How a turbine makes electricity
A wind turbine does 2 jobs. It catches moving air with a rotor, the blades and hub spinning together, and turns that spin into electricity with a generator, copper windings turning inside a magnetic field. Wind moving across a blade lowers the air pressure on one side, and that pressure difference creates lift, which spins the rotor. Most turbines carry 3 fiberglass blades. A modern blade built for use on land exceeds 170 feet, 52 metres, and an offshore blade can reach 351 feet, 107 metres, close to the length of a football field.
The rotor spins at 8 to 20 rotations a minute, turning a shaft that runs into the nacelle, the housing on top of the tower. Inside sits the gearbox, which speeds up that slow turn into the faster turn the generator needs, though some turbines skip the gearbox and use a ring of magnets instead. The tower is tubular steel. Height matters because wind moving above about 30 metres, roughly 100 feet, travels faster and with less turbulence than wind close to the ground, where hills, trees and buildings slow it.
What starts, aims and stops it
A control system runs the turbine without a person on site. An anemometer measures wind speed and a wind vane measures direction, both reporting to a yaw system, which turns the nacelle into the wind. A pitch system turns each blade to control how much energy it pulls from the wind, and can turn the blades edge on to stop the rotor in a storm. A controller starts the turbine at 7 to 11 miles an hour and shuts it down at 55 to 65 miles an hour to protect the machine.
The turbine actually makes power in the gap between these 2 ranges, roughly 11 to 55 miles an hour, which is not drawn here.
Show the numbers
| Starts turning | 7 to 11 miles an hour |
| Shuts down | 55 to 65 miles an hour |
How big a turbine is today
Size is measured in rated capacity, the most power a turbine can put out at once, in megawatts, each equal to 1,000,000 watts. The average new American turbine installed in 2023 was rated at 3.4 megawatts, and the Department of Energy states it can power over 1,000 United States households a day.
The first row is the example the Department of Energy uses to describe nacelle weight, source 1, not a national average. The last row is the Haliade X, source 4, a single named machine already generating power at sea, not a fleet average.
Show the numbers
| A 1.5 megawatt turbine, an example machine | 1.5 |
| Average new American turbine, 2023 | 3.4 |
| Haliade X, already turning at sea | 14.7 |
A far larger machine is already making power at sea. The Haliade X, built by GE Vernova, is rated at 14.7 megawatts with a 220 metre rotor, more than 4 times the rated capacity of the average new American turbine, a MAOWCE calculation from the 2 figures. On a typical North Sea site it is rated for up to 76 gigawatt hours of energy a year, which the company credits with avoiding up to 53,000 metric tons of carbon dioxide a year.
It began generating electricity at the Dogger Bank wind farm off the United Kingdom in October 2023, after 3 years of prototype testing in Rotterdam. DNV, an independent body, certified the design in December 2022. Kim Sandgaard Mork, executive vice president for renewables certification at DNV, assessed what turbines this size mean for the industry.
Continued increases in turbine, blade, and tower size will lead to improvements in capacity factors.
Kim Sandgaard Mork, executive vice president for renewables certification at DNV, an independent certification body. Source 4.
How many are being built worldwide
Wind power is growing fast worldwide. Builders installed 28,395 turbines across 57 countries in 2025, adding 165 gigawatts of new capacity, each gigawatt equal to 1,000 megawatts, 40% more than the previous best year. Cumulative wind capacity worldwide reached 1,299 gigawatts, and the Global Wind Energy Council counts 138 countries now drawing some power from wind.
Ben Backwell, chief executive of the Global Wind Energy Council, called the jump a new benchmark for a fast growing industry meeting rising demand for reliable, affordable, home produced power.