Glossary of electric industry, energy & cooperative terms

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Easement
An agreement allowing a utility to use property belonging to another individual or organization for a specific purpose, such as building a transmission line.

Eaves
The margin or lower part of a roof projection over a wall.

EER
See Energy Efficiency Ratio. Used to evaluate the efficiency of air conditioners. The EER ranges from 4.5 to 15.0; the higher the EER, the better.

Efficiency
Making maximum use of a resource. Requires less sacrifice than conservation, but stresses getting the most benefit out of each unit of a resource used.

Electric and Magnetic Fields (EMF)
When energy flows through an energized conductor two types of fields are created: electric and magnetic. The electric field is created by the voltage impressed on the conductors. The magnetic field is created by current in the conductors. Electric and magnetic fields surround the conductors. Electric and magnetic fields are frequently pictured as "lines of force" emanating in the vicinity of the transmission line. Electric fields are measured in units of volts per meter (v/m) or kilovolts per meter (kv/m). Magnetic fields are measured in units called gauss (G) or tesla (T). One gauss is equal to 10,000 tesla. Transmission line electric and magnetic fields are not constant or "static" fields. The fields created by alternating current (AC) voltages cycle above and below zero at the power frequency. North American AC power lines operate at 60 cycles per second (noted as Hertz or Hz). Voltage, current, and electric and magnetic fields each alternate at this frequency.

Electric Distribution
The delivery of electric energy o customers on the distribution system. Electric energy is carried at high voltages along transmission lines. For consumers needing lower voltages, it is reduced in voltage and delivered over primary distribution lines extending throughout the area where the electricity is distributed. For users needing even lower voltages, the voltage is reduced once again by a distribution transformer or a line transformer. At this point it changes from primary to secondary distribution voltage. The distribution system consists of all the primary distribution lines, distribution transformers, secondary distribution lines and services. Voltages in the distribution system range from 120 to 50,000 volts and link directly to the customer’s meter. In addition to transformers for reducing voltage, distribution systems include regulating and protective equipment to help ensure steady and safe operation of electrical equipment. The size of a distribution system generally need not be designed to meet the highest coincident peak demand on a utility’s electrical system. Rather, the size depends on the peak of the customer or customer class that it serves.

Electric Generator
Any device that converts one form of energy (Mechanical, chemical or heat) into electric energy. The following description discusses a mechanical generator that relies on rotational motion to produce electric energy. The process is based on the relative motion of an electric conductor and a magnetic field. When an electrically conductive material moves across a magnetic field, an electric current is set in motion as the oppositely charged particles move toward each other. The conductor can move with respect to a stationary field or the field can move with respect to a stationary conductor. Electric utilities use large generators with stationary conductors. A magnet, attached to the end of a rotating shaft turned by mechanical energy, is positioned inside a stationary ring that is wrapped with a long, continuous piece of wire. When the magnet rotates, it induces a small electric current in each section of wire as it passes by. For the magnet’s purposes, each section of wire constitutes a small, separate electric conductor. However, the individual sections actually make up one long loop of wire, and all the small currents add up to one current of considerable size. If the loop of wire is closed by connecting the ends through an external load such as a light bulb or electric motor, the induced voltage will cause an electric current to flow through the loop and to the load, thus lighting the bulb or driving the motor.

Electric Generation
The generation of electricity o a large scale is a very complex technology that requires sophisticated equipment. But the basic process of electrical production is simple. The heart of an electric generating station, call the "power block," has only three major components: the boiler, the steam turbine and the generator. To produce electricity, fuel is first burned to heat up water and produce steam inside of a boiler. Next, the pressurized steam is used t drive the blades of a turbine, which is a large motor. The turbine then rotates a generator, which includes a large electromagnet spinning inside a major grouping of wire coils, to create electric current.

In a steam generating plant, such as Florida’s coal- and oil-burning units, fuel is burned in the combustion chamber of the boiler. The resulting fire heats water in the boiler tubes, producing steam. The steam forms at a very high heat and pressure – typically 1,000 degrees Fahrenheit and 2,400 pounds per square inch. A nuclear plant differs from other steam-generating stations only in the nature of the heat source. The heat source in a nuclear plant is the nuclear reactor, a device that generates heat through nuclear fission, or the splitting of atoms. This head also creates steam, so the rest of the generation process is the same. In practice, the production of electric power involves much more complex systems than our brief description suggests. Yet, this simple discussion accurately reflects the principle.

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 Generation
The large-scale production of electricity in a central plant. A power plant consists of one or more units. Each unit includes an individual turbine generator. Turbine generators – turbines directly connected to electric generators -- use steam, wind, hot gas or falling water to generate power. Florida’s power plants generated over 103 billion kilowatt hours (kwh) of electric power in 1986, while purchasing 14 billion kwh from other generation sources.

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 oversite authority.

Electric Service Provider
An entity that provides electric service to a retail or end-use customer.

Electric Thermal Storage (ETS)
A type of heater that uses electricity during periods of low use to heat a ceramic material in an insulated cabinet to high temperatures, then releases the stored heat when electric use is high.

Electric Transmission
The process of moving bulk electric energy from generating sources to load centers or other principal parts of an electric system. A transmission system includes all high-voltage lines, both overhead and underground that carry electric energy ranging from 69 kilovolts (kv) to 765 kv. The largest transmission lines in Florida are 500 kv. Motors or appliances cannot use electricity at thigh transmission voltages, so the voltages must eventually be reduced and delivered to a distribution system. However, electricity can be delivered directly to customers at transmission voltages – that is, 69 kv or above – as part of an arrangement known as transmission service. Such customers usually have demands of 5,000 kilowatts or greater and must supply and maintain their own transformers to reduce the transmission voltage to that of their own system.

Electric Utilities
Enterprises engaged in the generation, transmission and distribution of electricity to end-use customers. Electric utilities are often categorized based on ownership, including investor and cooperatively owned electric utilities, as well as government-owned electric utilities such as municipal systems, federal agencies, state projects and public power districts. 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 co-generators or small power producers under the Public Utility Regulatory Policies Act (PURPA) are not considered electric utilities.

Electricity
Electric current or power that results from the movement of electrons in a conductor from a negatively charged point to a positively charged point. The class of physical phenomena arising from the existence and interactions of an electric charge. Electric energy results from the movement of parts of atoms comprised of protons (positively charged), neutrons (uncharged) and orbiting electrons (negatively charged).

The attractive force between positively charged protons and negatively charged electrons holds the atom together. An atom that has become charged by losing an electron is positively charges; one that gains an extra electron is negatively charged. Like water behind a dam, a charged atom has potential electric energy through its position in an electric field. This potential electric energy is called voltage. Devices such as generators and batteries create voltage by polarizing ions into positive and negative accumulations. And, like water that becomes kinetic energy when it flows over a dam. Voltage can produce electric current when the two groups of oppositely charged particles are connected with a conductive material, most often metal wire. For example, in a battery the positive charges are gathered on an electrode or terminal, and the negative charges are gathered at the other. When a conductor connects these electrodes, a circuit is formed. The negatively charged electrons, seeking their opposites, migrate from the negative electrode toward the positive electrode. This flow of electrons constitutes electricity.

Electronic Meter Reading
A system that used a hand-held computer to record and store electric-use information from consumers’ meters, then transmits that information to a central computer that prepares bills.

Electrostatic Precipitator
A device for collecting particulate material from waste gases such as those released by coal-fuel powered stations. The basic principle of operation is based on the fact that particulates, moving through a region of high electrostatic potential, tend to become charged and are then attracted to an oppositely charged electrode when they can be collected and removed.

Embedded Cost
Funds already expended for investment in plant and operating expenses (i.e. a utility's historic average costs as shown on its books, in contrast to its "marginal cost," which is the change in costs caused by the production of each additional unit of electricity).

Eminent Domain
The right of the government – local, state or federal – to authorize the taking of private property at a fair price for projects that benefit the public good.

Energy
The work that is physical system is capable of doing in changing from its actual state to a specified reference state, the total including, in general, contributions of fossil fuels, geothermal energy, hydropower energy, kinetic energy, nuclear energy, potential energy, solar energy, thermal energy, wind energy.

Energy Audit
An audit of residential or commercial/industrial dwellings to show energy users how to cut down on the use of energy and save money.

Energy Broker
A mechanism for marketing non-firm electric energy among electric utilities that have sufficient generating capacity to meet their individual loads. This accomplished generally by a shared computer program/communication system. Every hour it matches potential sellers of electric energy with potential buyers. Successfully working for 16 municipal, one cooperative and three investor-owned electric utilities in Florida, energy brokering saves Florida consumers millions of dollars in fuel costs each year by coordinating the buying and selling of energy.

Under this voluntary system, participating utilities enter buy or sell bids into the Broker. The bid (or cost of the energy) is based upon the incremental costs (the additional production expense incurred to increase generation to meet demand) or decremental costs (the operation costs avoided by decreasing generation that is not necessary to meet demand). A utility dispatcher reviews these costs to determine whether the best economic decision is to change internal generation or buy or sell energy with another utility.

The Broker matches the utility with the highest buy bid to the utility with the lowest sell bid. The matching process continues in descending order (second highest to second lowest, etc.). The price at which the energy is exchanged is a midpoint between the two bids. For example, if the buy bid is $30/MW and the sell bid is $10/MW, the price at which the energy is sold is $20/MW. The buyer has the additional energy it needs at a price lower that that at which it could have generated the power internally, and the seller makes a profit on its energy. The customers are the direct beneficiaries. The buyer passes on fuel cost savings to the customer and the seller can use profits to keep costs down for its customers.

Energy Charge
Any method of rate charged for electric service based upon the amount of kilowatt-hours consumed. This is one component of a customer’s energy bill, along with the customer charge and the demand charge. This charge recovers operating costs, including the costs of fuel used to generate electricity. It varies with the number of kilowatt-hours consumed. Energy charges can also be called commodity charges.

Energy Deliveries
Energy generated by one electric utility system and delivered to another system through one or more transmission lines.

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 megawatt-hours), 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 Rating (EER)
A numerical indicator of relative efficient energy usage among appliances. EER is determined by dividing the BTU per hour output by the number of watts used. The higher the EER, the greater is the efficiency.

Energy Receipts
Energy generated by one electric utility system and received by another system through one or more transmission lines.

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 Policy Act of 1992 (EPACT)
Federal legislation enacted in 1992 that removed restrictions on ownership of electric generation facilities and limitations on access to long-distance transmission of wholesale electric power by independent power producers. It paved the way for a major expansion of the power industry by creating a new class of independent power facilities called Exempt Wholesale Generators, which are not subject to restrictive regulations under the Public Utility Holding Company Act of 1935.

Environmental Impact Statement
A report required by many state and federal regulators that outlines the likely environmental consequences of building and operating large-scale facilities such as power plants.

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Page last updated: Friday, March 5, 2010