There are a variety of options available for creating alternative power sources and something that greatly interests environmental engineers is the idea of wind power and how community wind farms might be an option for reducing fossil fuel output. Wind power in a given area is measured by a calculation commonly referred to as "Wind Power Density" and will vary according to how high the area being measured is off the ground. Although a particular area might be considered low density, that doesn't mean that some positions might not otherwise be a good spot for wind power.