Performance Modeling and Techno-Economic Analysis of Concentrating Solar-Thermal Power Systems for Electricity Generation and Heat Supply in Low-to-Medium Industrial Process Heat Applications

Abstract

The utilization of concentrating solar-thermal power (CSP) technologies for electricity generation and industrial process heat (IPH) supply is promising due to their cost-effective and efficient solar thermal collection and energy storage. This work aims to perform a techno-economic analysis of CSP technologies i.e., solar power tower (SPT) and parabolic trough collector (PTC) for electricity generation, and investigate the use of pressurized water in a relocatable small-scale SPT system for low to medium-temperature IPH applications. Therefore, the first part of this research assesses the CSP technologies' potential to supply electricity, focusing on the country of Sudan as an example, where most of the attention is given to solar photovoltaic (PV) systems and no thorough CSP techno-economic study has been carried out. The main goal is to investigate the feasibility and profitability of CSP technologies under Sudan’s conditions and encourage Sudan’s authorities to pursue these technologies and overcome the associated challenges. The study’s methodology applied a techno-economic analysis for two of the most mature CSP technologies – SPT and PTC technologies – to produce electricity under the weather conditions of Sudan. Two well-known commercial CSP plants in Spain, namely GEMASOLAR (SPT-based) and ANDASOL-1 (PTC-based), have been modeled, validated, and “hypothetically” relocated in six Sudanese zones using the system advisor model (SAM). These zones were scrutinized based on a rigorous Geographic Information System (GIS) and technical CSP site assessment study. Moreover, the use of SPT systems for low to medium-temperature IPH (below 400 ˚C) is particularly not well addressed in the literature. Hence, in the second part of the research, an algorithm is developed to model, evaluate, and optimize the performance of a novel relocatable SPT that can provide low to medium-temperature process heat for use in applications such as oil fracking, district heating, and the mining industry. A 1.3 MWth SPT-based IPH plant is considered to supply heat at a reference location, in Tucson, Arizona. The study mainly focuses on modeling and optimizing a biomimetic heliostat field of small-size removable heliostats (4 m2) and a 40 m-high steel truss tower, based on an optimized light-weight external receiver that utilizes pressurized hot water as the heat transfer fluid (HTF) for steam production in a temperature range of 120 – 220 ˚C, which is the dominant temperature requirement in process heating. Also, the study conducts comprehensive techno-economic and environmental analyses, comparing a 1 MWth SPT-based IPH plant with other CSP technologies like parabolic trough collectors and linear Fresnel reflector (LFR), as well as Natural Gas (NG) and PV-based IPH technologies. The results show that the proposed relocatable SPT-based IPH (PR-SPT-IPH) plant generates an annual thermal energy of 5.61 GWth with a capacity factor of 48.27% and it can mitigate 1,111,908.6 kg of CO2 saving $129,168 annually. It also achieves the lowest LCOH of 2.42 cents/kWhth and with certain applicable assumptions, this cost can be further reduced to 1.55 cents/kWhth, meeting the DOE's "SunShot Initiative" targets. The study indicates that the PR-SPT-IPH plant surpasses PTC-, LFR-, NG-, and PV-based IPH plants both technically and financially. In summary, with reduced capital costs and appropriate financial incentives, the PR-SPT-IPH plant emerges as an economically and environmentally viable choice for low to medium-temperature IPH applications.