Design and analysis of a CO 2 -to-olefins process, using renewable energy Farbod Aleaziz , Nassim Tahouni * , M.Hassan Panjeshahi School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran ARTICLE INFO Keywords: Carbon dioxide Electricity generation Green hydrogen Light olefins Solar and wind energy ABSTRACT This paper presents a light olefins production plant that hydrogenates carbon dioxide to C 2 -C 4 using green hydrogen and electricity produced from solar and wind energy resources. In this regard, combining Fischer- Tropsch and methanol-mediated pathways on a large scale is analyzed as a new method to increase light ole- fins production. Additionally, an optimized hybrid renewable energy system comprised of solar panels, wind turbines, electrolyzers, batteries, converters, and so on is designed to supply the necessary utilities for the plant. The simulation results indicate that 590.9, 744.8, and 522.9 kg/h of ethylene, propylene, and butylene can be produced by processing 10% of carbon dioxide emitted from a cement factory, resulting in the negative emission of 2.14 kg CO 2 /kg C 2 -C 4 . This plant needs 1420 kg/h of hydrogen to convert carbon dioxide into light olefins and 32 MW of electricity to meet hot, cold, and electric utility requirements, all powered by renewable energy. The optimization results demonstrate that the initial capital and net present costs of the renewable energy system are $1.15B and $1.38B, respectively, leading to the levelized costs of hydrogen and electricity of 3.56 $/kg and 0.12 $/kWh, respectively. 1. Introduction With energy infrastructure built mainly on fossil fuels around the world, carbon dioxide emissions have skyrocketed in recent decades. Hence, it is unavoidable to utilize renewable energies and create the essential conditions for harnessing these resources [1]. Using renewable energy resources, especially wind and solar, to electrolyze water and produce green hydrogen is a key step towards a low- or even zero-emission industry. Having recently attracted a great deal of attention, this clean hydrogen could have many applications, varying from the chemical and energy sectors to the transportation in- dustry [2]. Currently, about 4% of the needed hydrogen is produced by water electrolysis, with steam methane reforming accounting for most of the rest using natural gas [3]. Thus, designing and optimizing new green hydrogen production plants are of utmost importance in reducing de- pendency on fossil fuels. One of the viable ways of phasing in green hydrogen while phasing out conventional petrochemicals is to produce electrofuels (e-fuels). E- fuels are manufactured by combining clean hydrogen and carbon di- oxide, which can be captured from the flue gas of emission sources, such as process industries and power stations, or even directly from the air [4]. Many researchers worldwide are trying to simulate and optimize the process of producing e-fuels, such as e-methanol, e-ethanol, and e-diesel, in order to help industries achieve net-zero emissions. Zang et al. [5] performed a detailed techno-economic analysis of liquid e-fuels pro- duction from concentrated carbon dioxide, with an emphasis on the flue gas of ethanol plants. In this integrated system, CO 2 was first reacted with H 2 to produce syngas (CO and H 2 ), which was then converted to liquid fuels using the Fischer-Tropsch synthesis and hydroprocessing. They indicated that 90, 164, and 97 t/d of naphtha, jet fuel, and diesel could be produced from 223 and 2387 t/d of hydrogen and carbon di- oxide in this plant. Furthermore, they concluded that the hydrogen cost is the salient factor in the fuel selling price, and future work could be concentrated on the H 2 recycle contribution. Sherwin [6] conducted a techno-economic analysis of liquid e-fuels, mainly jet fuel, production using the optimization tool to offer an insight into changes in the fuel costs over a range of scenarios. In this analysis, the required carbon dioxide and hydrogen was supplied from the air and a proton exchange membrane (PEM) electrolyzer using solar or wind energy. He claimed that the costs of the electrolyzer, renewable electricity, and direct air capture system accounted for 17.7–36.5, 24.6–38.9, and 16.4–23.2% of liquid e-fuel cost, respectively, with fuel synthesis costs being the minor parameter. Taherzadeh et al. [7] implemented a heat integration be- tween the e-fuels production unit and its feedstocks, i.e., H 2 and CO 2 production processes. H 2 was obtained by a high-temperature electrol- ysis system and CO 2 is captured from a power plant flue gas stream with high purity. By integration, the power-to-liquid efficiency was * Corresponding author. E-mail address: ntahuni@ut.ac.ir (N. Tahouni). Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman https://doi.org/10.1016/j.enconman.2024.119277 Received 25 August 2024; Received in revised form 10 November 2024; Accepted 11 November 2024 Energy Conversion and Management 324 (2025) 119277 Available online 30 November 2024 0196-8904/© 2024 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.