Publications

Green hydrogen has been identified as a critical enabler in the global transition to sustainable energy and decarbonized society but it is still not economically competitive compared to fossil-fuel-based hydrogen. To overcome this limitation we propose to couple photoelectrochemical (PEC) water splitting with the hydrogenation of chemicals. Here we evaluate the potential of coproducing hydrogen and methyl succinic acid (MSA) by coupling the hydrogenation of itaconic acid (IA) inside a PEC water splitting device. A negative net energy balance is predicted to be achieved when the device generates only hydrogen but energy breakeven can already be achieved when a small ratio (~2%) of the generated hydrogen is used in situ for IA-to-MSA conversion. Moreover the simulated coupled device produces MSA with much lower cumulative energy demand than conventional hydrogenation. Overall the coupled hydrogenation concept offers an attractive approach to increase the viability of PEC water splitting while at the same time decarbonizing valuable chemical production.

Hydrogen may play a significant part in sustainable energy transition. This paper discusses the sociotechnical interactions that are driving and hindering development of hydrogen value chains in Norway. The study is based on a combination of qualitative and quantitative methods. A multi-level perspective (MLP) is deployed to discuss how exogenous trends and uncertainties interact with processes and strategies in the national energy system and how this influences the transition potential associated with Norwegian hydrogen production. We explore different transition pathways towards a low-emission society in 2050 and find that Norwegian hydrogen production and its deployment for decarbonization of maritime and heavy-duty transport decarbonisation of industry and flexibility services may play a crucial role. Currently the development is at a branching point where national coordination is crucial to unlock the potential. The hybrid approach provides new knowledge on underlying system dynamics and contributes to the discourse on pathways in transition studies.

Hydrogen plays a leading role in achieving a future with net zero greenhouse gas emissions. The present challenge is producing green hydrogen to cover the fuel demands of transportation and industry to gain independence from fossil fuels. This review’s goal is to critically demonstrate the existing methods of biomass treatment and assess their ability to scale up. Biomass is an excellent hydrogen carrier and biomass-derived processes are the main target for hydrogen production as they provide an innovative pathway to green hydrogen production. Comparing the existing processes thermochemical treatment is found to be far more evolved than biological or electrochemical treatment especially with regard to scaling prospects.

Green hydrogen is considered the most suitable choice for the future energy market both as energy storage media energy vector and fuel for transportation industry and other applications. In the last twenty years increasing efforts have been dedicated to green hydrogen technologies development but still today a number of issues are claimed in justifying the delay in its large scale application and the star vation of its market. Moreover some new questions seem ready to be put on the table for justifying the delay in green hydrogen technologies applications. In this paper a critical analysis of recent literature and institutional reports is carried out with the aim of understanding what is the real state of the play. In particular peculiar advantages and shortcomings of different green hydrogen technologies (biomass pyrolysis and gasification water electrolysis etc.) have been analysed and compared with a focus on the electrolysis process as the most promising method for large scale and distributed generation of hydrogen. Some geopolitical and economic aspects associated with the transition to a green hydrogen economy - including the feared exacerbation of the water crisis - have been widely examined and discussed with the purpose of identifying approaches and solutions to accelerate the mentioned transition.

With more than 140 offshore platforms identified in Malaysian water to be decommissioned within 10 years it is critical for the Oil and Gas operators to re-evaluate the overall decommissioning strategies for a more sustainable approach. A revision to the current decommissioning options with inclusion of green decommissioning plan to the overall decision tree will assist in accelerating sustainable decision making. Using the advantage of the available 3D modelling from Naviswork and convert to PVSyst software for solar analysis to the one of the shortlisted offshore gas complexes in Malaysia three solar powered generation scenario was evaluated with aimed to establish the best integrated system on a modified decommissioned unmanned processing platform to generate cleaner energy. Financial assessment inclusive of Levelized Cost of Electricity as well as environmental assessment for each scenario are evaluated together. From the study optimum tilt angle was determined resulted to best annual solar yield of 257MWh with performance ratio (PR) of 87% for on-grid scenario 1. Off-grid scenario 3 is used to understand the estimated green hydrogen production. A desktop investigation conducted to three (3) type of electrolysers resulted to 8.6 kg to 18 kg of green hydrogen based on the average daily solar yield produced in scenario 3. Using Proton Electron Membrane electrolyser to simulate the PV solar-to-hydrogen offshore system it is observed that 98% of annual solar fraction can be achieved with annual performance ratio of 74.5% with levelized cost of Hydrogen (LCOH) of $10.95 per kg. From financial assessment this study justifies platforms repurpose to renewable energy concept to be an attractive option since cost to decommission the identified complex was observed to be 11 times greater compared to investing for this proposed concept.

Steer was appointed by the Directorate-General of Research and Innovation (DG RTD) to undertake an overview of key green aviation technologies and conditions for their market uptake. Steer is being supported in delivery by the Institute of Air Transport and Airport Research of the German Aerospace Centre DLR. The study was undertaken in the context of the Clean Aviation Partnership’s Strategic Research and Innovation Agenda (SRIA) for the period 2030-2050. The objective of the project is to identify the prerequisites for the market entry of climate-neutral aviation technologies as well as the flanking measures required for this to be successful. The scope of the study is hydrogen and electrically powered aircraft in the regional and short/medium range categories taking a holistic view on the technological development and keeping the economic context in mind. The outcome of the study will serve as guidance for the Commission and other actors with regard to further policy or industry initiatives such as in the context of Horizon Europe or the Alliance Zero Emission Aviation.

Hydrogen recombiners are catalyst-based hydrogen mitigation systems that have been successfully implemented in the nuclear industry but have not yet received serious interest from the hydrogen industry. Recombiners have been installed in the containment buildings of many nuclear power plants to prevent the accumulation of hydrogen in potential accidents. The attractiveness of hydrogen recombiners for the nuclear industry is due to the confined state of the containment building where hydrogen cannot be vented easily and its passive design where no power or actions are needed for the unit to operate. Alternatively in the hydrogen industry most applications utilize ventilation to mitigate potential hydrogen accumulation in confined areas and passive safety is not essential. However many applications in the hydrogen industry may utilize hydrogen recombiners from a different approach. For instance recombiners could be utilized in emerging hydrogen areas to minimize the costs of ventilation upgrades or built into hydrogen appliances to avoid vent connections. The potential applications for recombiners in the hydrogen industry have different atmospheric conditions than the nuclear industry which may impact the catalyst in the units and render them less effective. Thus experiments have been performed to investigate the limits of the recombiner catalyst and if modifications to the catalyst can extend their use to the hydrogen industry. This paper will present and discuss the applications of interest conditions that may affect the catalyst and results from experiments investigating the catalyst behaviour at temperatures less than 0 °C and carbon monoxide concentrations up to 1000 ppm.

The aim of the present work is the analysis of a solar‐driven unit that is located on the non‐interconnected island of Kythnos Greece that can produce electricity and green hydrogen. More specifically solar energy is exploited by parabolic trough collectors and the produced heat is stored in a thermal energy storage tank. Additionally an organic Rankine unit is incorporated to generate electricity which contributes to covering the island’s demand in a clean and renewable way. When the power cannot be absorbed by the local grid it can be provided to a water electrolyzer; therefore the excess electricity is stored in the form of hydrogen. The produced hydrogen amount is compressed afterward stored in tanks and then finally can be utilized as a fuel to meet other important needs such as powering vehicles or ferries. The installation is simulated parametrically and optimized on dynamic conditions in terms of energy exergy and finance. According to the results considering a base electrical load of 75 kW the annual energy and exergy efficiencies are found at 14.52% and 15.48% respectively while the payback period of the system is deter‐ mined at 6.73 years and the net present value is equal to EUR 1073384.

This study examines the potential market for residential hydrogen systems in light of the trends towards digitalisation and environmental awareness. Based on a survey of 350 participants the results indicate that although energy experts are sceptical about the benefits of residential hydrogen systems due to their high costs households are highly interested in this technology. The sample shows a willingness to invest in hydrogen applications with some households willing to pay an average of 24% more. An economic assessment compared the cost of a residential hydrogen system with conventional domestic energy systems revealing significant additional costs for potential buyers interested in hydrogen applications.

Climate concerns require immediate actions to reduce the global average temperature increase. Renewable electricity and renewable energy-based fuels and chemicals are crucial for progressive de-fossilization. Hydrogen will be part of the solution. The main issues to be considered are the growing market for H2 and the “green” feedstock and energy that should be used to produce H2 . The electrolysis of water using surplus renewable energy is considered an important development. Alternative H2 production routes should be using “green” feedstock to replace fossil fuels. We firstly investigated these alternative routes through using bio-based methanol or ethanol or ammonia from digesting agro-industrial or domestic waste. The catalytic conversion of CH4 to C and H2 was examined as a possible option for decarbonizing the natural gas grid. Secondly water splitting by reversible redox reactions was examined but using a renewable energy supply was deemed necessary. The application of renewable heat or power was therefore investigated with a special focus on using concentrated solar tower (CST) technology. We finally assessed valorization data to provide a tentative view of the scale-up potential and economic aspects of the systems and determine the needs for future research and developments.

Multi-energy systems that combine different energy sources and carriers to improve the overall technical economic and environmental performance can boost the energy transition. In this paper we posit an innovative multi-energy system for green hydrogen production that achieves negative carbon emissions by combining bio-fuel membraneintegrated steam reforming and renewable electricity electrolysis. The system produces green hydrogen and carbon dioxide both at high purity. We use thermo-chemical models to determine the system performance and optimal working parameters. Specifically we focus on its ability to achieve negative carbon emissions. The results show that in optimal operating conditions the system can capture up to 14.1 g of CO2 per MJ of stored hydrogen and achieves up to 70% storage efficiency. Therefore we prove that a multi-energy system may reach the same efficiency of an average electrolyzer while implementing carbon capture. In the same optimal operating conditions the system converts 7.8 kg of biogas in 1 kg of hydrogen using 3.2 kg of oxygen coming from the production of 6.4 kg of hydrogen through the electrolyzer. With such ratios we estimate that the conversion of all the biogas produced in Europe with our system could result in the installation of additional dedicated 800 GWp - 1280 GWp of photovoltaic power or of 266 GWp - 532 GWp of wind power without affecting the distribution grid and covering yearly the 45% of the worldwide hydrogen demand while removing from the atmosphere more than 2% of the European carbon dioxide emissions.

The measures needed to limit global warming pose a particular challenge to current fossil fuel exporters who must not only decarbonise their local energy systems but also compensate for the expected decline in fossil fuel revenues. One possibility is seen in the export of green hydrogen. Using Algeria as a case study this paper analyses how different levels of ambition in hydrogen exports energy efficiency and fuel switching affect the costoptimal expansion of the power sector for a given overall emissions reduction path. Despite falling costs for photovoltaics and wind turbines the results indicate that in countries with very low natural gas prices such as Algeria a fully renewable electricity system by 2050 is unlikely without appropriate policy measures. The expansion of renewable energy should therefore start early given the high annual growth rates required which will be reinforced by additional green hydrogen exports. In parallel energy efficiency is a key factor as it directly mitigates CO2 emissions from fossil fuels and reduces domestic electricity demand which could instead be used for hydrogen production. Integrating electrolysers into the power system could potentially help to reduce specific costs through load shifting. Overall it seems advisable to analyse hydrogen exports together with local decarbonisation in order to better understand their interactions and to reduce emissions as efficiently as possible. These results and the methodology could be transferred to other countries that want to become green hydrogen exporters in the future and are therefore a useful addition for researchers and policy makers.

There exists no single optimal way for transporting hydrogen and other hydrogen carriers from one port to the other globally. Its delivery depends on several factors such as the quantity distance economics and the availability of the required infrastructure for its transportation. Europe has a strategy to invest in the production of green hydrogen in Africa to meet its needs. This study assessed the economic viability of shipping liquefied hydrogen (LH2 ) and hydrogen carriers to Germany from six African countries that have been identified as countries with great potential in the production of hydrogen. The results obtained suggest that the shipping of LH2 to Europe (Germany) will cost between 0.47 and 1.55 USD/kg H2 depending on the distance of travel for the ship. Similarly the transportation of hydrogen carriers could range from 0.19 to 0.55 USD/kg H2 for ammonia 0.25 to 0.77 USD/kg H2 for LNG 0.24 to 0.73 USD/kg H2 for methanol and 0.43 to 1.28 USD/kg H2 for liquid organic hydrogen carriers (LOHCs). Ammonia was found to be the ideal hydrogen carrier since it recorded the least transportation cost. A sensitivity analysis conducted indicates that an increase in the economic life by 5 years could averagely decrease the cost of LNG by some 13.9% NH3 by 13.2% methanol by 7.9% LOHC by 8.03% and LH2 by 12.41% under a constant distance of 6470 nautical miles. The study concludes with a suggestion that if both foreign and local participation in the development of the hydrogen market is increased in Africa the continent could supply LH2 and other hydrogen carriers to Europe at a cheaper price using clean fuel.

Unprecedented investments in clean energy technology are required for a net-zero carbon energy system before temperatures breach the Paris Agreement goals. By performing a Monte-Carlo Analysis with the detailed ETSAPTIAM Integrated Assessment Model and by generating 4000 scenarios of the world’s energy system climate and economy we find that the uncertainty surrounding technology costs resource potentials climate sensitivity and the level of decoupling between energy demands and economic growth influence the efficiency of climate policies and accentuate investment risks in clean energy technologies. Contrary to other studies relying on exploring the uncertainty space via model intercomparison we find that the CO2 emissions and CO2 prices vary convexly and nonlinearly with the discount rate and climate sensitivity over time. Accounting for this uncertainty is important for designing climate policies and carbon prices to accelerate the transition. In 70% of the scenarios a 1.5 ◦C temperature overshoot was within this decade calling for immediate policy action. Delaying this action by ten years may result in 2 ◦C mitigation costs being similar to those required to reach the 1.5 ◦C target if started today with an immediate peak in emissions a larger uncertainty in the medium-term horizon and a higher effort for net-zero emissions.

Bioelectrochemical systems (BES) are becoming popular technologies with a plethora of applications in the environmental field. However research on the scale-up of these systems is scarce. To understand the limiting factors of hydrogen production in microbial electrolysis cell (MEC) at pilot scale a 135 L MEC was operated for six months under a wide range of operational conditions: applied potential [0.8-1.1 V] hydraulic residence time [1.1-3.9 d] and temperature [18-30 ºC] using three types of wastewater; synthetic (900 mg CODs L-1) raw urban wastewater (200 mg CODs L-1) and urban wastewater amended with acetate (1000 mg CODs L-1). The synthetic wastewater yielded the maximum current density (1.23 A m-2) and hydrogen production (0.1 m3 m-3 d-1) ever reported in a pilot scale MEC with a cathodic recovery of 70% and a coulombic efficiency of 27%. In contrast the use of low COD urban wastewater limited the plant performance. Interestingly it was possible to improve hydrogen production by reducing the hydraulic residence time finding the optimal applied potential or increasing the temperature. Further the pilot plant demonstrated a robust capacity to remove the organic matter present in the wastewater under different conditions with removal efficiencies above 70%. This study shows improved results compared to similar MEC pilot plants treating domestic wastewater in terms of hydrogen production and treatment efficiency and also compares its performance against conventional activated sludge processes.

The Russian invasion of Ukraine has undeniably disrupted the EU's energy system and created a window of opportunity for an acceleration of the low-carbon energy transition in Europe. As the trading bloc's biggest gas supplier Norway faces the imminent threat of fast-depleting gas reserves and declining value for its exports. Norway is trying to beat the clock by aggressively exploring more petroleum therefore delaying its energy transition. In anticipation of the future drop in gas prices Norway is counting on blue hydrogen to valorise its gas resources before gradually shifting to green hydrogen export. Against this background this article seeks to understand how changes in the EU's energy landscape have affected the energy export sector and low-carbon hydrogen export developments in Norway from a multi-level perspective. Using the exploratory scenario approach the article assesses the implications of the different petroleum exploration outcomes on the development of the low-carbon hydrogen export market in Norway. The findings show that despite gas discoveries there is an urgent need for a phase-out plan for the Norwegian petroleum sector. For low-carbon hydrogen to play an important role in Norway's energy transition time is of the essence and action needs to be taken during this window of opportunity. An industrial sector and its value chain could take 25 years to transform which means that actions and policies for a full transformation pathway need to take place in Norway by 2025 to be ready for a climate-neutral Europe in 2050.

As hydrogen becomes an increasingly popular alternative fuel for transportation the need for tools to predict ignition events has grown. Recently a cost-effective passive scalar formulation has been developed to address this need [1]. This approach employs a self-reacting scalar to model the hydrogenair chain-branched explosion (due to reactions of the type Reactant + Radical → Radical + Radical). The scalar branching rate is derived analytically from the kinetic Jacobian matrix [2]. The method accurately reproduces ignition delays obtained by detailed chemistry for temperatures above crossover where branching is the dominant process. However for temperatures below the crossover temperature where other phenomena like thermal runaway are more significant the scalar approach fails to predict ignition events correctly. Therefore modifications to the scalar framework have been made to extend its validity across the entire temperature range. Additionally a simple technique for approximating the molecular diffusion of the scalar has been developed using the eigenvector of the Jacobian which accounts for differences in the radical pool’s composition and non-unity Lewis number effects. The complete modified framework is presented and its capability is evaluated in canonical scenarios and a more challenging double mixing layer.

Clean technologies play a crucial role in reducing greenhouse gas emissions and protecting the climate. Hydrogen is a promising energy carrier and fuel that can be used in many applications. We explore the global hydrogen technological innovation system (TIS) by analyzing the three knowledge and technology transfer channels of publications patents and standards. Since the adoption of hydrogen technologies requires trust in their safety this study specifically also focuses on hydrogen safety. Our results show that general and hydrogen safety research has increased significantly while patenting experienced stagnation. An analysis of the non-patent literature in safety patents shows little recognition of scientific publications. Similarly publications are under-represented in the analyzed 75 international hydrogen and fuel cell standards. This limited transfer of knowledge from published research to standards points to the necessity for greater involvement of researchers in standardization. We further derive implications for the hydrogen TIS and recommendations for a better and more impactful alignment of the three transfer channels.

Currently hydrogen and electric drives used in various means of transport is a leading topic in many respects. This article discusses the most important aspects of the operation of vehicles with electric drives (passenger cars) and hydrogen drives. In both cases the official reason for using both drives is the possibility of independence from fossil fuel supplies especially oil. The desire for independence is mainly dictated by political considerations. This article discusses the acquisition of basic raw materials for the construction of lithium-ion batteries in electric cars as well as methods for obtaining hydrogen as a fuel. The widespread use of electric passenger cars requires the construction of a network of charging stations. This article shows that taking into account the entire production process of electric cars including lithium-ion batteries the argument that they are ecological cannot be used. Additionally it was indicated that there is no concept for the use of used accumulator batteries. If hydrogen drives are used in trains there is no need to build the traction network infrastructure and then continuously monitor its technical condition and perform the necessary repairs. Of course the necessary hydrogen tanks must be built but there must be similar tanks to store oil for diesel locomotives. This paper also deals with other possibilities of hydrogen application for transformational usage e.g. the use of combustion engines driven with liquid hydrogen. Unfortunately an optimistic approach to this issue does not allow for a critical view of the whole matter. In public discussion there is no room for scientific arguments and emotions to dominate.

Further development of hydrogen-fuelled transport and associated infrastructure requires fundamentally based validated and publicly accepted models for fuelling protocol development particularly for heavy-duty transport applications where protocols are not available yet. This study aims to use computational fluid dynamics (CFD) for modelling the entire hydrogen refuelling station (HRS) including all its components starting from high-pressure (HP) tanks a mass flow meter pressure control valve (PCV) a heat exchanger (HE) nozzle hose breakaway and up to 3 separate onboard tanks. The paper focuses on the initial phase of the refuelling procedure in which the main purpose is to check for leaks in the fuelling line and determine if it is safe to start fuelling. The simulation results are validated against the only publicly available data on hydrogen fuelling by Kuroki and co-authors (2021) from the NREL hydrogen fuelling station experiment. The simulation results – mass flow rate dynamics as well as pressure and temperature at different station locations - show good agreement with the measured experimental data. The development of such models is crucial for the further advancement of hydrogen-fuelled transport and infrastructure and this study presents a step towards this goal.

Significant research efforts are directed towards finding new ways to reduce the cost increase efficiency and decrease the environmental impact of power-generation systems. The poly-generation concept is a promising strategy that enables the development of a sustainable power system. Over the past few years the Proton Exchange Membrane Fuel Cell-based Poly-Generation Systems (PEMFC-PGSs) have received accelerated developments due to the low-temperature operation high efficiency and low environmental impact. This paper provides a comprehensive review of the main PEMFC-PGSs including Combined Heat and Power (CHP) co-generation systems Combined Cooling and Power (CCP) co-generation systems Combined Cooling Heat and Power (CCHP) tri-generation systems and Combined Water and Power (CWP) co-generation systems. First the main technologies used in PEMFC-PGSs such as those related to hydrogen production energy storage and Waste Heat Recovery (WHR) etc. are detailed. Then the research progresses on the economic energy and environmental performance of the different PEMFC-PGSs are presented. Also the recent commercialization activities on these systems are highlighted focusing on the leading countries in this field. Furthermore the remaining economic and technical obstacles of these systems along with the future research directions to mitigate them are discussed. The review reveals the potential of the PEMFC-PGS in securing a sustainable future of the power systems. However many economic and technical issues particularly those related to high cost and degradation rate still need to be addressed before unlocking the full benefits of such systems.

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.

Water electrolysis using solid oxide electrolysis cells is a promising method for hydrogen production because it is highly efficient clean and scalable. Recently a lot of researches focusing on development of high-power stack system have been introduced. However there are very few studies of economic analysis for this promising system. Consequently this study proposed 20-kW-scale high-power solid oxide electrolysis cells system config urations then conducted economic analysis. Especially the economic context was in South Korea. For com parison a low-power system with similar design was used as a reference; the levelized cost of hydrogen of each system was calculated based on the revenue requirement method. Furthermore a sensitivity analysis was also performed to identify how the economic variables affect the hydrogen production cost in a specific context. The results show that a high-power system is superior to a low-power system from an economic perspective. The stack cost is the dominant component of the capital cost but the electricity cost is the factor that contributes the most to the hydrogen cost. In the first case study it was found that if a high-power system can be installed inside a nuclear power plant the cost of hydrogen produced can reach $3.65/kg when the electricity cost is 3.28¢/kWh and the stack cost is assumed to be $574/kW. The second case study indicated that the hydrogen cost can decrease by 24% if the system is scaled up to a 2-MW scale.

The mechanical properties of materials deteriorate when hydrogen embrittlement (HE) occurs seriously threatening the reliability and durability of the hydrogen system. Therefore it is important to summarize the status and development trends of research on HE. This study reviewed 6676 publications concerned with HE from 1997 to 2022 based on the Web of Science Core Collection. VOSviewer was used to conduct the bibliometric analysis and produce visualizations of the publications. The results showed that the number of publications on HE increased after 2007 especially between 2017 and 2019. Japan was the country with the highest numbers of productive authors and citations of publications and the total number of citations of Japanese publications was 24589. Kyushu University was the most influential university and the total number of citations of Kyushu University publications was 7999. Akiyama was the most prolific and influential author publishing 88 publications with a total of 2565 citations. The USA South Korea and some European countries are also leading in HE research; these countries have published more than 200 publications. It was also found that the HE publications generally covered five topics: “Hydrogen embrittlement in different materials” “Effect of hydrogen on mechanical properties of materials” “Effect of alloying elements or microstructure on hydrogen embrittlement” “Hydrogen transport” and “Characteristics and mechanisms of hydrogen related failures”. Research hotspots included “Fracture failure behavior and analysis” “Microstructure” “Hydrogen diffusion and transport” “Mechanical properties” “Hydrogen resistance” and so on. These covered the basic methods and purposes of HE research. Finally the distribution of the main subject categories of the publications was determined and these categories covered various topics and disciplines. This study establishes valuable reference information for the application and development of HE research and provides a convenient resource to help researchers and scholars understand the development trends and research directions in this field.

Although alkaline water electrolysis (AWE) is the most widespread technology for hydrogen production by electrolysis its electrochemical and fluid dynamic optimization has rarely been addressed simultaneously using Computational Fluid Dynamics (CFD) simulation. In this regard a two-dimensional (2D) CFD model of an AWE cell has been developed using COMSOL® software and then experimentally validated. The model involves transport equations for both liquid and gas phases as well as equations for the electric current conservation. This multiphysics approach allows the model to simultaneously analyze the fluid dynamic and electrochemical phenomena involved in an electrolysis cell. The electrical response was evaluated in terms of polarization curve (voltage vs. current density) at different operating conditions: temperature electrolyte conductivity and electrode-diaphragm distance. For all cases the model fits very well with the experimental data with an error of less than 1% for the polarization curves. Moreover the model successfully simulates the changes on gas profiles along the cell according to current density electrolyte flow rate and electrode-diaphragm distance. The combination of electrochemical and fluid dynamics studies provides comprehensive information and makes the model a promising tool for electrolysis cell design.

This review provides a comprehensive overview of the dynamics of low-temperature water electrolyzers and their influence on coupling the three major technologies alkaline Proton Exchange Membrane (PEM) and Anion Exchange Membrane (AEM) with photovoltaic (PV) systems. Hydrogen technology is experiencing considerable interest as a way to accelerate the energy transition. With no associated CO2 emissions and fast response water electrolyzers are an attractive option for producing green hydrogen on an industrial scale. This can be seen by the ambitious goals and large-scale projects being announced for hydrogen especially with solar energy dedicated entirely to drive the process. The electrical response of water electrolyzers is extremely fast making the slower variables such as temperature and pressure the limiting factors for variable operation typically associated with PV-powered electrolysis systems. The practical solar-to-hydrogen efficiency of these systems is in the range of 10% even with a very high coupling factor exceeding 99% for directly coupled systems. The solar-to-hydrogen efficiency can be boosted with a battery potentially sacrificing the cost. The intermittency of solar irradiance rather than its variability is the biggest challenge for PV-hydrogen systems regarding operation and degradation.

Despite the potential of hydrogen as a sustainable energy carrier existing studies analysing the recent evolution of this technology are scattered typically focusing on a specific type of hydrogen technology within a single country or region. In this paper we adopt a broader perspective providing an overview of the evolution of knowledge generation across different types of hydrogen fuel and the leading countries in developing new technologies in this field. Using data from the European Patent Office we map knowledge generation on hydrogen fuel technologies exploring its geographic distribution and its link with environmental sustainability. While the United States leads the generation of new knowledge other Asian and European countries show greater dynamism in growth and specialisation. Our study shows that although hydrogen fuel is considered environmentally friendly most recent technological developments are still related to fossil energy sources. However a faster growth rate is observed in the knowledge of hydrogen fuel from renewable sources pointing to a promising path towards sustainability. Moreover our analysis of the knowledge interconnection between different hydrogen types suggests that those technologies developed for hydrogen based on fossil energy sources have enabled novel applications based on renewable energies.

The decarbonization of the energy sector has been a subject of research and of political discussions for several decades gaining significant attention in the last years. It is commonly acknowledged that the most obvious way to achieve decarbonization is the use of renewable energy sources. Within the context of the energy sector decarbonization many mainly industrialized countries recently started developing national plans to establish a hydrogen-based economy in the very near future. The plans for green hydrogen initially try to (a) target sectors that are difficult to decarbonize and (b) address issues related to the storage and transportation of CO2-free energy. To achieve almost complete decarbonization electric power must be generated exclusively from renewable sources. In so-called Power-to-X (PtX) technologies green hydrogen is generated from electricity and subsequently converted to another energy carrier which can be further stored transported and used. In PtX X stands for example for liquid hydrogen methanol or ammonia. The challenges associated with decarbonization include those associated with (a) the expansion of renewable energies (e.g. high capital demand political and social issues) (b) the production transportation and storage of hydrogen and the energy carriers denoted by X in PtX (e.g. high cost and low overall efficiency) and (c) the expected significant increase in the demand for electrical energy. The paper discusses whether and under which conditions the current national and international hydrogen plans of many industrialized countries could lead to a maximization of decarbonization in the world. It concludes that in general as long as the conditions for generating large excess amounts of green electricity are not met the quick establishment of a hydrogen economy could not only be very expensive but also counterproductive to the worldwide decarbonization efforts.

Contrary to microgrids (MGs) for which grid code or legislative support are lacking in the majority of cases energy communities (ECs) are one of the cornerstones of the energy transition backed up by the EU’s regulatory framework. The main difference is that unlike MGs ECs grow and develop organically through citizen involvement and investments in the existing low-voltage (LV) distribution networks. They are not planned and built from scratch as closed distribution systems that are independent of distribution system operator plans as assumed in the existing literature. An additional benefit of ECs could be the ability to transition into island mode contributing to the resilience of power networks. To this end this paper proposes a three-stage framework for analyzing the islanding capabilities of ECs. The framework is utilized to comprehensively assess and compare the islanding capabilities of ECs whose organic development is based upon three potential energy vectors: electricity gas and hydrogen. Detailed dynamic simulations clearly show that only fully electrified ECs inherently have adequate islanding capabilities without the need for curtailment or additional investments.

High-accuracy gas dispersion models are necessary for predicting hydrogen movement and for reducing the damage caused by hydrogen release accidents in chemical processes. In urban areas where obstacles are large and abundant computational fluid dynamics (CFD) would be the best choice for simulating and analyzing scenarios of the accidental release of hydrogen. However owing to the large computation time required for CFD simulation it is inappropriate in emergencies and real-time alarm systems. In this study a non-linear surrogate model based on deep learning is proposed. Deep convolutional layer data-driven autoencoder and batch normalized deep neural network is used to analyze the effects of wind speed wind direction and release degree on hydrogen concentration in real-time. The typical parameters of hydrogen diffusion accidents at hydrogen refuelling stations were acquired by CFD numerical simulation approach and a database of hydrogen diffusion accident parameters is established. By establishing an appropriate neural network structure and associated activation function a deep learning framework is created and then a deep learning model is constructed. The accuracy and timeliness of the model are assessed by comparing the results of the CFD simulation with those of the deep learning model. To develop a dynamic reconfiguration prediction model for the hydrogen refuelling station diffusion scenario the algorithm is continuously enhanced and the model is improved. After training is finished the model's prediction time is measured in seconds which is 105 times quicker than field CFD simulations. The deep learning model of hydrogen release in hydrogen refuelling stations is established to realize timely and accurate prediction and simulation of accident consequences and provide decision-making suggestions for emergency rescue and personnel evacuation which is of great significance for the protection of human life health and property safety.

Alternative sources of energy are on the rise primarily because of environmental concerns in addition to the depletion of fossil fuel reserves. Currently there are many alternatives approaches and attempts to introduce alternative energy sources in the field of transport. This article centers around the need to explore additional energy sources beyond the current ones in use. It delves into individual energy sources that can be utilized for transportation including their properties production methods and the advantages and disadvantages associated with their use across different types of drives. The article not only examines the situation in the Czech Republic but also in other nations. In addition to addressing future mobility the thesis also considers how the utilization of new energy sources may impact the environment.

This paper investigates the performance of hydrogen-fueled spark-ignited single-cylinder Cooperative Fuel Research using experimental and numerical approaches. This study examines the effect of the air–fuel ratio on engine performance emissions and knock behaviour across different compression ratios. The results indicate that λ significantly affects both engine performance and emissions with a λ value of 2 yielding the highest efficiency and lowest emissions for all the tested compression ratios. Combustion analysis reveals normal combustion at λ ≥ 2 while knocking combustion occurs at λ < 2 irrespective of the tested compression ratios. The Livenwood–Wu integral approach was evaluated to assess the likelihood of end-gas autoignition based on fuel reactivity demonstrating that both normal and knocking combustion possibilities are consistent with experimental investigations. Combustion analysis at the ignition timing for maximum brake torque conditions demonstrates knock-free stable combustion up to λ = 3 with increased end-gas autoignition at lower λ values. To achieve knock-free combustion at those low λs the spark timings are significantly retarded to after top dead center crank angle position. Engine-out NOx emissions consistently increase in trend with a decrease in the air–fuel ratio of up to λ = 3 after which a distinct variation in NOx is observed with an increase in the compression ratio.

Compressed hydrogen storage is an energy-efficient alternative to liquefaction and in the absence of underground salt formations reservoirs like rock caverns mining shafts and cased boreholes are gaining traction. The limited reservoir volume constrained by excavation or drilling results in short high-pressure cycles. Thus effective temperature control is crucial to maintain integrity and maximize hydrogen density. This study presents a validated numerical model with open-access code for simulating heat exchange and predicting operating pressure and temperature for underground hydrogen storage in tanks or caverns. The validation encompasses analytical solutions and existing cylindrical models. Results highlight the heat transfer’s impact on hydrogen density and the limited penetration depth of the thermal perturbation underscoring the need for simulating heat transfer across multiple layers especially in restrictive media like cement. Managing injection and extraction flow rates is crucial to limit temperature peaks for larger radius reservoirs where heat transfer is less efficient.

The European Union is committed to a 55% reduction in greenhouse gas emissions by 2030 as outlined in the Green Deal and Climate Law initiatives. In response to geopolitical events the RePowerEU initiative aims to enhance energy self-sufficiency reduce reliance on Russian natural gas and promote hydrogen utilization. Hydrogen valleys localized ecosystems integrating various hydrogen supply chain elements play a key role in this transition particularly benefiting isolated regions like islands. This manuscript focuses on optimizing a Centralized Green Hydrogen Production Facility (CGHPF) on the island of Crete. A mixed-integer linear programming framework is proposed to optimize the CGHPF considering factors such as land area wind and solar potential costs and efficiency. Additionally an in-depth sensitivity analysis is conducted to explore the impact of key factors on the economic feasibility of hydrogen investments. The findings suggest that hydrogen can be sold in Crete at prices as low as 3.5 EUR/kg. Specifically it was found in the base scenario that selling hydrogen at 3.5 EUR/kg the net profit of the investment could be as high as EUR 6.19 million while the capacity of the solar and wind installation supplying the grid hydrogen facility would be 23.51 MW and 52.97 MW respectively. It is noted that the high profitability is justified by the extraordinary renewable potential of Crete. Finally based on our study a policy recommendation to allow a maximum of 20% direct penetration of renewable sources of green hydrogen facilities into the grid is suggested to encourage and accelerate green hydrogen expansion.

Green hydrogen presents a promising solution for transitioning from fossil fuels to a clean energy future particularly with the application of fuel cell electric vehicles (FCEVs). However the hydrogen refuelling process for FCEVs requires extensive pre-cooling to achieve fast filling times. This study presents experiments and simulations of a hydrogen refuelling station equipped with an adaptable cold-fill unit aiming to maximize fuelling efficiencies. For this purpose we developed and experimentally validated simulation models for a hydrogen tank and an aluminium block heat exchanger. Different pre-cooling parameters affect the final tank temperatures during the parallel filling of three 350 L type IV tanks. The results indicate significant potential for optimizing the required cooling energy with achievable savings of over 50 % depending on the pre-cooling strategy. The optimized pre-cooling strategies and energy savings aid in advancing the refuelling process for FCEVs effectively contributing to the transition to clean energy.

New hypotheses for reusing platforms reaching their end-of-life have been investigated in several works discussing the potential conversions of these infrastructures from recreational tourism to fish farming. In this perspective paper we discuss the conversion options that could be of interest in the context of the current energy transition with reference to the off-shore Italian scenario. The study was developed in support of the development of a national strategy aimed at favoring a circular economy and the reuse of existing infrastructure for the implementation of the energy transition. Thus the investigated options include the onboard production of renewable energy hydrogen production from seawater through electrolyzers CO2 capture and valorization and platform reuse for underground fluid storage in depleted reservoirs once produced through platforms. Case histories are developed with reference to a typical fictitious platform in the Adriatic Sea Italy to provide an engineering-based approach to these different conversion options. The coupling of the platform with the underground storage to set the optimal operational conditions is managed through the forecast of the reservoir performance with advanced numerical models able to simulate the complexity of the phenomena occurring in the presence of coupled hydrodynamic geomechanical geochemical thermal and biological processes. The results of our study are very encouraging because they reveal that no technical environmental or safety issues prevent the conversion of offshore platforms into valuable infrastructure contributing to achieving the energy transition targets as long as the selection of the conversion option to deploy is designed taking into account the system specificity and including the depleted reservoir to which it is connected when relevant. Socio-economic issues were not investigated as they were out of the scope of the project.

Thermodynamic modeling of hydrogen tank refueling i.e. 0 dimension (0D) model considers the gas in the tank as a single homogeneous volume. Based on thermodynamic considerations i.e. mass and energy balance equations the gas temperature and pressure predicted at each time step are volume-averaged. These models cannot detect the onset of the thermal stratification nor the maximum local temperature of the gas inside the tank.<br/>For safety reasons the temperature must be maintained below 85 °C in the composite tank. When thermal stratification occurs the volume-averaged gas temperature predicted by 0D models can be below 85 °C while local temperature may significantly exceed 85 °C. Then thermally stratified scenarios must be predicted to still employ 0D models safely.<br/>Up to now only computational fluid dynamics (CFD) approaches can predict the onset of the thermal stratification and estimate the amplitude of thermal gradients. However CFD approaches require much larger computational resources and CPU time than 0D models. This makes it difficult to use CFD for parametric studies or a live-stream temperature prediction for embedded applications. Previous CFD studies revealed the phenomenon of jet deflection during horizontal refueling of hydrogen tanks. The cold hydrogen injected into the warm gas bulk forms a round jet sinking down towards the lower part of the tank due to buoyancy forces. The jet breaks the horizontal symmetry and dumps the cold gas towards the lower part of the tank.<br/>The jet behavior is a key factor for the onset of the thermal stratification for horizontally filled tanks. Free round jets released in a homogeneous environment with a different density than the jet density were extensively investigated in the literature. A buoyant round jet modeling can be applied to predict the jet deflection in the tank. It requires initial conditions that can be provided by 0D refueling models. Therefore 0D models coupled with a buoyant round jet modeling can be used to predict the onset of the thermal stratification without CFD simulation. This approach clarifies the validity domain of 0D models and thus improves the safety of engineering applications

The impact of ship emission reductions can be maximised by considering climate health and environmental effects simultaneously and using solutions fitting into existing marine engines and infrastructure. Several options available enable selecting optimum solutions for different ships routes and regions. Carbon-neutral fuels including low-carbon and carbon-negative fuels from biogenic or non-biogenic origin (biomass waste renewable hydrogen) could resemble current marine fuels (diesel-type methane and methanol). The carbon-neutrality of fuels depends on their Well-to-Wake (WtW) emissions of greenhouse gases (GHG) including carbon dioxide (CO2) methane (CH4) and nitrous oxide emissions (N2O). Additionally non-gaseous black carbon (BC) emissions have high global warming potential (GWP). Exhaust emissions which are harmful to health or the environment need to be equally removed using emission control achieved by fuel engine or exhaust aftertreatment technologies. Harmful emission species include nitrogen oxides (NOx) sulphur oxides (SOx) ammonia (NH3) formaldehyde particle mass (PM) and number emissions (PN). Particles may carry polyaromatic hydrocarbons (PAHs) and heavy metals which cause serious adverse health issues. Carbon-neutral fuels are typically sulphur-free enabling negligible SOx emissions and efficient exhaust aftertreatment technologies such as particle filtration. The combinations of carbon-neutral drop-in fuels and efficient emission control technologies would enable (near-)zero-emission shipping and these could be adaptable in the short- to mid-term. Substantial savings in external costs on society caused by ship emissions give arguments for regulations policies and investments needed to support this development.

Low-carbon hydrogen could be an important component of a net-zero carbon economy helping to mitigate emissions in a number of hard-to-abate sectors. The United States recently introduced an escalating production tax credit (PTC) to incentivize production of hydrogen meeting increasingly stringent embodied emissions thresholds. Hydrogen produced via electrolysis can qualify for the full subsidy under current federal accounting standards if the input electricity is generated by carbon-free resources but may fail to do so if emitting resources are present in the generation mix. While use of behind-the-meter carbon-free electricity inputs can guarantee compliance with this standard the PTC could also be structured to allow producers using grid-supplied electricity to qualify subject to certain clean energy procurement requirements. Herein we use electricity system capacity expansion modeling to quantitatively assess the impact of grid-connected electrolysis on the evolution of the power sector in the western United States through 2030 under multiple possible implementations of the clean hydrogen PTC. We find that subsidized grid-connected hydrogen production has the potential to induce additional emissions at effective rates worse than those of conventional fossil-based hydrogen production pathways. Emissions can be minimized by requiring grid-based hydrogen producers to match 100% of their electricity consumption on an hourly basis with physically deliverable ‘additional’ clean generation which ensures effective emissions rates equivalent to electrolysis exclusively supplied by behind-the-meter carbon-free generation. While these requirements cannot eliminate indirect emissions caused by competition for limited clean resources which we find to be a persistent result of large hydrogen production subsidies they consistently outperform alternative approaches relying on relaxed time matching or marginal emissions accounting. Added hydrogen production costs from enforcing an hourly matching requirement rather than no requirements are less than $1 kg−1 and can be near zero if clean firm electricity resources are available for procurement.

Underground hydrogen storage in saline aquifers is a promising way to store large amounts of energy. Utilization of gas cushion enhances the deliverability of the storage and increases the volume of recovery gas. The key factor for the cushion characterization is cushion gas and storage gas mixing which can be used for simulation of mixing zone evolution. In this work coreflooding setup utilizing Raman spectroscopy is built and used for dispersion coefficient determination. Berea sandstone rock core is used as a test sample for setup validation and core entry/exit effects estimation. Dispersion for hydrogen and methane as displacing fluids is determined for 4 locations perspective for hydrogen storage in Poland is found. Reservoir structures most suitable for pure hydrogen or hydrogen/methane blend storage are selected.

The continued use of energy sources based on fossil fuels has various repercussions for the environment. These repercussions are being minimized through the use of renewable energy supplies and new techniques to decarbonize the global energy matrix. For many years hydrogen has been one of the most used gases in all kinds of industry and now it is possible to produce it efficiently on a large scale and in a non-polluting way. This gas is mainly used in the chemical industry and in the oil refining industry but the constant growth of its applications has generated the interest of all the countries of the world. Its use in transportation petrochemical industries heating equipment etc. will result in a decrease in the production of greenhouse gases which are harmful to the environment. This means hydrogen is widely used and needed by countries creating great opportunities for hydrogen export business. This paper details concepts about the production of green hydrogen its associated technologies and demand projections. In addition the current situation of several countries regarding the use of this new fuel their national strategy and advances in research carried out in different parts of the world for various hydrogen generation projects are discussed. Additionally the great opportunities that Chile has for this new hydrogen export business thanks to the renewable energy production capacities in the north and south of the country are discussed. The latter is key for countries that require large amounts of hydrogen to meet the demand from various industrial energy and transportation sectors. Therefore it is of global importance to determine the real capacities that this country has in the face of this new green fuel. For this modeling was carried out through mathematical representations showing the behavior of the technologies involved in the production of hydrogen for a system composed of an on-grid photovoltaic plant an electrolyser and compressor together with a storage system. The program optimized the capacities of the equipment in such a way as to reduce the costs of hydrogen production and thereby demonstrate Chile’s capacity for the production of this fuel. From this it was found that the LCOH for the case study was equivalent to 3.5 USD/kg which is not yet considered a profitable value for the long term. Due to this five case studies were analyzed to see what factors influence the LCOH and thereby reduce it as much as possible.

Hydrogen barrier coatings are protective layers consisting of materials with a low intrinsic hydrogen diffusivity and solubility showing the potential to delay reduce or hinder hydrogen permeation. Hydrogen barrier coatings are expected to enable steels which are susceptible to hydrogen embrittlement specifically cost-effective low alloy-steels or light-weight high-strength steels for applications in a hydrogen economy. Predominantly ceramic coating materials have been investigated for this purpose including oxides nitrides and carbides. In this review the state of the art with respect to hydrogen permeation is discussed for a variety of coatings. Al2O3 TiAlN and TiC appear to be the most promising candidates from a large pool of ceramic materials. Coating methods are compared with respect to their ability to produce layers with suitable quality and their potential for scaling up for industrial use. Different setups for the characterisation of hydrogen permeability are discussed using both gaseous hydrogen and hydrogen originating from an electrochemical reaction. Finally possible pathways for improvement and optimisation of hydrogen barrier coatings are outlined.

This manuscript presents a thorough review of unitized regenerative fuel cells (URFCs) and their importance in Remote Area Power Supply (RAPS). In RAPS systems that utilize solar and hydrogen power which typically include photovoltaic modules a proton exchange membrane (PEM) electrolyzer hydrogen gas storage and PEM fuel cells the cost of these systems is currently higher compared to conventional RAPS systems that employ diesel generators or batteries. URFCs offer a potential solution to reduce the expenses of solar hydrogen renewable energy systems in RAPS by combining the functionalities of the electrolyzer and fuel cell into a single unit thereby eliminating the need to purchase separate and costly electrolyzer and fuel cell units. URFCs are particularly well-suited for RAPS applications because the electrolyzer and fuel cell do not need to operate simultaneously. In electrolyzer mode URFCs function similarly to stand-alone electrolyzers. However in fuel cell mode the performance of URFCs is inferior to that of stand-alone fuel cells. The presented review summarizes the past present and future of URFCs with details on the operating modes of URFCs limitations and technical challenges and applications. Solar hydrogen renewable energy applications in RAPS and challenges facing solar hydrogen renewable energy in the RAPS is discussed in detail.

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

Hydrogen as a carbon-free energy carrier has emerged as a crucial component in the decarbonization of the energy system serving as both an energy storage option and fuel for dispatchable power generation to mitigate the intermittent nature of renewable energy sources. However the unique physical and combustion characteristics of hydrogen which differ from conventional gaseous fuels such as biogas and natural gas present new challenges that must be addressed. To fully integrate hydrogen as an energy carrier in the energy system the development of low-emission and highly reliable technologies capable of handling hydrogen combustion is imperative. This study presents a ground-breaking achievement - the first successful test of a micro gas turbine running on 100% hydrogen with NOx emissions below the standard limits. Furthermore the combustor of the micro gas turbine demonstrates exceptional fuel flexibility allowing for the use of various blends of hydrogen biogas and natural gas covering a wide range of heating values. In addition to a comprehensive presentation of the test rig and its instrumentation this paper illuminates the challenges of hydrogen combustion and offers real-world operational data from engine operation with 100% hydrogen and its blends with methane.

A clean energy revolution is occurring across the world. As iron and steelmaking have a tremendous impact on the amount of CO2 emissions there is an increasing attraction towards improving the green footprint of iron and steel production. Among reducing agents hydrogen has shown a great potential to be replaced with fossil fuels and to decarbonize the steelmaking processes. Although hydrogen is in great supply on earth extracting pure H2 from its compound is costly. Therefore it is crucial to calculate the partial pressure of H2 with the aid of reduction reaction kinetics to limit the costs. This review summarizes the studies of critical parameters to determine the kinetics of reduction. The variables considered were temperature iron ore type (magnetite hematite goethite) H2/CO ratio porosity flow rate the concentration of diluent (He Ar N2 ) gas utility annealing before reduction and pressure. In fact increasing temperature H2/CO ratio hydrogen flow rate and hematite percentage in feed leads to a higher reduction rate. In addition the controlling kinetics models and the impact of the mentioned parameters on them investigated and compared concluding chemical reaction at the interfaces and diffusion of hydrogen through the iron oxide particle are the most common kinetics controlling models.

This article proposes using recycled aluminum generating hydrogen in situ at low pressure to power a 250 W electric bicycle with a fuel cell (FC) to increase the average speed and autonomy compared to a conventional electric bicycle with a battery. To generate hydrogen the aluminum–water reaction with a 6 M NaOH solution is used as a catalyst. This article details the parts of the generation system the electronic configuration used the aluminum- and reagent-loading procedure and the by-products obtained as well as the results of the operation without pedaling with a resistance equivalent to a flat terrain and at maximum power of the accelerator for one and two loads of about 100 g of aluminum each. This allows us to observe different hybrid strategies with a low-capacity battery in each case. The goal is to demonstrate that it is possible to store energy in a long-lasting transportable low-pressure and sustainable manner using recycled-aluminum test tubes and to apply this to mobility

This study presents a novel framework for improving the resilience of microgrids based on the power-to-hydrogen concept and the ability of microgrids to operate independently (i.e. islanded mode). For this purpose a model is being developed for the resilient operation of microgrids in which the compressed hydrogen produced by power-to-hydrogen systems can either be used to generate electricity through fuel cells or sold to other industries. The model is a bi-objective optimization problem which minimizes the cost of operation and resilience by (i) reducing the active power exchange with the main grid (ii) reducing the ohmic power losses and (iii) increasing the amount of hydrogen stored in the tanks. A solution approach is also developed to deal with the complexity of the bi-objective model combining a goal programming approach and Generalized Benders Decomposition due to the mixed-integer nonlinear nature of the optimization problem. The results indicate that the resilience approach although increasing the operation cost does not lead to load shedding in the event of main grid failures. The study concludes that integrating distributed power-to-hydrogen systems results in significant benefits including emission reductions of up to 20 % and cost savings of up to 30 %. Additionally the integration of the decomposition method improves computational performance by 54 % compared to using commercial solvers within the GAMS software.

Over the last years the European Union has seen a rapid increase in installed capacity of generating units based on renewable energy sources (RES). The most significant increase in installed capacity was recorded in 2015 in wind farms and solar PV installations. One of the most serious is the volatile character of RES on a time basis. Therefore for a further expected increase in the use of RES and their effectiveness improvements investments are needed allowing for electricity to be stored. One of the electricity storage options is to use excess electricity in order to produce hydrogen by electrolysis of water. Although this process plays a marginal role in obtaining hydrogen on a worldwide basis due to high costs experience in recent years has shown that periodically low (negative) electricity prices developing on the power exchanges in the situation where there is surplus electricity available affect economic requirements for hydrogen production technologies. The paper shows activities undertaken by European countries (mainly Germany) aiming at making it possible for hydrogen to be stored in the natural gas grids. A particular attention is given to material resource issues and possible operational problems that might arise while blending natural gas with hydrogen into the grid. The experiences of selected European countries are of particular interest from the Polish perspective having regard to significant increase of RES in electricity generation during the last few years and adopted objectives for the growing importance of RES in the Poland’s energy balance.

Many initiatives and policies attempt to make our air cleaner by reducing the carbon foot imprint on our planet. Most of the existing and planned initiatives have as their objectives the reduction of carbon dependency and the enhancement of newer or better technologies in the near future. However numerous policies exist for electric vehicles (EVs) and only some policies address specific issues related to fuel cell electric vehicles (FCEV). The lack of a distinction between the policies for EVs and FCEVs provides obstacles for the advancement of FCEV-related technologies that may otherwise be successful and competitive in the attempt to create a cleaner planet. Unfortunately the lack of this distinction is not always based on intellectual or scientific evidence. Therefore governments may need to introduce clearer policy distinctions in order to directly address FCEV-related challenges that may not pertain to other EVs. Unfortunately lobbyism continues to exist that supports the maintenance of the status quo as new technologies may threaten traditional less sustainable approaches to provide opportunities for a better environment. This lobbyism has partially succeeded in hindering the advancement of new technologies partially because the development of new technologies may reduce profit and business opportunities for traditionalists. However these challenges are slowly overcome as the demand for cleaner air and lower carbon emissions has increased and a stronger movement toward newer and cleaner technologies has gained momentum. This paper will look at policies that have been either implemented or are in the process of being implemented to address the challenge of overcoming traditional obstacles with respect to the automobile industry. The paper reviewed synthesized and discussed policies in the USA Japan and the European Union that helped implement new technologies with a focus on FCEVs for larger mass markets. These regions were the focus of this paper because of their particular challenges. South Korea and China were not included in this discussion as these countries already have equal or even more advanced policies and initiatives in place.