Thermo-economic investigation of transcritical Carbon Dioxide solar-thermal power plants, Part 1: System modeling and simulation for design with validation of results

• CO 2 solar-thermal power plant for medium-to-small-scale industrial/campus cogeneration. • Thermodynamic analysis of CO 2 power cycles compared to references. • Comprehensive design and modeling of a transcritical CO 2 power cycle parabolic trough collector (PTC) solar plant. • Levelized Cost of Energy (LCOE) of $0.2915/kWh calculated with median-day plant simulation and validated with empirical data. • Compared with state-of-the-art technologies, further LCOE-based optimization could facilitate market penetration. This study comprises the engineering design and economic assessment of a novel trans -critical-point Carbon Dioxide cycle integrated with a solar Parabolic Trough Collector (PTC) power plant. A 1-MW facility with a Rankine transcritical CO 2 cycle providing combined heat and power for a small industrial facility in Texas was proposed as the baseline power plant to perform the analysis. A design and modeling effort was performed in Engineering Equation Solver (EES) for the many systems and components of the power plant, including the solar field, the power block, and sub-components such as turbomachinery and heat exchangers. The model created enabled the simulation of plant performance for the median day of each month in the year by inputting meteorological TMY3 data, and results were extrapolated to estimate the annual energy and monetary income yield. Data processing was performed with MATLAB. Economic analysis included estimation of capital and O&M costs for the baseline plant. Results were verified through empirical performance simulation, using System Advisor Model (SAM), a software provided by NREL. The levelized cost of energy (LCOE) for the modeled plant was $0.2915/kWh, as calculated with EES/MATLAB, and $0.305/kWh, as calculated with SAM, resulting in a difference of less than 5%, between the two different simulation approaches. The design and simulation work presented herein provides the means to perform an optimization analysis, which reveals important clues as to how the energy cost could be reduced so as to make this technology a competitive alternative within the energy market.