Systems and methods for controlling the state of charge of an energy storage system used in conjunction with a renewable energy source or other power generation system are provided. More particularly, a future output requirement of the energy storage system can be predicted based at least in part on data indicative of anticipated conditions, such as weather conditions, wake conditions, or other suitable conditions. A control system can adjust a state of charge setpoint from a nominal setpoint (e.g. 50%) to an adjusted setpoint based at least in part on the future output requirement. In this way, the energy storage system can better accommodate the output requirements of the energy storage system during varying weather conditions.