Disclosed is a power control system for a container vessel. The power control system has a power interface for supplying energy to at least one reefer container transportable by the container vessel. The power control system also has a controller configured to obtain load data representative of a load on a generator of the container vessel, and target load range data representative of a target load range for the generator. The power control system is configured to control the load such that the load falls within the target load range by the controller increasing energy supplied to the power interface for storage at the at least one reefer container, when the load is below the target load range.