Spain

The production of hydrogen through water electrolysis is a promising pathway to decarbonize the energy sector. This paper presents a techno-economic model of electrolysis plants based on multiple states of operation: production hot standby and idle. The model enables the calculation of the optimal hourly dispatch of electrolyzers to produce hydrogen for different end uses. This model has been tested with real data from an existing installation and compared with a simpler electrolyzer model that is based on two states. The results indicate that an operational strategy that considers the multi-state model leads to a decrease in final hydrogen production costs. These reduced costs will benefit businesses especially while electrolysis plants grow in size to accommodate further increases in demand.

Magnesium hydride owns the largest share of publications on solid materials for hydrogen storage. The “Magnesium group” of international experts contributing to IEA Task 32 “Hydrogen Based Energy Storage” recently published two review papers presenting the activities of the group focused on magnesium hydride based materials and on Mg based compounds for hydrogen and energy storage. This review article not only overviews the latest activities on both fundamental aspects of Mg-based hydrides and their applications but also presents a historic overview on the topic and outlines projected future developments. Particular attention is paid to the theoretical and experimental studies of Mg-H system at extreme pressures kinetics and thermodynamics of the systems based on MgH₂ nanostructuring new Mg-based compounds and novel composites and catalysis in the Mg based H storage systems. Finally thermal energy storage and upscaled H storage systems accommodating MgH₂ are presented.

End-of-Life (EoL) technologies and strategies are needed to support the deployment of fuel cells and hydrogen (FCH) products. This article explores current and novel EoL technologies to recover valuable materials from the stacks of proton exchange membrane fuel cells and water electrolysers alkaline water electrolysers and solid oxide fuel cells. Current EoL technologies are mainly based on hydrometallurgical and pyro-hydrometallurgical methods for the recovery of noble metals while novel methods attempt to recover additional materials through efficient safe and cost-competitive pathways. Strengths weaknesses opportunities and threats of the reviewed EoL technologies are identified under techno-economic environmental and regulatory aspects. Beyond technologies strategies for the EoL of FCH stacks are defined mainly based on the role of manufacturers and recovery centres in the short- mid- and long-term. In this regard a dual role manufacturer/recovery centre would characterise long-term scenarios within a potential context of a well-established hydrogen economy.

Grand Canonical Monte Carlo GCMC simulations are used to study the gravimetric and volumetric hydrogen storage capacities of different carbon nanopores shapes: Slit-shaped nanotubes and torusenes at room temperature 298.15 K and at pressures between 0.1 and 35 MPa and for pore diameter or width between 4 and 15 A. The influence of the pore shape or curvature on the storage capacities as a function of pressure temperature and pore diameter is investigated and analyzed. A large curvature of the pores means in general an increase of the storage capacities of the pores. While torusenes and nanotubes have surfaces with more curvature than the slit-shaped planar pores their capacities are lower than those of the slit-shaped pores according to the present GCMC simulations. Torusene a less studied carbon nanostructure has two radii or curvatures but their storage capacities are similar or lower than those of nanotubes which have only one radius or curvature. The goal is to obtain qualitative and quantitative relationships between the structure of porous materials and the hydrogen storage capacities in particular or especially the relationship between shape and width of the pores and the hydrogen storage capacities of carbon-based porous materials.

The aim of this work is to study the effect of the displacement rate on the hydrogen embrittlement of two different structural steels grades used in energetic applications. With this purpose samples were pre-charged with gaseous hydrogen at 19.5 MPa and 450 °C for 21 h. Then fracture tests of the pre-charged specimens were performed using different displacement rates. It is showed that the lower is the displacement rate and the largest is the steel strength the strongest is the reduction of the fracture toughness due to the presence of internal hydrogen.

Continuous developments in Proton Exchange Membrane Fuel Cells (PEMFC) make them a promising technology to achieve zero emissions in multiple applications including mobility. Incremental advancements in fuel cells materials and manufacture processes make them now suitable for commercialization. However the complex operation of fuel cell systems in automotive applications has some open issues yet. This work develops and compares three different controllers for PEMFC systems in automotive applications. All the controllers have a cascade control structure where a generator of setpoints sends references to the subsystems controllers with the objective to maximize operational efficiency. To develop the setpoints generators two techniques are evaluated: off-line optimization and Model Predictive Control (MPC). With the first technique the optimal setpoints are given by a map obtained off-line of the optimal steady state conditions and corresponding setpoints. With the second technique the setpoints time profiles that maximize the efficiency in an incoming time horizon are continuously computed. The proposed MPC architecture divides the fast and slow dynamics in order to reduce the computational cost. Two different MPC solutions have been implemented to deal with this fast/slow dynamics separation. After the integration of the setpoints generators with the subsystems controllers the different control systems are tested and compared using a dynamic detailed model of the automotive system in the INN-BALANCE project running under the New European Driving Cycle.

This paper presents a simplified procedure to analyse the Hydrogen Induced Cracking (HIC) of structural steels by means of the Small Punch Test (SPT). Two types of notched specimens were used: one with through-thickness lateral notch and another with surface longitudinal notch. The results for conventional specimens were compared with those for hydrogen pre-charged specimens. For this purpose two different methods to introduce hydrogen in the specimens were used: cathodic/electrochemical pre-charging and pressurized gaseous hydrogen pre-charging. The results obtained with both methods are also discussed.

This paper evaluates the economic viability of a combined wind-based green-hydrogen facility from an investor’s viewpoint. The paper introduces a theoretical model and demonstrates it by example. The valuation model assumes that both the spot price of electricity and wind capacity factor evolve stochastically over time; these state variables can in principle be correlated. Besides it explicitly considers the possibility to use curtailed wind energy for producing hydrogen. The model derives the investment project’s net present value (NPV) as a function of hydrogen price and conversion capacity. Thus the NPV is computed for a given price and a range of capacities. The one that leads to the maximum NPV is the ‘optimal’ capacity (for the given price). Next the authors estimate the parameters underlying the two stochastic processes from Spanish hourly data. These numerical estimates allow simulate hourly paths of both variables over the facility’s expected useful lifetime (30 years). According to the results green hydrogen production starts becoming economically viable above 3 €/kg. Besides it takes a hydrogen price of 4.7 €/kg to reach an optimal conversion capacity half the capacity of the wind park. The authors develop sensitivity analyses with respect to wind capacity factor curtailment rate and discount rate.

Synthetic fuels or e-fuels produced from captured CO2 and renewable hydrogen are envisaged as a feasible path towards a climate-neutral transportation in medium/heavy-duty and maritime sectors. EU is presently debating energy targets by 2030 for these fuels. As their production involves chemical processing of hydrogen it must be evaluated if the extra cost is worthy at least in applications where hydrogen use is possible. This manuscript focuses on the performance and environmental impact when hydrogen and methanol are fed to a heavy-duty compression-ignition engine working under dual-fuel combustion. The trade-off thermal efficiency-NOx emissions is primary considered in the assessment by combining both variables in an own defined function. During the work engine operating settings were adjusted to exploit the potential of methanol and hydrogen. Compared to conventional combustion methanol required centering the combustion towards TDC and doubling the EGR rate resulting in a low temperature highly premixed combustion almost soot-free and with extremely low NOx emissions. The best settings for hydrogen were in the middle of those for methanol and conventional combustion. Results showed great dependance with the engine load but methanol proved superior to hydrogen for all conditions. At high load 20–60 % methanol even improved the efficiency and reduced the NOx emissions obtained by conventional combustion. However at low load hydrogen could substitute 90 % of the diesel fuel while methanol failed at substitutions higher than 55 %.

In recent years growing interest has emerged in investigating the integration of energy storage and green hydrogen production systems with renewable energy generators. These integrated systems address uncertainties related to renewable resource availability and electricity prices mitigating profit loss caused by forecasting errors. This paper focuses on the operation of a hybrid farm (HF) combining an alkaline electrolyzer (AEL) and a battery energy storage system (BESS) with a wind turbine to form a comprehensive HF. The HF operates in both hydrogen and day-ahead electricity markets. A linear mathematical model is proposed to optimize energy management considering electrolyzer operation at partial loads and accounting for degradation costs while maintaining a straightforward formulation for power system optimization. Day-ahead market scheduling and real-time operation are formulated as a progressive mixed-integer linear program (MILP) extended to address uncertainties in wind speed and electricity prices through a two-stage stochastic optimization model. A bootstrap sampling strategy is introduced to enhance the stochastic model’s performance using the same sampled data. Results demonstrate how the strategies outperform traditional Monte Carlo and deterministic approaches in handling uncertainties increasing profits up to 4% per year. Additionally a simulation framework has been developed for validating this approach and conducting different case studies.

Hydrogen (H2) production combined with carbon capture and storage (CCS) is anticipated to be an important technology contributing to reduce the carbon footprint of current fossil-based H2 production systems. This work addresses for the first time the techno-environmental assessment of a CCS process based on the ionic liquid [Bmim][Acetate] for H2 production by steam methane reforming (SMR) and the comparison to conventional amine-based systems. Two different SMR plants using MDEA or [Bmim][Acetate] for CO2 capture were rigorously modelled using Aspen Plus to compute material and energy needs and emissions. Literature and simulation results were then used to perform a life cycle impact assessment (LCIA) of these processes based on the ReCiPe model. Solvent synthesis CCS process and hydrogen production stages were considered for the cradle-to-gate analysis. Results showed that although [Bmim][Acetate] is a priori more harmful to the environment than amines (in a kg-to-kg comparison) LCIAs carried out for both CCS processes showed from 5 to 17 % lower environmental impacts values for all estimated categories when using [Bmim][Acetate] due to a 9.4 % more energy-efficient performance than MDEA which also reduced a 17.4 % the total utility cost. Indeed if a typical amine loss rate of 1.6 kg/tCO2 is assumed the values of the environmental impacts increase up to 14 % for the IL-based CCS plant but still maintaining its favorable results over MDEA. As consequence the SMR plant with the IL-based CCS system exhibited 3–20 % lower values for most of the studied impact categories. These results contribute to shed some light on evaluating the sustainability of ILs with respect to conventional solvents for CO2 capture and to guide the synthesis of new more sustainable ILs but also they would be used to compare the environmental burdens from the synthesis and process performance of other promising ILs for CO2 capture that are not environmentally assed yet.

H2 production via membrane-assisted steam methane reforming (MA-SMR) can ensure higher energy efficiency and lower emissions compared to conventional reforming processes (SMR). Ceramic-supported Pd–Ag membranes have been extensively investigated for membrane-assisted steam methane reforming applications with outstanding performance. However costs sealings for integration in the reactor structure and resistance to solicitations remain challenging issues. In this work the surface quality of a low-cost porous Hastelloy-X filter is improved by asymmetric filling with α-Al2O3 of decreasing size and deposition of γ-Al2O3 as an interdiffusion barrier. On the modified support a thin Pd–Ag layer was deposited via electroless plating (ELP) resulting in a membrane with H2/N2 selectivity >10000. The permeation characteristics of the membrane were studied followed by testing for membrane-assisted methane steam reforming. The results showed the ability of the membrane reactor to overcome thermodynamic conversion of the conventional process for all explored operating conditions as well as ensuring 99.3% H2 purity in the permeate stream at 500 ◦C and 4 bar.

We analyze the use of hydrogen as a fuel for the automotive industry with the aim of decarbonizing the economy. Hydrogen is a suitable option for avoiding pollutant gas emissions developing environmentally friendly technologies replacing fossil fuels with clean renewable energies and complying with the Paris Agreement and Glasgow resolutions. In this sense renewable energies such as wind solar photovoltaic geothermal biomass etc. can be used to produce the necessary hydrogen to power vehicles. In this way the entire process from hydrogen production to its consumption as fuel will be 100% clean. If we are to meet future energy demands it is necessary to forecast the amount of hydrogen needed taking into account the facilities currently available and new ones that will be required for its generation storage and distribution. This paper presents a process for optimizing hydrogen production for the automotive industry that considers the amount of hydrogen needed the type of facilities from which it will be produced how the different sources of production are to be combined to achieve a competitive product and the potential environmental impacts of each energy source. It can serve as a frame of reference for the various actors in the hydropower and automotive industries so that more efficient designs can be planned for the gradual introduction of hydrogen fuel cell vehicles (HFCVs). The methodology implemented in this paper sets an optimization problem for minimizing energy production costs and reducing environmental impacts according to the source of energy production. The EU framework with respect to the decarbonization of the economy the percentages of the different types of energy sources used and the non-polluting vehicle fleet in the automotive sector will be considered.

Variable renewable energy (VRE) has seen rapid growth in recent years. However VRE deployment requires a fleet of dispatchable power plants to supply electricity during periods with limited wind and sunlight. These plants will operate at reduced utilization rates that pose serious economic challenges. To address this challenge this paper presents the techno-economic assessment of flexible power and hydrogen production from integrated gasification combined cycles (IGCC) employing the gas switching combustion (GSC) technology for CO₂ capture and membrane assisted water gas shift (MAWGS) reactors for hydrogen production. Three GSC-MAWGS-IGCC plants are evaluated based on different gasification technologies: Shell High Temperature Winkler and GE. These advanced plants are compared to two benchmark IGCC plants one without and one with CO₂ capture. All plants utilize state-of-the-art H-class gas turbines and hot gas clean-up for maximum efficiency. Under baseload operation the GSC plants returned CO₂ avoidance costs in the range of 24.9–36.9 €/ton compared to 44.3 €/ton for the benchmark. However the major advantage of these plants is evident in the more realistic mid-load scenario. Due to the ability to keep operating and sell hydrogen to the market during times of abundant wind and sun the best GSC plants offer a 6–11%-point higher annual rate of return than the benchmark plant with CO₂ capture. This large economic advantage shows that the flexible GSC plants are a promising option for balancing VRE provided a market for the generated clean hydrogen exists.

Commonly used materials constituting the core components of polymer electrolyte membrane fuel cells (PEMFCs) including the balance‐of‐plant were classified according to the EU criticality methodology with an additional assessment of hazardousness and price. A life‐cycle assessment (LCA) of the materials potentially present in PEMFC systems was performed for 1  g of each material. To demonstrate the importance of appropriate actions at the end of life (EoL) for critical materials a LCA study of the whole life cycle for a 1‐kW PEMFC system and 20000 operating hours was performed. In addition to the manufacturing phase four different scenarios of hydrogen production were analyzed. In the EoL phase recycling was used as a primary strategy with energy extraction and landfill as the second and third. The environmental impacts for 1 g of material show that platinum group metals and precious metals have by far the largest environmental impact; therefore it is necessary to pay special attention to these materials in the EoL phase. The LCA results for the 1‐kW PEMFC system show that in the manufacturing phase the major environmental impacts come from the fuel cell stack where the majority of the critical materials are used. Analysis shows that only 0.75 g of platinum in the manufacturing phase contributes on average 60% of the total environmental impacts of the manufacturing phase. In the operating phase environmentally sounder scenarios are the hydrogen production with water electrolysis using hydroelectricity and natural gas reforming. These two scenarios have lower absolute values for the environmental impact indicators on average compared with the manufacturing phase of the 1‐kW PEMFC system. With proper recycling strategies in the EoL phase for each material and by paying a lot of attention to the critical materials the environmental impacts could be reduced on average by 37.3% for the manufacturing phase and 23.7% for the entire life cycle of the 1‐kW PEMFC system.

The present research work deals with prediction of hydrogen consumption of a fuel cell in an energy storage system. Due to the fact that these kind of systems have a very nonlinear behaviour the use of traditional techniques based on parametric models and other more sophisticated techniques such as soft computing methods seems not to be accurate enough to generate good models of the system under study. Due to that a hybrid intelligent system based on clustering and regression techniques has been developed and implemented to predict the necessary variation of the hydrogen flow consumption to satisfy the variation of demanded power to the fuel cell. In this research a hybrid intelligent model was created and validated over a dataset from a fuel cell energy storage system. Obtained results validate the proposal achieving better performance than other well-known classical regression methods allowing us to predict the hydrogen consumption with a Mean Absolute Error (MAE) of 3.73 with the validation dataset.

Today in the field of energy the main goal is to reduce emissions with 7 the aim of maintaining a clean environment. To reduce energy consumption 8 from fossil fuels new tools for micro-grids have been proposed. In the context 9 of multi-vector energy management systems the present work proposes an 10 optimal scheduler based on genetic algorithms to manage flexible assets in the 11 energy system such as energy storage and manageable demand. This tool is 12 applied to a case study for a Spanish technology park (360 kW consumption 13 peak) with photovoltaic and wind generation (735 kW generation peak) 14 hydrogen production (15 kW) and electric and fuel cell charging stations. 15 It provides an hourly day-ahead scheduling for the existing flexible assets: 16 the electrolyser the electric vehicle charging station the hydrogen refuelling 17 station and the heating ventilation and air conditioning system in one 18 building of the park. 19 A set of experiments is carried out over a period of 14 days using real 20 data and performing computations in real time in order to test and validate 21 the tool. The analysis of results show that the solution maximises the use of 22 local renewable energy production (demand is shifted to those hours when 23 there is a surplus of generation) which means a reduction in energy costs 24 whereas the computational cost allows the implementation of the tool in real 25 time.

Alternatives to cope with the challenges of high shares of renewable electricity in power systems have been addressed from different approaches such as energy storage and low-carbon technologies. However no model has previously considered integrating these technologies under stability requirements and different climate conditions. In this study we include this approach to analyse the role of new technologies to decarbonise the power system. The Spanish power system is modelled to provide insights for future applications in other regions. After including storage and low-carbon technologies (currently available and under development) batteries and hydrogen fuel cells have low penetration and the derived emission reduction is negligible in all scenarios. Compressed air storage would have a limited role in the short term but its performance improves in the long term. Flexible generation technologies based on hydrogen turbines and long-duration storage would allow the greatest decarbonisation providing stability and covering up to 11–14 % of demand in the short and long term. The hydrogen storage requirement is equivalent to 18 days of average demand (well below the theoretical storage potential in the region). When these solutions are considered decarbonising the electricity system (achieving Paris targets) is possible without a significant increase in system costs (< € 114/MWh).

Water electrolysis to obtain hydrogen in combination with intermittent renewable energy resources is an emerging sustainable alternative to fossil fuels. Among the available electrolyzer technologies anion exchange membrane water electrolysis (AEMWE) has been paid much attention because of its advantageous behavior compared to other more traditional approaches such as solid oxide electrolyzer cells and alkaline or proton exchange membrane water electrolyzers. Recently very promising results have been obtained in the AEMWE technology. This review paper is focused on recent advances in membrane electrode assembly components paying particular attention to the preparation methods for catalyst coated on gas diffusion layers which has not been previously reported in the literature for this type of electrolyzers. The most successful methodologies utilized for the preparation of catalysts including co-precipitation electrodeposition sol–gel hydrothermal chemical vapor deposition atomic layer deposition ion beam sputtering and magnetron sputtering deposition techniques have been detailed. Besides a description of these procedures in this review we also present a critical appraisal of the efficiency of the water electrolysis carried out with cells fitted with electrodes prepared with these procedures. Based on this analysis a critical comparison of cell performance is carried out and future prospects and expected developments of the AEMWE are discussed.

Green hydrogen—a carbon-free renewable fuel—has the capability to decarbonise a variety of sectors. The generation of green hydrogen is currently restricted to water electrolysers. The use of freshwater resources and critical raw materials however limits their use. Alternative water splitting methods for green hydrogen generation via photocatalysis and photoelectrocatalysis (PEC) have been explored in the past few decades; however their commercial potential still remains unexploited due to the high hydrogen generation costs. Novel PEC-based simultaneous generation of green hydrogen and wastewater treatment/high-value product production is therefore seen as an alternative to conventional water splitting. Interestingly the organic/inorganic pollutants in wastewater and biomass favourably act as electron donors and facilitate the dual-functional process of recovering green hydrogen while oxidising the organic matter. The generation of green hydrogen through the dual-functional PEC process opens up opportunities for a “circular economy”. It further enables the end-of-life commodities to be reused recycled and resourced for a better life-cycle design while being economically viable for commercialisation. This review brings together and critically analyses the recent trends towards simultaneous wastewater treatment/biomass reforming while generating hydrogen gas by employing the PEC technology. We have briefly discussed the technical challenges associated with the tandem PEC process new avenues techno-economic feasibility and future directions towards achieving net neutrality.

Green hydrogen produced by water electrolysis with renewable energy plays a crucial role in the revolution towards energy sustainability and it is considered a key source of clean energy and efficient storage. Its ability to address the intermittency of renewable sources and its potential to decarbonize sectors that are difficult to electrify make it a strategic component in climate change mitigation. By using a method based on a bibliometric review of scientific publications this paper represents a significant contribution to the emerging field of research on green hydrogen and provides a detailed review of electrolyzer technologies identifying key areas for future research and technology development. The results reflect the immaturity of a technology which advances with different technical advancements waiting to find the optimal technical solution that allows for its massive implementation as a source of green hydrogen generation. According to the results found in this article alkaline (ALK) and proton exchange membrane (PEM) electrolyzers seem to be the ones that interest the scientific community the most. Similarly in terms of regional analysis Europe is clearly committed to green hydrogen in view of the analysis of its scientific results on materials and electrolyzer capacity forecasts for 2030.

Europe has set ambitious targets to reduce the final energy consumption of buildings in concerning the degree of electrification energy efficiency and penetration of renewable energy sources (RES). So far hydrogen is becoming an increasingly important energy vector offering huge opportunities to promote the share of intermittent RES. Thus this manuscript proposes an energy model for the complete decarbonization of the estimated electricity consumed by the Spanish building stock in 2030 and 2050 scenarios; the model is based on the combination of photovoltaic and wind primary sources and hydrogen technologies considering both distributed and centralized configurations applying also geospatial criteria for their optimal allocation. Large-scale RES generation centralized hydrogen production and re-electrification along with underground hydrogen storage result in the lowest levelized cost of energy (LCOE) hydrogen production costs (HPC) and the highest overall efficiency (μSYS). Wind energy is mainly harvested in the north of Spain while large PV farms are deployed in the mid-south. Furthermore reinforcement of underground hydrogen storage enhances the overall system performance reducing surplus energy and the required RES generation capacity. Finally all the considered scenarios achieve LCOE below the Spanish utility grid benchmark apart from accomplishing the decarbonization goals established for the year 2030.

The transition to energy systems with a high share of renewable energy depends on the availability of technologies that can connect the physical distances or bridge the time differences between the energy supply and demand points. This study focuses on energy storage technologies due to their expected role in liberating the energy sector from fossil fuels and facilitating the penetration of intermittent renewable sources. The performance of 27 energy storage alternatives is compared considering sustainability aspects by means of data envelopment analysis. To this end storage alternatives are first classified into two clusters: fast-response and long-term. The levelized cost of energy energy and water consumption global warming potential and employment are common indicators considered for both clusters while energy density is used only for fast-response technologies where it plays a key role in technology selection. Flywheel reveals the highest efficiency between all the fast-response technologies while green ammonia powered with solar energy ranks first for long-term energy storage. An uncertainty analysis is incorporated to discuss the reliability of the results. Overall results obtained and guidelines provided can be helpful for both decision-making and research and development purposes. For the former we identify the most appealing energy storage options to be promoted while for the latter we report quantitative improvement targets that would make inefficient technologies competitive if attained. This contribution paves the way for more comprehensive studies in the context of energy storage by presenting a powerful framework for comparing options according to multiple sustainability indicators.

Urban population and the trend towards online commerce leads to an increase in delivery solution in cities. The growth of the transport sector is very harmful to the environment being responsible for approximately 40% of greenhouse gas emissions in the European Union. The problem is aggravated when transporting perishable foodstuffs as the vehicle propulsion engine (VPE) must power not only the vehicle but also the refrigeration unit. This means that the VPE must be running continuously both on the road and stationary (during delivery) as the cold chain must be preserved. The result is costly (high fuel consumption) and harmful to the environment. At present refrigerated transport does not support full-electric solutions due to the high energy consumption required which motivates the work presented in this article. It presents a turnkey solution of a hydrogen-powered refrigeration system (HPRS) to be integrated into standard light trucks and vans for short-distance food transport and delivery. The proposed solution combines an air-cooled polymer electrolyte membrane fuel cell (PEMFC) a lithium-ion battery and low-weight pressurised hydrogen cylinders to minimise cost and increase autonomy and energy density. In addition for its implementation and integration all the acquisition power and control electronics necessary for its correct management have been developed. Similarly an energy management system (EMS) has been developed to ensure continuity and safety in the operation of the electrical system during the working day while maximizing both the available output power and lifetime of the PEMFC. Experimental results on a real refrigerated light truck provide more than 4 h of autonomy in intensive intercity driving profiles which can be increased if necessary by simply increasing the pressure of the stored hydrogen from the current 200 bar to whatever is required. The correct operation of the entire HPRS has been experimentally validated in terms of functionality autonomy and safety; with fuel savings of more than 10% and more than 3650 kg of CO2/ year avoided.

A potential method of storing and transporting hydrogen safely in a cost-effective and practical way involves the utilization of molecules that contain hydrogen in their structure such as ammonia. Because of its high hydrogen content and carbon-free molecular structure as well as the maturity of related technology (easy liquefaction) ammonia has gained attention as a “hydrogen carrier” for the generation of energy. Unfortunately hydrogen production from ammonia requires an efficient catalyst to achieve high conversion at low reaction temperatures. Recently very attractive results have been obtained with low-surface-area materials. This review paper is focused on summarizing and comparing recent advances in novel economic and active catalysts for this reaction paying particular attention to materials with low surface area such as silicon carbide (SiC) and perovskites (ABO3 structure). The effects of the supports the active phase and the addition of promoters in such low-porosity materials have been analyzed in detail. Advances in adequate catalytic systems (including support and active metal) benefit the perspective of ammonia as a hydrogen carrier for the decarbonization of the energy sector and accelerate the “hydrogen economy”.

In this paper different techniques to test notched Small Punch (SPT) samples in fracture conditions in aggressive environments are studied based on the comparison of the micromechanisms at different rates. Pre-embrittled samples subsequently tested in air at rates conventionally employed (0.01 and 0.002 mm/s) are compared to embrittled ones tested in environment at the same rates (0.01 and 0.002 mm/s) and at a very slow rate (5E-5 mm/s). A set of samples tested in environment under a set of constant loads that produce very slow rates completes the experimental results. As a conclusion it is recommended to test SPT notched specimens in environment at very slow rates of around E-6 mm/s when characterizing in Hydrogen Embrittlement (HE) scenarios in order to allow the interaction material-environment to govern the process.

This paper offers a numerical approach to the problem of hydrogen embrittlement and notch tensile strength of sharply notched specimens of high-strength pearlitic steel supplied in the form of hot rolled bars by using the finite element method in order to determine how the notch depth influences the concentration of hydrogen in the steady-state regime for different loading values. Numerical results show that the point of maximum hydrostatic stress (towards which hydrogen is transported by a mechanism of stress-assisted diffusion) shifts from the notch tip to the inner points of the specimen under increasing load with numerical evidence of an elevated inwards gradient of hydrostatic stress “pumping” hydrogen inside the sample.

One alternative for the storage and transport of hydrogen is blending a low amount of hydrogen (up to 15 or 20%) into existing natural gas grids. When demanded hydrogen can be then separated close to the end users using membranes. In this work composite alumina carbon molecular sieves membranes (Al-CMSM) supported on tubular porous alumina have been prepared and characterized. Single gas permeation studies showed that the H₂/CH₄ separation properties at 30 °C are well above the Robeson limit of polymeric membranes. H₂ permeation studies of the H2–CH4 mixture gases containing 5–20% of H2 show that the H2 purity depends on the H₂ content in the feed and the operating temperature. In the best scenario investigated in this work for samples containing 10% of H₂ with an inlet pressure of 7.5 bar and permeated pressure of 0.01 bar at 30 °C the H₂ purity obtained was 99.4%.

Protonic ceramic fuel cells (PCFCs) are promising electrochemical devices for the efficient and clean conversion of hydrogen and low hydrocarbons into electrical energy. Their intermediate operation temperature (500–800 °C) proffers advantages in terms of greater component compatibility unnecessity of expensive noble metals for the electrocatalyst and no dilution of the fuel electrode due to water formation. Nevertheless the lower operating temperature in comparison to classic solid oxide fuel cells places significant demands on the cathode as the reaction kinetics are slower than those related to fuel oxidation in the anode or ion migration in the electrolyte. Cathode design and composition are therefore of crucial importance for the cell performance at low temperature. The different approaches that have been adopted for cathode materials research can be broadly classified into the categories of protonic–electronic conductors oxide-ionic–electronic conductors triple-conducting oxides and composite electrodes composed of oxides from two of the other categories. Here we review the relatively short history of PCFC cathode research discussing trends highlights and recent progress. Current understanding of reaction mechanisms is also discussed.

Diesel generators are currently used as an off-grid solution for backup power but this causes CO2 and GHG emissions noise emissions and the negative effects of the volatile diesel market influencing operating costs. Green hydrogen production by means of water electrolysis has been proposed as a feasible solution to fill the gaps between demand and production the main handicaps of using exclusively renewable energy in isolated applications. This manuscript presents a business case of an off-grid hydrogen production by electrolysis applied to the electrification of isolated sites. This study is part of the European Ely4off project (n◦ 700359). Under certain techno-economic hypothesis four different system configurations supplied exclusively by photovoltaic are compared to find the optimal Levelized Cost of Electricity (LCoE): photovoltaic-batteries photovoltaic-hydrogen-batteries photovoltaic-diesel generator and diesel generator; the influence of the location and the impact of different consumptions profiles is explored. Several simulations developed through specific modeling software are carried out and discussed. The main finding is that diesel-based systems still allow lower costs than any other solution although hydrogen-based solutions can compete with other technologies under certain conditions.

We investigate the implications of conducting hydrogen-assisted fatigue crack growth experiments in a hydrogen gas environment (in-situ hydrogen charging) or in air (following exposure to hydrogen gas). The study is conducted on welded 42CrMo4 steel a primary candidate for the future hydrogen transport infrastructure allowing us to additionally gain insight into the differences in behavior between the base steel and the coarse grain heat affected zone. The results reveal significant differences between the two testing approaches and the two weld regions. The differences are particularly remarkable for the comparison of testing methodologies with fatigue crack growth rates being more than one order of magnitude higher over relevant loading regimes when the samples are tested in a hydrogen-containing environment relative to the pre-charged samples. Aided by finite element modelling and microscopy analysis these differences are discussed and rationalized. Independent of the testing approach the heat affected zone showed a higher susceptibility to hydrogen embrittlement. Similar microstructural behavior is observed for both testing approaches with the base metal exhibiting martensite lath decohesion while the heat affected zone experienced both martensite lath decohesion and intergranular fracture.

After nearly 25 years of service some of the wires of the tendons of “La Arena” bridge (Spain) started to exhibit the effects of environmental degradation processes. “La Arena” is cable-stayed bridge with 6 towers and a reference span between towers of about 100 meters. After a maintenance inspection of the bridge evidences of corrosion were detected in some of the galvanized wires of the cables. A more in-deep analysis of these wires revealed that many of them exhibited loss of section due to the corrosion process. In order to clarify the causes of this degradation event and to suggest some remedial actions an experimental program was designed. This program consisted of tensile and fatigue tests on some strand samples of the bridge together with a fractographic analysis of the fracture surfaces of the wires its galvanized layer thickness and some hydrogen measurements (hydrogen embrittlement could be another effect of the environmental degradation process).Once the type and extension of the flaws in the wires was characterized a structural integrity assessment of the strands was performed with the aim of quantifying the margins until failure and establishing some maintenance recommendations.

Hydrogen will become a key player in transitioning toward a net-zero energy system. However a clear pathway toward a unified European hydrogen infrastructure to support the rapid scale-up of hydrogen production is still under discussion. This study explores plausible pathways using a fully sector-coupled energy system model. Here we assess the emergence of hydrogen infrastructure build-outs connecting neighboring European nations through hydrogen import and domestic production centers with Western and Central European demands via four distinct hydrogen corridors. We identify a potential lock-in effect of blue hydrogen in the medium term highlighting the risk of longterm dependence on methane. In contrast we show that a self-sufficient Europe relying on domestic green hydrogen by 2050 would increase yearly expenses by around 3% and require 518 gigawatts of electrolysis capacity. This study emphasizes the importance of rapidly scaling up electrolysis capacity building hydrogen networks and storage facilities deploying renewable electricity generation and ensuring coherent coordination across European nations.

Whilst various new technologies for power generation are continuously being evaluated the owners of almost-new facilities such as combined-cycle gas turbine (CCGT) plants remain motivated to adapt these to new circumstances and avoid the balance-sheet financial impairments of underutilization. Not only are the owners reluctant to decommission the legacy CCGT assets but system operators value the inertia and flexibilities they contribute to a system becoming predominated with renewable generation. This analysis therefore focuses on the reinvestment cases for adapting CCGT to hydrogen (H2 ) synthetic natural gas (SNG) and/or retrofitted carbon capture and utilization systems (CCUS). Although H2 either by itself or as part of SNG has been evaluated attractively for longer-term electricity storage the business case for how it can be part of a hybrid legacy CCGT system has not been analyzed in a market context. This work compares the power to synthetic natural gas to power (PSNGP) adaptation with the simpler and less expensive power to hydrogen to power (P2HP) adaptation. Both the P2HP and PSNGP configurations are effective in terms of decarbonizations. The best results of the feasibility analysis for a UK application with low CCGT load factors (around 31%) were obtained for 100% H2 (P2HP) in the lower range of wholesale electricity prices (less than 178 GBP/MWh) but in the higher range of prices it would be preferable to use the PSNGP configuration with a low proportion of SNG (25%). If the CCGT load factor increased to 55% (the medium scenario) the breakeven profitability point between P2HP and PSNGP decreased to a market price of 145 GBP/MWh. Alternatively with the higher load factors (above 77%) satisfactory results were obtained for PSNGP using 50% SNG if with market prices above 185 GBP/MWh.

Stress corrosion cracking (SCC) of metals is an issue of major concern in engineering since this phenomenon causes many catastrophic failures of structural components in aggressive environments. SCC is even more harmful under cathodic conditions promoting the phenomenon known as hydrogen assisted cracking (HAC) hydrogen assisted fracture (HAF) or hydrogen embrittlement (HE). A common way to assess the susceptibility of a given material to HAC HAF or HE is to subject a cracked rod to a constant extension rate tension (CERT) test until it fractures in this harsh environment. This paper analyzes the influence of a residual stress field generated by fatigue precracking on the sample’s posterior susceptibility to HAC. To achieve this goal numerical simulations were carried out of hydrogen diffusion assisted by the stress field. Firstly a mechanical simulation of the fatigue precracking was developed for revealing the residual stress field after diverse cyclic loading scenarios and posterior stress field evolution during CERT loading. Afterwards a simulation of hydrogen diffusion assisted by stress was carried out considering the residual stresses after fatigue and the superposed rising stresses caused by CERT loading. Results reveal the key role of the residual stress field after fatigue precracking in the HAC phenomena in cracked steel rods as well as the beneficial effect of compressive residual stress.

The generation of hydrogen from water using light is currently one of the most promising alternative energy sources for humankind but faces significant barriers for large-scale applications due to the low efficiency of existing photo-catalysts. In this work we propose a new route to fabricate nano-hybrid materials able to deliver enhanced photo-catalytic hydrogen evolution combining within the same nanostructure a plasmonic antenna nanoparticle and semiconductor quantum dots (QDs). For each stage of our fabrication process we probed the chemical composition of the materials with nanometric spatial resolution allowing us to demonstrate that the final product is composed of a silver nanoparticle (AgNP) plasmonic core surrounded by satellite Pt decorated CdS QDs (CdS@Pt) separated by a spacer layer of SiO2 with well-controlled thickness. This new type of photoactive nanomaterial is capable of generating hydrogen when irradiated with visible light displaying efficiencies 300% higher than the constituting photo-active components. This work may open new avenues for the development of cleaner and more efficient energy sources based on photo-activated hydrogen generation.

The susceptibility of high strength ferritic steels to hydrogen-assisted fracture in hydrogen gas is usually evaluated by mechanical testing in high-pressure hydrogen gas or testing in air after pre-charging the specimens with hydrogen. We have used this second methodology conventionally known as internal hydrogen. Samples were pre-charged in an autoclave under 195 bar of pure hydrogen at 450ºC for 21 hours.<br/>Different chromium-molybdenum steels submitted to diverse quenching and tempering heat treatments were employed. Diverse specimens were also used: small cylindrical samples to measure hydrogen contents and the kinetics of hydrogen egression at room temperature tensile specimens notched tensile specimens with a sharp notch and also compact fracture toughness specimens. Fractographic examination in SEM was finally performed in order to know the way hydrogen modify fracture micromechanisms.<br/>The presence of hydrogen barely affects the conventional tensile properties of the steels but it clearly alters their notched tensile strength and fracture toughness. This is due to the strong effect that stress triaxiality (dependent also on the steel yield strength) has on the accumulation of hydrogen on the notch/crack front region being the displacement rate used in the test another important variable to be controlled due to its influence on hydrogen diffusion to the embrittled process zone. Moreover the modification of fracture micromechanisms was finally determined being ductile (initiation growth and coalescence of microvoids) in the absence of hydrogen and brittle and intergranular under the material conditions of maximum embrittlement.

Experimental evidence exists for the enhancement of the hydrogen storage capacity of porous carbons when these materials are doped with metal nanoparticles. One of the most studied dopants is palladium. Dissociation of the hydrogen molecules and spillover of the H atoms towards the carbon substrate has been advocated as the reason for the enhancement of the storage capacity. We have investigated this mechanism by performing ab initio density functional molecular dynamics (AIMD) simulations of the deposition of molecular hydrogen on Pd6 clusters anchored on graphene vacancies. The clusters are initially near-saturated with atomic and molecular hydrogen. This condition would facilitate the occurrence of spillover since our energy calculations based on density functional theory indicate that migration of preadsorbed H atoms towards the graphene substrate becomes exothermic on Pd clusters with high hydrogen coverages. However AIMD simulations show that the H atoms prefer to intercalate and absorb within the Pd cluster rather than migrate to the carbon substrate. These results reveal that high activation barriers exist preventing the spillover of hydrogen from the anchored Pd clusters to the carbon substrate.

Currently the technology associated with charging stations for electric vehicles (EV) needs to be studied and improved to further encourage its implementation. This paper presents a new energy management system (EMS) based on a Biogeography-Based Optimization (BBO) algorithm for a hybrid EV charging station with a configuration that integrates Z-source converters (ZSC) into medium voltage direct current (MVDC) grids. The EMS uses the evolutionary BBO algorithm to optimize a fitness function defining the equivalent hydrogen consumption/generation. The charging station consists of a photovoltaic (PV) system a local grid connection two fast charging units and two energy storage systems (ESS) a battery energy storage (BES) and a complete hydrogen system with fuel cell (FC) electrolyzer (LZ) and hydrogen tank. Through the use of the BBO algorithm the EMS manages the energy flow among the components to keep the power balance in the system reducing the equivalent hydrogen consumption and optimizing the equivalent hydrogen generation. The EMS and the configuration of the charging station based on ZSCs are the main contributions of the paper. The behaviour of the EMS is demonstrated with three EV connected to the charging station under different conditions of sun irradiance. In addition the proposed EMS is compared with a simpler EMS for the optimal management of ESS in hybrid configurations. The simulation results show that the proposed EMS achieves a notable improvement in the equivalent hydrogen consumption/generation with respect to the simpler EMS. Thanks to the proposed configuration the output voltage of the components can be upgraded to MVDC while reducing the number of power converters compared with other configurations without ZSC.

Covalent organic frameworks (COFs) are crystalline porous organic polymers built from covalent organic blocks that can be photochemically active when incorporating organic semiconducting units such as triazine rings or diacetylene bridges. The bandgap charge separation capacity porosity wettability and chemical stability of COFs can be tuned by properly choosing their constitutive building blocks by extension of conjugation by adjustment of the size and crystallinity of the pores and by synthetic post-functionalization. This review focuses on the recent uses of COFs as photoactive platforms for the hydrogen evolution reaction (HER) in which usually metal nanoparticles (NPs) or metallic compounds (generally Pt-based) act as co-catalysts. The most promising COF-based photocatalytic HER systems will be discussed and special emphasis will be placed on rationalizing their structure and light-harvesting properties in relation to their catalytic activity and stability under turnover conditions. Finally the aspects that need to be improved in the coming years will be discussed such as the degree of dispersibility in water the global photocatalytic efficiency and the robustness and stability of the hybrid systems putting emphasis on both the COF and the metal co-catalyst.

This paper investigates environmental impacts of high pressure alkaline water electrolysis systems. An advanced system with membranes on polymer basis is compared to a state-of-the-art system with asbestos membranes using a Life Cycle Assessment (LCA) approach. For the advanced system a new improved membrane technology has been investigated within the EU research project “ELYGRID”. Results indicate that most environmental impacts are caused by the electricity supply necessary for operation. During the construction phase cell stacks are the main contributor to environmental impacts. New improved membranes have relatively small contributions to impacts caused by cell construction within the advanced systems. As main outcome the systems comparison illustrates a better ecological performance of the new developed system

In this study the optimal sizing of a hybrid battery/hydrogen Energy Storage System “ESS” is assessed via a model-based parametric analysis in the context of a real hybrid renewable microgrid located in Huelva Spain supplying a real-time monitored residential load (3.5 kW; 5.6 MWh/year) in island mode. Four storage configurations (battery-only H2-only hybrid battery priority and hybrid H2 priority) are assessed under different Energy Management Strategies analysing system performance parameters such as Loss of Load “LL” (kWh;%) Over Production “OP” (kWh;%) round-trip storage efficiency ESS (%) and total storage cost (€) depending on the ESS sizing characteristics. A parallel approach to the storage optimal sizing via both multi-dimensional sensitivity analysis and PSO is carried out in order to address both sub-optimal and optimal regions respectively. Results show that a hybridised ESS capacity is beneficial from an energy security and efficiency point of view but can represent a substantial additional total cost (between 100 and 300 k€) to the hybrid energy system especially for the H2 ESS which presents higher costs. Reaching 100% supply from renewables is challenging and introducing a LL threshold induces a substantial relaxation of the sizing and cost requirements. Increase in battery capacity is more beneficial for the LL abatement while increasing H2 capacity is more useful to absorb large quantities of excess energy. The optimal design via PSO technique is complemented to the parametric study.

This paper presents an analysis of Stress Corrosion Cracking (SCC) based on the Theory of Critical Distances (TCD). The research is based on an experimental program composed of fracture specimens with notch radius varying from 0 mm (crack-like defect) up to 1 mm and tensile specimens. A pipeline steel was used in this work (X80). It has been analysed in one hydrogen embrittlement situation. The study has been completed with Finite Elements Simulation analysis. The capacity of the TCD to analyse SCC processes has been proven.

To limit the global temperature change to no more than 2 ◦C by reducing global emissions the European Union (EU) set up a goal of a 20% improvement on energy efficiency a 20% cut of greenhouse gas emissions and a 20% share of energy from renewable sources by 2020 (10% share of renewable energy (RE) specifically in the transport sector). By 2030 the goal is a 27% improvement in energy efficiency a 40% cut of greenhouse gas emissions and a 27% share of RE. However the integration of RE in energy system faces multiple challenges. The geographical distribution of energy supply changes significantly the availability of the primary energy source (wind solar water) and is the determining factor rather than where the consumers are. This leads to an increasing demand to match supply and demand for power. Especially intermittent RE like wind and solar power face the issue of energy production unrelated to demand (issue of excess energy production beyond demand and/or grid capacity) and forecast errors leading to an increasing demand for grid services like balancing power. Megawatt electrolyzer units (beyond 3 MW) can provide a technical solution to convert large amounts of excess electricity into hydrogen for industrial applications substitute for natural gas or the decarbonization of the mobility sector. The demonstration of successful MW electrolyzer operation providing grid services under dynamic conditions as request by the grid can broaden the opportunities of new business models that demonstrate the profitability of an electrolyzer in these market conditions. The aim of this work is the demonstration of a technical solution utilizing Pressurized Alkaline Electrolyzer (PAE) technology for providing grid balancing services and harvesting Renewable Energy Sources (RES) under realistic circumstances. In order to identify any differences between local market and grid requirements the work focused on a demonstration site located in Austria deemed as a viable business case for the operation of a largescale electrolyzer. The site is adapted to specific local conditions commonly found throughout Europe. To achieve this this study uses a market-based solution that aims at providing value-adding services and cash inflows stemming from the grid balancing services it provides. Moreover the work assesses the viability of various business cases by analyzing (qualitatively and quantitatively) additional business models (in terms of business opportunities/energy source potential grid service provision and hydrogen demand) and analyzing the value and size of the markets developing recommendations for relevant stakeholder to decrease market barriers.

In order to favor a transition to a renewable energy economy it is necessary to study the possible permeation of renewable energy sources not only in the electric grid or industrial scale but also in the small householding scale. One of the most interesting technologies available for this purpose is solar energy since it is a mature technology that can be easily installed in every rooftop. Thus a techno-economic assessment was carried out to evaluate the installation of a solar-based power-heat hybrid microgrid considering the use of hydrogen as an energy vector in a typical residential house in Spain. Lead-acid batteries plus the photovoltaic and solar thermal energy installation are complemented with a hydrogen system composed of an electrolyzer two metal hydride bottles and a fuel cell. A simulation tool has been generated using experimental models developed and validated with real equipment for each one of the electric microgrid component. Three operating modes were tested making use of this tool to better manage the energy consumed/produced and optimize the economic output of the facility. The results show that setting up a hydrogen-based microgrid in a residential house is unviable today mainly due to the high cost of hydrogen generation and consumption equipment. If only solar energy is considered the microgrid inversion (12.500 €) is recovered in ten years. On the other hand selling the electricity output has almost no repercussions considering current electrical rates in Spain. Finally while using an optimization algorithm to manage energy use battery life-spam and economic benefit slightly increase. However this profit may not be enough to justify the use of a more complex control system. The results of this research will help users renewable energy companies investigators and policymakers to better understand the different factors influencing the spread of renewable smart grids in households and propose solutions to address these.

This paper deals with the concept of micro-fracture map (MFM) and its role in structural integrity evaluations in materials science and engineering on the basis of previous research by the author on notch-induced fracture and hydrogen embrittlement of progressively cold drawn pearlitic steels and 316L austenitic stainless steel. With regard to this some examples are provided of assembly of MFMs in particular situations.

The paper presents the first outcomes of the experimental numerical and theoretical studies performed in the funded by Fuel Cell and Hydrogen Joint Undertaking (FCH2 JU) project HyTunnel-CS. The project aims to conduct pre-normative research (PNR) to close relevant knowledge gaps and technological bottlenecks in the provision of safety of hydrogen vehicles in underground transportation systems. Pre normative research performed in the project will ultimately result in three main outputs: harmonised recommendations on response to hydrogen accidents recommendations for inherently safer use of hydrogen vehicles in underground traffic systems and recommendations for RCS. The overall concept behind this project is to use inter-disciplinary and inter-sectoral prenormative research by bringing together theoretical modelling and experimental studies to maximise the impact. The originality of the overall project concept is the consideration of hydrogen vehicle and underground traffic structure as a single system with integrated safety approach. The project strives to develop and offer safety strategies reducing or completely excluding hydrogen-specific risks to drivers passengers public and first responders in case of hydrogen vehicle accidents within the currently available infrastructure.

In this paper a new isolated hybrid system is simulated and analyzed to obtain the optimal sizing and meet the electricity demand with cost improvement for servicing a small remote area with a peak load of 420 kW. The major configuration of this hybrid system is Photovoltaic (PV) modules Biomass gasifier (BG) Electrolyzer units Hydrogen Tank units (HT) and Fuel Cell (FC) system. A recent optimization algorithm namely Mayfly Optimization Algorithm (MOA) is utilized to ensure that all load demand is met at the lowest energy cost (EC) and minimize the greenhouse gas (GHG) emissions of the proposed system. The MOA is selected as it collects the main merits of swarm intelligence and evolutionary algorithms; hence it has good convergence characteristics. To ensure the superiority of the selected MOA the obtained results are compared with other well-known optimization algorithms namely Sooty Tern Optimization Algorithm (STOA) Whale Optimization Algorithm (WOA) and Sine Cosine Algorithm (SCA). The results reveal that the suggested MOA achieves the best system design achieving a stable convergence characteristic after 44 iterations. MOA yielded the best EC with 0.2106533 $/kWh the net present cost (NPC) with 6170134 $ the loss of power supply probability (LPSP) with 0.05993% and GHG with 792.534 t/y.

This article proposes a new model of power supply for mobile low power machines applications between 10 W and 30 W such as radio-controlled (RC) electric cars. This power supply is based on general hydrogen from residual aluminum and water with NaOH so it is proposed energy valorization of aluminum waste. In the present research a theoretical model allows us to predict the requested aluminum surface and the required flow of hydrogen has been developed also considering in addition to the geometry and purity of the material two key variables as the temperature and the molarity of the alkaline solution used in the hydrogen production process. Focusing on hydrogen production isopropyl alcohol plays a key role in the reactor’s fuel cell vehicle as it filters out NaOH particles and maintains a constant flow of hydrogen for the operation of the machine keeping the reactor temperature controlled. Finally a comparison of the theoretical and experimental data has been used to validate the developed model using aluminum sheets from ring cans to generate hydrogen which will be used as a source of hydrogen in a power fuel cell of an RC car. Finally the manuscript shows the parts of the vehicle’s powertrain its behavior and mode of operation.

Mountain huts as special stand-alone micro-grid systems are not connected to a power grid and represent a burden on the environment. The micro-grid has to be flexible to cover daily and seasonal fluctuations. Heat and electricity are usually generated with fossil fuels due to the simple on-off operation. By introducing renewable energy sources (RESs) the generation of energy could be more sustainable but the generation and consumption must be balanced. The paper describes the integration of a hydrogen-storage system (HSS) and a battery-storage system (BattS) in a mountain hut. The HSS involves a proton-exchange-membrane water electrolyser (PEMWE) a hydrogen storage tank (H₂ tank) a PEM fuel cell (PEMFC) and a BattS consisting of lead-acid batteries. Eight micro-grid configurations were modelled using HOMER and evaluated from the technical environmental and economic points of view. A life-cycle assessment analysis was made from the cradle to the gate. The micro-grid configurations with the HSS achieve on average a more than 70% decrease in the environmental impacts in comparison to the state of play at the beginning but require a larger investment. Comparing the HSS with the BattS as a seasonal energy storage the hydrogen-based technology had advantages for all of the assessed criteria.