<![CDATA[Bangkanai Gas Engine Power Plant exhibits a substantial waste heat potential within its exhaust gas, with manifold temperatures post-turbocharger ranging from 386.40 °C to 515.00 °C. Currently, this high temperature thermal energy is underutilized. This study aims to evaluate the technical and financial feasibility of integrating an Organic Rankine Cycle (ORC) bottoming system into the exhaust stack of PLTMG Bangkanai. A dynamic computational model was constructed using the MATLAB R2023a-CoolProp platform. The thermodunamic property pf the mixed flue gas – characterized bt a molecular weight of 28.164 g/mol – were dynamically tarcked across a 24 – hour daily cycle utilizing the JANAF/NIST Shomate Polynomial functions. The simulation evaluated four working fluids (R245fa, Toluene, Benzene, R1233zd(E)) across three optimization scenarios, constrained by an acid dew point stack safety limit (≥ 160.00 °C). The results reveal that R1233zd(E) yields the most superior performance, maintaining an absolute dry vapor phase at the turbine outlet ( ) and completely eliminating turbine blade cavitation risks. The integrated ORC system successfully harvested a peak net clean power output 6,152.40 kW. This addition elevated the overall system thermal efficiency from 38.50 % to 42.10 % and reduced the Specific Gas Comsumption (SGC) by 3.66%. Eviromental assessment utilizing the Higher-Tier Tier 3 IPCC direct stoichiometry approach indicates a greenhouse gas mitigation potential of 1,382.328 Tons of per year. Financial feasibility analysis was conducted over a 20-year Power Purchase Anreement (PPA) horizon, calibrated with a 10.00% Cost Of Capital (CoC) and a flat exchange rate of Rp17,500/USD. The initial Capital Expenditure (CapEx) allocation of Rp236.87 Billion is economically viable, generating a positive Net Present Value (NPV) of +Rp49.72 Billion, an Internal Rate of Return (IRR) of 14.52%, a Benefit-Cost Ratio (B/C) of 1.177, and a Payback Period (PBP) of 8.2 years]]>
