A Novel Optimized Solar Trough Profile for Better Solar Energy Collection, Storage, and Levelized Cost

Abstract

Clean and sustainable renewable energy resources provide a feasible solution for electrical power generation nowadays. This encourages many countries around the world to increase their renewable energy share. In a reference case, Egypt aims at increasing its renewable energy share in electricity generation from 9% in 2014 to 25% in 2030. [1] High rates of solar energy are available most of the year in Egypt. According to the solar atlas of Egypt, [2] the annual averaged direct normal irradiance (DNI) in Egypt is 292 W m À2 while the monthly averaged maximum DNI reaches 450 W m À2 . Moreover, Egypt has 2554 and 2208 kWh m À2 of available solar energy for concentrated solar power (CSP) and photovoltaic (PV), [2] respectively. Therefore, both the CSP and PV technologies are implemented in Egypt. While PV is cheaper than CSP, the latter is fully dispatchable. [3] Moreover, a PV with storage batteries is more expensive than a CSP with thermal energy storage (TES). [3] Therefore, recent investigations show that CSP and PV are complementary technologies rather than competitive ones. [3][4][5] However, Egypt has not integrated CSP and PV technologies in commercial power plants so far. CSP is a good choice for Egypt due to the high DNI and the hot climate conditions. Accordingly, Egypt has constructed a CSP plant in Kuraymat (100 km south of Cairo). The solar field in Kuraymat implements parabolic trough collectors (PTCs) with a total field aperture area of 130 800 m 2 . [6] Figure 1 shows the main components of the parabolic trough collector (PTC). A parabolic-shaped reflector collects the sun's rays and reflects them through a glass tube onto a receiver tube. The receiver tube absorbs the incident and reflected solar radiation and utilizes this energy to increase the temperature of a heat transfer fluid (HTF) that flows inside the receiver tube. The levelized cost of energy (LCOE) is one of the most significant parameters that indicate the feasibility of an electrical power generation technology. It is always desired to reduce the LCOE of every power generation technology to make it commercially competitive. Reducing the LCOE of the CSP plants with PTC technology can be attained by increasing the overall thermal efficiency while reducing the capital and running costs. El Hamdani et al. [7] estimated the impact of the DNI, solar multiple, mirrors efficiency, cycle efficiency, and absorber efficiency on the reduction of the LCOE of a 1MWe parabolic trough plant at different sites in Morocco. Aseri et al. [8] investigated the possibility of reducing the high capital cost of PTCs. They attained a 29.9% reduction in capital cost by implementing large aperture area PTCs with molten salt as both HTF and storage medium. Lopes et al. [9] showed a 6.3% reduction in LCOE when applying the HitecXL molten salt in a 50 MWe/7.5 h-of-storage power plant. They simulated the plant performance using NREL's System Advisor Model (SAM) software. [10] Tahir et al. [11] estimated the minimum LCOE for a 100 MW PTC power plant in six different ...