Glossary

Wind Industry Glossary

A

Alternative Energy

A popular term for non-conventional energy like renewables

Asynchronous Generator

A type of electric generator that produces alternating current (AC) electricity to match an existing power source.

B

Battery

An energy storage device made up of one or more electrolyte cells. An electrolyte is a non-metallic conductor that carries current.

Beaufort Scale

Created by Admiral Sir Francis Beaufort (1774-1857) of the British navy to describe different wind effects on a sailing vessel. Later the scale was expanded to include descriptions of the wind’s effects on land as well.

C

Carbon Dioxide

A colorless, odorless but poisonous combustible gas. Carbon monoxide is produced in the incomplete combustion of carbon and carbon compounds. For example, fossil fuels like coal and petroleum.

Central Power Plant

A large power plant that generates power for distribution to multiple customers.

Chemical Energy

The energy liberated in a chemical reaction as in the combustion of fuels.

Circuit

A device or system of devices that allows electrical current to flow through and voltage to occur across positive and negative terminals.

Circuit Breaker

A device used to interrupt of break an electrical circuit when an overload condition exists. Circuit breakers are used to protect electrical equipment from potential damage.

Climate

The prevailing or average weather conditions of a geographic region.

Conductor

The material through which electricity is transmitted, such as an electrical wire.

Conduit

A tubular material used to encase and protect electrical conductors.

Constant-Speed Wind Turbines

Wind turbines that operate at a constant RPM. They are designed for optimal energy capture at a specific rotor diameter and at a particular wind speed.

Conventional Fuel

The fossil fuels: coal, oil and natural gas.

Converter

A device for transforming electricity to a desired quality and quantity.

Cycle

In alternating current electricity, the current flows in one direction from zero to a maximum voltage, then goes back down to zero, then to a maximum voltage in the opposite direction. This comprises one cycle. The number of complete cycles per second determines the current frequency. In the US the standard for alternating current is 60 cycles.

Cyclone

Air spinning inward toward centers of low air pressure. Cyclones spin counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

D

Deregulation

The process of changing policies and laws of regulation in order to increase competition among suppliers of commodities and services. The Energy Policy Act initiated deregulation of the electric power industry in 1992.

Direct Current

A type of electricity transmission and distribution by which electricity flows in one direction through the conductor. Usually the electricity is a relatively low voltage and high current. Direct current is abbreviated as DC.

Distribution

The process of distributing electricity. Distribution usually refers to the portion of power lines between a utility’s power pole and transformer and a customer’s point of connection.

Doldrums

A narrow, virtually windless zone near the Equator created as heated air rises upward leaving the ocean’s surface calm and glassy.

Downburst

A severe localized downdraft from a thunderstorm. Also called a microburst.

Downwind Wind Turbine

A horizontal axis wind turbine in which the rotor is downwind of the tower.

E

Electricity

The energy of moving electrons, the current of which is used as a source of power.

Electricity Generation

The process of producing electricity by transforming other forms or sources of energy into electrical energy. Electricity is measured in kilowatt hours (kWh).

Emission

A substance or pollutant emitted as a result of a process.

Energy

The capacity for work. Energy can be converted into different forms but the total amount of energy remains the same.

Energy Storage

The process of storing or converting energy from one form to another for later use. An example of a storage device is a battery.

Environment

All the natural and living things around us. The earth, air, weather, plants, and animals all make up our environment.

F

Fossil Fuels

Fuels formed in the ground from the decayed remains of dead plants and animals. It takes millions of years to form fossil fuels. Oil, natural gas and coal are fossil fuels.

Frequency

The number of cycles through which an alternating current passes per second, measured in hertz.

Fuel

Any material that can be consumed to make energy.

G

Gearbox

A protective casing for a system of gears.

Generator

A device for converting mechanical energy to electrical energy.

Gigawatt (GW)

A unit of power equal to 1 million kilowatts.

Global Warming

A term used to describe the increase in average global temperatures due to the greenhouse effect.

Green Credit

Green credits are a new way to purchase renewable electric generation that divides the generation into two separate products; the commodity energy and the renewable attributes. The green credit represents the renewable attributes of a single megawatt of renewable energy. Also know as green tags, renewable energy credits or renewable energy certificates.

Green Power

A popular term for energy produced from renewable energy resources

Greenfield

A site on which a power plant has not previously existed.

Greenhouse Effect

The heating effect resulting from long wave radiation from the sun being trapped by greenhouse gases that have been produced from natural and human sources.

Grid (power/utility)

A common term referring to an electricity transmission and distribution system.

Gust

A sudden brief increase in the speed of the wind.

H

Hertz (Hz)

A measure of the number of cycles or wavelengths of electrical energy per second. The US electricity supply has a standard frequency of 60 hertz.

Horizontal-Axis Wind Turbines

Turbines on which the axis of the rotor’s rotation is parallel to the wind stream and the ground.

J

Jet Stream

A meandering and relatively narrow belt of strong winds embedded in the normal wind flow, generally found at high altitudes.

Joule (J)

A metric unit of energy or work. One joule per second equals 1 watt.

K

Kilowatt (kW)

A standard unit of electrical power to 1000 watts.

Kilowatt-Hour (kWh)

A unit of measure of electricity supply or consumption of 1000 watts over the period of one hour.

Kinetic Energy

Energy available as a result of motion. Kinetic energy is equal to one half the mass of the body in motion multiplied by the square of its sped.

Knot

One nautical mile per hour (1.15 MPH).

L

Landman

An in-house or independent land management consultant who negotiates terms of land leases with land owners.

Leading Edge

The surface part of a wind turbine blade that first comes into contact with the wind.

Lift

The force that pulls a wind turbine blade.

M

Mean Power Output (of a Wind Turbine)

The average power output of a wind energy conversion system at any given mean wind speed.

Mean Wind Speed

The average wind speed over a specified time period and height above the ground.

Mechanical Energy

The energy possessed by an object due to its motion (kinetic energy) or its potential energy.

Median Wind Speed

The wind speed with 50% probability of occurring.

Megawatt (MW)

The standard measure of electric power plant generating capacity. One megawatt is equal to one thousand kilowatts or 1 million watts.

Megawatt-hour (MWh)

1000 kilowatt-hours or 1 million watt hours.

N

Nacelle

The cover for the gearbox, drive train and generator of a wind turbine.

Natural Gas

A hydrocarbon gas obtained from underground sources, often in association with petroleum and coal deposits. It generally contains a high percentage of methane, varying amounts of ethane and inert gases. Natural gas is used as a heating fuel and for electricity generation.

Nitrogen Oxides (NOx)

The products of all combustion processes formed by the combustion of nitrogen and oxygen. Nitrogen oxides and sulfur dioxide are the two primary causes of acid rain.

Non-Renewable Fuels

Fuels that cannot be easily renewed or reproduced such as oil, natural gas and coal.

O

Oil (fuel)

A product of crude oil that is used for space heating, diesel engines and electricity generation.

P

Peak Wind Speed

The maximum instantaneous wind speed that occurs with a specific time period.

Power

Energy that is capable or available for doing work.

Power Grid

See Grid.

Power Quality

Stability of frequency and voltage and lack of electrical noise on the power grid.

Prevailing Wind Direction

The direction from which the wind predominantly blows as a result of the seasons, high and low pressure zones and tilt of the earth on its axis and the rotation of the earth.

R

Radioactive Waste

Materials left over from making nuclear energy. Radioactive waste can damage or destroy living organisms if it is not stored safely.

Renewable Energy

Energy derived from resources that are regenerative or cannot be depleted. Types of renewable energy resources include wind, solar, biomass, geothermal and moving water.

Restructuring

The process of changing the structure of the electric power industry from one of a guaranteed monopoly that is regulated to one of open competition between power suppliers.