| H2net: is devoted to sustainable architecture and natural building, including building techniques, principles of sustainability, the environment, vernacular architecture, building codes, financing, owner/builder considerations, manufactured systems, and advice. / (added 09/2005) |
| Healthy Homes Institute: |
| Heartland Renewable Energy Society: Greenpeace International’s climate change campaign. |
| Helsinki University Of Technology (Hut): partnership of several major corporations with the goal of creating 1,000 MW of new green power by 2010. |
| Hydrogen Fuel Cell Institute: |
| Hyweb: |
| Industrial Heating Equipment Association (Ihea) : |
| Infinet: |
| Institut National De La Recherche Agronomique (Inra) : promotes technologies, energy efficiency, and sustainable design. / (added 09/2005) |
| Institute For Energy Technology (Ife): The Centre for Energy Technology at HUT carries out research in areas such as energy economics, power plant engineering, combustion and gasification technology. / (added 09/2005) |
| Institute For Self-Reliance: |
| Inter-American Development Bank : IHEA represents major segments in the industrial heat processing equipment industry, producing a range of information and publications. |
| International Association For Energy Efficient Lighting: Austin’s homegrown environmental BBS, by Chris Burton |
| International Association For Hydrogen Energy: INRA is responsible to the French Ministries of Research and Agriculture, and investigates the interaction between the greenhouse effect and agriculture. / (added 09/2005) |
| International Association For Natural Gas Vehicles (Iangv): Norway’s national research centre for nuclear and energy technology, carrying out R&D activities into environmentally acceptable technologies for oil and gas production, power generation and supply, and energy use. / (added 09/2005) |
| International Atomic Energy Agency (Iaea): The National Research Council’s construction technology centre (IRC) provides research, building code development and materials evaluation services. |
| International Climate Action Network: The Institute for Local Self Reliance (ILSR) is a small organization with a remarkable track record for breaking new ground in promoting sustainable communities. In 1978 RAIN magazine described ILSR as an organization that "puts hard numbers on soft dreams". In 1993 United States Senator Paul Wellstone called ILSR "one of this country’s leading practical thinkers in the area of sustainable economic development". |
| International Energy Agency (Iea): The Bank was established to help economic and social development in Latin America and the Caribbean. The Bank provides technical assistance for the preparation, financing, and implementation of development plans and projects. |
| International Energy Association Bioenergy : IAEEL is a global high-quality, energy-efficient lighting network and information resource. Resource index and listing of events. |
| International Facility Management Association (Ifma) : / (added 09/2005) |
| International Geothermal Association: |
| International Network For Sustainable Energy (Inforse): The Climate Action Network (CAN) is a worldwide network of over 340 NGOs working to promote government and individual action to limit human-induced climate change. |
Uncategorized
Links to Renewable (Alternative) Organizations
| International Office For Water: The IEA is the energy forum for 26 Member countries. IEA Member governments are committed to taking joint measures to meet oil supply emergencies. They have also agreed to share energy information, to co-ordinate their energy policies and to co-operate in the development of rational energy programmes. |
| International Performance Measurement And Verification Protocol: IFMA is a professional association for facility managers with responsibilities in areas such as administration, architecture and the behavioural and engineering sciences. |
| International Research Center On Environment And Development (Cired): Information on geothermal energy in use around the world, world conferences on geothermal, and links to related web sites. / (added 09/2005) |
| Irish Bioenergy Association (Irbea): Non-profit environmental organization working globally to accelerate the adoption of energy-efficient policies, technologies, and practices in developing countries to enable economically and environmentally sustainable development. |
| Japan’s Ministry Of Economy, Trade And Industry (Meti): INFORSE provide news and information on the implementation of sustainable energy solutions. Worldwide NGO network formed at the Global Forum in Rio in 1992 with 200 member organizations worldwide. |
| Kentucky Clean Fuels Coalition: Paris, FR |
| Lawrence Berkeley National Laboratory : CIRED was set up to study the relationships between the environment, the long-term management of natural resources and economic development. |
DSE Energy Glossary
| Landfill Gas | Gas generated by the natural degrading and decomposition of municipal solid waste by anaerobic microorganisms in sanitary landfills. The gases produced, carbon dioxide and methane, can be collected by a series of low-level pressure wells and can be processed into a medium Btu gas that can be burned to generate steam or electricity. |
| Landman | An in-house or independent land management consultant who negotiates terms of land leases with land owners. |
| Landscaping | Features and vegetation on a section of ground for decoration and/or energy conservation. |
| Langley | Unit of solar irradiance, one calorie per square centimeter. 1 L = 41.84 kj/m2. |
| Langley (L) | Unit of solar irradiance. One gram calorie per square centimeter. 1 L = 85.93 kwh/m2. |
| Laser | The light energy amplified by electrical impulses. |
| Latent Heat | A change in the heat content that occurs without a corresponding change in temperature, usually accompanied by a change of state (as from liquid to vapor during evaporation). |
| Latent Load | The cooling load caused by moisture in the air. |
| Latitude | A location’s distance north or south of the equator measured in degrees. |
| Lattice | The regular periodic arrangement of atoms or molecules in a crystal of semiconductor material. |
| Lava | molten magma that has reached the Earth’s surface. |
| Lay Up | Lay up is another term for cold storage and describes the status of equipment (such as a power plant) that has been placed in storage ("mothballed") for latter use. |
| Layoff (Electric Utility) | Excess capacity of a generating unit, available for a limited time under the terms of a power sales agreement. |
| Lead Acid Battery | A battery that consists of lead based plates surrounded by a sulfuric acid electrolyte. |
| Lead-Acid Battery | A general category that includes batteries with plates made of pure lead, lead-antimony, or lead-calcium immersed in an acid electrolyte. |
| Leaded Gasoline | Gasoline containing tetraethyl lead, an important constituent in antiknock gasoline. Leaded gasoline is no longer sold in the United States. |
| Leading Edge | The blade edge that faces toward the direction of rotation. |
| Levanter | Wind that blows through the Straits of Gibraltar, funneled through the gap between the high plateau of Spain and the Atlas Mountains of North Africa. |
| Life | The period during which a system can operate above a specified performance level. |
| Life Extension | A term used to describe capital expenses which reduce operating and maintenance costs associated with continued operation of electric utility boilers. Such boilers usually have a 40 year operating life under normal circumstances. |
| Life-Cycle Cost | The estimated cost of owning and operating a photovoltaic system for the period of its useful life. |
| Lifeline Rates | Rates charged by a utility company for the low income, the disadvantaged and senior citizens. The rates provide a discount for minimum necessary utilities, such as electricity requirements of typically 300 to 400 kilowatt/hours per month. |
| Lift | The force that pulls a wind turbine blade. |
| Light Emitting Diode | A semi conductor device composed of a p-n junction designed such that electrons emit visible light during their migration across the junction. |
| Light Emitting Diode (Led) | A semiconductor device composed of a PN junction designed such that electrons cause visible light during their migration across the junction. |
| Light Trapping | The trapping of light inside a semiconductor material by refracting and reflecting the light at critical angles; trapped light will travel further in the material, greatly increasing the probability of absorption and hence of producing charge carriers. |
| Light Water Reactor (Lwr) | A nuclear power unit that uses ordinary water to cool its core. The LWR may be a boiling water reactor or a pressurized water reactor. |
| Light-Induced Defects | Defects, such as dangling bonds, induced in an amorphous silicon semiconductor upon initial exposure to light. |
| Lightning | A static electrical discharge beween two clouds or between a cloud and the earth accompanied by a flash of light. |
| Lightning Arrestor | Devices that protect electronics from lightning-induced surges by carrying the charge to ground. |
| Lignite | Brownish black coal having qualities in between those of bituminous coal and peat. The texture of the original wood often is visible in lignite. |
| Line Loss | Voltage drop over a length or wire. You are at risk to this if your wire is too small for the load going through it or the voltage is too low for the distance it must travel. |
| Line Wire Loss | refers to the voltage or power lost due to the resistance of any wire or wires in any electrical circuit. |
| Line/Wire Loss | The voltage drop or energy loss due to the resistance of wire in an electrical circuit. See VOLTAGE DROP |
| Linear Current Booster | an electronic circuit that matches PV output directly to a motor. Used in array direct water pumping. |
| Linear Current Booster (Lcb) | An electronic circuit that matches PV output directly to a motor by converting unneeded voltage to higher usable current. Used in array-direct water pumping. |
| Line-Commutated Inverter | An inverter that is tied to a power grid or line. The commutation of power (conversion from direct current to alternating current) is controlled by the power line, so that, if there is a failure in the power grid, the photovoltaic system cannot feed power into the line. |
| Liquefaction | The process of making synthetic liquid fuel from coal. The term also is used to mean a method for making large amounts of gasoline and heating oil from petroleum. |
| Liquefied Gases | Gases that have been or can be changed into liquid form. These include butane, butylene, ethane, ethylene, propane and propylene. |
| Liquid Brine | A type of geothermal energy resource that depends on naturally occurring hot water solution found within the earth. Technology for this novel energy source is being developed in the Salton Sea area in Southern California. |
| Liquid Electrolyte Battery | A battery containing a liquid solution of an electrolyte in a solvent. Can be called a flooded battery too. |
| Liquid Petroleum Gas | See LPG. |
| Lng (Liquefied Natural Gas) | Natural gas that has been condensed to a liquid, typically by cryogenically cooling the gas to minus 260 degrees Fahrenheit (below zero). |
| Load | Anything that draws power from an electric circuit. |
| Load Centers | A geographical area where large amounts of power are drawn by end-users. |
| Load Circuit | The wire, switches, fuses, etc. That connect the load to the power source. |
| Load Current | The current required to power the electrical device. |
| Load Current (A) | The current required by the electrical device. |
| Load Diversity | The condition that exists when the peak demands of a variety of electric customers occur at different times. This is the objective of "load molding" strategies, ultimately curbing the total capacity requirements of a utility. |
| Load Factor | A percent telling the difference between the amount of electricity a consumer used during a given time span and the amount that would have been used if the usage had stayed at the consumer’s highest demand level during the whole time. The term also is used to mean the percentage of capacity of an energy facility |
| Load Management | Steps taken to reduce power demand at peak load times or to shift some of it to off-peak times. This may be with reference to peak hours, peak days or peak seasons. The main thing affecting electric peaks is air-conditioning usage, which is therefore a prime target for load management efforts. Load management may be pursued by persuading consumers to modify behavior or by using equipment that regulates some electric consumption. |
| Load Resistance | The electrical resistance of the load. |
| Loop Flow | The difference between scheduled and actual power flows on electric transmission lines. |
| Losses (Electric Utility) | Electric energy or capacity that is wasted in the normal operation of a power system. Some kilowatt-hours are lost in the form of waste heat in electrical apparatus such as substation conductors. LINE LOSSES are kilowatts or kilowatt-hours lost in transmission and distribution lines under certain conditions. |
| Low Voltage Cut-Off | The voltage at which a controller will disconnect the load from the battery. |
| Low Voltage Cutoff (LVC) | The voltage level at which a charge controller will disconnect the load from the battery. |
| Low Voltage Disconnect | The voltage at which a charge controller will disconnect the load from the batteries to prevent over-discharging. |
| Low Voltage Disconnect (LVD) | The voltage at which the charge controller will disconnect the load from the batteries to prevent over-discharging. |
| Low Voltage Disconnect Hysteresis | The voltage difference between the low voltage disconnect set point and the voltage at which the load will be reconnected. |
| Low Voltage Warning | A warning buzzer or light that indicates the low battery voltage set-point has been reached. |
| Low-E | A special coating that reduces the emissivity of a window assembly, thereby reducing the heat transfer through the assembly. |
| Low-E Glass | Glass coated with layers of metal or metal oxide. The coating emits very little radiation in the long-wave (infrared) spectrum, which diminishes heat loss from the building interior, and reduces heat gain in hot weather. |
| Low-Sulfur Oil | Oil having one percent or less of sulfur by weight. |
| LPG (Liquefied Petroleum Gas) | A mixture of gaseous hydrocarbons, mainly propane and butane that change into liquid form under moderate pressure. LPG or propane is commonly used as a fuel for rural homes for space and water heating, as a fuel for barbecues and recreational vehicles, and as a transportation fuel. It is normally created as a by-product of petroleum refining and from natural gas production. |
| Lumen | A unit of measurement quantifying the amount of light emitted from a light source. |
| Lumen Maintenance Control | An electrical control device designed to vary the electrical consumption of a lighting system in order to maintain a specified illumination level. |
| Lumens/Watt | A measure of the efficacy of a light fixture; the number of lumens output per watt of power consumed. |
| Luminaire | A complete lighting unit consisting of a lamp or lamps together with the parts designed to distribute the light, to position and protect the lamps and to connect the lamps to the power supply. |
| Lux | A unit of illumination equal to the direct illumination on a surface that is everywhere one meter from a uniform point source of one candle; a unit of illumination that is equal to one lumen per square meter. Also see footcandle. |
DSE Energy Glossary
| M100 | 100 percent (neat) methanol used as a motor fuel in dedicated methanol vehicles, such as some heavy-duty truck engines. |
| M85 | a blend of 85 percent methanol and 15 percent unleaded regular gasoline, used as a motor fuel. |
| Magma | hot, thick, molten (liquid) rock found beneath the Earth’s surface; formed mainly in the mantle. |
| Magnet | A piece of material that has the natural ability to attract iron. |
| Magnetic Declination | The number of degrees east or west of true south from magnetic south. |
| Magnetic Field | A detected force that exists around a magnet or electrical field. |
| Magneto Hydro Dynamics (Mhd) | A means of producing electricity directly by moving liquids or gases through a magnetic field. |
| Maintenance Free Battery | A sealed battery to which water cannot be added to maintain the level of the electrolyte solution. |
| Maintenance-Free Battery | A sealed battery to which water cannot be added to maintain electrolyte level. |
| Major Natural Gas Producer | any person who produces natural gas in amounts determined by the commission as having a major effect on energy supplies. MAJOR MARKETER |
| Majority Carrier | Current carriers (either free electrons or holes) that are in excess in a specific layer of a semiconductor material (electrons in the n-layer, holes in the p-layer) of a cell. |
| Mantle | the semi-molten interior of the Earth that lies between the core and the crust making up nearly 80% of the Earth’s total volume; extends down to a depth of about 1800 miles (2,900 kilometers) from the surface. |
| Marginal Cost | In the utility context, the cost to the utility of providing the next (marginal)kilowatt-hour of electricity, irrespective of sunk costs. |
| Market Clearing Price | The price at which supply equals demand. The Day Ahead and Hour Ahead Markets. |
| Market Participant | An entity, including a Scheduling Coordinator, who participates in the energy marketplace through the buying, selling, transmission, or distribution of energy or ancillary services into, out of, or through the ISO-controlled grid. |
| Market-Based Price | A price set by the mutual decisions of many buyers and sellers in a competitive market. |
| Marketer | An agent for generation projects who markets power on behalf of the generator.The marketer may also arrange transmission, firming or other ancillary services as needed. Though a marketer may perform many of the same functions as a broker, the difference is that a marketer represents the generator while a broker acts as a middleman. |
| Marsh Gas | A common term for gas that bubbles to the surface of the water in a marsh or swamp. It is colorless, odorless and can be explosive. |
| Master File | A file maintained by the PX for use in bidding and bid evaluation protocol that contains information on generating units, loads, and other resources eligible to bid into the PX. |
| Maximum Power Point | The point on a PV module’s voltage/amperage curve where the product of current and voltage is a maximum (measured in watts). |
| Maximum Power Point (MPP) | Operating a PV array at that voltage will produce maximum power. The point on the current-voltage (I-V) curve of a module under illumination, where the product of current and voltage is maximum. [UL 1703] This corresponds to the point on an I-V curve that represents the largest area rectangle that can be drawn under the curve. For a typical silicon cell panel, this is about 17 volts for a 36 cell configuration. |
| Maximum Power Point Tracker (MPPT) | A power conditioning unit that automatically operates the PV generator at its MPP under all conditions. An MPPT will typically increase power delivered to the system by 10% to 40%, depending on climate conditions and battery state of charge. |
| Maximum Power Point Tracking (Mppt) | Electronically tracking the maximum power point of a PV module to achieve the highest possible output, by (in simplest terms) using surplus voltage to boost amperage. |
| Maximum Power Tracking | Operating a photovoltaic array at the peak power point of the array’s I-V curve where maximum power is obtained. Also called peak power tracking. |
| MCF | One thousand cubic feet or natural gas, having an energy value of one million Btu. A typical home might use six MCF in a month. |
| Mean Power Output (Of A Wind Turbine) | The average power output of a wind energy conversion system at any given mean wind speed. |
| Mean Wind Speed | The average wind speed over a specified time period and height above the ground. |
| Mechanical Energy | the energy an object has because of its motion or position and the forces acting on it. |
| Mechanical System | See HVAC system. |
| Median Wind Speed | The wind speed with 50% probability of occurring. |
| Megawatt | 1,000,000 watts of power or 1,000 kilowatts. |
| Megawatt (MW) | 1,000 kilowatts, or 1 million watts; standard measure of electric power plant generating capacity. |
| Megawatt Hour (MwH) | One thousand kilowatt-hours, or an amount of electricity that would supply the monthly power needs of 1,000 typical homes in the Western U.S. (This is a rounding up to 8,760 kWh/year per home based on an average of 8,549 kWh used per household per year [U.S. DOE EIA, 1997 annual per capita electricity consumtpion figures]). |
| Megawatt-Hour | 1,000 kilowatt-hours or 1 million watt-hours. |
| Megawatt-Hour (MwH) | 1,000 kilowatt-hours or 1 million watt-hours. |
| Met Tower | Meteorological towers erected to verify the wind resource found within a certain area of land. |
| Meter | A device which measures and records the production or consumption of electrical energy. |
| Methane | A light hydrocarbon that is the main component of natural gas and marsh gas. It is the product of the anaerobic decomposition of organic matter, enteric fermentation in animals and is one of the greenhouse gases. Chemical formula is CH4. |
| Methane (Ch4) | the simplest of hydrocarbons and the principal constituent of natural gas. Pure methane has a heating value of 1,1012 Btu per standard cubic foot. |
| Methane Gas | A chemical compound that is a major part of natural gas. |
| Methanol (Also Known As Methyl Alcohol, Wood Alcohol, Ch3oh) |
a liquid formed by catalytically combining carbon monoxide (CO) with hydrogen (H2) in a 1:2 ratio, under high temperature and pressure. Commercially it is typically made by steam reforming natural gas. Also formed in the destructive distillation of wood. |
| Methyl Tertiary Butyl Ether (MTBE) | an ether manufactured by reacting methanol and isobutylene. The resulting ether has a high octane and low volatility. MTBE is a fuel oxygenate and is permitted in unleaded gasoline up to a level of 15 percent. It is one of the primary ingredients in reformulated gasolines. |
| Microburst | A strong localized downdraft from a thunderstorm. Also called a downburst. |
| Microgroove | A small groove scribed into the surface of a cell which may be filled with metal for contacts. |
| Microhydro | Hydro-electric plants producing more than 100 watts and less than 2,000 watts. |
| Micrometer | One millionth of a meter. |
| Microwave | Electromagnetic radiation with wavelengths of a few centimeters. It falls between infrared and radio wavelengths on the electromagnetic spectrum. The radio wave beam can deliver electrical energy over long distances. |
| Mil | One-tenth of one cent $0.001. |
| Milliamps | One Thousandth of an amp. |
| Mineralized | containing minerals; for example, mineralized geothermal water contains dissolved minerals from inside the Earth. |
| Minimum Generation | Generally, the required minimum generation level of a utility systemós thermal units. Specifically, the lowest level of operation of oil-fired and gas-fired units at which they can be currently available to meet peak load needs. |
| Minority Carrier | A current carrier, either an electron or a hole, that is in the minority in a specific layer of a semiconductor material; the diffusion of minority carriers under the action of the cell junction voltage is the current in a photovoltaic device. |
| Minority Carrier Lifetime | The average time a minority carrier exists before recombination. |
| Mistral | A penetrating, stormy, dry and cold wind that blows through the Rhone Valley of France toward the Mediterranean coast. |
| Modified Sine Wave | A waveform that has at least three states (i.e., positive, off, and negative). Has less harmonic content than a square wave. |
| Modularity | The use of complete sub-assemblies to produce a larger system. Also the use of multiple inverters connected in parallel to service different loads. |
| Module | An encapsulated panel containing a number of electrically connected PV cells. |
| Module Derate Factor | A factor that lowers the photovoltaic module current to account for field operating conditions such as dirt accumulation on the module. |
| Module De-Rating Factor | A factor that lowers the power output of a module to account for field operating conditions e.g. Dirt build-up on the module. |
| Molecule | The smallest group of atoms held together by electrostatic forces. |
| Molecules | extremely tiny particles of which all materials are made . |
| Monocrystalline Solar Cell | A form of solar cell made from a thin slice of a single large crystal of silicon. |
| Monolithic | Fabricated as a single structure, as used to describe thin film series interconnected PV cells on a single sheet substrate. |
| Monopoly | The only seller with control over market sales. |
| Monopsony | The only buyer with control over market purchases. |
| Monsoon | Any seasonal wind that blows toward a continent in summer and away from it in winter. |
| Motor | A device that converts electrical energy into mechanical energy. |
| Movistor | Metal Oxide Varistor. Used to protect electronic circuits from surge currents such as those produced by lightning. |
| MTBE (Methyl Tertiary-Butyl Ether) | A clean- burning oxygenate with high octane and low volatility added to unleaded gasoline to reduce carbon monoxide emissions. |
| Mud Pot (Paint Pot) | thermal surface feature which occurs where there is not enough water to support a geyser or hot spring even though there may be some hot water below. Steam and gas vapors bubble up through mud formed by the interaction of gases with rock. |
| Multi-Bladed | More than two blades. |
| Multicrystalline | A material that has solidified at a rate such that many small crystals (crystallites) form. The atoms within a single crystallite are symmetrically arranged with a particular orientation, whereas the crystallites themselves are differently oriented. The multitude of grain boundaries in the material (between the crystallites) reduce the cell efficiency. Multicrystalline is also referred to as polycrystalline. |
| Multicrystalline Cell | See POLYCRYSTALLINE CELL |
| Multijunction Device | A high-efficiency photovoltaic device containing two or more cell junctions, each of which is optimized for a particular part of the solar spectrum. |
| Multi-Junction Device | A PV device containing two or more cell junctions each of which may be different in nature and optimized to absorb a particular part of the solar spectrum in order to achieve higher overall cell efficiency. |
| Multi-Stage Controller | A charge controller that allows different charging currents as the battery approaches full state of charge. |
| Municipal Electric Utility | A power utility system owned and operated by a local jurisdiction. |
| Municipal Solid Waste | Locally collected garbage, which can be processed and burned to produce energy. |
| Municipal Utility | A provider of utility services owned and operated by a municipal government. |
| Municipalization | The process by which a municipal entity assumes responsibility for supplying utility service to its constituents. In supplying electricity, the municipality may generate and distribute the power or purchase wholesale power from other generators and distribute it. |
Links to Energy Maps
|
DSE Energy Glossary
| Nacelle | The cover for the gearbox, drive train, and generator of a wind turbine. |
| Nanohydro | Any hydro plant that produces less than 100 watts. |
| Nasuca | The National Association of Utility Consumer Advocates. NASUCA includes members from 38 states and the District of Columbia. It was formed "to exchange information and take positions on issues affecting utility rates before federal agencies, Congress and the courts. |
| National Electrical Code (Nec) | A document that describes the legal standards for residential and commercial wiring practices with safety as the prime objective. Many U.S. jurisdictions base their wiring inspections on the NEC. |
| National Electrical Manufacturers Association (Nema) |
This organization sets standards for some non-electronic products like junction boxes. |
| National Grid | The sum of all the connected transmission systems and distribution systems within the participating jurisdictions. In Australia it is called the National Electricity Market (NEM). |
| Natural Gas | A colourless gas that can be used as fuel in the generation of electricity, in the production of mechanical energy or in heat. |
| Natural Gas Vehicle | vehicles that are powered by compressed or liquefied natural gas. |
| Natural Gasoline | A mixture of liquids extracted from natural gas and suitable for blending with ordinary oil-derived gasoline. |
| Natural Monopoly | A situation where one firm can produce a given level of output at a lower total cost than can any combination of multiple firms. Natural monopolies occur in industries which exhibit decreasing average long-run costs due to size (economies of scale). According to economic theory, a public monopoly governed by regulation is justified when an industry exhibits natural monopoly characteristics. |
| NEC | See National Electrical Code. |
| Nema | See National Electrical Manufacturers Association. |
| Net Metering | State by state legislation that requires utilities to purchase renewably produced electricity at the same price that they sell it, until a building’s monthly or annual energy use is offset. |
| Neutron | A basic particle that is a little heavier than a proton. It is said to have neutral electrical charge. |
| Newton | The newton [N] is the SI unit of force. One newton is the force required to give a mass of 1 kilogram an acceleration of 1 metre per second per second. It is named after the English mathematician and physicist Sir Isaac Newton (1642-1727). |
| NGV (Natural Gas Vehicle) | vehicles that are powered by compressed or liquefied natural gas. |
| Nickel Cadmium Battery | A battery containing nickel and cadmium plates and an alkaline electrolyte. |
| Nickel-Cadmium Battery | A rechargeable battery high a higher storage densities than that of lead-acid. |
| Nickel-Cadmium Battery (Nicad) | A form of rechargable battery, having higher storage densities than that of lead-acid batteries, that uses a mixture of nickel hydroxide and nickel oxide for the anode, and cadmium metal for the cathode. The electrolyte is potassium hydroxide. |
| Nitrogen Oxides (NOX) | formed in combustion; appear as yellowish-brown clouds; can irritate lungs, cause lung diseases, lead to formation of ozone (which is harmful in the lower atmosphere, but necessary as protection from UV rays in the upper atmosphere). |
| Noise | Unwanted electrical signals produced by electric motors and other machines that can cause circuits and appliances to malfunction. |
| Nominal Voltage | A reference voltage used to describe batteries, modules, or systems (for example, a 12 volt or 24 volt battery, module, or system). |
| Non-Depletable Energy Sources | Energy which is not obtained from depletable energy sources. |
| Non-Firm Energy | Electricity that is not required to be delivered or to be taken under the terms of an electric purchase contract. |
| Non-Renewable Fuels | Fuels that cannot be easily renewed or reproduced, such as oil, natural gas, and coal. |
| Nonrenewable Resource | resources that are not replaced or regenerated naturally within a period of time that is useful; this includes fossil fuels, uranium and other minerals. |
| Nonresidential Building | — any building which is heated or cooled in its interior, and is of an occupancy type other than Type H, I, or J, as defined in the Uniform Building Code, 1973 edition, as adopted by the International Conference of Building Officials. |
| NOPR | A Notice of Proposed Rulemaking. A designation used by the FERC for some of its dockets. |
| Normal Operating Cell Temperature (NOCT) | The estimated temperature of a solar PV module when it is operating under 800 W/m2 irradiance, 20°C ambient temperature and a wind speed of 1 meter per second. NOCT is used to estimate the nominal operating temperature of a module in the field. |
| Northeaster Or Nor’easter | A strong wind blowing across New England from the northeast, typically bringing gales and wet weather. Northeasters can also blow across the Great Lakes. |
| Norther | A winter wind that sweeps across the southern United States and then out over the Gulf of Mexico. It can start in Canada and eventually cover the entire Mississippi Valley. |
| Nosecone | The pointed piece farthest toward the wind on a wind generator, designed primarily for cosmetic purposes, but also protects the blade attachment points and generator from the weather. |
| Notus | The South Wind in Greek mythology. (“Auster” in Latin.) |
| NOX | Oxides of nitrogen that are a chief component of air pollution that can be produced by the burning of fossil fuels. Also called nitrogen oxides. |
| N-Type | Negative semiconductor material in which there are more electrons than holes; current is carried through it by the flow of electrons. |
| N-Type Semiconductor | A semiconductor produced by doping an intrinsic semiconductor with an electron-donor impurity (e.g., phosphorus in silicon). |
| N-Type Silicon | Silicon doped with an element (usually phosphorus) that has more electrons in it’s atomic structure than silicon does. |
| Nuclear Energy | Power obtained by splitting heavy atoms (fission) or joining light atoms (fusion). A nuclear energy plant uses a controlled atomic chain reaction to produce heat. The heat is used to make steam run conventional turbine generators. |
| Nuclear Power | The energy produced by splitting atoms (such as uranium) in a nuclear reactor. |
| Nuclear Regulatory Commission (NRC) | An independent federal agency that ensures that strict standards of public health and safety, environmental quality and national security are adhered to by individuals and organizations possessing and using radioactive materials. The NRC is the agency that is mandated with licensing and regulating nuclear power plants in the United States. It was formally established in 1975 after its predecessor, the Atomic Energy Commission, was abolished. |
| NUG | A non-utility generator. A generation facility owned and operated by an entity who is not defined as a utility in that jurisdictional area. |
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. |
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
| 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
| 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. |