University of Central Florida (UCF) PHY1038 Physics of Energy, Climate Change and Environment Final Practice Exam

The assertion that a windmill can extract 90% of the energy from the wind is not feasible based on the principles of physics. According to Betz's Law, the maximum efficiency that a wind turbine can achieve is 59.3%. This limit arises because, for a wind turbine to extract energy from the wind, some wind must continue to flow past the blades; if all the energy were extracted, the wind would halt, preventing further energy extraction.

Understanding this concept clarifies why extracting 90% of wind energy is not realistic—it exceeds the theoretical limits established by Betz's Law. Therefore, any claim of achieving such high energy extraction efficiency does not align with the laws of physics governing wind energy conversion.