Production & Supply Chain
Energy and Environmental Assessment of Hydrogen from Biomass Sources: Challenges and Perspectives
Aug 2022
Publication
Hydrogen is considered as one of the pillars of the European decarbonisation strategy boosting a novel concept of the energy system in line with the EU’s commitment to achieve clean energy transition and reach the European Green Deal carbon neutrality goals by 2050. Hydrogen from biomass sources can significantly contribute to integrate the renewable hydrogen supply through electrolysis at large-scale production. Specifically it can cover the non-continuous production of green hydrogen coming from solar and wind energy to offer an alternative solution to such industrial sectors necessitating of stable supply. Biomass-derived hydrogen can be produced either from thermochemical pathways (i.e. pyrolysis liquefaction and gasification) or from biological routes (i.e. direct or indirect-biophotolysis biological water–gas shift reaction photo- and dark-fermentation). The paper reviews several production pathways to produce hydrogen from biomass or biomass-derived sources (biogas liquid bio-intermediates sugars) and provides an exhaustive review of the most promising technologies towards commercialisation. While some pathways are still at low technology readiness level others such as the steam bio-methane reforming and biomass gasification are ready for an immediate market uptake. The various production pathways are evaluated in terms of energy and environmental performances highlighting the limits and barriers of the available LCA studies. The paper shows that hydrogen production technologies from biomass appears today to be an interesting option almost ready to constitute a complementing option to electrolysis.
A Techno-Economic Study for Off-Grid Green Hydrogen Production Plants: The Case of Chile
Jul 2023
Publication
In this study we present a pre-feasibility analysis that examines the viability of implementing autonomous green hydrogen production plants in two strategic regions of Chile. With abundant renewable energy resources and growing interest in decarbonization in Chile this study aims to provide a comprehensive financial analysis from the perspective of project initiators. The assessment includes determining the optimal sizing of an alkaline electrolyzer stack seawater desalination system and solar and wind renewable energy farms and the focus is on conducting a comprehensive financial analysis from the perspective of project initiators to assess project profitability using key economic indicators such as net present value (NPV). The analyses involve determining appropriate sizing of an alkaline electrolyzer stack a seawater desalination system and solar and wind renewable energy farms. Assuming a base case production of 1 kiloton per year of hydrogen the capital expenditures (CAPEX) and operating expenses (OPEX) are determined. Then the manufacturing and production costs per kilogram of green hydrogen are calculated resulting in values of USD 3.53 kg−1 (utilizing wind energy) and USD 5.29 kg−1 (utilizing photovoltaic solar energy). Cash flows are established by adjusting the sale price of hydrogen to achieve a minimum expected return on investment of 4% per year yielding minimum prices of USD 7.84 kg−1 (with wind energy) and USD 11.10 kg−1 (with photovoltaic solar energy). Additionally a sensitivity analysis is conducted to assess the impact of variations in investment and operational costs. This research provides valuable insights into the financial feasibility of green hydrogen production in Chile contributing to understanding renewable energy-based hydrogen projects and their potential economic benefits. These results can provide a reference for future investment decisions and the global development of green hydrogen production plants.
Modeling of Hydrogen Production System for Photovoltaic Power Generation and Capacity Optimization of Energy Storage System
Sep 2022
Publication
Hydrogen production using solar energy is an important way to obtain hydrogen energy. However the inherent intermittent and random characteristics of solar energy reduce the efficiency of hydrogen production. Therefore it is necessary to add an energy storage system to the photovoltaic power hydrogen production system. This paper establishes a model of a photovoltaic power generation hydrogen system and optimizes the capacity configuration. Firstly the mathematical model is modeled and analyzed and the system is modeled using Matlab/Simulink; secondly the principle of optimal configuration of energy storage capacity is analyzed to determine the optimization strategy we propose the storage capacity configuration algorithm based on the low-pass filtering principle and optimal time constant selection; finally a case study is conducted whose photovoltaic installed capacity of 30 MW verifying the effectiveness of the proposed algorithm analyzing the relationship between energy storage capacity and smoothing effect. The results show that as the cut-off frequency decreases the energy storage capacity increases and the smoothing effect is more obvious. The proposed algorithm can effectively reduce the 1 h maximum power variation of PV power generation. In which the maximum power variation of PV generation 1 h before smoothing is 4.31 MW. We set four different sets of time constants the maximum power variation of PV generation 1 h after smoothing is reduced to 0.751 0.389 0.078 and 0.04 MW respectively.
Towards a Multi-color Hydrogen Production Network? Competing Imaginaries of Development in Northern Patagonia, Argentina
Feb 2024
Publication
Green hydrogen has recently gained importance as a key element in the transition to a low-carbon energy future sparking a boom in possible production regions. This article aims at situating incipient hydrogen production in the Argentine province of Río Negro within a global production network (GPN). The early configuration of the hydrogen-GPN includes several stakeholders and is contested in many ways. To explore the possible materialization of the hydrogen economy in Argentina this article links GPN literature to the concept of sociotechnical imaginaries. In so doing this study finds three energy imaginaries linked to hydrogen development: First advocates of green hydrogen (GH2) project a sociotechnical imaginary in which GH2 is expected to promote scientific and technological progress. Second proponents of blue hydrogen point to Vaca Muerta and the role of natural gas for energy autonomy. Third opponents of the GH2 project question the underlying growth and export model emphasizing conservation and domestic energy sovereignty. The competition between different capital fractions i.e. green and fossil currently poses the risk of pro-fossil path decisions and lock-in effects. Current power constellations have led to the replacement of green with low-emission resulting in the promotion of multi-colored hydrogen. This is particularly evident in the draft for the new national hydrogen law and the actors involved in defining the national hydrogen strategy. The conceptual combination of actors and their interests their current power relations and the sociotechnical imaginaries they deploy illustrates how Argentina's energy future is already being shaped today.
Hydrogen for Harvesting the Potential of Offshore Wind: A North Sea Case Study
Dec 2023
Publication
Economical offshore wind developments depend on alternatives for cost-efficient transmission of the generated energy to connecting markets. Distance to shore availability of an offshore power grid and scale of the wind farm may impede export through power cables. Conversion to H2 through offshore electrolysis may for certain offshore wind assets be a future option to enable energy export. Here we analyse the cost sensitivity of offshore electrolysis for harvesting offshore wind in the North Sea using a technology-detailed multi-carrier energy system modelling framework for analysis of energy export. We include multiple investment options for electric power and hydrogen export including HVDC cables new hydrogen pipelines tie-in to existing pipelines and pipelines with linepacking. Existing hydropower is included in the modelling and the effect on offshore electrolysis from increased pumping capacity in the hydropower system is analysed. Considering the lack of empirical cost data on offshore electrolysis as well as the high uncertainty in future electricity and H2 prices we analyse the cost sensitivity of offshore electrolysis in the North Sea by comparing costs relative to onshore electrolysis and energy prices relative to a nominal scenario. Offshore electrolysis is shown to be particularly sensitive to the electricity price and an electricity price of 1.5 times the baseline assumption was needed to provide sufficient offshore energy for any significant offshore electrolysis investments. On the other hand too high electricity prices would have a negative impact on offshore electrolysis because the energy is more valuable as electricity even at the cost of increased wind power curtailment. This shows that there is a window-of-opportunity in terms of onshore electricity where offshore electrolysis can play a significant role in the production of H2 . Pumped hydropower increases the maximum installed offshore electrolysis at the optimal electricity and H2 prices and makes offshore electrolysis more competitive at low electricity prices. Linepacking can make offshore electrolysis investments more robust against low H2 and high electricity prices as it allow for more variable H2 production through storing excess energy from offshore. The increased electrolysis capacity needed for variable electrolyser operation and linepacking is installed onshore due to its lower CAPEX compared to offshore installations.
Electrocatalysts for the Generation of Hydrogen, Oxygen and Synthesis Gas
Sep 2016
Publication
Water electrolysis is the most promising method for efficient production of high purity hydrogen (and oxygen) while the required power input for the electrolysis process can be provided by renewable sources (e.g. solar or wind). The thus produced hydrogen can be used either directly as a fuel or as a reducing agent in chemical processes such as in Fischer–Tropsch synthesis. Water splitting can be realized both at low temperatures (typically below 100 °C) and at high temperatures (steam water electrolysis at 500– 1000 °C) while different ionic agents can be electrochemically transferred during the electrolysis process (OH− H+ O2− ). Singular requirements apply in each of the electrolysis technologies (alkaline polymer electrolyte membrane and solid oxide electrolysis) for ensuring high electrocatalytic activity and long-term stability. The aim of the present article is to provide a brief overview on the effect of the nature and structure of the catalyst–electrode materials on the electrolyzer’s performance. Past findings and recent progress in the development of efficient anode and cathode materials appropriate for large-scale water electrolysis are presented. The current trends limitations and perspectives for future developments are summarized for the diverse electrolysis technologies of water splitting while the case of CO2/H2O co-electrolysis (for synthesis gas production) is also discussed.
Water Consumption from Electrolytic Hydrogen in a Carbon-neutral US Energy System
Feb 2023
Publication
Hydrogen is an energy carrier with potential applications in decarbonizing difficult-to-electrify energy and industrial systems. The environmental profile of hydrogen varies substantially with its inputs. Water consumption is a particular issue of interest as decisions are made about capital and other investments that will affect the scale and scope of hydrogen use. This study focuses on electrolytic hydrogen due to its path to greenhouse gas neutrality and irreducible water demand (though other pathways might be more water intensive). Specifically it evaluates life cycle consumptive freshwater intensity of electrolytic hydrogen in the United States at volumes associated with 12 scenarios for a deeply decarbonized 2050 US energy system from two modeling efforts for which both electricity fuel mix and electrolytic hydrogen production were projected (America’s Zero Carbon Action Plan and Net Zero America) in addition to volumes for a stylized energy storage project (500 MW hydrogen-fired turbine). Freshwater requirements for hydrogen could be large. Under a central estimate for 2050 US electrolytic hydrogen production electrolytic freshwater demand for process and feedstock inputs alone (i.e. excluding water for electricity) would be about 7.5% of total 2014 US freshwater consumption for energy (1 billion cubic meters/year 109 m3 /y; [0.2% 15%] across scenarios for 2050 electrolytic hydrogen production of [0.3 18] exajoules EJ). Including water associated with production of input electricity doubles this central estimate to 15% (2 × 109 m3 /y; [1% 23%] across scenarios). Turbines using electrolytic hydrogen are estimated to be about as freshwater intensive as a coal or nuclear plant assuming decarbonized low-water electricity inputs. Although a decarbonized energy system is projected to require less water for resource capture and electricity conversion than the current fossil-dominated energy system additional conversion processes supporting decarbonization like electrolysis could offset water savings.
Genesis and Energy Significance of Natural Hydrogen
Jan 2023
Publication
H2 is clean energy and an important component of natural gas. Moreover it plays an irreplaceable role in improving the hydrocarbon generation rate of organic matter and activating ancient source rocks to generate hydrocarbon in Fischer-Tropsch (FT) synthesis and catalytic hydrogenation. Compared with hydrocarbon reservoir system a complete hydrogen (H2) accumulation system consists of H2 source,reservoirs and seal. In nature the four main sources of H2 are hydrolysis organic matter degradation the decomposition of substances such as methane and ammonia and deep mantle degassing. Because the complex tectonic activities the H2 produced in a geological environment is generally a mixture of various sources. Compared with the genetic mechanisms of H2 the migration and preservation of H2 especially the H2 trapping are rarely studied. A necessary condition for large-scale H2 accumulation is that the speed of H2 charge is much faster than diffusion loss. Dense cap rock and continuous H2 supply are favorable for H2 accumulation. Moreover H2O in the cap rock pores may provide favorable conditions for short-term H2 accumulation.
Deep Learning for Wind and Solar Energy Forecasting in Hydrogen Production
Feb 2024
Publication
This research delineates a pivotal advancement in the domain of sustainable energy systems with a focused emphasis on the integration of renewable energy sources—predominantly wind and solar power—into the hydrogen production paradigm. At the core of this scientific endeavor is the formulation and implementation of a deep-learning-based framework for short-term localized weather forecasting specifically designed to enhance the efficiency of hydrogen production derived from renewable energy sources. The study presents a comprehensive evaluation of the efficacy of fully connected neural networks (FCNs) and convolutional neural networks (CNNs) within the realm of deep learning aimed at refining the accuracy of renewable energy forecasts. These methodologies have demonstrated remarkable proficiency in navigating the inherent complexities and variabilities associated with renewable energy systems thereby significantly improving the reliability and precision of predictions pertaining to energy output. The cornerstone of this investigation is the deployment of an artificial intelligence (AI)-driven weather forecasting system which meticulously analyzes data procured from 25 distinct weather monitoring stations across Latvia. This system is specifically tailored to deliver short-term (1 h ahead) forecasts employing a comprehensive sensor fusion approach to accurately predicting wind and solar power outputs. A major finding of this research is the achievement of a mean squared error (MSE) of 1.36 in the forecasting model underscoring the potential of this approach in optimizing renewable energy utilization for hydrogen production. Furthermore the paper elucidates the construction of the forecasting model revealing that the integration of sensor fusion significantly enhances the model’s predictive capabilities by leveraging data from multiple sources to generate a more accurate and robust forecast. The entire codebase developed during this research endeavor has been made available on an open access GIT server.
Global Land and Water Limits to Electrolytic Hydrogen Production Using Wind and Solar Resources
Sep 2023
Publication
Proposals for achieving net-zero emissions by 2050 include scaling-up electrolytic hydrogen production however this poses technical economic and environmental challenges. One such challenge is for policymakers to ensure a sustainable future for the environment including freshwater and land resources while facilitating low-carbon hydrogen production using renewable wind and solar energy. We establish a country-by-country reference scenario for hydrogen demand in 2050 and compare it with land and water availability. Our analysis highlights countries that will be constrained by domestic natural resources to achieve electrolytic hydrogen self-sufficiency in a net-zero target. Depending on land allocation for the installation of solar panels or wind turbines less than 50% of hydrogen demand in 2050 could be met through a local production without land or water scarcity. Our findings identify potential importers and exporters of hydrogen or conversely exporters or importers of industries that would rely on electrolytic hydrogen. The abundance of land and water resources in Southern and Central-East Africa West Africa South America Canada and Australia make these countries potential leaders in hydrogen export.
Renewable Hydrogen Production: A Techno-economic Comparison of Photoelectrochemical Cells and Photovoltaic-electrolysis
Aug 2020
Publication
The present paper reports a techno-economic analysis of two solar assisted hydrogen production technologies: a photoelectrochemical (PEC) system and its major competitor a photovoltaic system connected to a conventional water electrolyzer (PV-E system). A comparison between these two types was performed to identify the more promising technology based on the levelized cost of hydrogen (LCOH). The technical evaluation was carried out by considering proven designs and materials for the PV-E system and a conceptually design for the PEC system extrapolated to future commercial scale. The LCOH for the off-grid PV-E system was found to be 6.22 $/kgH2 with a solar to hydrogen efficiency of 10.9%. For the PEC system with a similar efficiency of 10% the LCOH was calculated to be much higher namely 8.43 $/kgH2. A sensitivity analysis reveals a great uncertainty in the LCOH of the prospective PEC system. This implies that much effort would be needed for this technology to become competitive on the market. Therefore we conclude that the potential techno-economic benefits that PEC systems offer over PV-E are uncertain and even in the best case limited. While research into photoelectrochemical cells remains of interest it presents a poor case for dedicated investment in the technology’s development and scale-up.
Levelized Cost of Biohydrogen from Steam Reforming of Biomethane with Carbon Capture and Storage (Golden Hydrogen)—Application to Spain
Feb 2024
Publication
The production of biohydrogen with negative CO2 emissions through the steam methane reforming of biomethane coupled with carbon capture and storage represents a promising technology particularly for industries that are difficult to electrify. In spite of the maturity of this technology which is currently employed in the production of grey and blue hydrogen a detailed cost model that considers the entire supply chain is lacking in the literature. This study addresses this gap by applying correlations derived from actual facilities producing grey and blue hydrogen to calculate the CAPEX while exploring various feedstock combinations for biogas generation to assess the OPEX. The analysis also includes logistic aspects such as decentralised biogas production and the transportation and storage of CO2 . The levelized cost of golden hydrogen is estimated to range from EUR 1.84 to 2.88/kg compared to EUR 1.47/kg for grey hydrogen and EUR 1.93/kg for blue hydrogen assuming a natural gas cost of EUR 25/MWh and excluding the CO2 tax. This range increases to between 3.84 and 2.92 with a natural gas cost of EUR 40/MWh with the inclusion of the CO2 tax. A comparison with conventional green hydrogen is performed highlighting both prices and potential thereby offering valuable information for decision-making.
Research on Hydrogen Production System Technology Based on Photovoltaic-Photothermal Coupling Electrolyzer
Dec 2023
Publication
Solar hydrogen production technology is a key technology for building a clean low-carbon safe and efficient energy system. At present the intermittency and volatility of renewable energy have caused a lot of “wind and light.” By combining renewable energy with electrolytic water technology to produce high-purity hydrogen and oxygen which can be converted into electricity the utilization rate of renewable energy can be effectively improved while helping to improve the solar hydrogen production system. This paper summarizes and analyzes the research status and development direction of solar hydrogen production technology from three aspects. Energy supply mode: the role of solar PV systems and PT systems in this technology is analyzed. System control: the key technology and system structure of different types of electrolytic cells are introduced in detail. System economy: the economy and improvement measures of electrolytic cells are analyzed from the perspectives of cost consumption efficiency and durability. Finally the development prospects of solar hydrogen production systems in China are summarized and anticipated. This article reviews the current research status of photovoltaic-photothermal coupled electrolysis cell systems fills the current research gap and provides theoretical reference for the further development of solar hydrogen production systems.
Renewable-power-assisted Production of Hydrogen and Liquid Hydrocarbons from Natural Gas: Techno-economic Analysis
Jun 2022
Publication
The declining cost of renewable power has engendered growing interest in leveraging this power for the production of chemicals and synthetic fuels. Here renewable power is added to the gas-to-liquid (GTL) process through Fischer–Tropsch (FT) synthesis in order to increase process efficiency and reduce CO2 emissions. Accordingly two realistic configurations are considered which differ primarily in the syngas preparation step. In the first configuration solid oxide steam electrolysis cells (SOEC) in combination with an autothermal reformer (ATR) are used to produce synthesis gas with the right composition while in the second configuration an electrically-heated steam methane reformer (E-SMR) is utilized for syngas production. The results support the idea of adding power to the GTL process mainly by increased process efficiencies and reduced process emissions. Assuming renewable power is available the process emissions would be 200 and 400 gCO2 L1 syncrude for the first and second configurations respectively. Configuration 1 and 2 show 8 and 4 times less emission per liter syncrude produced respectively compared to a GTL plant without H2 addition with a process emission of 1570 gCO2 L1 syncrude. By studying the two designs based on FT production carbon efficiency and FT catalyst volume a better alternative is to add renewable power to the SOEC (configuration 1) rather than using it in an E-SMR (configuration 2). Given an electricity price of $100/MW h and natural gas price of 5 $ per GJ FT syncrude and H2 can be produced at a cost between $15/MW h and $16/MW h. These designs are considered to better utilize the available carbon resources and thus expedite the transition to a low-carbon economy
Review on Techno-economics of Hydrogen Production Using Current and Emerging Processes: Status and Perspectives
Feb 2024
Publication
This review presents a broad exploration of the techno economic evaluation of different technologies utilized in the production of hydrogen from both renewable and non-renewable sources. These encompass methods ranging from extracting hydrogen from fossil fuels or biomass to employing microbial processes electrolysis of water and various thermochemical cycles. A rigorous techno-economic evaluation of hydrogen production technologies can provide a critical cost comparison for future resource allocation priorities and trajectory. This evaluation will have a great impact on future hydrogen production projects and the development of new approaches to reduce overall production costs and make it a cheaper fuel. Different methods of hydrogen production exhibit varying efficiencies and costs: fast pyrolysis can yield up to 45% hydrogen at a cost range of $1.25 to $2.20 per kilogram while gasification operating at temperatures exceeding 750°C faces challenges such as limited small-scale coal production and issues with tar formation in biomass. Steam methane reforming which constitutes 48% of hydrogen output experiences cost fluctuations depending on scale whereas auto-thermal reforming offers higher efficiency albeit at increased costs. Chemical looping shows promise in emissions reduction but encounters economic hurdles and sorptionenhanced reforming achieves over 90% hydrogen but requires CO2 storage. Renewable liquid reforming proves effective and economically viable. Additionally electrolysis methods like PEM aim for costs below $2.30 per kilogram while dark fermentation though cost-effective grapples with efficiency challenges. Overcoming technical economic barriers and managing electricity costs remains crucial for optimizing hydrogen production in a low-carbon future necessitating ongoing research and development efforts.
Techno-economic Analysis of Green-H2@Scale Production
Sep 2023
Publication
The International Energy Agency (IEA) established the "H2 Implementing Agreement (HIA)" to promote H2 transition in various economic sectors. Today less than one percent of the world's H2 production is “Green”. Lack of regulations high production costs and inadequate infrastructure are significant impediments. The U.S. Department of Energy set a "111-target" which translates into $1/kg-H2 in the next decade. Many countries in the Middle East and North Africa (MENA) region have announced ambitious plans to produce green H2. Through techno-economic metrics and the impact of economies of scale this study investigates H2@Scale production. H2 Production Analysis and the System Advisor Model developed by the U.S. Department of Energy were used for analysis. The results demonstrate a significant decrease in the levelized cost of H2 (LCOH) when the production volume is scaled up. It was determined that the key cost drivers are capital cost energy installed balance of the plant and mechanical and electrical subsystems. The studied location is found promising for scaled production and developing its commodity status. The findings could serve as a benchmark for key stakeholders investors policymakers and the developer of relevant strategies in the infrastructure and H2 value chain.
An Estimation of Green Hydrogen Generation from Wind Energy: A Case Study from KSA
Sep 2023
Publication
Actually green hydrogen is viewed as a fundamental component in accelerating energy transition and empowering a sustainable future. The current study focuses on the estimation of green hydrogen generation by using wind energy via electrolysis in four sites located in Saudi Arabia. Results showed that the yearly amount of hydrogen that could be generated by using wind turbine ranges between 2542877 kg in Rafha and 3676925 kg in Dhahran. The hydrogen generated could be used to fuel vehicles and decrease the amount of GHG emission from vehicles in KSA. Also hydrogen may be used to store the excess of wind energy and to support the achievement of vision 2030 of the Kingdom. An economic assessment is carried out also in this paper. Results showed that the LCOH by using wind energy in KSA ranges from 2.82 $/kg to 3.81 $/kg.
Performance Assessment of a 25 kW Solid Oxide Cell Module for Hydrogen Production and Power Generation
Jan 2024
Publication
Hydrogen produced via water electrolysis from renewable electricity is considered a key energy carrier to defossilize hard-to-electrify sectors. Solid oxide cells (SOC) based reactors can supply hydrogen not only in electrolysis but also in fuel cell mode when operating with (synthetic) natural gas or biogas at low conversion (polygeneration mode). However the scale-up of SOC reactors to the multi-MW scale is still a research topic. Strategies for transient operation depending on electricity intermittency still need to be developed. In this work a unique testing environment for SOC reactors allows reversible operation demonstrating the successful switching between electrolysis (− 75 kW) and polygeneration (25 kW) modes. Transient and steady state experiments show promising performance with a net hydrogen production of 53 kg day− 1 in SOEL operation with ca. − 75 kW power input. The experimental results validate the scaling approach since the reactor shows homogenous temperature profiles.
Green Hydrogen: Resources Consumption, Technological Maturity, and Regulatory Framework
Aug 2023
Publication
Current climate crisis makes the need for reducing carbon emissions more than evident. For this reason renewable energy sources are expected to play a fundamental role. However these sources are not controllable but depend on the weather conditions. Therefore green hydrogen (hydrogen produced from water electrolysis using renewable energies) is emerging as the key energy carrier to solve this problem. Although different properties of hydrogen have been widely studied some key aspects such as the water and energy footprint as well as the technological development and the regulatory framework of green hydrogen in different parts of the world have not been analysed in depth. This work performs a data-driven analysis of these three pillars: water and energy footprint technological maturity and regulatory framework of green hydrogen technology. Results will allow the evaluation of green hydrogen deployment both the current situation and expectations. Regarding the water footprint this is lower than that of other fossil fuels and competitive with other types of hydrogen while the energy footprint is higher than that of other fuels. Additionally results show that technological and regulatory framework for hydrogen is not fully developed and there is a great inequality in green hydrogen legislation in different regions of the world.
A Systematic Study on Techno-Economic Evaluation of Hydrogen Production
Sep 2023
Publication
This paper aims to perform a systematic review with a bibliometric approach of the technoeconomic evaluation studies of hydrogen production. To achieve this objective a comprehensive outline of hydrogen production processes from fossil and renewable sources is presented. The results reveal that electrolysis classified as water splitting is the most investigated process in the literature since it contributes to a reduction in greenhouse gas emissions and presents other advantages such as maturity and applicability energy efficiency flexibility and energy storage potential. In addition the processes of gasification classified as thermochemical and steam reforming classified as catalytic reforming are worth mentioning. Regarding the biological category there is a balance between research on photo fermentation and dark fermentation. The literature on the techno-economic evaluation of hydrogen production highlights significant gaps including a scarcity of comprehensive studies a lack of emphasis on commercial viability an absence of sensitivity analysis and the need for comparative analyses between production technologies.
No more items...