Wind Power - Glossary

Alternator

A device that turns the rotation of a shaft into alternating current (AC).

Ampere (Amp)

A unit of electrical current, can be thought of like the rate of water flowing through a pipe (liters per minute).

Ampere-hour

Amperes times hour, used to measure energy production over time, and battery capacity.

Wind speed measurement device, used to send data to the controller (see below).  Also used to conduct wind site surveys.

Angle of Attack

The angle of the airflow relative to the blade.

Battery

An electrochemical energy storage device. See flow battery.

Blades

Most wind turbines have 2 or 3 blades, which catch the wind and turn the generator.

Brake

Stops the rotor in emergencies.

British Thermal Unit (BTU)

A unit of energy, equal to 1,055 Joules.  See Watts.

The power generating or carrying potential of a device.

Capacity Factor

The amount of energy a device generates in a year divided by the amount it could generate, based on it running at full capacity the entire time.  

Manages the turbine in relation to wind velocity, starting up at minimum useable windspeed, shutting off at the maximum.

Cowling

Contains and protects the gearbox and generator, sometimes large enough for an engineer or technician to stand in while doing maintenance. See Nacelle.

Cut-in speed

The speed at which a shaft must turn in order to generate electricity and send it over a wire.

Diode

A solid-state device that acts as a one-way valve for electricity.

Downwind Turbine

A Turbine that does not face into the wind, and whose direction is controlled directly by the wind.

A device which allows excess energy to be safely disposed of.  

Dynamo

See Generator.

Efficiency

The comparison of energy input, to energy output, expressed as a ratio or percentage.

Emissions

A byproduct of a process which is released into the environment, can be solid, liquid, gaseous, sonic, or radiation (including light).  

Energy

The ability to do work.

Environmental Impact Assessment (or Statement)

A document created from a study of the expected environmental effects of a new development or installation.

Flow Battery

An electrochemical enertgy storage device, which utilizes tanks of rechargable electrolyte to refresh the energy producing reaction.  Since its capacity is limited only by the size of its electrolyte tanks, it is useful for large scale backup systems to supplement other forms of generation which may be intermittant in nature.

Increases the rpm of the low-speed shaft, transferring its energy to the high-speed  shaft in order to provide enough speed to generate electricity.

Generator

Device for converting kinetic energy from the rotation of the blades into direct current (DC) electrical energy. 

Global Warming

The recently observed rise in average temperature of the Earth, which is responsible for the melting of polar ice, stronger storms, and local climate changes.  

Synonymous with Clean Energy, Green Energy is electricity made using relatively non-polluting, non-destructive methods.

Greenhouse Effect (The)

The anthropogenic cause of Global Warming, created by the insulating properties of Carbon Dioxide, Methane, and other "Greenhouse Gases" released into the atmosphere, often as a product of energy generation.

Grid (The)

An interconnected electricity distribution system.  A Grid often covers a large area, and incorporate many forms of generation.

Transmits force from the Gearbox to the Generator.

Hub

The center part of the rotor assembly, which connects the blades to the low-speed shaft.

Kilowatt-hour (kWh)

One kilwatt-hour is the expression used for one kilowatt of energy produced for one hourur.  Equal to 1,000 watt-hours, or keeping 10, 100 watt lightbulbs lit for one hour.  Energy is normally sold in this unit of measurement.

Leeward

Away from the direction of the wind.  Opposite of Windward.

Keeping the amount of electricy produced,( the supply) equal to the comsumption (the demand).  This is one of the challenges of wind energy production, which produces energy on a less predictable schedule than other methods.

Connects the Rotor to the Gearbox. 

Nacelle

Contains and protects the gearbox and generator, sometimes large enough for an engineer or technician to stand in while doing maintenance. See Cowling.

Renewable Energy

Energy that is produced using resources which regenerate quickly, or are inexhaustible. Wind energy is considered inexhaustible, because while it may blow intermittantly, it will never stop. 

The blades and hub assembly.

Spinning Reserve

A reserve of generation capacity, where generators are kept online, but at idle, in anticipation of an unexpected increase in demand or decrease in supply.  

Start-up speed

The windspeed at which a rotor begins to rotate.

Tip Speed Ratio (TSR)

A comparison of the speed of the tips of the blades, and the speed of the wind turning the rotor. 

Steel structures which support the turbine assembly.  Higher towers allow for longer blades, and the capture of faster moving air at higher altitudes.

Used to change the voltage of AC current.

Turbine

A device for capturing kinetic energy from a moving mass of wind, water, steam, or other gas or liquid.

Upwind Turbine

A Turbine that faces into the wind, requires a Wind Vane and Yaw Drive in order to maintain proper orientation in relation to the wind.

Viewshed

The scenic characteristics of an area, when referred to as a resource.

Voltage

The measure of electrical potential difference.

A measurement of energy equal to one joule per second.  Wind turbine capacity is measured in kW (kilowatts, or 1,000 watts) or MW (megawatts, or 1,000,000 watts).  1 kW is an approximation of the capacity needed to serve one household.

Wind direction measurement device, used to send data to the Yaw Drive.

Windward

Into, or facing the direction of the wind.  Opposite of Leeward.

Wind Turbine or Windmill

Motor that keeps an Upwind Turbine facing into the wind.