propane that are derived from natural gas or biomass materials. |
| Alternator | A device for producing Alternating Current ("AC") electricity. Usually driven by a motor, but can also be driven by other means, including water and wind power. |
| Altitude Angle | The angle of the sun above the horizon, measured in degrees. In winter, the sun is at a low solar altitude, and in the summer, the sun is at a high solar altitude. |
| Ambient | The surrounding atmosphere; encompassing on all sides; the environment surrounding a body but undisturbed or unaffected by it. |
| Ambient Air Temperature | Surrounding temperature, such as the outdoor air temperature around a building. |
| Ambient Temperature | The temperature of the surrounding area. |
| American Wire Gauge (Awg) | American Wire Gauge, a set of standards in the U.S. specifying the diameter of wire. A higher number indicates smaller wire. |
| Ammeter | A device used for measuring the current (amperage) at any point in an electrical circuit. |
| Amorphous Semiconductor | A non-crystalline semiconductor material that has no long-range order. |
| Amorphous Silicon | A thin-film solar PV cell material which has a glassy rather than crystalline structure. Made by depositing layers of doped silicon on a substrate normally using plasma-enhanced chemical vapor deposition of silane. |
| Amp Hour | The quantity of electrical energy corresponding to the flow of current of one ampere for one hour. The term is used to quantify the energy stored in a battery. Most batteries are rated in Ah. |
| Ampacity | Refers to the highest safe amount of electrical current through conductors, overcurrent devices, or other electrical equipment. Ampacity is determined by the cross-sectional area and the material of the conductor, or the manufacturer’s equipment rating. |
| Amperage Interrupt Capability (AIC) | direct current fuses should be rated with a sufficient AIC to interrupt the highest possible current. |
| Ampere (A) Or Amp | The unit for the electric current; the flow of electrons. One amp is 1 coulomb passing in one second. One amp is produced by an electric force of 1 volt acting across a resistance of 1 ohm. |
| Ampere (A)(Amp) | Unit of electrical current, the flow of electrons. |
| Ampere (Amp) | The unit of measure that tells how much electricity flows through a conductor. It is like using cubic feet per second to measure the flow of water. For example, a 1,200 watt, 120-volt hair dryer pulls 10 amperes of electric current (watts divided by volts). |
| Ampere Hour Meter | An instrument that monitors current with time. The indication is the product of current (in amperes) and time (in hours). |
| Ampere, Amps | The measurement of the flow of an electric current through a conductor. |
| Ampere-Hour (Amp-Hour; Ah) | A measure of electron flow over time, used to measure battery capacity and state of charge. For example, a current of 1 amp drawn from a battery for 10 hours would result in 10 amp-hours of charge cycling through the battery. |
| Ampere-Hour Meter | An instrument that monitors electron flow over time. Amp-hours are the product of electron flow (in amperes) and time (in hours). |
| Amp-Hour (Ah) | Unit of electrical energy, the flow of 1 Amp for 1 Hour. Often used to describe the quantity of energy stored in a battery. |
| Amplitude | Generally refers to the maximum and minimum voltage attained by an alternating or pulsed current in each complete cycle or pulse of that current. |
| Ancillary Services | The services other than scheduled energy that are required to maintain system reliability and meet WSCC/NERC operating criteria. Such services include spinning, non-spinning, and replacement reserves, voltage control, and black start capability. |
| Anemometer | An instrument for measuring and indicating the force or speed of the wind. |
| Angle Of Incidence | The angle that the sun’s rays make with a line perpendicular to a surface. The angle of incidence determines the percentage of direct sunshine intercepted by a surface. |
| Animal Waste Conversion | Process of obtaining energy from animal wastes. This is a type of biomass energy. |
| Annual Maximum Demand | The greatest of all demands of the electrical load which occurred during a prescribed interval in a calendar year. |
| Annual Solar Savings | The annual solar savings of a solar building is the energy savings attributable to a solar feature relative to the energy requirements of a non-solar building. |
| Anode | The positive electrode in an electrochemical cell (battery). Also, the earth or ground in a cathodic protection system. Also, the positive terminal of a diode. |
| Anode | (Battery) the electrode within a battery cell that undergoes the chemical process of oxidation. Electrically, the anode is the cell’s positive terminal. (Water heater) An aluminum or magnesium sacrificial rod installed within steel tanks that is used to help prevent corrosion of the tank itself. |
| Ansi | American National Standards Institute is the national organization that coordinates development and maintenance of consensus standards and sets rules for fairness in their development. ANSI also represents the USA in developing international standards. |
| Anthracite | Hard coal, found deep in the earth. It burns very hot, with little flame. It usually has a heating value of 12,000-15,000 British thermal units (Btus) per pound. |
| Anti-Reflection Coating | A thin coating of a material with a specific refractive index applied to a cell to reduce the reflection of light. |
| Appliance Saturation | A percentage telling what proportion of all households in a given geographical area have a certain appliance. |
| Applicant | Applicant means any person who submits an application for certification pursuant to the provisions of this division, including, but not limited to, any person who explores for or develops geothermal resources. |
| Application | Application means any request for certification of any site and related facility filed in accordance with the procedures established pursuant to this division. An applicant for a geothermal powerplant and related facilities may propose more than one site and related geothermal facilities in the same application. |
| Aquaculture | the farming of fish and other water-dwelling organisms in freshwater or seawater. Geothermal water is used to help speed the growth of fish, prawns and alligators. China is probably has more aquaculture operations than any other country. |
| Aquifer | a large permeable body of underground rock capable of yielding quantities of water to springs or wells. Aquifers provide about 60 percent of American drinking water. Underground aquifers of hot water and steam are called geothermal reservoirs. |
| Aquilo | The Latin word for the North Wind in Greek mythology. |
| Arbor Or Arbor Shaft | An adaptor which converts your motor shaft to a useable threaded bolt |
| Area Load | The total amount of electricity being used at a given point in time by all consumers in a utility’s service territory. |
| Array | Any number of photovoltaic modules connected together electrically to provide a single electrical output. Also see photovoltaic (PV) array. |
| Array Current | The electrical current produced by a photovoltaic array when it is exposed to sunlight. |
| Array Operating Voltage | The voltage produced by a photovoltaic array when exposed to sunlight and connected to a load. |
| Ash | Non-organic, non-flammable substance left over after combustible material has been completely burned. |
| Ashrae | Acronym for American Society of Heating, Refrigerating and Air- Conditioning Engineers. |
| Associated Gas | Natural gas that can be developed for commercial use, and which is found in contact with oil in naturally occurring underground formations. |
| Asynchronous Generator | A type of electric generator that produces alternating current (AC) electricity to match an existing power source. |
| Atgas | Synthetic gas produced by dissolving coal in a bath of molten iron. The process was developed by Applied Technology, Inc. Synthetic gas may be used as a substitute for natural gas in industrial and home uses. |
| Atom | Primary basis of all matter. It has a nucleus consisting of protons and neutrons surrounded by orbiting electrons . |
| Auster | The Latin word for the South Wind in Greek mythology. |
| Autonomous System | A PV System that operates without any other energy generating source. Also see: Stand-Alone System |
| Auxiliary Energy Subsystem | Equipment using conventional fuel to supplement the energy output of a solar system. This might be, for example, an oil- fueled generator that adds to the electrical output of a substitutes for the solar system during long overcast periods when there is not enough sunlight. |
| Auxiliary Equipment | Extra machinery needed to support the operation of a power plant or other large facility. |
| Availability | The quality or condition of a photovoltaic system being available to provide power to a load. Usually measured in hours per year. One minus availability equals downtime. |
| Average Cost | The revenue requirement of a utility divided by the utility’s sales. Average cost typically includes the costs of existing power plants, transmission, and distribution lines, and other facilities used by a utility to serve its customers. It also included operating and maintenance, tax, and fuel expenses. |
| Average Demand | The energy demand in a given geographical area over a period of time. For example, the number of kilowatt-hours used in a 24-hour period, divided by 24, tells the average demand for that period. |
| Average Hydro | Rain, snow and runoff conditions that provide water for hydroelectric generation equal to the most commonly occurring levels. Average hydro usually is a mean indicating the levels experienced most often in a 104-year period. |
| Avoided Cost | (Regulatory) The amount of money that an electric utility would need to spend for the next increment of electric generation to produce or purchase elsewhere the power that it instead buys from a cogenerator or small-power producer. Federal law establishes broad guidelines for determining how much a qualifying facility (QF) gets paid for power sold to the utility. |
| Awg (American Wire Gauge) | a standard system for designating the size of electrical wire. The higher the number, the smaller the wire. Most house wiring is #12 or 14. |
| Azimuth | The Angle between the north direction and the projection of the surface normal into the horizontal plane; measured clockwise from north. As applied to the PV array, 180 degree azimuth means the array faces due south. |
| Azimuth Angle | The angle between true south and the point on the horizon directly below the sun. |
| Azimuth | The Angular Distance Between True South And The Point On The Horizon Directly Below The Sun. Typically Used As An Input For Opaque Surfaces And Windows In Computer Programs For Calculating The Energy Performance Of Buildings. |