In this paper, a hybrid turboexpander-fuel cell (TE-FC) is investigated for extraction of electrical energy from high pressure gas in which the fuel cells are used for preheating the gas. Combination of expanders and fuel cells will reduce the fuel consumption and greenhouse gas emission. This study reveals that there are some circumstances in which the use of fuel cells in conjunction with a turboexpander is not recommended from an economic point of view. This paper seeks the region in which utilization of fuel cells along with a turboexpander presents maximum economic profit. Using the strategy provided in this paper one can decide whether to invest in the hybrid fuel cells-turboexpander or individually planned turboexpander with a conventional gas fired preheating system. Almost all effective parameters are taken into account and this can be considered a superiority of the present paper.