WIND POWER - GLOSSARY

Blade

The blade is the aerodynamic element of the wind turbine. Modern turbines generally have three blades. Wind blowing over the blades causes the blades to "lift" and rotate.

Consumption equivalent

This corresponds to the annual production of a wind farm compared to electricity consumption per capita. According to figures issued by the ADEME, average domestic electricity consumption per capita and per annum is 2500Kwh. For example: our Cuxac wind farm produces approximately 36 million kWh per annum, that is to say a "consumption equivalent" of approximately 14.400 people.

CO2 savings

This corresponds to the quantity of CO2 avoided per kilowatt-hour produced by a wind farm. To calculate this figure, the relative value is the figure used for the implementation of a national campaign to fight global warming which was carried out by the Inter-ministerial Greenhouse Effect Commission (MIES), and it corresponds to 292g/Kwh. For example our Cuxac wind farm produces approximately 36 million kWh per annum and thus contributes to avoiding the emission of approximately 10 000 tonnes of CO2 a year.

Decibels

A decibel (dB) is a logarithmic unit of measurement that expresses the magnitude of a physical quantity (usually power or intensity). In this particular case, it is used to characterise and compare different noise levels.

To give an idea of the different acoustic levels:
Source : AWEA

- Between 0 & 10 dB : desert
- Between 10 & 20 dB : sound studio
- Between 20 & 30 dB : murmured conversation
- Between 30 & 40 dB : forest
- Between 40 & 50 dB : library

- Wind Farm

- Between 50 & 60 dB : dish-washer
- Between 60 & 70 dB : television
- Between 70 & 80 dB : vacuum cleaner
- Between 80 & 90 dB : lawn mower
- Between 90 & 100 dB : heavy trafic road
- Between 100 & 110 dB : pneumatic drill
- 120 dB : pain threshold
- Between 110 & 120 dB : discotheque
- Between 120 & 130 dB : plane taking off
(300 metres away)
- 180 dB : Ariane space rocket taking off

Sounds are practically inaudible for the human ear the under around 20 dB. It begins becoming painful beyond 80 dB, dangerous from 100 dB and unbearable as early as 120 dB.

Decommissioning

The decommissioning of a wind farm is regulated by article 98 of the Urbanism and Habitat law of July 2nd 2003 which complements article L553-3 of the Code of the Environment. Article L553-3 specifies that the owner of an installation which produces electricity using the mechanical energy of wind is responsible for its dismantling and the restoration of the site at the end of commissioning. The owner must constitute the financial guarantees necessary for this decommissioning under the conditions defined by decree. The methods of dismantling the site consist of levelling the foundations of the wind turbines and disassembling all infrastructures above ground.

Full power generation

Corresponds to the kilowatt-hours produced by a wind turbine over one year when it functions to the maximum of its capabilities. This concept can be also expressed in a number of operating hours at full power. This information makes it possible to compare sites or the various models of turbines available on the market in order to choose those best adapted to local conditions. Indeed, the annual production of a wind turbine depends largely on its design features and its characteristics have to be adapted to the recorded wind speed.

Hub

Central part of the rotor which supports the blades.

Megawatts

The watt (symbol: W) is the SI derived unit of power, equal to one joule of energy per second. The megawatt (symbol: MW) is one of its multiples :

-1 Megawatt = 1 million Watts
-1MW = 1 000 000 W

Nacelle

The nacelle holds up the whole of the rotor and contains the generator which transforms mechanical wind energy into electrical energy. The nacelle sits atop the tower and moves to face the wind thanks to its sophisticated orientation system. Some nacelles are large enough for a helicopter to land on.

Regulatory requirements

Refers to the all the different constraints and regulations which must be respected when planning the construction of a wind farm.

Rotor

The blades and the hub of the wind turbine are known as the rotor.

Tower

The tower supports the nacelle and the rotor. There are different types of tower for industrial wind turbines, either tubular steel, steel lattice or concrete. The tubular guy-wire supported towers are only used for small turbines. The most common towers used for industrial wind turbines are steel.

Wind power

Is the conversion of wind energy into a useful form, such as electricity, using a generator such as a wind turbine or a wind mill. Wind power is a renewable energy source and can be used in two ways:

Use of mechanical energy: wind is used to propel a means of transport (sailing boat or sandsailer), to pump water (wind mills in Majorca, wind pumps to irrigate or water cattle) or to turn the mill-stone of a wind mill.
Conversion into electricity: the wind turbine is connected to an electrical generator to create direct or alternating current. The generator is either connected to a power grid or it feeds a portable power plant and / or a battery park or any other type of energy stocking device.

More on Wind Power: en.wikipedia.org/wiki/Wind_energy

Wind rose
Is a graphical representation of the distribution of wind speeds and directions. For example, the wind rose below which corresponds to weather data measured in Caen indicates that practically all the wind power comes from the west and south-west.

The wind rose corresponds to "a compass" where each direction is expressed in degrees from 0° to 360° (North 0°, East 90°, South 180° and West 270°). Here, the compass is divided into twelve 30 degree arcs. Certain information is represented in the example and is read from the centre to the outside of the circle.

This wind rose indicates that most of time the wind blows from the west and south-west and that these winds are also the strongest and therefore potentially those which will generate the most energy.

Wind speed

Is defined by the average wind speed in m/s and the direction of all the winds blowing in a given place over one year. The wind speed can be represented graphically by using a wind rose.