How wind turbines work
We’ve all seen hills covered in giant wind turbines dotted throughout the countryside. But what is wind energy, and how do those futuristic windmills power our homes and workplaces? Here we discover why wind turbines whirl and how they actually work…
What is wind energy?
Wind turbines harness the power of wind energy to create electricity. Like solar energy with sunshine, this is a form of energy that exists all the time, just waiting for us to take advantage of it. Stick a wind turbine high in the air, in a windy spot, and it will whirl.
Wind contains ‘kinetic energy’ – energy created by motion. Lots of forces set the wind in motion, including sunlight, the earth’s rotation, the bumpiness of the earth’s terrain, and changes in temperature. Thanks to all these variables, the air in our atmosphere doesn’t stay in one place, but is constantly thrust into motion. It’s this motion that powers a wind turbine.
So, how do wind turbines work?
Harnessing the kinetic energy of the wind to create electricity requires a simple – but ingenious – mechanism:
- First, there are the giant rotor blades, which span about 45 metres. They are placed about 120 metres off the ground so they receive the maximum amount of wind. They are also curved, so they spin even in a light breeze, and they can swivel to catch the wind at the optimum angle.
- The giant blades are connected to a mechanism inside the ‘Nacelle’. The Nacelle is where all the real action happens. It’s the wind turbine’s ‘cockpit’, where you’ll find everything you need to turn motion into electricity.
- The first port of call in the Nacelle is the ‘low-speed’ shaft. This is connected to the giant blades, and spins at the same rate. But there is a gearbox on the end of this shaft, connecting it to another shaft. The gearbox gets everything going. It ups the revs, increasing the rotation from about 30-60 revolutions per minute on the low-speed shaft to 1000-1800 rpm on the second shaft.
- This second, ‘high-speed’ shaft is connected to a generator. Once this shaft is spinning along nicely, the generator turns its energy into an electric current. The current runs down through a cable inside the turbine tower, eventually ending up at a substation and, ultimately, powering our communities.
Each year, the average wind turbine produces enough electricity to supply 850 houses. It is the fastest growing renewable energy source for electricity generation in Australia and contributes to almost 4% of our electricity.
Although their noise level has received some bad press, the truth is you can stand right underneath a wind turbine and have a chat, without so much as raising your voice.
22 March 2016