Wind is a renewable energy source. As the windiest country in Europe, the UK is well placed to harness wind energy. Wind is the 'fuel' that wind turbines use to generate electricity.
Wind turbines use kinetic energy to generate electrical energy for homes and businesses. Individual wind turbines can be used to generate electricity on a small scale – to help power a single home, for example. Many wind turbines grouped together (known as a wind farm or wind park) can generate electricity on a much larger scale.
A wind turbine works like a high-tech version of a windmill. The wind blows on the angled blades of the rotor, causing it to spin and converting some of the wind’s kinetic energy into mechanical energy. Sensors in the turbine detect how strongly the wind is blowing and from which direction. The rotor turns to face the wind and brakes in dangerously high winds to protect the turbine from damage.
A shaft and gearbox connect the rotor to a generator (1) – when the rotor spins, so does the generator. The generator uses an electromagnetic field to convert this mechanical energy into electrical energy.
Electrical energy from the generator is transmitted along cables to a substation (2). Here the electrical energy generated by all the turbines in the wind farm is combined and converted to a high voltage. The national grid uses high voltages to transmit electricity efficiently through the power lines (3) to the homes and businesses that need it (4). Here other transformers reduce the voltage to a usable level.
EDF Energy builds and operates wind farms in the UK through its subsidiary company, EDF Energy Renewables, which operates 27 onshore wind farms with a total installed capacity of 489MW. We also operate an offshore wind farm just less than a mile off the north east coast, between the mouth of the River Tees and the town of Redcar. Total installed capacity is 62MW: enough to fulfil the electricity needs of some 40,000 households.
Onshore wind turbines
Onshore wind turbines can produce electricity at costs closely competitive with other low-carbon sources of energy. But there are only a limited number of suitably windy sites in the UK, and concerns about the visual impact of wind turbines can sometimes make it difficult to secure planning permission.
Offshore wind turbines
Offshore wind turbines have much less negative visual impact and there is much more space available offshore in which to build them. They can also take advantage of higher and more consistent wind speeds. But the offshore environment makes constructing and maintaining offshore wind turbines more complex and hazardous than onshore projects. Thus, they are currently a more expensive way to generate electricity than onshore turbines.
The main advantage of wind turbines is their small carbon footprint. But turbines can only generate electricity when the wind is blowing at a suitable speed, so they need to be backed up by other forms of electricity generation.