Renewable Energy

Wind Power

Wind power, harnessed using wind turbines, is a clean, renewable source of energy which produces no carbon dioxide emissions or waste products. The UK has an estimated 40% of Europe's total wind energy.

Wind turbines within new communities would generate electricity and then feed it into the National Grid. Power from the wind turbines would not be used directly in the homes and public buildings across the community.

How it works

The wind turbines are built high enough to most effectively capture the wind as it blows. The wind passes across the turbine blades and makes them turn. This is the most economic form of renewable energy in the UK for areas where high wind speeds are prevailing. Exposure to wind is obviously crucial and locating the system near buildings or other obstructions (trees and buildings in particular) needs to carefully consider turbulence which can reduce energy generation.

The blades are connected to the primary shaft inside the nacelle, which is the box at the top of the turbine. This shaft passes into a gearbox which, like the gears on a bike or a car, increase the rotation speed of a secondary shaft.

This then passes to the generator which the secondary shaft turns. The generator uses magnetic fields to convert the rotational energy into electrical energy, a tried and tested system similar to that found in normal power stations.

Instruments to measure the wind speed and direction are fitted on top of the nacelle. When the wind changes direction motors turn the nacelle, and the blades along with it, so that it faces into the wind. The nacelle is also fitted with brakes, so that the turbine can be turned off in very high winds and storms. This prevents the turbine being damaged. Modern turbines are designed to be much quieter and efficient than some of their predecessors. Direct drive turbines have no gearbox, and consequently no high speed mechanical (or electrical) components. Direct drive turbines are therefore much quieter than gearbox machines as they do not produce mechanical or tonal noise. Variable speed turbines rotate more slowly or quickly depending on the wind speed and can therefore blend with the background noise that also tends to increase or decrease depending upon wind speed.

A 600kW wind turbine that is around 50m in diameter and 50-70m in height can reduce carbon emissions by as much as 600,000kg CO₂ or 600 tonnes a year.

The power output from the turbine, generated at around 700 volts, goes to a transformer which converts the electricity to around 33,000 volts. At this point the power can be accepted by the National Grid and transmitted around the country.

Smaller wind turbines generate Direct Current (DC) so these also need an inverter to convert their power output to Alternating Current (AC) so that it can be accepted into the National Grid for mains use.