Glossary of Terms - E

• Earth-Coupled Ground Source (Geothermal) Heat Pump - A type of heat pump that uses sealed horizontal or vertical pipes, buried in the ground, as heat exchangers through which a fluid is circulated to transfer heat.
• East Central Area Reliability Coordination Agreement (ECAR) - One of the ten regional reliability councils that make up the North American Electric Reliability Council (NERC).
• Economic Dispatch - The distribution of total generation requirements among alternative sources for optimum system economy with consideration to both incremental generating costs and incremental transmission losses.
• 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).
• Economizer - A heat exchanger for recovering heat from flue gases for heating water or air.
• Economy Energy - Energy produced and substituted for the traditional but less economical source of energy. Economic energy is usually sold without capacity and is priced at variable costs plus administration costs.
• Edge-Defined Film-Fed Growth (EFG) - A method for making sheets of polycrystalline silicon (for solar photovoltaic devices) in which molten silicon is drawn upward by capillary action through a mold.
• Effective Capacity - The maximum load that a device is capable of carrying.
• Efficacy - The amount of energy service or useful energy delivered per unit of energy input. Often used in reference to lighting systems, where the visible light output of a luminary is relative to power input; expressed in lumens per Watt; the higher the efficacy value, the higher the energy efficiency.
• Efficiency - Under the First Law of Thermodynamics, efficiency is the ratio of work or energy output to work or energy input, and cannot exceed 100 percent. Efficiency under the Second Law of Thermodynamics is determined by the ratio of the theoretical minimum energy that is required to accomplish a task relative to the energy actually consumed to accomplish the task. Generally, the measured efficiency of a device, as defined by the First Law, will be higher than that defined by the Second Law.
• Efficiency Service Company - A company that offers to reduce a client's electricity consumption with the cost savings being split with the client.
• EFP - See Exchange of Futures for Physicals.
• Elasticity of Demand - The ratio of the percentage change in the quantity demanded of a good to the percentage change in price.
• Electric Capacity - This refers to the ability of a power plant to produce a given output of electric energy at an instant in time, measured in kilowatts or megawatts (1,000 kilowatts).
• Electric Circuit - The path followed by electrons from a generation source, through an electrical system, and returning to the source.
• Electric Distribution Company - The company that owns the power lines and equipment necessary to deliver purchased electricity to the customer.
• Electric Energy - The amount of work accomplished by electrical power, usually measured in kilowatt-hours (kWh). One kWh is 1,000 Watts and is equal to 3,413 Btu.
• Electric Furnace - An air heater in which air is blown over electric resistance heating coils.
• Electric Plant (Physical) - A facility containing prime movers, electric generators, and auxiliary equipment for converting mechanical, chemical, and/or fission energy into electric energy.
• Electric Power Plant - A facility or piece of equipment that produces electricity.
• Electric Power Supplier - Non-utility provider of electricity to a competitive marketplace.
• Electric Power Transmission - The transmission of electricity through power lines.
• Electric Rate - The unit price and quantity to which it applies as specified in a rate schedule or contract.
• Electric Rate Schedule - A statement of the electric rate and the terms and conditions governing its application, including attendant contract terms and conditions that have been accepted by a regulatory body with appropriate oversight authority.
• Electric Reliability Council of Texas (ERCOT) - One of the ten regional reliability councils that make up the North American Electric Reliability Council (NERC).
• Electric Resistance Heating - A type of heating system where heat, resulting when electric current flows through an "element" or conductor, such as Nichrome, which has a high resistance, is radiated to a room.
• Electric System - This term refers to all of the elements needed to distribute electrical power. It includes overhead and underground lines, poles, transformers, and other equipment.
• Electric System Loss(es) - The total amount of electric energy loss in an electric system between the generation source and points of delivery.
• Electric Utility - A corporation, person, agency, authority, or other legal entity or instrumentality that owns and/or operates facilities within the United States, its territories, or Puerto Rico for the generation, transmission, distribution, or sale of electric energy primarily for use by the public and files forms listed in the Code of Federal Regulations, Title 18, Part 141. Facilities that qualify as cogenerators or small power producers under the Public Utility Regulatory Policies Act (PURPA) are not considered electric utilities.
• Electric Utility Affiliate - This refers to a subsidiary or affiliate of an electric utility. Many utilities form affiliates to develop, own, and operate independent power facilities.
• Electric Utility Sector - Those privately or publicly owned establishments that generate, transmit, distribute, or sell electricity.
• Electric Vehicles - A battery-powered electrically driven vehicle.
• Electric Wholesale Generator - A power producer who sells power at cost to a customer.
• Electrical Charge - A condition that results from an imbalance between the number of protons and the number of electrons in a substance.
• Electrical Energy - The energy of moving electrons.
• Electrical Grid - An integrated system of electricity distribution, usually covering a large area.
• Electrical System - All the conductors and electricity using devices that are connected to a source of electromotive force (or generator).
• Electrical System Energy Losses - A measure of the amount of energy lost during the generation, transmission, and distribution of electricity.
• Electricity Generation - The process of producing electricity by transforming other forms or sources of energy into electrical energy; measured in kilowatt-hours.
• 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 - A conductor that is brought in conducting contact with a ground.
• Electrodeposition - Electrolytic process in which a metal is deposited at the cathode from a solution of its ions.
• Electrolysis - A chemical change in a substance that results from the passage of an electric current through an electrolyte. The production of commercial hydrogen by separating the elements of water, hydrogen, and oxygen, by charging the water with an electrical current.
• Electrolyte - A nonmetallic (liquid or solid) conductor that carries current by the movement of ions (instead of electrons) with the liberation of matter at the electrodes of an electrochemical cell.
• Electromagnetic Energy - Energy generated from an electromagnetic field produced by an electric current flowing through a superconducting wire kept at a specific low temperature.
• Electromagnetic Field (EMF) - The electrical and magnetic fields created by the presence or flow of electricity in an electrical conductor or electricity consuming appliance or motor.
• Electromotive Force - The amount of energy derived from an electrical source per unit quantity of electricity passing through the source.
• Electron - An elementary particle of an atom with a negative electrical charge and a mass of 1/1837 of a proton; electrons surround the positively charged nucleus of an atom and determine the chemical properties of an atom.
• Electron Volt - 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^-12; a unit of energy or work; abbreviated as eV.
• Electronic Ballast - A device that uses electronic components to regulate the voltage of fluorescent lamps.
• Electrostatic Precipitator - A device used to remove particulate matter from the waste gasses of a combustion power plant.
• Ellipsoidal Reflector Lamp - A lamp where the light beam is focused 2 inches ahead of the lamp reducing the amount of light trapped in the fixture.
• Embedded Cost - A utility's average cost of doing business, which includes the costs of fuel, personnel, plants, poles, and wires.
• Emission Factor - A measure of the average amount of a specified pollutant or material emitted for a specific type of fuel or process.
• Emission(s) - A substance(s) or pollutant emitted as a result of a process.
• Emissivity - The ratio of the radiant energy (heat) leaving (being emitted by) a surface to that of a black body at the same temperature and with the same area; expressed as a number between 0 and 1.
• Endothermic - A heat absorbing reaction or a reaction that requires heat.
• End-Use - The specific purpose for which electric is consumed (I.e. heating, cooling, cooking, etc.).
• End-User - The ultimate consumer of petroleum products or natural gas; most commonly refers to large commercial, industrial, or utility consumers.
• Energize(d) - To send electricity through a electricity transmission and distribution network; a conductor or power line that is carrying current.
• Energy - The capacity for doing work as measured by the capability of doing work (potential energy) or the conversion of this capability to motion (kinetic energy). Energy has several forms, some of which are easily convertible and can be changed to another form useful for work. Most of the worldÌs convertible energy comes from fossil fuels that are burned to produce heat that is then used as a transfer medium to mechanical or other means in order to accomplish tasks. Electrical energy is usually measured in kilowatt-hours, while heat energy is usually measured in British thermal units.
• Energy Audit - A survey that shows how much energy you use in your house or apartment. It will help you find ways to use less energy.
• Energy Charge - That portion of the charge for electric service based upon the electric energy (kWh) consumed or billed.
• 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 Costs - Costs, such as for fuel, that are related to and vary with energy production or consumption.
• Energy Crops - Crops grown specifically for their fuel value. These include food crops such as corn and sugarcane, and nonfood crops such as poplar trees and switchgrass. Currently, two energy crops are under development: short-rotation woody crops, which are fast-growing hardwood trees harvested in 5 to 8 years; and herbaceous energy crops, such as perennial grasses, which are harvested annually after taking 2 to 3 years to reach full productivity.
• Energy Deliveries - Energy generated by one electric utility system and delivered to another system through one or more transmission lines.
• Energy Density - The ratio of energy available from a battery to its volume (Wh/1) or mass (Wh/kg).
• Energy Effect - The changes in aggregate electricity use (measured in megawatthours) for customers that participate in a utility DSM program. Energy Effects should represent changes at the consumer meter (i.e., exclude transmission and distribution effects) and reflect only activities that are undertaken specifically in response to utility-administered programs, including those activities implemented by third parties under contract to the utility. To the extent possible, Energy Effects should exclude non-program related effects such as changes in energy usage attributable to nonparticipants, government-mandated energy efficiency standards that legislate improvements in building and appliance energy usage, changes in consumer behavior that result in greater energy use after initiation in a DSM program, the natural operations of the marketplace, and weather and business cycle adjustments.
• Energy Efficiency - Refers to programs that are aimed at reducing the energy used by specific end-use devices and systems, typically without affecting the services provided. These programs reduce overall electricity consumption (reported in megawatthours), often without explicit consideration for the timing of program-induced savings. Such savings are generally achieved by substituting technically more advanced equipment to produce the same level of end-use services (e.g. lighting, heating, motor drive) with less electricity. Examples include high-efficiency appliances, efficient lighting programs, high-efficiency heating, ventilating and air conditioning (HVAC) systems or control modifications, efficient building design, advanced electric motor drives, and heat recovery systems.
• Energy Efficiency Ratio (EER) - The measure of the instantaneous energy efficiency of room air conditioners; the cooling capacity in Btu/hr divided by the watts of power consumed at a specific outdoor temperature (usually 95 degrees Fahrenheit).
• Energy Efficient Mortgages - A type of home mortgage that takes into account the energy savings of a home that has cost-effective energy saving improvements that will reduce energy costs thereby allowing the homeowner to more income to the mortgage payment. A borrower can qualify for a larger loan amount than otherwise would be possible.
• Energy End-Use Sectors - Major energy consuming sectors of the economy. The Commercial Sector includes commercial buildings and private companies. The Industrial Sector includes manufacturers and processors. The Residential Sector includes private homes. The Transportation Sector includes automobiles, trucks, rail, ships, and aircraft.
• Energy Factor (EF) - The measure of overall efficiency for a variety of appliances. For water heaters, the energy factor is based on three factors: 1) the recovery efficiency, or how efficiently the heat from the energy source is transferred to the water; 2) standby losses, or the percentage of heat lost per hour from the stored water compared to the content of the water: and 3) cycling losses. For dishwashers, the energy factor is defined as the number of cycles per kWh of input power. For clothes washers, the energy factor is defined as the cubic foot capacity per kWh of input power per cycle. For clothes dryers, the energy factor is defined as the number of pounds of clothes dried per kWh of power consumed.
• Energy Guide Labels - The labels placed on appliances to enable consumers to compare appliance energy efficiency and energy consumption under specified test conditions as required by the Federal Trade Commission.
• Energy Intensity - The relative extent that energy is required for a process.
• Energy Levels - The energy represented by an electron in the band model of a substance.
• Energy Policy Act of 1992 - (EPAct) - A comprehensive legislative package that mandates and encourages energy efficiency standards, alternative fuel use, and the development of renewable energy technologies. Public Law 102-486, October 24th, 1992. Also authorized the Federal Energy Regulatory Commission (FERC) to order the owners of electric power transmission lines to transmit or "wheel" power for power generators including electric utilities, federal power marketing authorities, and exempt wholesale generators. This act which was the first comprehensive federal energy law promulgated in more than a decade will help create a more competitive U.S. electric power marketplace by removing barriers to competition. By doing so, this act allows a broad spectrum of independent energy producers to compete in wholesale electric power markets. The act also made significant changes in the way power transmission grids are regulated. Specifically, the law gives the Federal Energy Regulatory Commission the authority to order electric utilities to provide access to their transmission facilities to other power suppliers.
• Energy Receipts - Energy generated by one electric utility system and received by another system through one or more transmission lines.
• Energy Reserves - The portion of total energy resources that is known and can be recovered with presently available technology at an affordable cost.
• Energy Resources - Everything that could be used by society as a source of energy.
• Energy Security Act of 1980 - Legislation authorizing a U.S. biomass and alcohol fuel program, and that authorized loan guarantees and price guarantees and purchase agreements for alcohol fuel production.
• Energy Services Companies (ESCOs) - ESCOs would be created in a deregulated, openly competitive electric marketplace. The Energy Services industry would be made up of power aggregators, power marketers and brokers, whose job is to match buyers and sellers, tailor both physical and financial instruments to suit the needs of particular customers, and to allow even the smallest residential customers to form buying groups or cooperatives that will give them the same bargaining power as large industrial customers.
• Energy Source - The primary source that provides the power that is converted to electricity through chemical, mechanical, or other means. Energy sources include coal, petroleum and petroleum products, gas, water, uranium, wind, sunlight, geothermal, and other sources.
• Energy Storage - The process of storing, or converting energy from one form to another, for later use; storage devices and systems include batteries, conventional and pumped storage hydroelectric, flywheels, compressed gas, and thermal mass.
• Energy Use -Energy consumed during a specified time period for a specific purpose (usually expressed in kWh).
• Enthalpy - A thermodynamic property of a substance, defined as the sum of its internal energy plus the pressure of the substance times its volume, divided by the mechanical equivalent of heat. The total heat content of air; the sum of the enthalpies of dry air and water vapor, per unit weight of dry air; measured in Btu per pound (or calories per kilogram).
• Entitlement - Electric energy or generating capacity that a utility has a right to access under power exchange or sales agreements.
• Entrained Bed Gasifier - A gasifier in which the feedstock (fuel) is suspended by the movement of gas to move it through the gasifier.
• Entrance Cable/Service Entrance Conductor - This is the cable running down the side of a customer's house into the meter. This cable is owned by the customer and its maintenance is the customer's responsibility. Work on this cable should be performed only by a licensed electrician.
• Entropy - A measure of the unavailable or unusable energy in a system; energy that cannot be converted to another form.
• Environmental Attributes - Environmental attributes quantity the impact of various options on the environment. These attributes include particulate emissions, SO2 or Nox, and thermal discharge (air and water).
• Epitaxial Growth - In reference to solar photovoltaic devices, 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.
• Equity Capital - The sum of capital from retained earnings and the issuance of stocks.
• ERCOT - Electric Reliability Council of Texas
• Erg - A unit of work done by the force of one dyne acting through a distance of one centimeter.
• Escape Provision - A contract provision which allows a party, such as an electric customer, to get out of it. Usually, there is a penalty.
• Ethanol - Ethyl alcohol (C2H5OH) - A colorless liquid that is the product of fermentation used in alcoholic beverages, industrial processes, and as a fuel additive. Also known as grain alcohol.
• Ethyl Tertiary Butyl Ether (ETBE) - A chemical compound produced in a reaction between ethanol and isobutylene (a petroleum-derived by-product of the refining process). ETBE has characteristics superior to other ethers: low volatility, low water solubility, high octane value, and a large reduction in carbon monoxide and hydrocarbon emissions.
• European Option - An option that may be exercised only on its expiration date.
• Eutectic - A mixture of substances that has a melting point lower than that of any mixture of the same substances in other proportions.
• Eutectic Salts - Salt mixtures with potential applications as solar thermal energy storage materials.
• Evacuated Tube Collector - A solar collector in which the absorber is contained in a sealed glass tube, thereby providing for relatively high temperature heat gain.
• Evaporative Cooling - The physical process by which a liquid or solid is transformed into the gaseous state. For this process a mechanical device uses the outside air's heat to evaporate water that is held by pads inside the cooler. The heat is drawn out of the air through this process and the cooled air is blown into the home by the cooler's fan.
• Evaporator Coil - The inner coil in a heat pump that, during the cooling mode, absorbs heat from the inside air and boils the liquid refrigerant to a vapor, which cools the house.
• Exchange Certified Stocks - Stocks of commodities held in depositories or warehouses certified by an Exchange-approved inspection authority as constituting good delivery against a futures contract position. Current total certified stocks are reported in the press for many important commodities such as platinum.
• Exchange of Futures for Cash - A transaction in which the buyer of a cash commodity transfers to the seller a corresponding amount of long futures contracts, or receives from the seller a corresponding amount of short futures, at a price difference mutually agreed upon. In this way, the opposite hedges in futures of both parties are closed out simultaneously.
• Exchange of Futures for Physicals - A futures contract provision involving an agreement for delivery of physical product that does not necessarily conform to contract specifications in all terms from one market participant to another and a concomitant assumption of equal and opposite futures positions by the same participants at the time of the agreement.
• Excitation - The power required to energize the magnetic field of a generator.
• Exempt Wholesale Generator (EWG) - An EWG is a category of power producer defined by the Energy Policy Act of 1992. EWG's are independent power facilities that generate electricity for sale in wholesale power markets at market-based rates. The Federal Energy Regulatory Commission is responsible for determining EWG status.
• Exercise - The process of converting an options contract into a futures position.
• Exercise Price - The price at which the underlying futures contract will be bought or sold in the event an option is exercised. Also called the strike price.
• Exothermic - A reaction or process that produces heat; a combustion reaction.
• Expanded Polystyrene - A type of insulation that is molded or expanded to produce coarse, closed cells containing air. The rigid cellular structure provides thermal and acoustical insulation, strength with low weight, and coverage with few heat loss paths. Often used to insulate the interior of masonry basement walls.
• Expansion Tank - A tank used in a closed-loop solar heating system that provides space for the expansion of the heat transfer fluid in the pressurized collector loop.
• Expansion Valve - The device that reduces the pressure of liquid refrigerant thereby cooling it before it enters the evaporator coil in a heat pump.
• Expenditure - The incurrence of a liability to obtain an asset or service.
• Expiration Date - The date and time after which trading in an options contracts terminates, and after which all contract rights or obligations become null and void.
• External Combustion Engine - An engine in which fuel is burned (or heat is applied) to the outside of a cylinder; a Stirling engine.
• Externality - The environmental, social, and economic impacts of producing a good or service that are not directly reflected in the market price of the good or service.
• Extrinsic Semiconductor - The product of doping a pure semiconductor.
• Extrinsic Value - The amount by which the premium exceeds its intrinsic value. Also known as time value.
• Extruded Polystyrene - A type of insulation material with fine, closed cells, containing a mixture of air and refrigerant gas. This insulation has a high R-value, good moisture resistance, and high structural strength compared to other rigid insulation materials.