From the point of view of the availability of the information and the frequency of the decision make on the system the optimal operation of hydropower system can be regarded as: Static, Dynamic not in real time and Real time. The all three kind of operation is depicted on the following figures. In the static process one single operational decision is taken at the beginning of the optimisation process based on the initial available information. In order to improve the operation the second process is developed. The difference from the static process is that there are multiple decisions taken during the time, but all are based on the information that was available at the beginning. This information may have changed and the system does not know about it. To overcome this real time processes are developed. The real time processes differ in that way that all future decision are made based on the latest available information as the information changes in real time, the system is reoptimised and new set of decisions is derived.