Indeed, it is not optimal to have an electricity system composed solely of steam-coal power plants and you are correct that by only satisfying the least-cost objective, this may not lead to the most realistic outcome. However, LEAP's optimized capabilities allows you to create a more accurate representation of the energy system you are modeling by allowing you to include capacity constraints. For instance, you can set the minimum capacity, or the minimum capacity to be added each year, for any intermediate or peak plant to ensure these processes are built and available to satisfy module requirements. The "Minimum Capacity" variable is used for setting the *total* minimum capacity for a process and the "Minimum Capacity Addition" variable represents the minimum capacity that needs to be added in a given year. Alternatively, you can set a "Maximum Capacity" or a "Maximum Capacity Addition" constraint to limit the capacity that is built for a given process. For example, these variables can be used to limit the amount of steam-coal capacity that is built.

As mentioned in the previous post, LEAP does not consider the merit order in the optimization calculations. However, by setting capacity constraints in the optimized scenario, LEAP will have a more realistic energy system to draw from when attempting to meet module energy requirements.

Hopefully this helps!

Emily