The pollution produced by power purchased from electrical network and the extensive effort of Iranian government toward the elimination of energy subsides are the encouraging factors in Iran for employing hybrid green power system (HGPS) to produce power. Therefore, in this study, the effect of current and future energy prices as well as energy budget on optimal design of an HGPS is studied. Three cases are considered to examine the optimization problem thoroughly: (i) autonomous HGPS; (ii) nonautonomous HGPS, but HGPS cannot sell electricity to electrical network; and (iii) nonautonomous HGPS and HGPS is allowed to sell electricity to electrical network. The results for Case 2 and Case 3 show that with the increase of energy price from three to five times (0.7 and 0.5), budgets for Cases 2 and 3 (0.6 and 0.2,, respectively) are required to ensure that the design is economical.