duty schedule to match varying flow conditions application_number US 36597182 A description referring now to the drawings in detail fig1 illustrates a hydroelectric power generating installation generally referred to by reference numeral 10 from which generated electrical energy is supplied through a power output bus 12 to a utility power grid the installation 10 includes a plurality of fixed hydraulic geometry turbines 14 respectively driving induction generators 16 supplying the electrical energy to the common output bus 12 without any load or voltage controls each of the turbines 14 and associated generators 16 are of a mass produced type of proven design and cost effectiveness with fixed hydraulic orifices and no means to control the amount of water flow therethrough such turbines operate at a rated efficiency when an optimum flow of water is conducted therethrough dependent on the size of the turbine thus such turbines cannot individually handle variable flow conditions since the efficiency thereof will drop for example from 100 rated value under 100 optimum flow toward zero efficiency below 40 optimum flow energy is derived from a hydropower source 18 such as a body of water at an elevation above the turbines from which a variable flow is available flow valves or gates 20 control water flow at optimum flow rates from source 18 parallel to the respective turbines 14.