How does a wind farm work?

Wind turbines generate electricity by harnessing the natural force of the wind in order to power an electrical generator.

Almost all the wind turbines that produce electricity consist of a rotor with blades that turns on a horizontal shaft; the latter is connected to a mechanical transmission assembly or gearbox and, finally, to an electrical generator, both of which are located in the nacelle mounted at the top of the mast.

The main components of a wind turbine are:

• Rotors.
• Usually 3 blades on the rotor.
• Blades made of fibreglass with polyester or epoxy reinforcements.
• Operation with constant or variable rotor speeds.
• Automatic power control depending on wind speed, with cut out at very high speeds (mechanical safety): by means of the angle of the blade (pitch) or its own aerodynamics (stall).
• Widespread use of gearboxes and, in certain cases, of direct shaft-generator transmission.
• Automatic positioning (yaw) according to variable wind direction (sensors for monitoring).
• Tubular towers made of steel and generally painted in light grey.

Onshore wind power contributes to local economies and creates jobs, with projects being developed by an increasingly diverse range of interest groups, from private individuals to large corporations. As high demand continues, considerable technological advances have been made. As a result, onshore wind has become one of the most competitive and cost-effective renewable energy sources, with more than 420,000 Megawatts installed worldwide.

The average power rating of wind turbines installed on land varies from two to three megawatts, with the crucial parameter being the diameter of the turbine: the greater the length of the blade, the greater the area swept and the energy produced. The size of wind turbines installed varies significantly between different locations and countries. An average onshore wind turbine with a capacity of 2.5 to 3 Megawatts can produce more than 6 million kWh per year.

In the last decade offshore wind energy has experienced an exponential rise. This development can be attributed to a number of factors - including abundance of space and greater, more consistent wind resources, which result in an energy output up to 40% higher than onshore, and reduced impact on the environment. Offshore wind energy counts for over 14,000 Megawatts installed capacity worldwide.

Wind power plants at sea are equipped with much more powerful machines, with development currently underway on prototypes of up to 8 MW. As offshore wind parks' size and distance to shore increase, so do the number of challenges. They operate for decades in the harsh marine environment, where conditions create the perfect storm for erosion. Along with the increase in size, this trend asks for a robust and proven technology and sophisticated logistical setup - from construction to transport to installation - to tap the full potential of offshore wind power.