I think it it likely that you may have different optimal dispatch values depending upon the scenarios, but the major dispatch generally depends on the "Base case (No contingencies and most likely condition)".

However, some researchers try to incorporate multiple scenarios also in their optimization problem, so that the dispatch obtained after solving the optimization problem not only satisfies the base scenario but also other scenarios.

Hope it helped

In this example, one of the scenarios occurs in practice.so, the operator can set the generated power of the unit based on the occurred scenario. You could present a better example for explaining your problem although I know what you mean. Please follow the two-stage stochastic programming approach. in this approach, we face "here and now variables" and "wait and see variables." "Here and now variables" can be the answer to your questions.

This is a problem that needs to be solved with stochastic optimization algorithms. I recommend you take a look at the Benders Decomposition, an algorithm that is well suited for stochastic problems with scenarios. The output of this algorithm is a single value of your variable, given that the algorithm handles the uncertainty in the parameters.

Article The Benders Decomposition Algorithm: A Literature Review