Wind energy is utilized by converting it into electrical power using wind plants. It is one of the fastest-growing sources of electricity nowadays. Wind power is produced from turbines that are usually more than 60 meters high and have long blades. The wind spins the blades which run the connected generator and hence produce electricity. The biggest wind turbine can generate enough electricity in one year that can feed approximately 600 homes. A wind farm has many turbines connected. The main parts of wind plant are consisting of rotors, controls, electronics, and gearboxes.
Wind plants do not produce air or water pollution with approximately zero operational cost once installed. The main drawback of wind plants is they are ugly and noisy. They can kill birds. The variability of wind affects the generation of electricity. Wind energy efficiency can be measured in different ways some of them are discussed below.
Wind energy is free and will never run out, even it is completely renewable resources but the wind is always not blowing all the time. The wind blows at different speeds due to which power is generated at an inconsistent level. Wind plant requires speed of wind approximately 33 miles/hour for a generation of electricity and at very high wind speed wind turbine usually shutdown. The position of a wind turbine is also important to factor it should be in a position where it gets maximum benefits from the wind.
Wind energy is free but the cost of manufacturing and installing wind farms is not negotiable or neglected. The wind turbine life span is approximately 20 years with low maintenance required. Wind plant efficiency can be measured by capacity factor and reliability. The capacity factor of the turbine is the generation of very low-cost energy by obtaining maximum possible power. 10 years ago turbines have a 25% capacity factor which is increased to 50% nowadays. Capacity factors can be increased by increasing the size of rotors on wind turbines. Turbines rotors are affected by two different forces that are torque which turn the rotors and create energy and second is thrust which operates turbines.
Wind power systems have achieved significant improvement in operating efficiencies, making them more economically competitive with other energy generation techniques. Along with the need for increased sustainability in the energy sector, wind energy systems are increasing their market share faster than any other renewable energy system. Horizontal axis wind turbine has emerged as the dominant technology in modern wind turbines technologies. In comparison to vertical axis turbine horizontal axis wind turbine can achieve higher energy efficiencies, thereby increasing the power production and reducing system expense per kW of power generated. But as the opportunity to expand wind capacity increases, it is important that all aspects of this sustainable and environmentally benign technology are fully developed.
Vertical axis wind turbines have demonstrated an ability to fulfill certain energy generation requirements that cannot be achieved by horizontal axis wind turbines. A horizontal axis wind turbines can achieve higher efficiencies only if the wind speed is high. High wind turbulence, wind fluctuations, and high directional variability can cause significant limitations for horizontal axis wind turbines whereas the vertical axis turbines can operate will in these conditions.
Local or distributed has got significant importance in recent years. The resurgence of this old technology is partly attributed to the need for environmentally benign and sustainable energy systems in smaller communities. This includes diversifying the generation techniques and increasing systems efficiencies while minimizing the environmental impact. Onsite power generation can overcome transmission losses and land costs. However, densely populated locations and urban centers generally coincide with a low quality of wind sources, including high turbulence, fluctuations in intensity and high variable direction of flow streams.
Variable pitch blades can improve turbines’ performance by varying the angle of attack to coincide with the various wind conditions, but this approach is generally not economically practical for a small installation. Fluctuating winds can greatly reduce a Horizontal axis wind turbine’s performance as long as idling periods are experienced at startup when the rotor accelerates slowly. Certain vertical axis wind turbines designs have the ability to operate in these harsh operating conditions.
During the last 10 years technologies have been developed for onshore as well as offshore wind power projects. Companies are also looking for the use of floating wind turbines, which use floating structures instead of wind towers to be set into foundation underwater.
There are several tools to improve the efficiency of wind plants such as the use of computer simulations that helps to design efficient blades. Modeling software can be used for a variety of other simulations, including manufacturing components, as well as monitoring the potential performance of generators and components, performing structural analysis or looking at electronic controllers. The technological advances and research in this field made wind power more efficient and affordable as compared to other power generation methods.