Production & Supply Chain

Green hydrogen production is a sustainable energy solution with great potential offering advantages such as adaptability storage capacity and ease of transport. However there are challenges such as high energy consumption production costs demand and regulation which hinder its largescale adoption. This study explores the role of simulation models in optimizing the technical and economic aspects of green hydrogen production. The proposed system which integrates photovoltaic and energy storage technologies significantly reduces the grid dependency of the electrolyzer achieving an energy self-consumption of 64 kWh per kilogram of hydrogen produced. By replacing the high-fidelity model of the electrolyzer with a reduced-order model it is possible to minimize the computational effort and simulation times for different step configurations. These findings offer relevant information to improve the economic viability and energy efficiency in green hydrogen production. This facilitates decision-making at a local level by implementing strategies to achieve a sustainable energy transition.

Growing energy demands and increasing concerns about climate change have spurred new approaches in both policy and industry with a focus on transforming current energy systems in modern energy hubs. In this context green hydrogen produced through electrolysis process powered by renewable energy sources emerges as a highly versatile and promising solution for decarbonising sectors and provide alternative fuels for process and transportation. This study models and simulates an integrated system comprising desalination brine treatment and electrolysis to generate green hydrogen fuelled entirely by solar energy. The desalination unit produces demineralised water suitable for electrolysis while alternative brine management strategies are explored for scenarios where brine discharge back to the sea is restricted. An economic analysis further evaluates cost-effective system configurations by varying component sizes. To demonstrate the model potential a case study for green hydrogen production based on seawater desalination was conducted for an Italian port city and extended to three other sites with different annual solar radiation. The objective is to determine configurations that minimise hydrogen cost and identify required incentives. The economic performance of the system in terms of the Levelized Cost of Hydrogen ranges from 5 to 8 €/kg while the required incentives to make green hydrogen competitive with blue hydrogen production systems vary between 7 and 12 M€ across the analysed configurations. Furthermore the analysis provides valuable insights into the potential of coastal areas to serve as critical hubs for green hydrogen production given the abundant availability of seawater. Ports with their existing infrastructure and proximity to maritime transport represent ideal locations for integrating renewable energy sources with hydrogen production facilities.

To combat global warming the decarbonisation of energy systems is essential. Hydrogen (H2) is an established chemical feedstock in many industries (fertiliser production steel manufacturing etc.) and has emerged as a promising clean energy carrier due to its high energy density and carbon-free usage. However most H2 is currently produced from fossil fuels undermining its sustainability. Biomass offers a renewable carbon-neutral feedstock for H2 production potentially reducing its environmental impact. This review examines thermochemical biological and electrochemical methods of bio-H2 generation. Thermochemical processes - including gasification fast pyrolysis and steam reforming - are the most technologically advanced offering high H2 yields. However challenges such as catalyst deactivation tar formation and pre- and post-processing limit efficiency. Advanced strategies like chemical looping sorption enhancement and membrane reactors are being developed to address these issues. Biological methods including dark and photo fermentation operate under mild conditions and can process diverse waste feedstocks. Despite their potential low H2 yields and difficulties in microbial inhibitors hinder scalability. Ensuring that microbial populations remain stable through the use of additives and optimising the bioreactors hydraulic retention rate also remain a challenge Combined fermentation systems and valorising byproducts could enhance performance and commercial viability. Electrochemical reforming of biomass-derived compounds is an emerging method that may enhance water electrolysis by co-producing value-added by-products. However current studies focus on biomass-derived compounds rather than complex biomass feedstocks limiting commercial relevance. Future research should focus on feedstock complexity electrocatalyst development and system scaling. A technology readiness comparison shows that thermochemical methods are the most commercially mature followed by biological and electrochemical approaches. Each method holds promise within specific niches warranting continued innovation and interdisciplinary development.

Deployment of innovative renewable-based energy applications are critical for reducing CO2 emissions and achieving global climate neutrality. This work evaluates the production of decarbonized green H2 based on sorption-enhanced biomass (sawdust) gasification. The calcium-based sorbent was evaluated in a looping cycle configuration as sorption material to enhance both the CO2 capture rate and the energy-efficient hydrogen production. The investigated concept is set to produce 100 MWth high purity hydrogen (>99.95% vol.) with very high decarbonization yield (>98–99%) using woody biomass as a fuel. Conventional biomass (sawdust) gasification systems with and without CO2 capture capability are also assessed for the calculation of energy and economic penalties induced by decarbonization. The results show that the decarbonized green hydrogen manufacture by sorption-enhanced biomass gasification shows attractive performances e.g. high overall energy efficiency (about 50%) reduced energy and economic penalties for almost total decarbonization (down to 8 net efficiency points) low specific carbon emissions at system level (lower than 7 kg/MWh) and negative CO2 emission for whole biomass value chain (about − 518.40 kg/MWh). However significant developments (e.g. improving reactor design and fuel/sorbent conversion yields reducing sorbent make-up etc.) are still needed to advance this innovative concept from present level to industrial sizes.

The integration of electrolyzers into modern power systems is a critical step toward sustainable hydrogen production. However their dynamic power consumption and stringent operational constraints present considerable challenges. This article proposes a comprehensive multiphysics model of an alkaline electrolyzer emphasizing its interaction with a power electronic converter to ensure efficient and reliable power delivery. The study incorporates electrochemical principles to develop mathematical models that accurately represent the alkaline electrolyzer’s electrical behavior and dynamic response. A single-stage active front-end (AFE) rectifier based on SiC MOSFETs is employed as the power electronic interface offering improved energy efficiency enhanced system stability and reduced power quality issues compared to conventional approaches. Experimental results validate the performance of the proposed alkaline electrolyzer and converter models highlighting the potential for effective integration of alkaline electrolyzers into converter-based systems within renewable energy environments.

Our energy system is facing major challenges in the course of the unavoidable shift from fossil fuels to fluctuating renewable energy sources. Regional hydrogen production by electrolysis utilizing regional available excess energy can support the expansion of renewable energy by converting surplus energy into hydrogen and sup plying it to the end energy sectors as a secondary energy carrier or process media. We developed a methodology which allows the identification of the regional optimal electrolysis scaling the achievable Levelized Costs of Hydrogen (LCOH) as well as the annually producible amount of hydrogen for Central European regions using renewable surplus energy from PV and wind production. The results show that as best case currently LCOH of 4.5 €/kg can be achieved in regions with wind energy and LCOH of 5.6 €/kg in regions with PV energy at 1485 €/kW initial investment costs for the hydrogen production infrastructure. In these cases regions with wind energy require electrolysis systems with a capacity of 60 % of the wind peak power. Regions with PV energy require a scaling factor of only 45 % of the PV peak power. However we show that the impact of regional electricity demand and grid expansion has a significant influence on the LCOH and the scaling of the electrolysis. These effects were illustrated in clear heatmaps and serve as a guideline for the dimensioning of grid-supporting electrolysis systems by defining the renewable peak power the regional electricity demand as well as the existing grid capacity of the region under consideration.

Due to hydrogen’s beneficial characteristics as a sustainable energy carrier the application of pulsing electric fields has been researched for its effectiveness during water electrolysis. Although there have been conflicting findings on the benefits of the application of pulsing electric fields this research highlights the potential it has to enhance the efficiency of water electrolysis while providing clarity on past discrepancies. This research achieves this by identifying distinctive energy flow profiles that result from various power input waveforms along with subsequent hydrogen production rates and efficiencies while also utilising a novel method of measuring the capacitance of the electrolyte to detect shifts in the molecular energy. The results indicate that pulsing electric fields can increase efficiency by up to 20 % or decrease efficiency by over 40 % depending on the energy flow profiles of the electrical molecular and electrochemical dynamics. Furthermore the use of pulsing electric fields also enabled load adaptability by allowing the electrolyser to operate effectively throughout a range of power inputs. For example the power input could be increased to cause a 279 % increase in hydrogen production without compromising efficiency; while conversely enabling electrolysis at >65 % efficiency using power input levels which were otherwise too low to drive electrochemical reactions. This study provides another step towards making renewable hydrogen viable as a sustainable energy carrier by identifying factors which influence and are influenced by changing electrical molecular and electrochemical dynamics while also providing a foundation for further research into more efficient use of energy to produce hydrogen gas.

Alkaline water electrolysis is a promising clean hydrogen production technology that accounts for a small percentage of global hydrogen production. Therefore the technique requires further research and development to achieve higher efficiencies and lower hydrogen production costs to replace the utilization of non-renewable energy sources for hydrogen production. In this study electrodes are fabricated through fused deposition modelling 3D printing technology for practical and accessible electrolyzer manufacturing where an initial nickel (Ni) catalyst layer is formed on the 3D printed electrode surface followed by copper modified nickel zinc iron oxide (NiZnFe4O4) layer to investigate a unique electrocatalyst. An alkaline electrolyzer is developed with Ni-NiZnFe4O4 coated 3D printed cathodes and stainless steel anodes to determine the hydrogen production capacities and efficiencies of the electrolysis process. Electrochemical measurements are used to assess the catalyst coated 3D printed electrodes ranging from physical electrochemistry to electrochemical impedance measurements. The results show that the triangular Ni-NiZnFe4O4 coated electrode with the highest aspect ratio exhibits the greatest current density of −183.17 mA/cm2 at −2.05 V during linear sweep voltammetry (LSV) tests where it also reaches a current density of −94.35 mA/cm2 at −1.2 V during cyclic voltammetry (CV) measurements. It is concluded that modification of surface geometry is also a crucial aspect of electrode performance as 30% lower overpotentials are achieved by the rectangular electrodes in this study. The hydrogen production capacities of the alkaline electrolyzer developed range from 4.22 to 5.82 × 10−10 kg/s operating at a cell voltage of 2.15 V. Furthermore the energy and exergy efficiencies of the alkaline electrolyzer are evaluated through the first and second laws of thermodynamics revealing the highest energy and exergy efficiencies of 14.34% and 13.86% for the highest aspect ratio rectangular electrode.

The hydrogen (H2) economy is seen as a crucial pathway for decarbonizing the energy system with green H2—i.e. obtained from water electrolysis supplied by renewable energy—playing a key role as an energy carrier in this transition. The growing interest in H2 comes from its versatility which means that H2 can serve as a raw material or energy source and various technologies allow it to be produced from a wide range of resources. Environmental impacts of H2 production have primarily focused on greenhouse gas (GHG) emissions despite other environmental aspects being equally relevant in the context of a sustainable energy transition. In this context Life Cycle Assessment (LCA) studies of H2 supply chains have become more common. This paper aims to compile and analyze discrepancies and convergences among recent reported values from 42 scientific studies related to different H2 production pathways. Technologies related to H2 transportation storage and use were not investigated in this study. Three environmental indicators were considered: Global Warming Potential (GWP) Energy Performance (EP) and Water Consumption (WF) from an LCA perspective. The review showed that H2 based on wind photovoltaic and biomass energy sources are a promising option since it provides lower GWP and higher EP compared to conventional fossil H2 pathways. However WF can be higher for H2 derived from biomass. LCA boundaries and methodological choices have a great influence on the environmental indicators assessed in this paper which leads to great variability in WF results as well as GWP variation due credits given to avoid GHG emissions in upstream process. In the case of EI the inclusion of energy embodied in renewable energy systems demonstrates great influence of upstream phase for electrolytic H2 based on wind and photovoltaic electricity.

Hydrogen is increasingly recognized as a key contributor to a low-carbon energy future and machine learning (ML) is emerging as a valuable tool to optimize hydrogen production processes. This review presents a comprehensive analysis of ML applications across various hydrogen production pathways including gray blue and green hydrogen with additional insights into pink turquoise white and black/brown hydrogen. A total of 51 peer-reviewed studies published between 2012 and 2025 were systematically reviewed. Among these green hydrogen—particularly via water electrolysis and biomass gasification—received the most attention reflecting its central role in decarbonization strategies. ML algorithms such as artificial neural networks (ANNs) random forest (RF) and gradient boosting regression (GBR) have been widely applied to predict hydrogen yield optimize operational conditions reduce emissions and improve process efficiency. Despite promising results real-world deployment remains limited due to data sparsity model integration challenges and economic barriers. Nonetheless this review identifies significant opportunities for ML to accelerate innovation across the hydrogen value chain. By highlighting trends key methodologies and current gaps this study offers strategic guidance for future research and development in intelligent hydrogen systems aimed at achieving sustainable and cost-effective energy solutions.