Biliran I Geothermal Project is one of the promising yet undeveloped intermediate-enthalpy geothermal resource in the Philippines. There were already drilled wells in the project site and in this paper, Well BN-06D was selected to evaluate its maximum power generation through exergy analysis. Exergy analysis is a tool which analyzes geothermal power plants from the optimum perspective of produced energy and it delivers sensible values for decision makers. Moreover, combined single flash-binary cycle has been chosen to utilize the power output capacity. Wellbore output measurements from the successful Fluid Management System (FMS) and mathematical models, were applied in Engineers Equation Solver (EES). Assumptions and simplifications were also considered. The energy efficiency from the combined single flash-binary cycle was calculated at 10.77%. Further, the exergy efficiency from the single flash and waste brine were calculated at 37.87% and 31.83%, respectively. By using binary cycle, the waste brine was utilized, and the exergy efficiency was increased to 37.90%. The large exergy destruction in the systems happened in condenser under single flash cycle (22%), pre-heater under binary cycle (15%) and both turbines; (9.8% in binary & 8% in single flash). A Grassmann diagrams were also illustrated to further visualize the process of the overall exergy flow in each system.