A system for monitoring maintenance information in a hydroelectric power generation facility comprises sensors coupled to a controller. The sensors detect actual levels of operating parameters for a desired operating period at an operating condition. The detected parameters include a stressor capable of affecting a life span, or mean time between failures, of the turbine or one of its components. The controller determines the amount of the life span used up. A method for monitoring maintenance information in a power generation facility includes the steps of monitoring levels of operating parameters including a stressor for a desired operating period at an operating condition. The stressor affects the life span of the turbine or one of its components, and the amount of the life span used up over the operating period is calculated. A method for monitoring losses in a hydroelectric power generation facility operating to satisfy environmental constraints involves storing predetermined reference signals representative of desired turbine efficiencies over a range of operating levels in a memory circuit. Current levels of operating parameters are sensed while the facility is operating to satisfy the environmental constraints. A sensed parameter signal representative of a current turbine efficiency is generated from the sensed levels of operating parameters. The generated parameter signal is compared to the predetermined reference signals to determine an environmental efficiency loss signal.