58867 - Impact of Plant Siting on Performance and Economics of Indirect Supercritical Co2 Coal Fired Power Plants 

Indirect-fired supercritical CO₂ (sCO₂) power cycles are being explored as an attractive alternative to steam Rankine cycles for a variety of heat sources including fossil, CSP, Nuclear, waste heat etc. Therefore, understanding their performance and cost potential is important for commercialization of the technology. Due to the near-ambient CO₂ critical temperature of 31 °C, the effects of ambient temperature on sCO₂ power cycles performance are expected to be more significant than for steam Rankine cycles.

This study investigates the impact of plant siting on the performance and economics of coal-fired utility scale power plants based on indirect sCO₂ power cycles with carbon capture and storage (CCS).  Four uniquely different plant sites across the United States – Chicago (IL), Kemmerer (WY), Houston (TX), Knoxville (TN) were selected for investigation. For each plant location, local parameters such as design ambient conditions, coal type and prices, captured CO₂ transportation and storage (T&S) costs are considered for the techno-economic analyses (TEA). To determine the optimum plant design for each location, two power cycle configurations (recompression cycle, partial cooling cycle with reheat) and two cooling technologies (dry and adiabatic cooling) were examined.

Several design variables were identified for each power cycle configuration and these design variables were optimized to minimize the levelized cost of electricity (LCOE) for each plant location. The optimization design variables include parameters such as turbine inlet temperatures and pressure, sCO₂ cooler outlet temperatures, recuperator approach temperatures and pressure drops etc. The total number of optimization design variables ranged from 14 – 17, depending on the power cycle configuration. The optimization was conducted using automated derivative-free optimization (DFO) algorithms available under NETL’s Framework for Optimization and Quantification of Uncertainty and Sensitivity (FOQUS) platform.  The study results demonstrate the variability in optimal plant design for different ambient and fuel input conditions, and will be used in future sCO₂ technology market analyses.

Keywords:  supercritical CO2 (sCO2), recompression cycle, partial cooling cycle, levelized cost of electricity (LCOE), automated derivative free optimization (DFO), plant siting

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ACKNOWLEDGEMENT

Team KeyLogic’s contributions to this work were funded by the US Department of Energy’s Office of Energy Efficiency and Renewable Energy under the Mission Execution and Strategic Analysis contract (DE-FE0025912) for support services. The authors would like to thank Travis Shultz (NETL) and Eric Liese (NETL) for their support and assistance in performing this work.