Economic and scenario analyses of new gas turbine combined cycles with no emissions of carbon dioxide

In this paper economic and scenario analyses of new gas turbine combined cycles with no emissions of carbon dioxide (CO₂) and nitrogen oxides are described. The cycles, already presented in a recent paper (ASME GT 2002-30117), have water/steam as a working fluid, the compression phase both in liquid and vapor phase, the internal combustion between pure oxygen (O-2) and chemically heated natural gas-based syngas, and the CO₂ capture and sequestration by water condensation from the exhaust gas. The aim of the economic analyses is to estimate the investment per MW and the levelized discounted cost of the electricity (COE) produced by a power plant based on the cycles proposed here in comparison with a standard reference combined cycle power plant (SRCC). To evaluate the equipment costs, several cost functions of the most important operative parameters have been introduced and tuned with the actual data. Using the least square regression technique, explicit functions of the COE have been proposed to highlight the cheapest operative conditions with a derivative approach. Moreover a wide scenario analysis has been carried out, varying the most important investment parameters, as, for example, the discount rate. In particular, some maps of the COE and break-even carbon tax (BECT) behavior have been constructed to test the importance of the market uncertainty on the economic results obtained. Finally, the possible technological progress effect on the BECT with a cost reduction of some innovative equipment and the O-2 production has been investigated in depth with the 2(k) factorial design scenario analysis. The O-2 production has resulted as the most important parameter from an economic point of view.