Abstract
This paper studies the integration of solar tower technology and thermal energy storage (TES) with a power plant and a high temperature Solid Oxide Steam Electrolyzer (SOSE) to produce hydrogen from solar energy. The different subsystems are integrated and optimized to achieve high overall energy efficiency, maintain continuous operation, and reduce exergy destruction. In this regard, energy and exergy analyses are conducted to investigate the requirements and performance of the SOSE while powered by a solar tower subsystem. Therefore, the SOSE cell performance is modeled and the hydrogen production is measured based on different cell and solar field operating conditions. The SOSE is modeled as an integral part of a concentrated solar power plant where the power produced is used for hydrogen production as a final product. In order to maintain continuous plant operation, a TES subsystem is integrated. Furthermore, a supercritical carbon dioxide (s-CO2) Brayton cycle is adapted for the power plant for high efficiency energy conversion from thermal to electric energy. The overall integrated system solar-to-hydrogen conversion efficiency is found to be about 12.7% while charging the TES, and 39.5% while discharging (TES-to-hydrogen). These high efficiencies rank this technology as competitive with other renewable hydrogen production technologies. The integrated high temperature TES achieved energy and exergy efficiencies of more than 96%. The main implementation challenges are discussed in addition to the comprehensive energy and exergy analyses which provide deeper insight into the performance of the system components, potential improvements and limitations.
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•A solar tower is utilized to power a CO2 Brayton cycle and Solid Oxide electrolyzer for hydrogen production.•A high temperature thermal energy storage (TES) is incorporated to extend the system operation.•Solid Oxide electrolyzer performance is modeled, validated, and assessed based on integrated system conditions.•Energy and exergy analyses are conducted for all subsystems including the TES.•The integrated system achieved a solar-to-hydrogen conversion efficiency of 12.7%.