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December 2010 ~ Wind Power Plant. The wind turbine aerodynamics of a horizontal-axis wind turbine (HAWT) are not straightforward. The air flow at the blades is not the same as the airflow further away from the turbine. The very nature of the way in which energy is extracted from the air also causes air to be deflected by the turbine. In addition the aerodynamics of a wind turbine at the rotor surface exhibit phenomena that are rarely seen in other aerodynamic fields. Axial momentum and the Betz limit Energy in fluid is contained in four different forms: gravitational potential energy, thermodynamic pressure, kinetic energy from the velocity and finally thermal energy. Albert Betz and Frederick W. Where: a is the axial induction factor, U1 is the wind speed far away upstream from the rotor, and U2 is the wind speed at the rotor. The first step to deriving the Betz limit is applying conservation of axial momentum. Another equation is needed to relate the pressure difference to the velocity of the flow near the turbine.

Wind turbine gearboxes and the effort to improve their reliability. Early "Danish-concept" wind turbine models played a key role during the pioneering days of the wind industry, and their heritage is still evident in current non-integrated drive systems. They feature a main bearing, main shaft, gearbox, intermediate shaft and generator all fitted in line. And it is from these models that many other alternative geared drive systems have since been developed. In the early days, the gearboxes and generators tended to be off-the-shelf products, which came from either an agricultural or industrial application - quite different from today's dedicated custom-developed components.

Yet, despite the initial scientific inexperience and inadequate knowledge base behind these designs, the track record of these wind turbines, particularly the Danish and German models, is good. This is often attributed to substantial safety margins that compensated for the gaps that existed in wind technology and in the understanding of wind-induced loads on turbines. No overloading. Nawind_PreventingBearingFailure.pdf (application/pdf Object) 14-brianmcniff.pdf (application/pdf Object) Generator Blog » Wind Generator. PHOENIX–(BUSINESS WIRE)–The National Renewable Energy Laboratory today released an initial study assessing the operational impacts and economics of increased contributions from wind and solar energy producers on the power grid.

The Western Wind and Solar Integration Study examines the benefits and challenges of integrating enough wind and solar energy capacity into the grid to produce 35 percent of its electricity by 2017. The study finds that this target is technically feasible and does not necessitate extensive additional infrastructure, but does require key changes to current operational practice.

The results offer a first look at the issue of adding significant amount of variable renewable energy in the West and will help utilities across the region plan how to ramp up their production of renewable energy as they incorporate more wind and solar energy plants into the power grid. Other key findings from the study include: