maximazing income of produced commodity

[kxxu]

In my model I've got these processes: 2 chp with back-pressure turibine, 2 chp with condensing turbine, 3 heat plants and heat storage. I want to maximize income of produced electricity, shifting producing more heat at night(condensing turbine) to produce more electricity at day(when prices are much higher), in chp with back-pressure turbine produce more elcticity and heat at day. I've got market prices for electricty for every hour, heat has got constant prices. All proceses and demand for heat is already done, demand for electricity is irrelevant, how to model it and what parameters use?

[kxxu]

any ideas???

[kxxu]

I've tried 2 options: 1)setting big flo_cost, when I want to not produce much electricity and store heat and 2)setting varom and fixom and setting negative flo_cost, they aren't working as I want, I'm uploading my project, so if you've got any ideas please reply uploads/206/project.zip

[kxxu]

Is there an option to change obj function to maximize costs???

[Antti-L]

To maximize costs, yes, it should be possible in several different ways, although I have never tried it.

As this is the VEDA Forum, I describe one way of doing it with the tools available in VEDA-FE:

1. Create a new scenario, where you use a ~TFM_UPD table to update all cost parameters, multiplying them by -1.
2. Make sure that you allow for negative values for the objective components in TIMES, by defining UC_RHS('OBJxxx','N') = <any value> for all cost components (OBJxxx = OBJINV, OBJFIX, OBJSAL, OBJVAR);
3. Run the model with the new scenario included.

Note that in this method, the objective function is just multiplied with -1 and it will still be minimized by the solver, but that is equivalent to maximizing the original objective (step 1). Note also that in TIMES the objective component variables are by default assumed non-negative, and therefore you must redefine their lower bounds to be -INF (step 2).  Finally, remember that in the results you will see all costs as their opposite values.

Good luck!

[kxxu]

thanks, but is it possible to do that solver itself maximize costs