Assess Your Site for WIND POWER

Wind power in the form of windmills has been around for a long time. Relatively short towers once hosted large rotors with many blades to produce the power and torque needed for tasks such as grinding grains and running machinery. During the 1930s, wind-electric generators made their way into rural areas lacking electric power lines. These low-voltage machines were primarily used to charge batteries that powered low-voltage direct current (DC) home appliances. Some were dedicated to pumping water.

Today, a handful of manufacturers produce wind-electric turbines for both grid-tied systems and off-grid battery-charging applications. “Turbine” generally refers to the combination of blade set and generator assembly, while “generator” refers specifically to the electricity-producing unit.

Modern wind machines use high-efficiency generators or alternators and highly refined blade designs and materials for maximum efficiency. Other wind-electric devices range from small rooftop wind machines to vertical axis wind turbine (VAWT) designs. While there is encouraging research on these new designs, current best practices for harvesting wind energy highlight the traditional horizontal axis wind turbine (HAWT). I’ll follow suit and focus on how wind fundamentals apply to HAWT.

Using Wind Energy

Wind turbines generate electricity by capturing the wind’s energy as it rotates two or three propeller-like blades attached to a generator that produces electricity when it spins. The turbines are mounted on towers