OPTIMAL SOLUTION WITH SOME VARIABLES ZERO

[Lawalmusa]

I ran my GAMS model and have an output thus:

**** SOLVER STATUS 1 Normal Completion
**** MODEL STATUS 1 Optimal

However, some variables which are part of the objective function are returning with Zeros (0) values in the results display.
Please how can help me to detect where the problem is and how to solve this problem. Please find attached the .gms file of the model.
Thank you and Best Regards
Musa

[abhosekar]

Why do you think some variables being zero is a problem? An optimal solution can very well contain zeros. Do you have constraints that force them to be non-zeros, can you be precise about what surprises you here?

Best, Atharv

[Lawalmusa]

Thanks for your kind response, what baffles me about the results is that some critical components of the objective function are zero.
For instance the Objective function is:

CWTSTAC.. TAC =E= CostFWater + CostRWater + TCostTre + PCapPipeTotal + PumpingCost + TTankCost ;

However, in the solution 1) CostFWater (2) CostRWater and (3) PCapPipeTotal and other variables such as; fFW, fFWp, fWWpi were all zero which i could not understand. Please forgive my naivety, i am new to GAMS modeling. I am willing to learn more. Thanks