ScholarWorks@동국대학교

초록

Various studies have been conducted to reduce the levelized cost of hydrogen (LCOH), but green hydrogen still has a relatively high LCOH. This study proposes the thermal integration of the Allam cycle with a solid oxide electrolysis cell (SOEC), resulting in improved energy efficiency, a reduction in LCOH through electricity sales, near-zero CO2 emissions, and water resource recycling. The Allam cycle is a power plant that utilizes supercritical CO2 as a working fluid, while SOEC is an electrolysis process that produces hydrogen from steam. Both processes require high-temperature heat. Additionally, the Allam cycle generates deionized water as a byproduct, which can be used in SOEC. The integrated process demonstrates an energy efficiency of 58.69 %, superior to the general Allam cycle, which exhibits approximately 55 % energy efficiency. Furthermore, the LCOH is reduced to $1.983duetothesaleofgeneratedelectricity,whichislowerthanthe$5.00 for green H2 produced via SOEC and comparable to the $2.00forblueH<inf>2</inf>.ContinuousadvancementsinSOECtechnologymayenabletheLCOHtofallbelow$1.5, which would be similar to that of grey H2. The carbon emissions are reduced to 0.07 kg-CO2/kg-H2, demonstrating a 97.08 % reduction compared to the 2.4 kg-CO2/kg-H2 emissions of blue H2. A sensitivity analysis was conducted for variables affecting LCOH, indicating that the LCOH remains lower than that of green H2 in all scenarios. This study contributes to achieving net-zero emissions and a feasible LCOH in the future. © 2025 Elsevier B.V., All rights reserved.

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