Is there an "If" function?

[twolde]

Hi;

I want to develop a constrain where if one plant is selected, other plant should not be selected.

This approach will help me to see alternatives within the same technology development. Do you have any suggestion please?

Thanks

Tibebe

[twolde]

Clarification

Here is the issue. It is not a new investment, but I want to use the existing thermal plants as they are AND at the same time, develop the same  thermal plants after retrofitting with dry cooling system. In doing so, There is performance and cost penalty (capital cost, OM cost, heat rate and generation loss accounted for each of the thermal plants).

 Then, I gave the plants with the retrofits a new process name different from the formers.

But my question is, is there a constraint that allows either the existing OR the one with retrofits but not both? Also, I want to know to use the constraint not to select both the existing and its derivative (after retrofits) at the same time? Is there any method to define issues?

Thanks

Tibebe

[AKanudia]

In the LP world, all you can do is to constrain the capacity of the sum of (original unit + retrofits) to be <= capacity of the original unit.

If the original unit is retiring in a known year then you can adjust the START of the retrofits to make sure that they don't coexist with the original units, but I don't know any way of selecting *only* one of the retrofits without going to MIP. However, one good thing about LP is that it is unlikely to choose multiple options unless you have many intersecting constraints like several different pollutants being controlled independently (and the retrofits handling them differently).

I suggest you look at the results before rejecting this approach.

If you take the above approach, you might want to introduce a "non-increasing capacity" constraint for the above sum, so that there is no gap between retirement and retrofitting.