Ideal turbine processes are constant entropy processes. That is, there is no change in disorder. The process retains the energy available to do work and there is no change in the energy unavailable to do work.
Therefore, you can measure the work done by an ideal turbine with the change in enthalpy of the steam.
In this video, I show you how to use a Mollier Diagram to solve the difference in work done by steam at 100% Quality over steam at 86% Quality.