Lowering the Levelized Cost of Electricity of a Concentrating Solar Power Tower With a Supercritical Carbon Dioxide Power Cycle

Abstract

In order to maintain viability as a future power-generating technology, concentrating solar power (CSP) must reduce its levelized cost of electricity (LCOE). The cost of CSP is assessed with the System Advisor Model (SAM) from the National Renewable Energy Laboratory (NREL). The performance of an integrally geared compressor-expander recuperated recompression cycle with supercritical carbon dioxide (sCO2) as the working fluid is modeled. A comparison of the cycle model to the integrated SAM cycle performance is made. The cycle model incorporates innovative cycle control methods to improve the range of efficiency, including inventory control. The SAM model is modified to accommodate the predicted cycle performance. The ultimate goal of minimizing the LCOE is targeted through multiple approaches, including the cost of the power block, the impact of system scale, the sizing of the thermal system relative to the power block system, the operating approach for changes in ambient temperature and availability of sunlight. Through reduced power block cost and a detailed cycle model, the LCOE is modeled to be 5.98 ȼ/kWh, achieving targeted techno-economic performance. The LCOE of the CSP system is compared to the cost of hybrid solar and fossil-fired systems. An analysis is made on the efficacy of a fossil backup system with CSP and how that relates to potential future costs of carbon dioxide emissions.

Potential of Supercritical Carbon Dioxide Power Cycles to Reduce the Levelised Cost of Electricity of Contemporary Concentrated Solar Power Plants

“…Two different dispatch control schemes are considered in this work: the default scheme reported by SAM and the scheme proposed by the SunShot Vision Study [28]. A graphical representation of these is presented in Figure 5 which confirms that these schemes merely define an overall schedule of plant operation but they do not substitute or interfere with the off-design control strategies described in another work from the same authors [11].…”

“…With this in mind, it is concluded that more accurate part-load models and integration schemes in SAM or equivalent software will prove that either the Allam or Partial Cooling cycle layouts have the potential to make a strong case for the next generation of CSP plants based on sCO 2 power cycles, enabling the ambitious objectives targeted by the SunShot Program. In this regard, it is interesting to see how the selection of a particular set of assumptions (both financial, economic and thermal) has the potential to turn the Recompression cycle into a competitive option to achieve the 6 g/kWh target of the SunShot programme [28], which is certainly in contrast with the conclusions obtained in this work. Far from discussing the credibility of other research works, the latter statement aims to highlight that much more work on the assessment of appropriate sets of non-technical boundary conditions is still required.…”

“…The resulting information is then combined with the installation costs to obtain LCoE, as discussed in detail by M. Martin [13]. To this end, the authors have relied on the System Advisor Model SAM developed by the National Renewable Energy Laboratory of the United States' Department of Energy, since this is widely accepted by the scientific community and already employed in cost estimation for sCO 2 power plants [28,29].…”

Review of supercritical CO2power cycles integrated with CSP

“…Namely, a drop range of 15.6 to 67.7% in terms of CSP LCOE has been witnessed. Higher turbine inlet conditions and longer storage duration generally translate into lower LCOE, as can been seen from Ty Neises 117 , Yuegeng Ma 118 , J. Schmitt 119 . However, it is not always right under the circumstance that higher operating conditions call for higher corrosion-resistance materials such as nickel based alloys instead of commonly used stainless steel, as summarized before.…”

Off-design and annual performance analysis of supercritical carbon dioxide cycle with thermal storage for CSP application

“…The annual simulation is performed using the System Advisory Model (SAM V2018.11.11), which designs a heliostat field layout optimised for the selected location of Dagget, California. A solar multiple of 2.8 and 14 hours of TES are used in this study [42]. SAM calculates the hourly optical efficiency and evaluates the energy absorbed by the HTF considering both the receiver and piping losses.…”