Production & Supply Chain

The application of hydrogen energy produced by proton exchange membrane electrolyzer (PEMEC) is conducive to the solution of the greenhouse effect and the energy crisis. In order to understand the development trends and research hotspot of PEMEC in recent years a total of 1874 research articles related to this field from 2003 to 2023 were obtained from the Web of Science Core Collection (WoS CC) database. The visualization software VOSviewer is used for bibliometric analysis and the research progress hotspots and trends in the PEMEC field are summarized. It was found that in the past two decades literature in the PEMEC field has shown a trend of stable increase at first and then rapidly increasing. And it is in a stage of rapid growth after 2021.Renewable Energy previously published research articles related to PEMEC with the highest frequency of citations. There are a total of 6128 researchers in this field but core authors only account for 4.5% of the total. Although China entered this field later than the United States and Canada it has the largest number of research articles. The research results provide a comprehensive overview of various aspects in the PEMEC field which is beneficial for researchers to grasp the development hotspots of PEMEC.

Chemical looping dry reforming of methane (CLDRM) using perovskites as a catalyst is considered a promising option for producing hydrogen from biogas. In this work the life-cycle performance of a system compiling a CLDRM unit paired with a water gas shift unit a pressure swing adsorption unit and a combined cycle scheme to provide steam and electricity was assessed. The main data needed to reflect the behavior of the reforming reaction was obtained experimentally and implemented in an Aspen Plus® simulation. Inventory data was obtained through process simulation and used to assess the environmental performance of the process in terms of carbon footprint acidification freshwater eutrophication ozone depletion photochemical ozone formation and depletion of minerals and metals. Overall the environmental viability of the production of green hydrogen from biogas was found to be heavily dependent on the biogas leakage in anaerobic digestion plants. The CLDRM system was benchmarked against a conventional DRM implementation for the same feedstock. While the conventional DRM plant environmentally outperformed the perovskite-based CLDRM the latter might present advantages from an implementation point of view.

Water splitting is an effective strategy to produce renewable and sustainable hydrogen energy. Especially seawater splitting avoiding use of the limited freshwater resource is more intriguing. Nowadays electrocatalysts explored for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) using natural seawater or saline electrolyte have been increasingly reported. To better understand the current status and challenges of the electrocatalysts for HER and OER from seawater we comprehensively review the recent advances in electrocatalysts for seawater splitting. The fundamentals challenges and possible strategies for seawater splitting are firstly presented. Then the recently reported electrocatalysts that explored for HER and OER from seawater are summarized and discussed. Finally the perspectives in the development of high-efficient electrocatalysts for seawater splitting are also proposed.

The decarbonization of industry heating and transportation is a major challenge for many countries’ energy transition. Hydrogen is a direct low-carbon fuel alternative to natural gas offering a higher flexibility in the range of possible applications yet currently most hydrogen is produced using carbonintensive steam methane reforming due to cost considerations. Therefore this study explores the economics of a prominent low-carbon method of hydrogen production comparing the cost of hydrogen generation from offshore wind farms with and without grid electricity imports to conventional hydrogen production methods. A novel techno-economic model for offshore electrolysis production costs is presented which makes hydrogen production fully dispatchable leveraging geological salt-cavern storage. This model determines the lifetime costs aportioned across the system components as well as the Levelized Cost of Hydrogen (LCOH). Using the United Kingdom as a case study LCOH from offshore wind power is calculated to be €8.68 /kgH2 using alkaline electrolysis (AEL) €10.49 /kgH2 using proton exchange membrane electrolysis (PEMEL) and €10.88 /kgH2 with grid electricity to backup the offshore wind power. A stochastic Monte-Carlo model is used to asses the uncertainty on costs and identify the cost of capital electrolyser and wind farm capital costs and cost of electricity as the most important drivers of LCOH across the different scenarios. Reducing the capital cost to comparative levels observed on today’s wind farms alone could see AEL LCOH fall to €5.32 /kgH2 near competitive with conventional generation methods.

This study presents a comprehensive 4E (energy exergy economic and exergo-environmental) analysis of a solar-powered multi-generation system (MGS) that integrates parabolic trough collectors (PTCs) thermal energy storage (TES) an organic Rankine cycle (ORC) an absorption refrigeration cycle (ARC) a proton exchange membrane electrolyzer (PEME) and a reverse osmosis (RO) unit to simultaneously produce electricity cooling potable water and hydrogen. A complete thermodynamic model is developed in Engineering Equation Solver (EES) to evaluate the system from technical economic and environmental perspectives. Results indicate that the MGS can convert solar energy into multiple outputs with energy and exergy efficiencies of 12.2% and 4.3% respectively. The highest and lowest energy efficiencies are found in PEME (58.6%) and ORC (7.4%) while the highest and lowest exergy efficiencies are related to PEME (57.4%) and PTC (11.9%) respectively. Despite notable environmental impacts from the complex subsystems (particularly PTC and PEME) the system demonstrates strong economic performance with a net present value of approximately USD 8 million an internal rate of return of 30% and a payback period of 3.8 years. Sensitivity analysis shows that increasing solar radiation reduces the number of required PTCs and shortens payback time with less effect on energy and exergy efficiencies due to increased thermal and radiative losses.

Hydrogen has attracted growing research interest due to its exceptionally high energy per mass content and being a clean energy carrier unlike the widely used hydrocarbon fuels. With the possibility of long-term energy storage and re-electrification hydrogen promises to promote the effective utilization of renewable and sustainable energy resources. Clean hydrogen can be produced through a renewable-powered water electrolysis process. Although alkaline water electrolysis is currently the mature and commercially available electrolysis technology for hydrogen production it has several shortcomings that hinder its integration with intermittent and fluctuating renewable energy sources. The proton exchange membrane water electrolysis (PEMWE) technology has been developed to offer high voltage efficiencies at high current densities. Besides PEMWE cells are characterized by a fast system response to fluctuating renewable power enabling operations at broader partial power load ranges while consistently delivering high-purity hydrogen with low ohmic losses. Recently much effort has been devoted to improving the efficiency performance durability and economy of PEMWE cells. The research activities in this context include investigations of different cell component materials protective coatings and material characterizations as well as the synthesis and analysis of new electrocatalysts for enhanced electrochemical activity and stability with minimized use of noble metals. Further many modeling studies have been reported to analyze cell performance considering cell electrochemistry overvoltage and thermodynamics. Thus it is imperative to review and compile recent research studies covering multiple aspects of PEMWE cells in one literature to present advancements and limitations of this field. This article offers a comprehensive review of the state-of-the-art of PEMWE cells. It compiles recent research on each PEMWE cell component and discusses how the characteristics of these components affect the overall cell performance. In addition the electrochemical activity and stability of various catalyst materials are reviewed. Further the thermodynamics and electrochemistry of electrolytic water splitting are described and inherent cell overvoltage are elucidated. The available literature on PEMWE cell modeling aimed at analyzing the performance of PEMWE cells is compiled. Overall this article provides the advancements in cell components materials electrocatalysts and modeling research for PEMWE to promote the effective utilization of renewable but intermittent and fluctuating energy in the pursuit of a seamless transition to clean energy.

The global push for clean hydrogen production has identified nuclear energy particularly high-temperature gas-cooled reactors (HTGRs) as a promising solution due to their ability to provide high-temperature heat. This study conducted a techno-economic analysis of hydrogen production in Saudi Arabia using the pebble bed modular reactor (HTRPM) focusing on two methods: high-temperature steam electrolysis (HTSE) and the sulfur– iodine (SI) thermochemical cycle. The Hydrogen Economic Evaluation Program (HEEP) was used to assess the economic viability of both methods considering key production factors such as the discount rate nuclear power plant (NPP) capital cost and hydrogen plant efficiency. The results show that the SI cycle achieves a lower levelized cost of hydrogen (LCOH) at USD 1.22/kg H2 compared to HTSE at USD 1.47/kg H2 primarily due to higher thermal efficiency. Nonetheless HTSE offers simpler system integration. Sensitivity analysis reveals that variations in the discount rate and NPP capital costs significantly impact both production methods while hydrogen plant efficiency is crucial in determining overall economics. The findings contribute to the broader discourse on sustainable hydrogen production technologies by highlighting the potential of nuclear-driven methods to meet global decarbonization goals. The paper concludes that the HTR-PM offers a viable pathway for large-scale hydrogen production in Saudi Arabia aligning with the Vision 2030 objectives.

This paper reports on the experimental data analysis and numerical results carried out by algorithms in order to meet the provisions of Industry 4.0 in the field of research of Solid Oxide Fuel Cell/Electrolyzer. A performance mapping of the analyzed SOFC/SOE systems is developed in order to enhance system efficiency when it is fed by biofuels. The analyses concern the main operative parameters such as pressure temperature fuel compositions and other main system parameters such as fuel and oxidant utilization factors and the recirculation of anode exhaust stream gas.

Despite Iran’s considerable renewable energy (RE) potential and excellent wind capacity and high solar radiation levels these sources contribute only a small fraction of the country’s total energy production. This paper addresses the techno-economic viability of gray hydrogen production by these renewables with a particular focus on solar energy. Given the considerable potential of solar energy and the strategic location of Shahrekord it would be an optimal site for a hydrogen generation plant integrated with a solar field. HOMER Pro 3.18.3 software was utilized to model and optimize the levelized cost of hydrogen (LCOH) of steam reforming using different hydrocarbons in various scenarios. The results of this study indicate that natural gas (NG) reforming represents the most cost-effective method of gray hydrogen production in this city with an LCOH of −0.423 USD/kg. Other hydrocarbons such as diesel gasoline propane methanol and ethanol have a price per kilogram of produced hydrogen as follows: USD −0.4 USD −0.293 USD 1.17 USD 1.48 and USD 2.15. In addition integrating RE sources into hydrogen production was found to be viable. Moreover by implementing RE technologies CO2 emissions can be significantly reduced and energy security can be achieved.

Methanol which can be derived from sustainable energy sources such as biomass solar power and wind power is widely considered an ideal hydrogen carrier for distributed and mobile hydrogen production. In this study a comprehensive comparison of the thermodynamic and techno-economic performance of the aqueous phase reforming (APR) and steam reforming (SR) of methanol was conducted using Aspen Plus and CAPCOST software to evaluate the commercial feasibility of the APR process. Thermodynamic analysis based on the Gibbs free energy minimization method reveals that while APR and SR have similar energy demands APR achieves higher energy efficiency by avoiding losses from evaporation and compression. APR typically operates at higher pressures and lower temperatures compared to SR suppressing CO formation and increasing hydrogen fraction but reducing methanol single-pass conversion. A techno-economic comparison of APR and SR for a distributed hydrogen production system with a 50 kg/h hydrogen output shows that although APR requires higher fixed operating costs and annual capital charges it benefits from lower variable operating costs. The minimum hydrogen selling price for APR was calculated to be 7.07 USD/kg compared to 7.20 USD/kg for SR. These results suggest that APR is a more economically viable alternative to SR for hydrogen production.