A decision variable is a variable whose optimal value is determined during the course of the optimization process. An example is the size of the PV array. If you are specifying your own Search Space , HOMER considers each different PV array size you specify and finds the value that results in the least net present cost.
The decision variables in HOMER are:
•the size of the PV array
•the number of wind turbines
•the size of the hydro system
•the size of each generator
•the number of batteries
•the size of the converter
•the size of the electrolyzer
•the size of the hydrogen storage tank
•the dispatch strategy
•the maximum grid demand
Decision variables are also known as optimization variables.