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. Sound pressure, like sound power, is given in A-weighted measurements (Laeq) to account for the sensitivity of human hearing.
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.)
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 occurs when the blades of the turbine rotor cast shadows that move across the ground and nearby structures.
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. It also furnishes and improves electric and telephone service in rural areas, fosters energy conservation,on-grid and off-grid renewable energy systems, and studies the condition and progress of rural electrification.
A minimum renewable energy requirement for a region's electricity mix. Under an RES, electricity suppliers are required to provide some percentage of its supply from renewable energy sources. RPS proposals frequently ease that requirement by including a tradable credit system under which electricity suppliers can meet the requirement by buying and selling renewable energy credits (RECs).
The “green” or renewable attribute of electricity that is generated utilizing a renewable energy resource. A wind turbine that produces 1 MWh of electricity has produced 1 REC which, in some electricity markets, can be sold separately from the electrical power.
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.
This is the production of reactive power to maintain stability on the transmission system. Power on the system comes in two main types: the first is the power that is actually delivered to end users, and the second is reactive power, which is power provided to the system to maintain the system, rather than for end-use consumption.
A state government agency responsible for the regulation of public utilities within a state or region. A state legislature oversees the PUC by reviewing changes to utility laws, rules, and regulations and approving the PUC's budget. The commission is usually made up of Commissioners appointed by the governor or legislature for a specific term which varies from state to state. The PUC focuses on adequate, safe, universal utility service at reasonable rates while also trying to balance the interests of consumers, environmentalists, utilities, and other stockholders.