Wind Energy

-Overview

Wind is caused when the earth's surface is heated unevenly by the sun. Wind energy can be used to generate electricity. 

Wind turbines, like windmills, are mounted on a tower to capture the most energy. At 100 feet (30 meters) or more aboveground, they can take advantage of the faster and less turbulent wind. Turbines catch the wind's energy with their propeller-like blades. Usually, two or three blades are mounted on a shaft to form a rotor. 

A blade acts much like an airplane wing. When the wind blows, a pocket of low-pressure air forms on the downwind side of the blade. The low-pressure air pocket then pulls the blade toward it, causing the rotor to turn. This is called lift. The force of the lift is actually much stronger than the wind's force against the front side of the blade, which is called drag. The combination of lift and drag causes the rotor to spin like a propeller, and the turning shaft spins a generator to make electricity.

- Wind Turbines

Wind turbines can be used as stand-alone applications, or they can be connected to a utility power grid or even combined with a photovoltaic (solar cell) system. For utility-scale (megawatt-sized) sources of wind energy, a large number of wind turbines are usually built close together to form a wind plant, also referred to as a wind farm. Several electricity providers today use wind plants to supply power to their customers. 

Stand-alone wind turbines are typically used for water pumping or communications. However, homeowners, farmers, and ranchers in windy areas can also use wind turbines as a way to cut their electric bills. 

Small wind systems also have potential as distributed energy resources. Distributed energy resources refer to a variety of small, modular power-generating technologies that can be combined to improve the operation of the electricity delivery system. For more information about distributed wind, visit the U.S. Department of Energy's Wind Energy Technologies Office. 

Offshore wind energy is a relatively new industry in the United States. America's first offshore wind farm, located in Rhode Island, off the coast of Block Island, powered up in December 2016. The Energy Department's Wind Vision Report shows that by 2050, offshore wind could be available in all coastal regions nationwide.

- The Operation and Management of Wind Energy Infrastructure

Amongst renewable sources in the global energy pool, wind energy holds the lead. However, the optimal operation and maintenance of wind energy infrastructure is non-trivial, because of its exposure to harsh environments, as well as repetitive, often extreme and highly variable loads. With a number of wind turbines currently reaching the end of their design span, the research and industrial communities need to turn to new methods and tools for reliable life-cycle assessment. Novel sensing and Non Destructive Evaluation solutions offer valuable tools for intelligent monitoring and assessment of wind energy infrastructure, at both the individual unit level, as well as the level of fleets - or populations. 

Structural Health Monitoring (SHM) can be used for early stage verification and investigation of design uncertainties, deliver early warnings on degradation/damage and abnormal operation, as well as provide input for prognostic tasks, such as remaining useful lifetime assessment, preventive maintenance and optimisation of operational/control conditions. SHM applications include - amongst others - the measurement of the environmental inflow conditions, the turbine’s operational conditions, structural load effects (extreme and fatigue cycles), system dynamics (vibrations), mode shapes, natural frequencies and damping characteristics, stress “hot-spots”, etc. Applications, especially on the wind-farm level, of probabilistic machine learning and artificial intelligence algorithms, such as neural networks, Bayesian networks and ensemble classifiers are encouraged.