Sanjay Sah Could you explain how do you understand "green power from the PHEV" while grid has energy from fossil power? Do the employees recharging their cars at work, or do they return energy back to the grid from their vehicles, which were charged from "green sources" before?

I do not get some of that.

Beside this, note the common problem for PHEV used in cars fleet is that their users usually do not recharge the batteries and use those cars like ordinary HEV running only on gasoline. :)

Marcin Noga Thank you for your answer sir. Let me explain more about this.

The employees charge their battery at their home from green sources. I need to model a system in such a way that power from PHEV can be used during the time when employees are in office and at the end there should be enough power left so that employees can return back home after work. Besides this i need to use solar power which is available at day time only. And grid should be modelled as well.

I need to make a plan, how could I manage the power drained from these three resources, such that the electricity cost is minimized?

Sanjay Sah In the very first I would start from the definition of the PHEV Vehicle and the estimation of the approximate distance of the employes' places residence to the their office. Then you can estimate residual SOC after they came to office and the SOC they can give to the grid having still safe SOC to go back home. I don't know what is the desired complexity of your calculations, but it may be very simple, and very complex too, if you consider many possible cases (vehicles, distances, SOH of PHEV batteriea and so on).