Wind turbines are actively used nowadays to produce electric energy. The efficiency of wind turbines in general is questionable. We get the green energy on the one hand, but a lot of cons on the other hand: low profitability (including manufacturing, installing, and service costs), inconveniences with energy transformation, unstable working mode.
However, the positive moment is that energy generation with wind turbines is possible in small scales, say, in home conditions. Building hand made turbines can bring a lot of joy for the one who has the arms growing from the right place. For instance, you can build Savonius type rotor with just two pieces of barrel cut in half.
In this section we will take a look at what calculations could be done while designing your own wind turbine.