A turbine generator system for use in a flow line from a water supply to a water usage, treatment or storage system employs a remotely controlled valve for control of the flow of water through the turbine. The system is arranged to shut down upon occurrence of under or over voltage at the generator or loss of pressure at the turbine, disconnecting the generator from the utility line and closing the control valve to stop flow through the turbine. Should failure of the utility line power decrease the generator load to increase turbine speed, restart is prevented until the control valve has closed to stop the turbine. A time delay in the control panel shuts down the system if the control valve does not open within a selected time interval after start up. To accomodate daily variation of flow rate to a water distribution and usage system, a first turbine generator and control valve have a capacity to handle a minimum flow rate and a second turbine generator and control valve, in parallel with the first, automatically come into operation when the flow rate exceeds the capacity of the first turbine generator and control valve.