Wind as energy source
Wind turbines / wind generators come in all shapes and sizes, but you will most likely recognise them in their industrial form, huge white propellers on giant white stems towering up to 80m high above ground. It is very unlikely your OffGrid project needs such a 150Kw monster. However in most areas a smaller wind turbine around the size of 400watt-3kw can be a worthwhile investment. The wingspan of these are 1m to 3m and will still fit into the landscape without standing out or producing too much noise. Simply put, the wind turns propeller / blades around a rotor, which spins a shaft, which connects to a generator to create electricity. A wind turbine will typically generate 30% of its theoretical maximum output on a slightly windy day. Having at least one wind generator in OffGrid projects is recommended, even when your location is not particularly windy on normal conditions. During bad weather phases especially Autumn wind can be a very good source of energy to keep your batteries happy over longer periods of little to no solar. It also helps on battery lifetime to have the occasional charge in the night, even if it may only be 20 minutes. Big difference to solar is, do not size wind generators to big! A wind turbine will need to “get rid” of produced energy, if your battery is full and you did not install a resistor to burn off the excessive power you risk damaging your equipment. to give a rough idea, some 500w input for every 300ah of battery should be considered maximum.
Types of windgenerators
Horizontal wind generators
These are the design you are probably most used to.
For best results they need to be put on a pole and above roof level, or in reasonable distance to any objects that influence wind flow. They provide very little to no power during slow air movement times, but will produce reasonable power during medium and high winds. Horizontal wind generators do create a certain level of noise. Although not loud, you can certainly hear it when the blades are spinning. Installing one right above your sleeping room might not be the smartest thing to do. Generally they are a bit cheaper than vertical ones.
Vertical wind generators
These provide power even with the smallest movement of air. Vertical wind generators are a lot less influenced by turbulence, as there is no nose that needs to point towards the wind, but instead they can utilise wind from all directions at the same time. If you plan on installing only a single wind generator for your project, a vertical one will provide more reliable power. These can be installed directly on the roof or such, there is no requirement to put them on a pole.