in the independent energy partners' geothermic fuels cells (gfc), a high-temperature stack of fuel cells is placed in situ or in place within a formation. during an initial warm-up period, the cells are fueled by an external source of natural gas. afterwards, the process is able to fuel itself using oil shale gas generated by its own waste heat. the formation is fractured by rising fluid pressure in the heated zone. alternatively, the formation can be pre-fractured to enhance the shale oil flow between heating and producing wells. the company asserts a ratio of approximately 7 units of energy produced per unit used, when primary recovery is combined with gasification of the residual char and use of the resulting oil shale gas. in addition, the fuel cell produces electric power as a by-product of the process.