There are two fundamental rules. First, do not be too concerned if the site does not meet all the criteria listed below. Very few do and yet many projects still prove viable. Secondly, some seemingly insurmountable problems may be 'engineered-out' with only a small loss of time and money.

Unlike many types of power station, hydro schemes are extremely versatile in the way that they can be located, designed, built and operated. One major point in their favour is that the generating equipment is usually located at the bottom of the hill. This means that access roads and powerlines are either more likely to be present or can readily be provided without causing unreasonable landscape impact.