# Technology for Green Hydrogen Production: Desk Analysis
###### Abstract  
The use of green hydrogen as a high-energy fuel of the future may be an opportunity to balance the unstable energy system, which still relies on renewable energy sources. This work is a comprehensive review of recent advancements in green hydrogen production. This review outlines the current energy consumption trends. It presents the tasks and challenges of the hydrogen economy towards green hydrogen, including production, purification, transportation, storage, and conversion into electricity. This work presents the main types of water electrolyzers: alkaline electrolyzers, proton exchange membrane electrolyzers, solid oxide electrolyzers, and anion exchange membrane electrolyzers. Despite the higher production costs of green hydrogen compared to grey hydrogen, this review suggests that as renewable energy technologies become cheaper and more efficient, the cost of green hydrogen is expected to decrease. The review highlights the need for cost-effective and efficient electrode materials for large-scale applications. It concludes by comparing the operating parameters and cost considerations of the different electrolyzer technologies. It sets targets for 2050 to improve the efficiency, durability, and scalability of electrolyzers. The review underscores the importance of ongoing research and development to address the limitations of current electrolyzer technology and to make green hydrogen production more competitive with fossil fuels. alkaline electrolyzers; anion exchange membrane electrolyzers; water electrolysis; green hydrogen; hydrogen economy; proton exchange membrane electrolyzers; renewable energy; solid oxide electrolyzers; water splitting +
Footnote †: journal: _Energies_  
0000-0002-4313-3300-0000-0000-0000-0000-0000-0000-0000-0000-0000-0000-0000-00000-00000-00000-00000-00000-00000-00000-00000-00000-  
or biophotolysis [60; 61; 62; 63; 64; 65; 66]; and high-temperature electrolysis (HTE), which operates similarly to SOEs and can use heat from nuclear reactors or concentrated solar power to improve efficiency [67; 68; 69; 70; 71]. The choice of technology for green hydrogen production depends on various factors, including the availability and cost of renewable energy, the scale of production, system efficiency, capital and operating costs, and the specific application or end-use of the hydrogen. As the demand for green hydrogen grows, it is expected that these technologies will continue to evolve and become more cost-effective and efficient [16; 72; 73]. A comprehensive analysis of recent scientific research on green hydrogen production technologies based on data from the Scopus database allowed us to determine the number of research papers published in this field. The bar chart illustrates the number of publications related to different green hydrogen production technologies from 2020 to 2024 (Figure 1). These key points from the chart regarding the AE, PEM, SOE, and AEM technologies of green hydrogen production were formulated as objectives for the refined analysis-based Scopus database search. The number of publications on green hydrogen production technologies demonstrates some notable trends. The largest number of publications is observed for PEM electrolysis, with 255 in total. Research on this technology is significantly advanced, demonstrating its importance and interest in green hydrogen production. AEs are followed by a total of 221 publications and remain a major focus of research, demonstrating their continued influence in the field. There are also 112 publications in total for SOEs. Although the number is relatively small, it still shows some research attention, indicating its potential in specific applications. AEMs have the lowest number of publications, with  
search results on more efficient and economical electrolysis technologies have been reported, including PEM electrolysis and alkaline electrolysis. There has been research on how to better integrate green hydrogen production with RESs, including optimizing energy storage and grid integration [74; 75; 76].