With growing concerns about pollution and climate change, an increasing number of renewable energy installations are popping up around the globe. Solar power is a major source of renewable energy many people think of, but don’t discount the efficacy of wind energy. If you’ve ever spotted a wind farm consisting of huge windmills, you’ve seen this renewable energy source in action.
What is a Wind Turbine?
Huge windmills, also called wind turbines, typically have two or three blades that turn when the wind blows fast enough. These turbines are strategically installed in windy places and are often grouped together in “farms” for the greatest efficiency.
How Do Wind Turbines Work?
The purpose of a wind turbine is to convert wind power into usable energy. In short, it converts the kinetic energy of the wind into mechanical power, which can be used to grind grain or pump water. Combined with a generator, a wind turbine can produce electricity to power nearby towns. Here’s a more in-depth look at how this works:
- Wind turns the blades: A controller powers up the turbine so the blades start spinning when the built-in anemometer reads wind speeds between 12 and 26 km per hour (kph). The controller powers down the turbine when winds blow faster than 55 mph to prevent damage in high winds. With the help of a wind vane, a yaw drive orients the wind turbine to keep it facing into the wind when it changes direction to maximize effectiveness. (Downwind turbines don’t feature a yaw drive since the wind automatically blows the rotor away from it.)
- Spinning blades turn a rotor: The blades and a hub together form the rotor. A pitch system turns the blades when necessary to prevent the rotor from spinning in winds that are too high or too low to generate power. A mechanical, electrical or hydraulic brake is also included in case the rotor needs to be manually stopped in an emergency.
- A gearbox increases rotational speed: A low-speed shaft connects the rotor to a gearbox, and a high-speed shaft connects the gearbox to a generator. The gearbox increases the rotational speed from between 30 and 60 rotations per minute (rpm) to as high as 1,800 rpm. The gearbox is one of the heaviest and most expensive parts of a wind turbine.
- The generator produces electricity: Thanks to the higher rotational speed produced by the high-speed shaft, the built-in induction generator produces 60-cycle AC electricity. Engineers are currently exploring the possibility of using direct-drive generators in wind turbines that can produce electricity at lower rotational speeds. This would eliminate the need for expensive gear boxes.
The Future of Wind Power
With growing concerns for the environment, increasingly competitive prices and a drive to reduce dependence on foreign oil, it appears wind power has a strong future. Already turbines are growing in size and capacity. The next frontiers include perfecting deep-water offshore and land-based technologies that can operate at lower wind speeds.