The efficiency of the turbine is a charisteristic of the machine given by the manufacturer. This efficiency depends on the waterflow. Indeed, if the inflow is, for example, only half of the expected speed (or nominal waterflow), it is easy to understand that the piece of the waterflow that will run between the rotating parts and the fixed parts without reacting on the blades of the machine does little or nothing. So the effective waterflow drops sharply and leads to an efficiency drop.
The potential of a site can be improved if the hydroelectric equipment is not a hydroelectric facility along the waterstream but equipped with an accumulation pond. In these circumstances it is possible to, for a few hours of the day, provide sufficient waterflow for periods of greater consumption of electricity. When the population of the village sleeps, they generally consume much less electricity. This decrease in electricityrequirements accompanies, trough the speedregulator discussed above, a decrease in waterconsumption. The saved amount can be used at times of greater need. This accumulation pond should be considered in the context of a daily regulation. If deals around overcoming the insufficiencies of low water flows, the accumulation intake reaches a size that is outside the context of small power plants.
===Assessment of electricity needs===