Wind Energy Glossary
Glossary Term | Definition |
|---|---|
| Restructuring | The process of changing the structure of the electric power industry from one of regulated monopoly over electrical customers to one of open competition between power producers for customers. |
| Rural Electrification Administration (REA) | An agency of the U.S. Dept. of Agriculture that makes loans to states and territories in the U.S. for rural electrification and for providing electricity to persons in rural areas who do not receive central station service. |
| Setback | A term used in siting and permitting for the construction of structures that refers to the distance from the base of the structure to existing easements, roads, buildings, bodies of water, or other geographic or man-made structures or property lines. |
| Shadow Flicker | Shadow flicker occurs when the blades of the turbine rotor cast shadows that move across the ground and nearby structures. |
| Sound Power | Strength of a sound source, measured in A-weighted decibels (LWA). Typical sound power values for wind turbines (which can be obtained from the turbine manufacturer) are in the range of 90-105 dB(A), LWA. (The measurement is A-weighted to account for the sensitivity of human hearing.) |
| Sound Pressure | Sound level measured at a receptor (e.g., a neighbor’s house, a microphone). Sound pressure decreases proportionately to the square of the distance from the source and can be affected by prevailing wind direction, topography, temperature, barometric pressure, and other factors. |
| Southern Minnesota Municipal Power Agency (SMMPA) | SMMPA is a company that generates and sells wholesale electricity, primarily for its eighteen member municipally-owned utilities. The member municipally-owned utilities are located mostly in Southeastern and South-central Minnesota. SMMPA website: www.smmpa.com |
| System Benefits Charge (SBC) | A required fee (also known as a public benefits charge) from all electricity customers to fund programs that are in the public interest that may or may not be competitive in a deregulated electricity market. |
| Tariff | A standardized set of terms for generation, purchase, transmission and/or delivery of electricity on a utility’s system, a state, region, or country. The term is commonly used in electric utility rate making in North America. The term is also commonly used in Europe. In this context tariffs are not taxes or customs duties on goods crossing international borders. |
| Tenor | The term or life of a contract, similar to maturity. |
| Three-Phase Distribution or Transmission Lines | Electrical power lines that carry electric energy from one point to another in an electric power system, using three power lines, to transmit three different electrical signals. The phases, or electrical signals, required for most large rotating machines which are used in many manufacturing processes and for many commercial/large wind turbines. The U.S. |
| Transmission | The transfer of electric current from a power plant to a destination that could be hundreds of miles away. |
| Turbine | A device for converting the flow of a fluid (air, steam, water, or hot gases) into mechanical motion that can be utilized to produce electricity. |
| Unbundling | The process of separating a service into component parts (generation, transmission, distribution, ancillary services, etc) to allow customers to choose where to buy each service separately. Utility unbundling, overseen by regulators, generally requires utilities to ensure that the price of each service accurately reflects the cost of that service (plus a margin for profit). |
| Wake Losses | The space behind a wind turbine that is marked by decreased wind power capacity due to the fact that the turbine itself used the energy in turning the blades. The wind behind the turbine, in its wake, is less effective at generating energy for a certain distance in the downwind direction due to turbulence created by the upwind machine. |
| Watt | A unit of electrical power: 1/1000 kW |
| Wheeling | Transmitting bulk electricity from a generating plant to a distribution system across a third party's lines. |
| Wind Power Class | A way of quantifying on a scale the strength of the wind at a project site. The Department of Energy’s National Renewable Energy Laboratory defines the wind class at a site on a scale from 1 to 7 (1 being low and 7 being high) based on average wind speed and power density to offer guidance to potential developers as to where wind projects might be feasible. |
| Wind Rose | A wind rose shows the direction and the frequency of that direction that the wind blows at a particular location. Wind roses are used in wind projects to portray the amount of energy that comes into the wind project from various directions. |
| Wind Shear | A term and calculation used to describe how wind speed increases with height above the surface of the earth. The degree of wind shear is a factor of the complexity of the terrain as well as the actual heights measured. Wind shear increases as friction between the wind and the ground becomes greater. Wind shear is not a measure of the wind speed at a site. |