Net Present Value in Gas Turbine Generator Selection for LNG Liquefaction Plants-a Case Study

With the gradual rise in the size of LNG liquefaction facilities where multiple LNG trains are built within a single site, the selection of optimum power generation capability while satisfying the economic requirements becomes a significant challenge. A structured approach is required for the selection of the primary power generation facility for the standalone industrial power system of LNG liquefaction plants. The task includes but not limited to managing performance at different ambient temperatures, heat integration and heat/power ratio, step load changes, load drops, emissions, product quality constraints; plant owner’s operating goals and other complexities. The paper presents a case study demonstrating integration of Gas Turbine Generator Loading Analysis and Net Present Value evaluation for the Gas Turbine Generator selection while showing a tradeoff amongst thermal efficiency and plant overall efficiency, capital costs and/or operation and maintenance costs. A comparative ranking of all candidate Gas Turbine Generators is presented based on a combination of lowest Net Present Value Rank, lowest Total Installed Cost Rank, an acceptable Gas Turbine Load Factor Operational Risk and Load Shedding over the entire design life of the plant.