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Ahmad HemamiAhmad Hemami received his BS degree in Mechanical Engineering from the University of Tehran and his PhD in System Dynamics and Control from the Department of Aeronautical and Mechanical Engineering at the University of Salford, UK. Dr Hemami has several years of industrial, academic and research experience. Among his areas of expertise are robotics, control and automation, and wind energy. He has supervised several MS and PhD students, and has served as a consultant for industry. He has over 100 journal and conference publications. He is an adjunct professor at McGill University (Montreal, Canada).

Are We Going in the Right Direction?

Windtech Future Failure percentageThinking about the time when a major portion of electricity will be provided by wind, solar and other renewable sources, in which power converters play a significant role, the question of power quality pops up. Presently, in many places the amount of generated energy that passes through these converters is very small but now that there is a shift from type 3 turbines (with doubly-fed induction generator, DFIG) to type 4 (direct drive) for the growing offshore turbines, the presence of harmonics lowers the quality of the generated power. In turbines equipped with a DFIG at least 2/3 of the power travels through the stator winding, i.e. there is a clean sinusoidal waveform with no harmonics, but with direct-drive turbines, inevitably all the generated electricity must pass through converters.
 
By Ahmad Hemami, McGill University, Montreal, Canada

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A Design Concept for Future Offshore Wind Turbines

Fig1 Windtech Future May JuneTremendous progress can be observed in wind turbines and their technology development, as demonstrated by the increase in their size and power capture capability. The growth in size, however, cannot be indefinite and eventually reaches a limit, from a practicality viewpoint. All newer generations of current wind turbines from almost all manufacturers in the past 40+ years have been based on improving the previous generation as well as making them larger. This is true except for a few models that could not survive or even could not enter the market, for whatever reason.
 
By Ahmad Hemami, McGill University, Montreal, Canada

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Wind Turbines in 2100

Windtech Future March April 21Predicting the status of wind turbines now for 80 years in the future can be not much different from predicting the future of home computers in 1950 for 2004. You can see the latter in Figure 1 and observe such a prediction to be far from reality.
 
By Ahmad Hemami, McGill University, Montreal, Canada

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Drones or Robots for Blade Repair?

wheel4Recently I have come across the development of a robotic device called BladeBug. It is a legged moving robot for maintenance work on wind turbine blades, specifically for offshore turbines. Suction caps stick to a body for which the robot is to do some work. Congratulations to the people involved in developing the device. There are a lot of challenges to overcome for any new development to achieve the expected capabilities.
 
By Ahmad Hemami, McGill University, Montreal, Canada

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Should Offshore Floating Wind Turbines be a Larger Copy of Onshore Turbines?

Ahmad WF fig 1The progress made in the wind energy industry, demonstrated by the design of larger wind turbines to harness more energy from wind, is admirable. All aspects of manufacturing, installation and operation of these giant structures to deliver multimegawatt energy require lots of expertise, ingenuity, determination and hard work. Probably in the beginning no one would have thought of having turbines in the middle of water capturing wind energy, with no complaints about noise, view and other legitimate or illegitimate issues.
 
By Ahmad Hemami, McGill University, Montreal, Canada

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The Race for Bigger Turbines Continues

supply side analysis 2019In the 1980s, the three-bladed, fixed speed Danish wind turbine was the dominant model with a rated capacity of less than 200kW. Forty years later, wind turbine manufacturers are continually breaking the proverbial glass ceiling by launching turbines bigger than we would ever have imagined just a few decades ago. In May 2020, Siemens Gamesa Renewable Energy launched the biggest turbine ever announced, clocking in at 14MW and with a 222-metre rotor diameter for offshore wind farms. Just one of these turbines could generate enough electricity to power 18,000 European households every year.
 
By Feng Zhao, Strategy Director at Global Wind Energy Council

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