Wind turbines are those white or pale grey structures you see on the horizon – each one consisting of a set of blades, a box beside them called a nacelle and a shaft. A breeze, even just a light wind, causes the blades to rotate. This creates kinetic energy which makes the shaft in the nacelle turn and then an electric generator converts this mechanical energy into electricity. This electricity can then be used directly or connected to the national grid so that it is sold on to homes and businesses. It can also be stored so that it can be used later.

Each type of turbine has its own maximum power generation within a range of wind speeds. For example, a standard three-bladed turbine can generate a maximum of 1.15 megawatts at a wind speed of 18 to 25 miles per hour. When the wind speed drops, the amount of electricity produced decreases but it does not stop completely (although some may shut down for safety reasons). There are also technologies such as batteries and pumped-storage hydropower that can be used to store excess electricity for future use.

Maintenance on a wind farm is carried out using different techniques, including from the ground with high-precision telephoto lenses, by climbing the blades with ropes, cranes or lifting platforms and remotely, by using drones. Preventative maintenance focuses on the condition of the blades and nacelle to identify any damage and ensure they are in good working order. Corrective maintenance, on the other hand, involves repair or reconstruction of the blades and nacelle to restore their original condition and continue producing renewable energy safely.

Concerns about wind projects sometimes focus on shadow flicker and noise, but both shadow flicker and noise are not significant or harmful to human health. Studies have shown that shadow flicker only occurs at dusk and dawn when the sun is low on the horizon and that noise levels from wind turbines are well below those of most other industrial sources of noise.

There are several different types of wind turbines, with most of the ones currently in operation being horizontal-axis turbines with three blades. These tower as tall as 20-story buildings and can have a diameter of over 100 feet. The taller the tower, the more electricity they can produce.

Each blade is connected to the nacelle by shafts which are powered by a yaw drive, that moves the nacelle to face the direction of the wind. An anemometer and wind vane measure the speed of the wind and communicate with the yaw drive to keep the nacelle correctly oriented. There are also a number of other control systems located in the nacelle to continuously monitor and modify operational parameters and produce electricity safely and reliably. These control systems include vibration sensors that monitor the vibration of the rotor, anemometers that measure the wind speed and direction, and a weather station that records ambient temperature, humidity and rainfall.