Ampere (amp) – The measure of the number of electrons flowing past a given point in an electrical conductor in a given amount of time; this is the electrical current.
Biofuels – Alcohols, ethers, esters, and other chemicals made from raw biological material such as herbaceous and woody plants, agricultural and forestry residues, and a large portion of municipal solid and industrial waste.
Biomass-Organic waste from agricultural, livestock, and lumber industry products, dead trees, foliage, etc., and is considered a renewable energy source. Biomass can be used as fuel and is most often burned to create steam that powers steam turbine generators. It is also used to make transportation fuels like ethanol and biodiesel, and chemicals like pyrolysis oil that can be burned like oil to produce energy.
Bottleneck Facility- point on the electric system, such as a transmission line, through which all electricity must pass to get to its intended buyers. If there is limited capacity at this point, some priorities must be developed to decide whose power gets through. It also must be decided if the owner of the bottleneck may, or must, build additional facilities to relieve the constraint.
Bulk Power Supply-Often this term is used interchangeably with wholesale power supply. In broader terms, it refers to the aggregate of electric generating plants, transmission lines, and related-equipment. The term may refer to those facilities within one electric utility, or within a group of utilities in which the transmission lines are interconnected.
C-BED (Community-Based Energy Development)-C-BED works toward renewable energy development in a way that optimizes local economic development and environmental benefits.
Co-generation- also Combined Heat and Power- Production of electricity from steam, heat, or other forms of energy produced as a by-product of another process.
Combined Cycle- An electric generating technology in which electricity and process steam is produced from otherwise lost waste heat exiting from one or more combustion turbines. The exiting heat is routed to a conventional boiler or to a heat recovery steam generator for use by a steam turbine in the production of electricity. This process increases the efficiency of the electric generating unit.
Commodity Price -The portion of a natural gas sales or transportation rate based upon the volume actually shipped or used.
Cooperative electric association or utility – utility owned and operated by its members.
Demand-The rate at which electric energy is delivered to or by a system or part of a system, generally expressed in kilowatts (kW), megawatts (MW), or gigawatts (GW), at a given instant or averaged over any designated interval of time. Demand should not be confused with Load or Energy.
Demand Charge – A fee based on the peak amount of electricity used during the billing cycle.
Deregulation-The elimination or restructuring of regulation from a previously regulated industry or sector of an industry.
Distributed Generation (DG)— (Also called distributed energy resources, distributed power, distributed energy, distributed generation, on-site generation) Both electric demand reduction (energy conservation, load management, etc.) and supply generated at or near where the power is used. A distributed generation system involves amounts of generation located on a utility’s distribution system for the purpose of meeting local (substation level) peak loads and/or displacing the need to build additional (or upgrade) local distribution lines.
Distribution – The delivery of electricity to the retail customer’s home or business through low voltage distribution lines.
DSM – Demand Side Management – Programs to influence the amount or timing of customers’ energy use.
Economies of Scale—Economies of scale exist where the industry exhibits decreasing average long run costs with increases in size.
Electric Energy—The generation or use of electric power by a device over a period of time, expressed in kilowatt-hours (kWh), megawatt-hours (MWh), or gigawatt-hours (GWh).
Electric System Losses—Total electric energy losses in the electric system. Losses are primarily due to electric resistance within transmission system lines and transformers.
Energy Conservation—Using less energy, either by greater energy efficiency or by decreasing the types of applications requiring electricity or natural gas to operate.
Energy Efficiency—Using less energy (electricity and/or natural gas) to perform the same function at the same level of quality. Programs designed to use energy more efficiently — doing the same with less.
EPBB – Expected Performance-Based Buy-Down – EPBB is a type of up-front incentive based on an estimate of your solar system’s expected performance. The performance estimate is based on system size, geographic location, orientation at time of application. Widespread in US and EU.
Gigawatt-hour (GWh)—The unit of energy equal to that expended in one hour at a rate of one billion watts. One GWh equals 1,000 megawatt-hours.
Greenhouse gases—Greenhouse gases are water vapor, carbon dioxide, tropospheric ozone, nitrous oxide, methane, and chlorofluorocarbons (CFCs).
Grid—A system of interconnected power lines and generators that is managed so that power from generators is dispatched as needed to meet the requirements of the customers connected to the grid at various points.
Independent System Operator (ISO)- A neutral and independent organization with no financial interest in generating facilities that administers the operation and use of the transmission system. ISOs exercise final authority over the dispatch of electricity from generators to customers to preserve reliability and facilitate efficiency, ensure non-discriminatory access, administer transmission tariffs, ensure the availability of ancillary services, and provide information about the status of the transmission system and available transmission capacity. An ISO may make some transmission investment decisions.
Interconnected System—A system consisting of two or more individual electric systems that have connecting tie lines and whose operations are synchronized.
Inverter – A device that changes direct current (DC) into alternating current (AC). Direct current is created by photovoltaic modules or batteries and converted to AC through the use of an inverter.
KV—A kilovolt equals 1,000 volts.
Kilowatt (kW)—This is a measure of demand for power. The rate at which electricity is used during a defined period (usually metered over 15-minute intervals). Utility customers generally are billed on a monthly basis; therefore, the kW demand for a given month would be the 15- minute period in which the most power is consumed. Customers may be charged a fee (demand charge) based on the peak amount of electricity used during the billing cycle. (Residential customers are generally not levied a demand charge.)
Kilowatt-hour (kWh)—This is a measure of consumption. It is the amount of electricity that is used over some period of time, typically a one-month period for billing purposes. Customers are charged a rate per kWh of electricity used.
Load Center or Load Pocket—A geographical area where large amounts of power are drawn by end-users.
Long Range Planning—The process of forecasting long term loads, determining a reasonable set of potential resources to meet these loads (including reduction of loads through energy efficiency), analyzing the costs (sometimes including externality costs) of several possible mixes of such resources, and identifying the resources to be secured to meet such future needs.
MVA—A megavolt-ampere equals 1,000 kVA.
Megawatt (MW)—A megawatt equals 1,000 kilowatts or 1 million watts.
Megawatt-hour (MWh)—The unit of energy equal to that expended in one hour at a rate of one million watts.
Monopoly—The only seller with control over market sales.
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 that 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.
Obligation to Serve—The obligation of a utility to provide nondiscriminatory electric service to any customer who seeks that service, and is willing to pay the rates set for that service. By law, utilities have the obligation to serve in return for exclusive service territories.
Peak Load or Peak Demand—The electric load that corresponds to a maximum level of electric demand within a specified time period, usually a year.
Power Purchase Agreement (PPA)—A financing option for residential solar in which a solar company owns (and installs, monitors, maintains) your solar panels; you pay for electricity. With PPAs, you avoid the high upfront costs of installing solar and pay a monthly rate that depends on how much energy your panels produce. Popular in US and old EU.
Power Pool—Two or more interconnected electric systems planned and operated to supply power for their combined demand requirements.
Public Good—A good (or a service) that will not be produced and delivered solely by the free market. Economists call these “public goods” because the public consumes them, but they do not solely benefit a single buyer or group of buyers. There is no way to produce a public good without producing a value to society at large. It is unlikely that an individual would pay out of his or her own pocket to ensure that a public good is produced because the value is not exclusively individual.
RDF—Refuse derived fuel, composed of processed garbage, that is used in some electric generation plants.
Real time Pricing—The instantaneous pricing of electricity based on the cost of the electricity available for use at the time the electricity is demanded by the customer.
Reliability- Electric system reliability has two components —adequacy and security. Adequacy is the ability of the electric system to supply the aggregate electric demand and energy requirements of the customers at all times, taking into account scheduled and unscheduled outages of system facilities. Security is the ability of the electric system to withstand sudden disturbances such as electric short circuits or unanticipated loss of system facilities. Reliability also refers to the security and availability of natural gas and petroleum supply, transportation and delivery.
Renewable Energy Certificate (REC) – A REC is the property right to the environmental benefits associated with generating renewable electricity.
Renewable Resources – Renewable energy resources are naturally replenishable, but flow-limited. They are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Some (such as geothermal and biomass) may be stock-limited in that stocks are depleted by use, but on a time scale of decades, or perhaps centuries, they can probably be replenished. Renewable energy resources include: biomass, hydro, geothermal, solar and wind. In the future they could also include the use of ocean thermal, wave, and tidal action technologies. Utility renewable resource applications include bulk electricity generation, on-site electricity generation, distributed electricity generation, non-grid-connected generation, and demand reduction (energy efficiency) technologies.
Reserve Margin – Capacity over and above anticipated peak loads, maintained for the purpose of providing operational flexibility and for preserving system reliability. Reserve margins cover for planned and unplanned outages of generation and/or transmission facilities.
Restructuring -The reconfiguration of the vertically integrated energy monopolies. Restructuring usually refers to separation of the various utility functions into individually operated and owned entities.
Silicon – A semiconducting material found in most solar cells. It absorbs photons in sunlight and creates energy.
Stand-Alone system – PV or any other renewable installation not connected to a utility power line. A ‘direct system’ can use the PV-produced electricity as it is produced, e.g., a solar-powered water-pumping station. A ‘battery storage system’ stores the PV-produced electricity for use a later time, e.g. at night or on cloudy days.
Tariff-A document, approved by the responsible regulatory agency, listing the terms and conditions, including a schedule of prices, under which utility services will be provided.
Thermal Rating-The maximum amount of electrical current that a transmission line or electrical facility can conduct over a specified time period before it sustains permanent damage by overheating or before it violates public safety requirements.
Time-of-Use (TOU) Rates—The pricing of delivered electricity based on the estimated cost of electricity during a particular time block. Time-of-use rates are usually divided into three or four time blocks per twenty-four hour period (on-peak, midpeak, off-peak and sometimes super off-peak) and by seasons of the year (summer and winter). Real time pricing differs from TOU rates in that it is based on actual (as opposed to forecasted) prices that may fluctuate many times a day and are weather sensitive, rather than varying with a fixed schedule.
Unbundling—Disaggregating utility service into its basic components and offering each component separately for sale with separate rates for each component. For example in electric service, generation, transmission and distribution could be unbundled and offered as discrete services with separate payment for each.
Universal Service—Energy service sufficient for basic needs (an evolving bundle of basic services) available to and affordable by virtually all members of the population.
Up-Front Incentive (UFI)—A payment or rebate up front for installing solar panels. Popular in the EU and US.
Utility—A corporation, person, agency, authority, or other legal entity that owns or operates facilities for the generation, transmission, distribution, or sale of electric energy or natural gas primarily for use by the public and is defined as a utility under the statutes and rules by which it is regulated. Frequently a sort of regulated entity that exhibits the characteristics of a natural monopoly. For the purposes of the electric industry, “utility” generally refers to a regulated, vertically integrated monopoly electric company. “Transmission utility” refers to the regulated owner/operator of the transmission system only. “Distribution utility” refers to the regulated owner/operator of the distribution system that serves retail customers.
Vertically Integrated Monopoly—A single entity (provider) which performs all of the basic functions of production, transportation and delivery. For example, in the electric industry a vertically integrated electric utility performs all three basic functions of generation (production), long distance transmission (transportation) and local distribution (delivery) of electrical energy to consumers.
Watt—The unit of measure for electric power or rate of doing work. The rate of energy transfer equivalent to one ampere flowing under pressure of one volt.