Wind turbines are devices which convert the kinetic energy from wind into electrical energy with the help of an associated electric generator. They are sometimes misunderstood with windmills, which is a much older technology. Windmills and wind turbines may be similar in a number of ways, notably the physical appearance and the mode of operation, but they are quite different. Windmills essentially convert the mechanical energy from blades into the physical work such as pumping water and grinding grain whilst wind turbines convert the mechanical energy of rotating blades into electrical energy with the help of an electric generator, for a clean and safe environment. There are different types of turbines such as horizontal axis and vertical axis turbines.
The efficiency of wind turbines is determined by Betz’ limit, which states that no turbine can capture more than 59.3% of the kinetic energy of the wind. In order to increase this efficiency, different prototypes and designs have been made, some of which will be discussed below.
New Bladeless wind turbines, believed to be twice as efficient as conventional wind turbine designs
A company based in Tunisia, Saphon, came up with a Zero Blade technology which they believe to be the future of wind turbines. This Zero Blade technology is largely inspired by the sailboat, and these zero-blade technology devices are capable of overcoming the Betz’ limit. While an average wind turbine captures only 30 to 40% of the kinetic energy of the wind, the Saphon tower is said to be 2.3 times more efficient. And due to the fact that there are no blades, no hub, no gearbox on this kind of turbine, it is expected to be 45% cheaper than the conventional turbine.
Modern horizontal-axis, tri-blade wind turbines are believed to generate the most electricity.
Some of the wind generation devices are:
i. Tri-blade horizontal axis wind turbines
ii. Vertical-axis wind turbines
iii. Cabled, flying wind generators
iv. WhalePower wind turbines
v. Quiet Revolution qr5
vii. Mageen Air Rotor System (MARS)
x. Spiral Drag Wind Turbine
xi. Sky Serpent
In the quest to constantly improve the efficiency and reduce the inconveniences of wind turbine devices, engineers come up with new designs every day. Below are six innovative wind turbine designs, each of them having a specific advantage with respect to the others.
The world’s first Typhoon Turbine:
Invented by Atsushi Shimizu, the typhoon turbine is designed to tap into the massive energy stored in a typhoon. It is a vertical-axis Magnus wind power generator. The turbine would convert this energy into electrical energy which could be used to power other loads or for domestic use, whatever the need may be. Shimizu estimates that the energy contained by one typhoon could power his country, Japan, for 50 years. He is currently looking for investors to construct many of such turbines and integrate them into the nation’s grid.
A Hybrid Wind-Hydro Turbine:
The world’s first hybrid wind-hydro turbine, set to be situated in Germany’s Swabian-Franconian forest is designed to operate when there is wind blowing as well as when there is none. It comes as a result of a project by Max Bögl Wind AG and GE Renewable Energy, set to be completed in 2018.
Helium-filled floating Wind Turbine:
This turbine works on the principle that there is more wind blowing up in the sky, and thus more energy would be obtained from it. Apart from their ability to capture more powerful winds than the turbine at ground level, these turbines transmit WiFi and cell signals and also serve as weather sensors.
The Vortex Bladeless Wind Turbine:
The main feature of this turbine lies in the absence of blades which usually disturb and endanger the lives of birds flying high in the sky. It reportedly cuts manufacturing costs by 53% and maintenance costs by as much as 80%.
SheerWind’s INVELOX Wind Tunnel Tower:
This turbine harnesses the wind at ground level and passes it through a tunnel, thereby accelerating the air taken in. Thus, it produces more energy than conventional wind turbines. It also operates in low-wind conditions and the absence of external blades means it doesn’t endanger the lives of the birds in the air. The manufacturing costs are also less than that of conventional turbines.
Bird-friendly Catching Wind Power:
This turbine also does not endanger the lives of birds and wildlife. It captures the wind in what looks like a giant megaphone and compresses it thus producing more power at the output. Suitable for both residential and industrial use.
Challenges Faced with Wind Turbines
While harnessing wind energy provides a great source of clean energy, it comes with a number of disadvantages which need to be mentioned.
- Threatening to wildlife
- The Wind is unpredictable
- Limited resource (wind)
- Storage issues
- Land occupation
- Poor television reception
- Initial costs