Session: 07-01: Technoeconomic Analysis of CSP Receivers and Particle Storage Technologies

Paper Number: 131174

131174 - A Techno-Economic Analysis of a 50MWth Light-Trapping Cavity-Planar Solar Receiver Tower Capital Expenditures and its Cost Mitigation Strategies 

Abstract: 

Concentrated Solar Power (CSP) is a growing technology in the renewable energy industry, utilizing heliostats surround a solar tower to concentrate solar radiation on a receiver that is atop the solar tower, and the receiver itself behaves as a heat exchanger to transfer radiative heat to a Heat Transfer Fluid (HTF) that can be used for electricity generation in the power block. The advantage of this technology is that the heat can be stored for later use with the implementation of Thermal Energy Storage systems in the case of low solar exposure, such as cloudy rainy days or throughout night cycles. While these systems are largely beneficial to the energy industry, the efficiencies of these systems are positively correlated to higher temperature HTF. For Gen3 CSP towers, it is expected that the HTF will have an outlet temperature greater than 700°C. Current systems that utilize fluidized particle as a HTF can theoretically have an outlet temperature of nearly 1000°C, where components that are under direct solar radiation can exceed the particle temperature

To overcome the barrier of improving thermal efficiency for high-temperature (>600°C) solar receiver in operating with low-heat transfer media as particles or gases, National Renewable Energy Laboratory has developed a light-trapping cavity-planar receiver concept intended to capture energy from shielding heat transfer panel surfaces. This receiver design implements a macroscale light trapping mechanism induced by panels with corrugated channels, this configuration allows flux spreading on the receiver panels in contact with the HTF; using this design coupled with the implementation of a fluidized particle flow as the HTF, it can be expected for some components to reach a peak working temperature of nearly 1000°C cyclically throughout each day-night cycle. While these temperatures correlate to higher efficiency of the CSP tower they also demand intense thermomechanical properties from the materials used to make the receiver panels.

Therefore, it is important to develop mitigation strategies to maximize the lifetime of components expected to operate in high-temperature low-cycle fatigue conditions. Considering the conditions in which the receiver is expected to operate, failure of components is expected; any downtime where a powerplant is not producing energy is critically detrimental to the potential Return on Investment (ROI) of a system. In this paper, we will identify components that are expected to fail with relative frequency. We will also discuss design and manufacturing options to maximize the lifetime, thus reducing maintenance costs and maintaining a desirable ROI. we will highlight the importance of material selection for components expected to operate at extreme temperatures and their impact on both initial Capital Expenditures (CAPEX) and Operational Expenditures (OPEX). Moreover, we will discuss the manufacturing methods such as choosing to weld or bend receiver panels to the prescribed geometry can have a large impact on component life and thus directly impact OPEX. To determine the impact this design can have on the industry the design has been upscaled to estimate the required CAPEX and OPEX for a 50 MWth solar tower designed for 30-year life, and the techno-economic analysis will be performed to determine the expected return on investment as well as the Levelized Cost of Electricity (LCOE).  The LCOE calculation is relatively simplistic and can be calculated by dividing the total CAPEX and OPEX by the overall production over the power plant lifetime; The assumptions made in an LCOE calculation can have a significant impact on the analysis, especially when considering the geographic conditions that the tower is expected to experience at their installation sites. In this analysis, we will list our assumptions to provide clarity on the significance of our calculation. This techno-economic analysis will be conducted using a combination of both case study data and surveying industry to determine material and manufacturing costs that are relevant to the current supply conditions. This analysis represents an early attempt to determine the feasibility and ROI of implementing such a system in industry.

Presenting Author: Ben Xu University of Houston

Presenting Author Biography: Dr. Xu is an Assistant Professor of Mechanical Engineering at University of Houston.

Authors:

Mathew Farias University of Houston
Zhiwen Ma National Renewable Energy Laboratory
Janna Martinek National Renewable Energy Laboratory
Ben Xu University of Houston