Steam Methane Reforming Research Articles

Emerging trends in hydrogen and synfuel generation: a state-of-the-art review.

The current work investigated emerging fields for generating and consuming hydrogen and synthetic Fischer-Tropsch (FT) fuels, especially from detrimental greenhouse gases, CO2 and CH4. Technologies for syngas generation ranging from partial oxidation, auto-thermal, dry, photothermal and wet or steam reforming of methane were adequately reviewed alongside biomass valorisation for hydrogen generation, water electrolysis and climate challenges due to methane flaring, production, storage, transportation, challenges and opportunities in CO2 and CH4 utilisation. Under the same conditions, dry reforming produces more coke than steam reforming. However, combining the two techniques produces syngas with a high H2/CO ratio, which is suitable for producing long-chain hydrocarbons. Although the steam methane reforming (SMR) process has been industrialised, it is well known to consume significant energy. However, coke production via catalytic methane decomposition, the prime hindrance to large-scale implementation of these techniques for hydrogen production, could be addressed by coupling CO with CO2 conversion to alter the H2/CO ratio of syngas, increasing the reaction temperatures in dry reforming, or increasing the steam content fed in steam reforming. Optimised hydrogen production and generation of green fuels from CO2 and CH4 can be achieved by implementing these strategies.

Evaluation and selection of sustainable hydrogen production technologies with unknown expert weights based on extended MARCOS under hybrid information

The selection of sustainable hydrogen production technologies (HPT) is a paradigm transformation for industrial enterprises to pursue commercial benefits and environmental performance, which has increasingly attracted the attention in academic circles. Therefore, the chief orientation of this research is to construct a novel sustainability-oriented decision-support framework for hydrogen production system. Firstly, an approach is developed to determine expert weights under each criteria in a linguistic environment. Secondly, the Measurement of Alternatives and Ranking according to Composite Solution (MARCOS) method is extended to prioritize sustainable HPT under hybrid information (HMARCOS). Finally, a case study of 5 typical HPT regarding 15 sustainability indicators is conducted. The results display the biomass gasification has the highest sustainability priority for hydrogen production compared with wind turbine electrolysis, photovoltaic electrolysis, steam methane reforming and coal gasification. Furthermore, the reliability and availability of the integrated framework is demonstrated by the comparisons with other approaches.

Integration of Methane Reforming and Chemical Looping Technologies for Power Generation from Waste Plastic: Technical and Economic Assessment

An imperative environmental concern is escalating due to the widespread disposal of plastic waste in oceans and landfills, adversely impacting ecosystems and marine life. In this context, sustainable methods for plastic waste utilisation were evaluated, particularly for power generation. Two case studies were developed to assess the potential utilisation of waste plastic, specifically polyethylene and polypropylene, by integrating gasification with steam methane reforming (SMR) alongside two oxygen-supplying techniques for combustion including cryogenic air separation (ASU) and chemical looping combustion (CLC) for case 1 and case 2, respectively. For this, thorough process simulations of both case studies were performed to obtain detailed material and energy balances. The techno-economic analysis was performed to assess the economic performance of the processes by estimating levelized cost of electricity (LCOE). The results indicated that case 2 is more efficient (5.4%) due to the lower utility requirement of the CLC process as compared to ASU. Consequently, case 2 generated a LCOE of USD 137/MW. It was also seen from the results that the power output is directly proportional to the methane input while the increase in gasifier temperature enhances the H2 and CO content in syngas.

Modelling Photocatalytic N2 Reduction to Ammonia: Where We Stand and Where We Are Going.

Artificial ammonia synthesis via the Haber-Bosch process is environmentally problematic due to the high energy consumption and corresponding CO emissions, produced during the reaction and before hand in hydrogen production upon methane steam reforming. Photocatalytic nitrogen fixation as a greener alternative to the conventional Haber-Bosch process enables us to perform nitrogen reduction reaction (NRR) under mild conditions, harnessing light as the energy source. Herein, we systematically review first-principles calculations used to determine the electronic/optical properties of photocatalysts, N2 adsorption and to expound possible NRR mechanisms. The most commonly studied photocatalysts for nitrogen fixation are usually modified with dopants, defects, co-catalysts and Z-scheme heterojunctions to prevent charge carrier recombination, improve charge separation efficiency and adjust a band gap to for utilizing a broader light spectrum. Most studies at the atomistic level of modeling are grounded upon density functional theory (DFT) calculations, wholly foregoing excitation effects paramount in photocatalysis. Hence, there is a dire need to consider methods beyond DFT to study the excited state properties more accurately. Furthermore, a few studies have been examined, which include higher level kinetics and macroscale simulations. Ultimately, we show there is still ample room for improvement with regard to first principles calculations and their integration in multiscale models.

An investigation of monolithic nickel-based catalyst for clean hydrogen production with CCS technology: The effect of structure

At present, hydrogen is recognised as a carbon-free energy carrier, but its major production via the steam methane reforming (SMR) process requires further decarbonisation as a considerable amount of carbon dioxide is simultaneously emitted. Carbon capture and storage (CCS) techniques can be integrated with typical SMR to produce clean hydrogen. Previously, a novel structured catalyst (Ni/SiC-M) was developed, and it was highly active for SMR under low operating temperature and high gas space velocity. By integrating CCS techniques, this structured catalyst is promising to produce clean hydrogen, however, there is a lack of knowledge about the catalytic performance when CCS is applied, especially the effect of structure. In this work, the feasibility of producing cleaner hydrogen with monolithic catalysts (Ni/SiC-M) coupled with sorbent particles was discussed. Different modified structures were applied for performance evaluation with a fixed bed reactor, to better understand the relationship between the structure and the activity. The results showed that sorbent particles can adsorb most of the generated carbon dioxide, leading to a higher hydrogen purity; the limitation of internal mass transfer caused by high pressure drops can result in a decrease in catalytic activity, but the impact was limited. The pore size could be the key factor to influence the performance of structured catalysts.

Aspen Plus simulation analysis of hydrogen production from biomass pyrolysis integrated with steam methane reformer unit

Abstract As a Paris Agreement signatory committed to reducing greenhouse gas emissions, Indonesia must shift from fossil fuels to renewable energy to reduce emissions and economic growth. Biomass, abundant in North Sumatra, particularly palm oil biomass, offers a potential solution. Biomass can be converted into hydrogen through a thermochemical pyrolysis integrated steam methane reformer (SMR). The Aspen Plus software simulates an integrated biomass pyrolysis system with an SMR unit in this study. Nickel oxide (NiO), used as a catalyst in the SMR unit, is particularly attractive due to its natural abundance and cost-effectiveness. With the batch process, the working pyrolysis temperature is 500°C and SMR is 450°C, respectively. For one process, feed pyrolysis and SMR are 6.54 kg of empty fruit bunch (EFB) palm oil biomass, and SMR supply with 1.515 kg of water vapor or the EFB/water vapor ratio are 81% and 19%, respectively. The above condition will produce 4.27 kg (53%) H2, 1.77 kg (22%) CO2, and 1.93 kg (24%) H2O. Overall, the integrated pyrolysis with SMR (steam methane reformer) for hydrogen production shows good conversion, where every 1 kg of EFB (Empty Fruit Bunches) produces 0.67 kg of hydrogen.

Experimental and numerical investigation of chemical-loop steam methane reforming on monolithic BaCoO3/CeO2 oxygen

Chemical looping steam methane reforming (CL-SMR) is a promising approach to co-production of syngas and hydrogen. As the CL-SMR process relies on the redox reaction of the oxygen carriers, the reactivity of oxygen carriers is crucial in the performance of CL-SMR. In this study, a monolithic BaCoO3/CeO2 oxygen carrier was synthesized, and the reaction performance was evaluated in CL-SMR. The kinetic parameters were determined based on Sestak-Berggren model, an unsteady-state CFD model was established to predict the dynamic reaction processes in three reaction stages of CL-SMR. The result suggests that the flow rate of inlet gas in reaction stages could affect the mass transfer during gas-solid reactions, and then change the evolution and distribution of reaction rate in monolithic oxygen carrier. Increasing the flow rate could improve the uniformity of reaction rate distribution and decrease the time consumption for cyclic process, but decreased the concentration of gas productions and increased the burden of gas product separation at the same time. Among three reaction stages, the conversion of oxygen carrier was accelerated with the increase of temperature, and the varied half-life time of conversions suggested that the reactivity in RS stage is intense and the reactivity in AC stage is mild.

Advancements in hydrogen energy systems: A review of levelized costs, financial incentives and technological innovations

Hydrogen energy systems (HES) are increasingly recognized as pivotal in cutting global carbon dioxide (CO2) emissions, especially in transportation, power generation, and industrial sectors. This paper offers a comprehensive review of HES, emphasizing their diverse applications and economic viability. By 2030, hydrogen energy is expected to revolutionize various sectors, significantly impacting CO2 abatement and energy demand. In electricity and power generation, hydrogen could reduce CO2 emissions by 50–100 million tons annually, requiring 10–20 million tons of hydrogen and an investment of $50–100 billion, underscoring its role in grid stabilization. Additionally, in the heating sector, hydrogen could facilitate a CO2 abatement of 30–50 million tons. We examine the levelized cost of hydrogen (LCOH) production, influenced by factors like production methods, efficiency, and infrastructure. While steam methane reforming is cost-effective, it poses a larger environmental impact compared to electrolysis. The global life-cycle cost of hydrogen production decreases as production scales up, with current costs ranging from $1–3 per kg for fossil-based sources to $3.4–7.5 per kg for electrolysis using low-emission electricity. These costs are projected to decrease, especially for electrolytic hydrogen in regions with abundant solar energy. However, despite the technical feasibility of decarbonization, high production costs still pose challenges. A systematic and effective transition to a hydrogen economy requires comprehensive policy and financial support mechanisms, including incentives, subsidies, tax measures, and funding for research and development of pilot projects. Additionally, the paper discusses hydrogen's role in advanced storage technologies such as hydrides and Japan's ENE-FARM solution for residential energy, emphasizing the need for strategic investments across the hydrogen value chain to enhance HES competitiveness, reduce LCOH, and advance the learning rates of hydrogen production technologies.

Design and analysis of steam methane reforming hydrogen liquefaction and waste heat recovery system based on liquefied natural gas cold energy

To improve the utilization rate of liquefied natural gas (LNG) cold energy, reduce hydrogen (H2) liquefaction cost, recover waste heat and reduce carbon dioxide (CO2) emission, this study designs a steam methane reforming (SMR) H2 liquefaction and waste heat recovery system based on LNG cold energy for the production of 10 tons of liquid hydrogen (LH2) per day. Parameters analyses and optimization, exergy analyses and economic analyses of the system are carried out and compared with other H2 liquefaction systems. The results show that: under the optimal conditions, the values of specific energy consumption (SEC), coefficient of performance (COP) and exergy efficiency (ƞex) were 5.93 kWh/kg LH2, 0.2225 and 53.24%, respectively. Exergy losses of system is mainly distributed in heat exchange equipment and compressors. Decreasing the heat exchange equipment cold and heat sources inlet temperature difference and reducing the compressors compression ratio were beneficial to reduce equipment exergy losses. The pre-cooling performance of LNG is better than that of liquid nitrogen (LN2) and mixed refrigerant (MR). Compared with the pre-cooling H2 liquefaction system without waste heat recovery, the SEC decreased by 0.26 kWh/kg LH2 and ƞex increased by 2.28%. Research results are conducive to resource conservation and environmental protection.

Critical Review of Life Cycle Assessment of Hydrogen Production Pathways

In light of growing concerns regarding greenhouse gas emissions and the increasingly severe impacts of climate change, the global situation demands immediate action to transition towards sustainable energy solutions. In this sense, hydrogen could play a fundamental role in the energy transition, offering a potential clean and versatile energy carrier. This paper reviews the recent results of Life Cycle Assessment studies of different hydrogen production pathways, which are trying to define the routes that can guarantee the least environmental burdens. Steam methane reforming was considered as the benchmark for Global Warming Potential, with an average emission of 11 kgCO2eq/kgH2. Hydrogen produced from water electrolysis powered by renewable energy (green H2) or nuclear energy (pink H2) showed the average lowest impacts, with mean values of 2.02 kgCO2eq/kgH2 and 0.41 kgCO2eq/kgH2, respectively. The use of grid electricity to power the electrolyzer (yellow H2) raised the mean carbon footprint up to 17.2 kgCO2eq/kgH2, with a peak of 41.4 kgCO2eq/kgH2 in the case of countries with low renewable energy production. Waste pyrolysis and/or gasification presented average emissions three times higher than steam methane reforming, while the recourse to residual biomass and biowaste significantly lowered greenhouse gas emissions. The acidification potential presents comparable results for all the technologies studied, except for biomass gasification which showed significantly higher and more scattered values. Regarding the abiotic depletion potential (mineral), the main issue is the lack of an established recycling strategy, especially for electrolysis technologies that hamper the inclusion of the End of Life stage in LCA computation. Whenever data were available, hotspots for each hydrogen production process were identified.

Validation of Effectiveness Factor Correlations for Steam Methane Reforming in Ni-Based Washcoat Catalyst Layers Using Commercial Computational Fluid Dynamics Software

Validation of Effectiveness Factor Correlations for Steam Methane Reforming in Ni-Based Washcoat Catalyst Layers Using Commercial Computational Fluid Dynamics Software

Fourth-generation fluid effect in geothermal-based hydrogen production combined system

In this study, hydrogen production using a Proton Exchange Membrane Electrolyser (PEME) integrated with a geothermal based dual Organic Rankine Cycle (ORC) designed using different organic fluids is investigated. Five dry fluids (R245fa, R600, R600a, butene and isobutene) were used in the medium-temperature ORC-1 unit. In the low temperature ORC-2 unit, fourth-generation ultra-low global warming potential (GWP) fluids (R1243zf, R1225ye(Z) and R1234ze(E)), whose role in hydrogen production has not been determined before, were used as organic fluids. In addition to these fluids, the conventional wet fluid R134a and zeotropic R450A (42% R134a-58% R1234ze(E)), which is a mixture of wet and fourth-generation, were added for performance comparison. In the study, it was aimed to increase hydrogen production by using low temperature geothermal heat from the medium temperature ORC-1 unit in the ORC-2 unit with organic fluid open heater (OFOH), determine the organic fluid effect on hydrogen production by using fourth-generation fluids with low critical temperature and determine the ideal fluid pair among the fluid groups used in two ORC units. It is also planned to analyze the effect of OFOH utilization on hydrogen production in ORC-PEME integration. The contribution of 25 different fluid pairs formed as a result of the 5*5 matrix to hydrogen production through PEME was determined. The best fluid pair was R245fa-R1234ze(E) while the lowest performance was obtained in R600a-R134a duo. In the best fluid pair, it was determined that the amount of natural gas preserved (NGP) was 3018 tons per year and the levelized cost of hydrogen (LCOH) was 1.901 $/kg with 104.4 kg hydrogen production per hour. The minimum specific investment cost (3270 $/kW) was reached in this fluid pair. Compared to the worst fluid pair; it was determined that LCOH was reduced by 8.15% with the best fluid pair. For the best and worst fluid pairs, a difference of 412 tons per year was found between the NGP considering the CH4 consumed versus the hydrogen produced based on the steam methane reforming (SMR). Carbon credit gain (CCG) was determined by enviro-economic analysis, while R245fa-R1234ze(E) has 365.8 k$ carbon recovery, this value decreases to 315.8 k$ in R600a-R134a duo.

Feedback control of an experimental electrically-heated steam methane reformer

Steam methane reforming (SMR) is the most common industrial process to produce hydrogen (H2) from methane and water vapor. The SMR reactions are overall highly endothermic and traditionally, fossil fuels are burned to provide the necessary heat of reaction. However, it was found that electrifying the tubular SMR reactors using renewable electrons instead of conventional heating gives the opportunity of producing H2 with lower carbon emissions, lower reactor volumes, and higher carbon conversion. While current studies in this new technology focus on improving the catalysts or heating sources, a more efficient process control scheme can also significantly contribute to the understanding of potential challenges and opportunities of combining renewables and natural gas in the production of H2 at industrial scales. In order to further develop the electrically-heated SMR process and the associated control strategies, we have constructed an experimental Joule-heated SMR system at UCLA. The system contains a tubular reactor with a washcoated Ni/ZrO2 catalyst, two thermocouples connected to the top and bottom of the reactor, a power supply for providing electrical heating, and an on-line gas chromatograph (GC) for measuring outlet gas concentrations. The synthesis procedure of the catalyst, SMR data collection, and thermal considerations for catalyst degradation are described in this paper and are all accounted for experimentally when using a proportional integral (PI) controller to gradually increase the reactor temperature without harming the catalyst. Advanced control strategies, such as model predictive control (MPC), require a process model that uses measurement feedback to make predictions of the process time-evolution in order to optimize the control actions in real-time. We have previously developed a lumped-parameter modeling strategy for the SMR process. The MPC objective is to control the H2 production rate by manipulating the current flowing through the outer reactor shell. However, to use this model in an MPC, feedback values for all state variables should be provided by the sensors. In our experimental system, the on-line GC only gives discrete measurements with a long sampling period. To this end, the process model is incorporated into an extended Luenberger observer (ELO) that uses the reactor temperature and GC measurements to provide estimates of all the variables needed by the MPC. The ELO-based MPC system is then experimentally implemented on the process and it is demonstrated to be more efficient in terms of speed of the closed-loop response than the PI controller using delayed, measurement feedback by the GC.

Small iridium clusters supported on TiO2 as catalysts for intensifying low-temperature methane activation and reforming

Hydrogen production via low-temperature (<550 °C) steam reforming of methane (SRM) has attracted increasing research attention due to its importance as an alternative, efficient, and environmentally benign energy carrier. The thermodynamic limitation of low-temperature SRM can be eased by process design such as using a membrane reactor or an adsorption-enhanced reforming process, and an active low-temperature SRM catalyst with high stability would be indispensable. Herein, we report a 2 wt% Ir/TiO2 catalyst that exhibits high methane conversion activity in low-temperature SRM with a relatively high turnover frequency (TOF) and a low activation energy in comparison with the literature. Long-term catalyst stability test demonstrates a good resistance to coking and sintering during low-temperature SRM reactions. In situ spectroscopy analyses and density functional theory (DFT) calculations reveal that the small Ir clusters and Ir single atoms (SAs) are both active for methane conversion, while the clusters exhibit higher activity than SAs for low-temperature SRM reaction. Microkinetic simulation based on DFT calculations shows consistent product formation temperatures and the simulation nicely reproduces the product distribution observed in experimental analysis, which confirms the superior SRM activity of the TiO2-supported Ir clusters in this work.

Megawatts to methane – a deep drop in emissions reduction transition for existing regional gas-based ammonia plants

Synthetic ammonia production sustains food production for more than half of the world’s population. Many regional ammonia plants convert all ammonia to ammonium nitrate fertiliser. With these, all carbon in the feed ends up as carbon dioxide (CO2), with around 2 tonnes of CO2 released per tonne of ammonia produced using natural gas. Conveniently, ammonia plants produce a substantial pre-concentrated CO2 stream. Ammonia plants are high-capex, long-life assets that operate for 40+ years. With the energy transition, replacing such assets is very high cost and will dramatically impact the cost of food production. Further, green energy is highly variable, leading to the need for additional supply side assets to stabilise energy supply. This paper outlines a transition approach for a 30% CO2 reduction (also a 43% case) to extend the useful life of these assets while re-using much of the plant, with the ability to turn on/off the green energy with minimal disruption for stable operation. The example plant is based on a typical 750 tpd ammonia gas Steam Methane Reforming (SMR) plant. The approach considers adding and integrating green power and biogas into this plant to reduce net reportable CO2 emissions. Methanation of CO2 has been demonstrated in several projects and is considered key in developing a transition pathway for an existing gas-based plant, extending its operational life and flexibility to operate with varying degrees of variable green energy supply. Further, whilst Synthetic Natural Gas (SNG) is used in this case, the approach can be beneficially applied with methanol and other Power-to-X opportunities.

Effect of Lanthanum and Iron Doping on Nickel‐Based Alumina and Ceria Supported Catalysts for Steam Reforming of Methane

AbstractMembrane reformers emerge as an efficient technology for ‘on‐site’ ultra‐pure hydrogen production. The membrane reformer can be integrated with PEM fuel cell (PEMFC) to provide power. However, as the PEMFC works at lower temperature hence, such integration requires a low temperature catalyst. Further, for successful integration of membrane reformer with PEMFC, a low CO selective catalyst is vital. In current work, Ni‐based alumina and ceria supported catalysts are used. The effect of La and Fe promoters on the performance of Ni‐based alumina and ceria supported catalysts are investigated. The catalysts are synthesized using wet impregnation method. A complete characterization of catalysts is performed using BET, XRD, FESEM, and EDX. Fe promoted catalysts shows low CO and high CO2 selectivity which is desirable for membrane reformer. However, the catalytic activity of Fe promoted Ni‐based alumina and ceria supported catalysts were low. La promoted Ni‐based catalysts show high catalytic activity on both alumina and ceria supported catalysts. La promoted catalysts also gives low start up time, high catalytic activity and low CO selectivity at low temperature. Ni−La/Al2O3 catalyst provides 50 % conversion and 12 % CO selectivity at 500 °C. This makes it suitable for ‘on‐site’ generation of ultra‐pure hydrogen through membrane reformer.

Reservoir Simulations of Hydrogen Generation from Natural Gas with CO2 EOR: A Case Study

This paper addresses the problem of hydrogen generation from hydrocarbon gases using Steam Methane Reforming (SMR) with byproduct CO2 injected into and stored in a partially depleted oil reservoir. It focuses on the reservoir aspects of the problem using numerical simulation of the processes. To this aim, a numerical model of a real oil reservoir was constructed and calibrated based on its 30-year production history. An algorithm was developed to quantify the CO2 amount from the SMR process as well as from the produced fluids, and optionally, from external sources. Multiple simulation forecasts were performed for oil and gas production from the reservoir, hydrogen generation, and concomitant injection of the byproduct CO2 back to the same reservoir. EOR from miscible oil displacement was found to occur in the reservoir. Various scenarios of the forecasts confirmed the effectiveness of the adopted strategy for the same source of hydrocarbons and CO2 sink. Detailed simulation results are discussed, and both the advantages and drawbacks of the proposed approach for blue hydrogen generation are concluded. In particular, the question of reservoir fluid balance was emphasized, and its consequences were presented. The presented technology, using CO2 from hydrogen production and other sources to increase oil production, also has a significant impact on the protection of the natural environment via the elimination of CO2 emission to the atmosphere with concomitant production of H2.

Techno-economic analysis of blue ammonia synthesis using cryogenic CO2 capture Process-A Danish case investigation

Ammonia is a vital chemical with numerous applications. Currently, the primary methods for generating the necessary reactants for ammonia production involve steam methane reforming (SMR) and cryogenic air separation unit (CASU), while the Haber-Bosch process converts these reactants into ammonia. However, the SMR process releases substantial amounts of CO2, making it imperative to employ an efficient and cost-effective CO2 capture technology to mitigate emissions. This investigation focuses on evaluating the cryogenic CO2 capture (CCC) process for blue ammonia production and provides a thorough economic analysis, estimating both the initial investment costs and operational expenses involved in producing blue ammonia. The results indicated that the CCC process can capture 90% of the CO2 content in the flue gas emitted by the SMR, incurring an energy penalty of 0.724 MJe/kgCO2 while capturing CO2 in the liquid phase with purities exceeding 99.9%. In this case, the estimated CO2 capture costs would be 18.05, 45.1, and 16.65 USD/ton in 2021, 2022, and 2023, respectively. This represents a 40% reduction compared to the CO2 capture costs associated with conventional amine-based technology. The results of this study indicate that the annual electricity costs for ammonia production increase by 38.5% and 64.2% when employing the CCC and amine-based processes, respectively. This investigation employed an isothermal reactor for ammonia synthesis, using the heat from the exothermic reaction in a water ammonia absorption refrigeration cycle (ARC) to condense and purify ammonia. The results show that the ARC system can effectively condense ammonia at −6 °C, producing a liquid ammonia stream with 99.3% purity. This leads to a 95% reduction in power consumption compared to a vapor compression refrigeration cycle (VCRC). Consequently, this method has the potential to decrease the annual operational costs for ammonia production by 2.92%, 2.69%, and 3.13% in 2021, 2022, and 2023, respectively. This study indicated that the hydrogen production unit incurs the highest initial investment costs, as well as operating costs, in the blue ammonia production process, followed by CASU and the Haber-Bosch process.

Effects of emissions caps on the costs and feasibility of low-carbon hydrogen in the European ammonia industry

The European ammonia industry emits 36 million tons of carbon dioxide annually, primarily from steam methane reforming (SMR) hydrogen production. These emissions can be mitigated by producing hydrogen via water electrolysis using dedicated renewables with grid backup. This study investigates the impact of decarbonization targets for hydrogen synthesis on the economic viability and technical feasibility of retrofitting existing European ammonia plants for on-site, semi-islanded electrolytic hydrogen production. Results show that electrolytic hydrogen cuts emissions, on average, by 85% (36%-100% based on grid price and carbon intensity), even without enforcing emission limits. However, an optimal lifespan average well-to-gate emission cap of 1 kg carbon dioxide equivalent (CO2e)/kg H2 leads to a 95% reduction (92%-100%) while maintaining cost-competitiveness with SMR in renewable-rich regions (mean levelized cost of hydrogen (LCOH) of 4.1 euro/kg H2). Conversely, a 100% emissions reduction target dramatically increases costs (mean LCOH: 6.3 euro/kg H2) and land area for renewables installations, likely hindering the transition to electrolytic hydrogen in regions with poor renewables and limited land. Increasing plant flexibility effectively reduces costs, particularly in off-grid plants (mean reduction: 32%). This work guides policymakers in defining cost-effective decarbonization targets and identifying region-based strategies to support an electrolytic hydrogen-fed ammonia industry.

Green hydrogen as a source of renewable energy: a step towards sustainability, an overview

AbstractHydrogen has emerged as a promising energy source for a cleaner and more sustainable future due to its clean-burning nature, versatility, and high energy content. Moreover, hydrogen is an energy carrier with the potential to replace fossil fuels as the primary source of energy in various industries. In this review article, we explore the potential of hydrogen as a part of the global energy mix and the current state of its development. The majority of hydrogen production currently occurs through steam methane reforming, which produces significant greenhouse gas emissions and limits the potential of hydrogen as a clean energy source. Significant investment and advancements in renewable hydrogen production through electrolysis are necessary to overcome this limitation. There is also a growing demand for hydrogen infrastructure, including hydrogen refueling stations and storage and transportation systems, which are crucial for the growth and success of the hydrogen industry. The future of hydrogen as a part of the global energy mix will depend on continued investment and commitment to develop and commercialize this promising energy source. Our review also explores the relationship between eco-industrial parks and hydrogen production, including the benefits and challenges of hydrogen production in EIPs and the various technologies being developed to facilitate this process.