Poland

Hydrogen is an energy carrier in which hopes are placed for an easier achievement of climate neutrality. Together with electrification energy efficiency development and RES hydrogen is expected to enable the ambitious energy goals of the European Green Deal. Hence the aim of the article is to query the development of the hydrogen economy in the Visegrad Group countries (V4). The study considers six diagnostic features: sources of hydrogen production hydrogen legislation financial mechanisms objectives included in the hydrogen strategy environmental impact of H2 and costs of green hydrogen investments. The analysis also allowed to indicate the role that hydrogen will play in the energy transition process of the V4 countries. The analysis shows that the V4 countries have similar approaches to the development of the hydrogen market but the hydrogen strategies published by each of the Visegrad countries are not the same. Each document sets goals based on the hydrogen production to date and the specifics of the domestic energy and transport sectors as there are no solutions that are equally effective for all. Poland’s hydrogen strategy definitely stands out the strongest.

This study presents a comprehensive methodology to evaluate plants that integrate renewable energy sources and hydrogen generation devices. The paper focuses on presenting the methods for devices’ operation assessment taking into account the annual operation. Multiple effectiveness indices have been presented. On the basis of experimental investigation with the hydrogen generator the methods for assessing its operation during start-up phase and sudden change in the supply current were proposed. The results of the experiments and the provided mathematical models show that dynamics of the hydrogen generator should be taken into account when selecting the suitable device for cooperation with variable renewable energy. It is especially important for multiple start-ups throughout the day due to significant differences in the amount of hydrogen produced by devices characterized by the same efficiency yet various time constants. Methodology for selecting the optimal nominal power for hydrogen generator to cooperate with given renewable sources was developed. It was proven the optimal power depends on the type of the renewable source and minimal load of the hydrogen generator. Several case studies including the integration of wind and solar energy farms to yield a 10 MW renewable energy farm were considered and the minimal load of the hydrogen generator impacts the annual operation of the device has been presented. The paper provides a set of tools to contribute to the development of sustainable energy plants. The methods proposed in this paper are universal and can be used for various renewable energy sources.

The state of environmental pollution brought about as a result of the modern civilization has been monitored in the interests of the environment and human health since the seventies of the last century. Ensuring the energy security is one of the most basic existential requirements for a functional civilized society. The growing civilizational needs caused by broadly understood development generate demand for the production of all kinds of goods in all sectors of the economy as well as world-wide information transfer. The current energy demand is mostly covered using fossil fuels such as coal oil and natural gas. Some of the energy demand is covered by the energy generated in nuclear reactions and a small part of it comes from renewable energy sources. Energy derived from fossil fuels is inevitably associated with fuel oxidation processes. These processes in addition to generating heat are responsible for the emission of harmful compounds to the atmosphere: carbon monoxide carbon dioxide nitrogen oxides hydrocarbons and particulate matter. These pollutants pose a serious threat to the people as well as the environment in which they live. Due to the large share of fossil fuel energy generation in the process of combustion it becomes necessary to seek other means of obtaining the so-called "clean energy". Fuel cells may have a very high potential in this respect. Their development has enabled attempts to use them in all modes of transport. An important factor in the development of fuel cells is their relatively high efficiency and the coinciding strictening of the emission norms from internal combustion engines used to power maritime transport. Therefore the aim of this article has been to assess the potential of fuel cells as a main source of propulsion power source. A review of the designs of fuel cell systems and their use was performed. The article summarizes the assessment of the potential role of fuel cells as a power source of maritime transport.

Hydrogen can be recognized as the most plausible fuel for promoting a green environment. Worldwide developed and developing countries have established their hydrogen research investment and policy frameworks. This analysis of 610 peer-reviewed journal articles from the last 50 years provides quantitative and impartial insight into the hydrogen economy. By 2030 academics and business professionals believe that hydrogen will complement other renewable energy (RE) sources in the energy revolution. This study conducts an integrative review by employing software such as Bibliometrix R-tool and VOSviewer on socio-economic consequences of hydrogen energy literature derived from the Scopus database. We observed that most research focuses on multidisciplinary concerns such as generation storage transportation application feasibility and policy development. We also present the conceptual framework derived from in-depth literature analysis as well as the interlinkage of concepts themes and aggregate dimensions to highlight research hotspots and emerging patterns. In the future factors such as green hydrogen generation hydrogen permeation and leakage management efficient storage risk assessment studies blending and techno-economic feasibility shall play a critical role in the socio-economic aspects of hydrogen energy research.  

The gasification of Polish coal to produce hydrogen could help to make the country independent of oil and gas imports and assist in the rational energy transition from gray to green hydrogen. When taking strategic economic or legislative decisions one should be guided not only by the level of CO2 emissions from the production process but also by other environmental impact factors obtained from comprehensive environmental analyses. This paper presents an analysis of the life cycle of hydrogen by coal gasification and its application in a vehicle powered by FCEV cells. All the main stages of hydrogen fuel production by Shell technology as well as hydrogen compression and transport to the distribution point are included in the analyses. In total two fuel production scenarios were considered: with and without sequestration of the carbon dioxide captured in the process. Life cycle analysis was performed according to the procedures and assumptions proposed in the FC-Hy Guide Guidance Document for performing LCAs on Fuel Cells and H2 Technologies by the CML baseline method. By applying the CO2 sequestration operation the GHG emissions rate for the assumed functional unit can be reduced by approximately 44% from 34.8 kg CO2-eq to 19.5 kg CO2-eq but this involves a concomitant increase in the acidification rate from 3.64·10−2 kg SO2-eq to 3.78·10−2 kg SO2-eq in the eutrophication index from 5.18·10−2 kg PO3− 4-eq to 5.57·10−2 kg PO3− 4-eq and in the abiotic depletion index from 405 MJ to 414 MJ and from 1.54·10−5 kg Sbeq to 1.61·10−5 kg Sbeq.

In this paper an innovative concept of an energy storage system that combines the idea of energy storage through the use of compressed air and the idea of energy storage through the use of hydrogen (with its further conversion to synthetic natural gas) has been proposed. The thermal integration of two sub-systems allows for efficient storage of large amounts of energy based on the use of pressure tanks with limited volumes. A thermodynamic assessment of the integrated hybrid system was carried out. For the assumed operation parameters an energy storage efficiency value of 38.15% was obtained which means the technology is competitive with intensively developed pure hydrogen energy storage technologies. The results obtained for the hybrid system were compared to the results obtained for three reference systems each of which uses hydrogen generators. The first is a typical Power-to-H2-to-Power system which integrates hydrogen generators with a fuel cell system. The other two additionally use a compressed air energy storage installation. In the first case the compressed air energy storage system consists of a diabatic system. In the second case the compressed air energy storage system is adiabatic. The article has discussed the disadvantages and advantages of all the analyzed systems.

In this work a metal cobalt catalyst was synthesized and its activity in the hydrogen production process was tested. The substrates were water and ethanol. Activity tests were conducted at a temperature range of 350–600 °C water to ethanol molar ratio of 3 to 5 and a feed flow of 0.4 to 1.2 mol/h. The catalyst had a specific surface area of 1.75 m2/g. The catalyst was most active at temperatures in the range of 500–600 °C. Under the most favorable conditions the ethanol conversion was 97% the hydrogen production efficiency was 4.9 mol (H2)/mol(ethanol) and coke production was very low (16 mg/h). Apart from hydrogen and coke CO2 CH4 CO and traces of C2H2 and C2H4 were formed.

This study concerns the production of hydrogen from a mixture of ethanol and water. The process was conducted in plasma generated by a spark discharge. The substrates were introduced in the liquid phase into the reactor. The gaseous products formed in the spark reactor were hydrogen carbon monoxide carbon dioxide methane acetylene and ethylene. Coke was also produced. The energy efficiency of hydrogen production was 27 mol(H2 )/kWh and it was 36% of the theoretical energy efficiency. The high value of the energy efficiency of hydrogen production was obtained with relatively high ethanol conversion (63%). In the spark discharge it was possible to conduct the process under conditions in which the ethanol conversion reached 95%. However this entailed higher energy consumption and reduced the energy efficiency of hydrogen production to 8.8 mol(H2 )/kWh. Hydrogen production increased with increasing discharge power and feed stream. However the hydrogen concentration was very high under all tested conditions and ranged from 57.5 to 61.5%. This means that the spark reactor is a device that can feed fuel cells the power load of which can fluctuate.

The present research focuses on the investigation of an in situ hydrogen charging effect during Crack Tip Opening Displacement testing (CTOD) on the fracture toughness properties of X65 pipeline steel. This grade of steel belongs to the broader category of High Strength Low Alloy Steels (HSLA) and its microstructure consists of equiaxed ferritic and bainitic grains with a low volume fraction of degenerated pearlite islands. The studied X65 steel specimens were extracted from pipes with 19.15 mm wall thickness. The fracture toughness parameters were determined after imposing the fatigue pre-cracked specimens on air on a specific electrolytic cell under a slow strain rate bending loading (according to ASTM G147-98 BS7448 and ISO12135 standards). Concerning the results of this study in the first phase the hydrogen cations’ penetration depth the diffusion coefficient of molecular and atomic hydrogen and the surficial density of blisters were determined. Next the characteristic parameters related to fracture toughness (such as J KQ CTODel CTODpl) were calculated by the aid of the Force-Crack Mouth Open Displacement curves and the relevant analytical equations.

Dark fermentation is a promising method to produce hydrogen from lignocellulosic biomass. This study assessed the influence of temperature phosphate buffer concentration and substrate concentration on direct hydrogen production form cellulose using response surface methodology. Mixed bacterial culture was successfully enriched on cellulose and used as an inoculum for hydrogen production. The model indicated that the highest cumulative hydrogen production (CHP) of 2.14 L H₂/Lmedium could be obtained at 13.5 gcellulose/L 79.5 mM buffer and 32.6 °C. However hydrogen yield is then only 0.58 mol H₂/molhexose due to low substrate conversion efficiency (SCE). Simultaneous optimization of CHP and SCE with desirability function approach resulted in the H₂ yield of 2.71 ± 0.1 mol H2/molhexose and 93.8 ± 1.8% SCE at 3.35 gcellulose/L 69 mM buffer and 32.9 °C. Phosphate concentration above 80 mM decreased H₂ production but had positive effect on cellulose consumption. The bacterial community analysis showed that Ruminiclostridium papyrosolvens was responsible for cellulose hydrolysis. Lachnoclostridium sp. was positively correlated with ethanol production at high phosphate buffer concentration while Caproiciproducens sp. with caproate production at low buffer concentration. The obtained results opens the possibility of simultaneous hydrogen and caproate production from cellulosic substrates.

This paper provides a comprehensive review and critical analysis of the latest research results in addition to an overview of the future challenges and opportunities regarding the use of hydrogen to power internal combustion engines (ICEs). The experiences and opinions of various international research centers on the technical possibilities of using hydrogen as a fuel in ICE are summarized. The advantages and disadvantages of the use of hydrogen as a solution are described. Attention is drawn to the specific physical chemical and operational properties of hydrogen for ICEs. A critical review of hydrogen combustion concepts is provided drawing on previous research results and experiences described in a number of research papers. Much space is devoted to discussing the challenges and opportunities associated with port and direct hydrogen injection technology. A comparison of different fuel injection and ignition strategies and the benefits of using the synergies of selected solutions are presented. Pointing to the previous experiences of various research centers the hazards related to incorrect hydrogen combustion such as early pre‐ignition late pre‐ignition knocking combustion and backfire are described. Attention is focused on the fundamental importance of air ratio optimization from the point of view of combustion quality NOx emissions engine efficiency and performance. Exhaust gas scrubbing to meet future emission regulations for hydrogen powered internal combustion engines is another issue that is considered. The article also discusses the modifications required to adapt existing engines to run on hydrogen. Referring to still‐unsolved problems the reliability challenges faced by fuel injection systems in particular are presented. An analysis of more than 150 articles shows that hydrogen is a suitable alternative fuel for spark‐ignition engines. It will significantly improve their performance and greatly reduce emissions to a fraction of their current level. However its use also has some drawbacks the most significant of which are its high NOx emissions and low power output and problems in terms of the durability and reliability of hydrogen‐fueled engines.

This paper summarizes a series of the authors’ research in the field of assessing the operational degradation of oil and gas transit pipeline steels. Both mechanical and electrochemical properties of steels are deteriorated after operation as is their resistance to environmentally-assisted cracking. The characteristics of resistance to brittle fracture and stress corrosion cracking decrease most intensively which is associated with a development of in-bulk dissipated microdamages of the material. The most sensitive indicators of changes in the material’s state caused by degradation are impact toughness and fracture toughness by the J-integral method. The degradation degree of pipeline steels can also be evaluated nondestructively based on in-service changes in their polarization resistance and potential of the fracture surface. Attention is drawn to hydrogenation of a pipe wall from inside as a result of the electrochemical interaction of pipe metal with condensed moisture which facilitates operational degradation of steel due to the combined action of operating stresses and hydrogen. The development of microdamages along steel texture was evidenced metallographically as a trend to the selective etching of boundaries between adjacent bands of ferrite and pearlite and fractographically by revealing brittle fracture elements on the fracture surfaces namely delamination and cleavage indicating the sites of cohesion weakening between ferrite and pearlite bands. The state of the X52 steel in its initial state and after use for 30 years was assessed based on the numerical simulation method.

Depleting fossil fuel resources and anthropogenic climate changes are the reasons for the intensive development of new sustainable technologies based on renewable energy sources. One of the most promising strategies is the utilization of hydrogen as an energy vector. However the limiting issue for large-scale commercialization of hydrogen technologies is a safe efficient and economical method of gas storage. In industrial practice hydrogen compression and liquefaction are currently applied; however due to the required high pressure (30–70 MPa) and low temperature (−253 ◦C) both these methods are intensively energy consuming. Chemical hydrogen storage is a promising alternative as it offers safe storage of hydrogen-rich compounds under ambient conditions. Although many compounds serving as hydrogen carriers are considered some of them do not have realistic perspectives for large-scale commercialization. In this review the three most technologically advanced hydrogen carriers—dimethyl ether methanol and dibenzyltoluene—are discussed and compared. Their potential for industrial application in relation to the energy storage transport and mobility sectors is analyzed taking into account technological and environmental aspects.

The article proposes the use of the analytic hierarchy process (AHP) method to select a risk assessment technique associated with underground hydrogen storage. The initial choosing and ranking of risk assessment techniques can be considered as a multi-criteria decision problem. The usage of a decision model based on six criteria is proposed. A ranking of methods for estimating the risks associated with underground hydrogen storage is presented. The obtained results show that the application of the AHP-based approach may be a useful tool for selecting the UHS risk assessment technique. The proposed method makes it possible to make an objective decision of the most satisfactory approach from the point of view of all the adopted decision criteria regarding the selection of the best risk assessment technique.

Hydrogen-based technologies are among the most promising solutions to fulfill the zero-emission scenario and ensure the energy independence of many countries. Hydrogen is considered a green energy carrier which can be utilized in the energy transport and chemical sectors. However efficient and safe large-scale hydrogen storage is still challenging. The most frequently used hydrogen storage solutions in industry i.e. compression and liquefaction are highly energy-consuming. Underground hydrogen storage is considered the most economical and safe option for large-scale utilization at various time scales. Among underground geological formations salt caverns are the most promising for hydrogen storage due to their suitable physicochemical and mechanical properties that ensure safe and efficient storage even at high pressures. In this paper recent advances in underground storage with a particular emphasis on salt cavern utilization in Europe are presented. The initial experience in hydrogen storage in underground reservoirs was discussed and the potential for worldwide commercialization of this technology was analyzed. In Poland salt deposits from the north-west and central regions (e.g. Rogóźno Damasławek Łeba) are considered possible formations for hydrogen storage. The Gubin area is also promising where 25 salt caverns with a total capacity of 1600 million Nm3 can be constructed.

The Pr and Sm co-doped ceria (with up to 20 mol.% of dopants) compounds were examined as catalytic layers on the surface of SOFC anode directly fed by biogas to increase a lifetime and the efficiency of commercially available DIR-SOFC without the usage of an external reformer.

The XRD SEM and EDX methods were used to investigate the structural properties and the composition of fabricated materials. Furthermore the electrical properties of SOFCs with catalytic layers deposited on the Ni-YSZ anode were examined by a current density-time and current density-voltage dependence measurements in hydrogen (24 h) and biogas (90 h). Composition of the outlet gasses was in situ analysed by the FTIR-based unit.

It has been found out that Ce_0.9Sm_0.1O_2-δ and Ce_0.8Pr_0.05Sm_0.15O_2-δ catalytic layers show the highest stability over time and thus are the most attractive candidates as catalytic materials in comparison with other investigated lanthanide-doped ceria enhancing direct internal reforming of biogas in SOFCs.

One of the strategic goals of developed countries is to significantly increase the share of renewable energy sources in electricity generation. However the process may be hindered by e.g. the storage and transport of energy from renewable sources. The European Union countries see the development of the hydrogen economy as an opportunity to overcome this barrier. Therefore since 2020 the European Union has been implementing a hydrogen strategy that will increase the share of hydrogen in the European energy mix from the current 2 percent to up to 13–14 percent by 2050. In 2021 following the example of other European countries the Polish government adopted the Polish Hydrogen Strategy until 2030 with an outlook until 2040 (PHS). However the implementation of the strategy requires significant capital expenditure and infrastructure modernisation which gives rise to question as to whether Poland is likely to achieve the goals set out in the Polish Hydrogen Strategy and European Green Deal. The subject of the research is an analysis of the sources of financing for the PHS against the background of solutions implemented by the EU countries and a SWOT/TOWS analysis on the hydrogen economy in Poland. The overall result of the SWOT/TOWS analysis shows the advantage of strengths and related opportunities. This allows for a positive assessment of the prospects for the hydrogen economy in Poland. Poland should continue its efforts to take advantage of the external factors (O/S) such as EU support an increased price competitiveness of hydrogen and the emergence of a competitive cross-border hydrogen market in Europe. At the same time the Polish authorities should not forget about the weaknesses and threats that may inhibit the development of the domestic hydrogen market. It is necessary to modernise the infrastructure; increase the share of renewable energy sources in hydrogen production; increase R&D expenditure and in particular to complete the negotiations related to the adoption of the Fit for 55 package.

The energy sector is nowadays facing new challenges mainly in the form of a massive shifting towards renewable energy sources as an alternative to fossil fuels and a diffusion of the distributed generation paradigm which involves the application of small-scale energy generation systems. In this scenario systems adopting one or more renewable energy sources and capable of producing several forms of energy along with some useful substances such as fresh water and hydrogen are a particularly interesting solution. A hybrid polygeneration system based on renewable energy sources can overcome operation problems regarding energy systems where only one energy source is used (solar wind biomass) and allows one to use an all-in-one integrated systems in order to match the different loads of a utility. From the point of view of scientific literature medium and large-scale systems are the most investigated; nevertheless more and more attention has also started to be given to small-scale layouts and applications. The growing diffusion of distributed generation applications along with the interest in multipurpose energy systems based on renewables and capable of matching different energy demands create the necessity of developing an overview on the topic of small-scale hybrid and polygeneration systems. Therefore this paper provides a comprehensive review of the technology operation performance and economical aspects of hybrid and polygeneration renewable energy systems in small-scale applications. In particular the review presents the technologies used for energy generation from renewables and the ones that may be adopted for energy storage. A significant focus is also given to the adoption of renewable energy sources in hybrid and polygeneration systems designs/modeling approaches and tools and main methodologies of assessment. The review shows that investigations on the proposed topic have significant potential for expansion from the point of view of system configuration hybridization and applications.

The gasification technology of refuse-derived fuels (RDF) can represent a future alternative to the global hydrogen production and a pathway for the development of the circular economy. The paper presents an innovative way of utilizing RDF through their oxygen/steam co-gasification with bituminous coal to hydrogen rich gas. Five different RDF samples (RDF1÷RDF5) were investigated. The in-depth analyses of the co-gasification of bituminous coal blends with different amounts of RDF (10 15 and 20%w/w) under various temperature conditions were conducted with the application of Hierarchical Clustering Analysis (HCA). The results of the research study revealed a decrease in the total gas yield as well as in the hydrogen yield observed with the increase in the RDF fraction in the fuel blend. The lowest hydrogen yield and the highest carbon conversion were noted for the co-gasification tests of coal blends with 20%w/w for all the studied RDFs. The SEM-EDS (Scanning Electron Microscopy with Energy Dispersive Spectroscopy) and WDXRF (Wavelength Dispersive X-ray Fluorescence) results showed a significantly higher H2 yield in RDF2 co-gasification with coal in comparison with all the remaining RDFs due to the higher concentration of calcium in the sample. The molecular structure analysis of polymers using Fourier transform infrared spectroscopy (FTIR) demonstrated that the most prevalent synthetic polymers in RDF2 are polyethylene terephthalate and polyvinyl chloride characterized by the lowest thermal stability compared to polyethylene and polypropylene.

Green hydrogen produced by water electrolysis using renewable energy sources (RES) is an emerging technology that aligns with sustainable development goals and efforts to address climate change. In addition to energy electrolyzers require ultrapure water to operate. Although seawater is abundant on the Earth it must be desalinated and further purified to meet the electrolyzer’s feeding water quality requirements. This paper reviews seawater purification processes for electrolysis. Three mature and commercially available desalination technologies (reverse osmosis multiple-effect distillation and multi-stage flash) were examined in terms of working principles performance parameters produced water quality footprint and capital and operating expenditures. Additionally pretreatment and post-treatment techniques were explored and the brine management methods were investigated. The findings of this study can help guide the selection and design of water treatment systems for electrolysis.

This article presents the concept of green transformation of the coal mining sector. Pump stations that belong to Spółka Restrukturyzacji Kopal´n S.A. (SRK S.A. Bytom Poland) pump out approximately 100 million m3 of mine water annually. These pump stations protect neighboring mines and lower-lying areas from flooding and protect subsurface aquifers from contamination. The largest cost component of maintaining a pumping station is the expenditure for purchasing electricity. Investment towards renewable energy sources will reduce the environmental footprint of pumping station operation by reducing greenhouse gas emissions. The concept of liquidation of an exemplary mining site in the context of a circular economy by proposing the development/revitalization of a coal mine site is presented. This concept involves the construction of a complex consisting of photovoltaic farms combined with efficient energy storage in the form of green hydrogen produced by water electrolysis. For this purpose the potential of liquidated mining sites will be utilized including the use of pumped mine wastewater. This article is conceptual. In order to reach the stated objective a body of literature and legal regulations was analyzed and an empirical study was conducted. Various scenarios for the operation of mine pumping stations have been proposed. The options presented provide full or nearly full energy self-sufficiency of the proposed pumping station operation concept. The effect of applying any option for upgrading the pumping station could result in the creation of jobs that are alternatives to mining jobs and a guarantee of efficient asset management.

To reach climate neutrality by 2050 a goal that the European Union set itself it is necessary to change and modify the whole EU’s energy system through deep decarbonization and reduction of greenhouse-gas emissions. The study presents a current insight into the global energy-transition pathway based on the hydrogen energy industry chain. The paper provides a critical analysis of the role of clean hydrogen based on renewable energy sources (green hydrogen) and fossil-fuels-based hydrogen (blue hydrogen) in the development of a new hydrogen-based economy and the reduction of greenhouse-gas emissions. The actual status costs future directions and recommendations for low-carbon hydrogen development and commercial deployment are addressed. Additionally the integration of hydrogen production with CCUS technologies is presented.

Hydrogen fuel and electricity are energy carriers viewed as promising alternatives for the modernization and decarbonization of public bus transportation fleets. In order to choose development pathways that will lead transportation systems toward a sustainable future the authors developed an environmental model based on the Life Cycle Assessment approach. The model tested the impact of energy carrier consumption during driving as well as the electricity origin employed to power electric buses and produce hydrogen. Energy sources such as wind solar waste and grid electricity were investigated. The scope of the study included the life cycles of the energy carrier and the necessary infrastructure. The results were presented from two perspectives: the total environmental impact and global warming potential. In order to create a roadmap an original method for choosing sustainable development pathways was prepared. It was shown that the modernization of conventional bus fleets using hydrogen and electrical pathways can provide significant environmental benefits from both perspectives but especially in terms of global warming potential. It was emphasized that attention should be paid to the use of low- and zero-emission energy sources because their impact often strongly influenced the final environmental judgment. The energy carrier consumption also had a strong impact on the results obtained and that is why efforts should be made to reduce it. In addition it was confirmed that hydrogen and electricity production systems based on electricity generated by a waste-to-energy plant could be an environmentally reasonable dual solution for both sustainable waste management and meeting transport needs.

The main results highlighted in this article underline the critical significance of hydrogen technologies in the move towards carbon neutrality. This research focuses on several key areas including the production storage safety and usage of hydrogen alongside innovative approaches for assessing hydrogen purity and production-related technologies. This study emphasizes the vital role of hydrogen storage technology for the future utilization of hydrogen as an energy carrier and the advancement of technologies that facilitate effective safe and cost-efficient hydrogen storage. Furthermore bibliometric analysis has been instrumental in identifying primary research fields such as hydrogen storage hydrogen production efficient electrocatalysts rotary engines utilizing hydrogen as fuel and underground hydrogen storage. Each domain is essential for realizing a sustainable hydrogen economy reflecting the significant research and development efforts in hydrogen technologies. Recent trends have shown an increased interest in underground hydrogen storage as a method to enhance energy security and assist in the transition towards sustainable energy systems. This research delves into the technical economic and environmental facets of employing geological formations for large-scale seasonal and long-term hydrogen storage. Ultimately the development of hydrogen technologies is deemed crucial for meeting sustainable development goals particularly in terms of addressing climate change and reducing greenhouse gas emissions. Hydrogen serves as an energy carrier that could substantially lessen reliance on fossil fuels while encouraging the adoption of renewable energy sources aiding in the decarbonization of transport industry and energy production sectors. This in turn supports worldwide efforts to curb global warming and achieve carbon neutrality.

Currently the issue of creating decarbonized energy systems in various spheres of life is acute. Therefore for gas turbine power systems including hybrid power plants with fuel cells it is relevant to transfer the existing engines to pure hydrogen or mixtures of hydrogen with natural gas. However significant problems arise associated with the possibility of the appearance of flashback zones and acoustic instability of combustion an increase in the temperature of the walls of the flame tubes and an increase in the emission of nitrogen oxides in some cases. This work is devoted to improving the efficiency of gas turbine power systems by combusting pure hydrogen and mixtures of natural gas with hydrogen. The organization of working processes in the premixed combustion chamber and the combustion chamber with a sequential injection of ecological and energy steam for the “Aquarius” type power plant is considered. The conducted studies of the basic aerodynamic and energy parameters of a gas turbine combustor working on hydrogen-containing gases are based on solving the equations of conservation and transfer in a multicomponent reacting system. A four-stage chemical scheme for the burning of a mixture of natural gas and hydrogen was used which allows for the rational parameters of environmentally friendly fuel burning devices to be calculated. The premixed combustion chamber can only be recommended for operations on mixtures of natural gas with hydrogen with a hydrogen content not exceeding 20% (by volume). An increase in the content of hydrogen leads to the appearance of flashback zones and fuel combustion inside the channels of the swirlers. For the combustion chamber of the combined-cycle power plant “Vodoley” when operating on pure hydrogen the formation of flame flashback zones does not occur.

Energy and environmental challenges are two key issues related to the sustainable development of the Earth. Fossil fuels (oil coal and natural gas) still supply more than 85% of world energy consumption. Several nations around the globe are striving to provide access to clean and sustainable energy by 2030 (Hostettler et al. 2015). When the Paris Agreement entered into force in 2016 many countries have recently announced serious commitments to significantly reduce their carbon dioxide emissions promising to achieve “net zero” by 2050. he main goal is to limit global warming to well below 2 degrees Celsius preferably to 1.5 degrees Celsius compared to pre-industrial levels (IEA 2021). his requires a total transformation of the energy systems that underpin our economies. In the case of renewable energy technology deployment hydrogen may provide a complementary solution due to its flexibility as an energy carrier and storage medium. The European Union (EU) a signatory to the Paris Agreement demonstrated interest in hydrogen as an invaluable raw material in considerably reducing CO2 emissions. Hydrogen inthe EU energy mix is estimated to increase from the current level (less than 2%) to 13–14% in 2050 (EC 2018).

The valorization of integrated steelworks process off-gases as feedstock for synthesizing methane and methanol is in line with European Green Deal challenges. However this target can be generally achieved only through process off-gases enrichment with hydrogen and use of cutting-edge syntheses reactors coupled to advanced control systems. These aspects are addressed in the RFCS project i3 upgrade and the central role of hydrogen was evident from the first stages of the project. First stationary scenario analyses showed that the required hydrogen amount is significant and existing renewable hydrogen production technologies are not ready to satisfy the demand in an economic perspective. The poor availability of low-cost green hydrogen as one of the main barriers for producing methane and methanol from process off-gases is further highlighted in the application of an ad-hoc developed dispatch controller for managing hydrogen intensified syntheses in integrated steelworks. The dispatch controller considers both economic and environmental impacts in the cost function and although significant environmental benefits are obtainable by exploiting process off-gases in the syntheses the current hydrogen costs highly affect the dispatch controller decisions. This underlines the need for big scale green hydrogen production processes and dedicated green markets for hydrogen-intensive industries which would ensure easy access to this fundamental gas paving the way for a C-lean and more sustainable steel production.

Underground hydrogen storage (UHS) in salt caverns is a sustainable energy solution to reduce global warming. Salt rocks provide an exceptional insulator to store natural hydrogen as they have low porosity and permeability. Nevertheless the salt creeping nature and hydrogeninduced impact on the operational infrastructure threaten the integrity of the injection/production wells. Furthermore the scarcity of global UHS initiatives indicates that investigations on well integrity remain insufficient. This study strives to profoundly detect the research gap and imperative considerations for well integrity preservation in UHS projects. The research integrates the salt critical characteristics the geomechanical and geochemical risks and the necessary measurements to maintain well integrity. The casing mechanical failure was found as the most challenging threat. Furthermore the corrosive and erosive effects of hydrogen atoms on cement and casing may critically put the well integrity at risk. The research also indicated that the simultaneous impact of temperature on the salt creep behavior and hydrogen-induced corrosion is an unexplored area that has scope for further research. This inclusive research is an up-to-date source for analysis of the previous advancements current shortcomings and future requirements to preserve well integrity in UHS initiatives implemented within salt caverns.

The successful commercialisation of underground hydrogen storage (UHS) is contingent upon technological readiness and social acceptance. A lack of social acceptance inadequate policies/regulations an unreliable business case and environmental uncertainty have the potential to delay or prevent UHS commercialisation even in cases where it is ready. The technologies utilised for underground hydrogen and carbon dioxide storage are analogous. The differences lie in the types of gases stored and the purpose of their storage. It is anticipated that the challenges related to public acceptance will be analogous in both cases. An assessment was made of the possibility of transferring experiences related to the social acceptance of CO2 sequestration to UHS based on an analysis of relevant articles from indexed journals. The analysis enabled the identification of elements that can be used and incorporated into the social acceptance of UHS. A framework was identified that supports the assessment and implementation of factors determining social acceptance ranging from conception to demonstration to implementation. These factors include education communication stakeholder involvement risk assessment policy and regulation public trust benefits research and demonstration programmes and social embedding. Implementing these measures has the potential to increase acceptance and facilitate faster implementation of this technology.

The publication presents methods and pre-test results of a stand for testing CHSS in terms of resistance to open fire. The basis for the conducted research is the applicable provisions contained in the UN/ECE Regulation R134. The study includes an overview of contemporary solutions for hydrogen storage systems in high-pressure tanks in means of transport. Development in this area is a response to the challenge of reducing global carbon dioxide emissions and limiting the emissions of toxic compounds. The variety of storage systems used is driven by constraints including energy demand and available space. New tank designs and conducted tests allow for an improvement in systems in terms of their functionality and safety. Today the advancement of modern technologies for producing high-pressure tanks allows for the use of working pressures up to 70 MPa. The main goal of the presented research is to present the requirements and research methodology verifying the tank structure and the security systems used in open-fire conditions. These tests are the final stage of the approval process for individual pressure vessels or complete hydrogen storage systems. Their essence is to eliminate the occurrence of an explosion in the event of a fire.

Energy transformation is one of the processes shaping contemporary urban transport systems with public transport being the subject of initiatives designed to enhance its attractiveness and transport utility including electromobility. This article presents a case study for a metropolitan conurbation—the GZM Metropolis in Poland—considering the economic efficiency of implementing buses with conventional diesel engines electric buses (battery electric buses) and hydrogen fuel cell-powered buses. The analysis is based on the cost-benefit analysis (CBA) method using the discounted cash flow (DCF) method.

Hydrogen (H2) production from biomass has emerged as a promising alternative to fossil-based pathways addressing the global demand for low-carbon energy solutions. This study compares the environmental impacts of two biomass-based H2 production processes biogas reforming and agricultural residue gasification through a life cycle assessment (LCA). Using real-world data from the literature the analysis considered key system boundaries for each process including biogas production reforming and infrastructure for the former and biomass cultivation syngas generation and offgas management for the latter. Environmental impacts were evaluated using SimaPro software (Version 9.4) and the ReCiPe midpoint (H) method. The results revealed that biogas reforming emits approximately 5.047 kg CO2-eq per kg of H2 which is 4.89 times higher than the emissions from agricultural residue gasification (1.30 kg CO2-eq/kg H2) demonstrating the latter’s superior environmental performance. Gasification consumes fewer fossil resources (3.20 vs. 10.42 kg oil-eq) and poses significantly lower risks to human health (1.51 vs. 23.28 kg 14-DCB-eq). Gasification water consumption is markedly higher (5.37 compared to biogas reforming (0.041 m3/kg H2)) which is an important factor to consider for sustainability. These findings highlight gasification as a more sustainable H2 production method and emphasize its potential as an eco-friendly solution. To advance sustainability in energy systems integrating socio-economic studies with LCA is recommended alongside prioritizing agricultural residue gasification for hydrogen production.

Alternative fuel opportunities can satisfy energy security and reduce carbon emissions. In this regard the hydrogen fuel is derived from the source of environmental pollutants like sewage and algae wastewater through hydrothermal gasification technique using a KOH catalyst with varied gasification process parameters of duration and temperature of 6–30 min and 500-800 ◦C. The novelty of the work is to identify the optimum gasification process parameter for obtaining the maximum hydrogen yield using a KOH catalyst as an alternative fuel for agricultural engine applications. Influences of gasification processing time and temperature on H2 selectivity Carbon gasification efficiency (CE) Lower heating value (LHV) Hydrogen yield potential (HYP) and gasification efficiency (GE) were studied. Its results showed that the gasifier operated at 800 ◦C for 30 min offering maximum hydrogen yield (26 mol/kg) and gasification efficiency (58 %). The synthesized H2 was an alternative fuel blended with diesel fuel/TiO2 nanoparticles. It was experimentally studied using an internal combustion engine. Influences of H2 on engine perfor mance like brake-specific fuel consumption brake thermal efficiency and emission performances were measured and compared with diesel fuel. The results showed that DH20T has the least (420g/kWh) brake-specific fuel consumption (BSFC) and superior brake thermal efficiency of about 25.2 %. The emission results revealed that the DH20T blend showed the NOX value increased by almost 10.97 % compared to diesel fuel whereas the CO UHC and smoke values reduced by roughly 31.25 28.34 and 42.35 %. The optimum fuel blend (DH20T) result is rec ommended for agricultural engine applications.

This article presents the findings of a bibliometric analysis of scientific publications in journals and materials indexed in the SCOPUS and Web of Science databases covering the broad topic of underground hydrogen storage (UHS). The use of VOSviewer software for keyword analysis enabled the identification of four key research areas related to UHS. These areas include hydrogen and hydrocarbon reservoir engineering; hydrogen economy and energy transformation; processes in hydrogen storage sites including lessons from CO2 sequestration; and the geology engineering and geomechanics of underground gas storage. The interdisciplinary nature of UHS research emphasises the synergy of research across diverse fields. A bibliographic analysis allowed for the identification of areas of intensive research and new directions of work related to UHS key research centres and the dynamics of the development of research topics related to UHS. This study revealed the chronological dispersion of the research results their geographical and institutional variability and the varying contributions of major publishing journals. The research methodology used can serve as an inspiration for the work of other researchers.

Geological storage is an integral element of the green energy transition. Geological formations such as aquifers depleted reservoirs and hard rock caverns are used mainly for the storage of hydrocarbons carbon dioxide and increasingly hydrogen. However potential adverse effects such as ground movements leakage seismic activity and environmental pollution are observed. Existing research focuses on monitoring subsurface elements of the storage while on the surface it is limited to ground movement observations. The review was carried out based on 191 research contributions related to geological storage. It emphasizes the importance of monitoring underground gas storage (UGS) sites and their surroundings to ensure sustainable and safe operation. It details surface monitoring methods distinguishing geodetic surveys and remote sensing techniques. Remote sensing including active methods such as InSAR and LiDAR and passive methods of multispectral and hyperspectral imaging provide valuable spatiotemporal information on UGS sites on a large scale. The review covers modelling and prediction methods used to analyze the environmental impacts of UGS with data-driven models employing geostatistical tools and machine learning algorithms. The limited number of contributions treating geological storage sites holistically opens perspectives for the development of complex approaches capable of monitoring and modelling its environmental impacts.

In Spain the winery industry exerts a great influence on the national economy. Proportional to the scale of production a significant volume of waste is generated estimated at 2 million tons per year. In this work a laboratory-scale reactor was used to study the feasibility of the energetic valorization of winery effluents into hydrogen by means of dark fermentation and its subsequent conversion into electrical energy using fuel cells. First winery wastewater was characterized identifying and determining the concentration of the main organic substrates contained within it. To achieve this a synthetic winery effluent was prepared according to the composition of the winery wastewater studied. This effluent was fermented anaerobically at 26 ◦C and pH = 5.0 to produce hydrogen. The acidogenic fermentation generated a gas effluent composed of CO2 and H2 with the percentage of hydrogen being about 55% and the hydrogen yield being about 1.5 L of hydrogen at standard conditions per liter of wastewater fermented. A gas effluent with the same composition was fed into a fuel cell and the electrical current generated was monitored obtaining a power generation of 1 W·h L−1 of winery wastewater. These results indicate that it is feasible to transform winery wastewater into electricity by means of acidogenic fermentation and the subsequent oxidation of the bio-hydrogen generated in a fuel cell.

Issues related to the components of modern fuel equipment wear processes have been discussed. The fuel injector is one of the key elements of the fuel equipment system because it is a device responsible for distributing and spraying hydrogen-containing fuel in the engine combustion chamber. It is mounted in the modern engine head directly in the combustion chamber. If the fuel injector is faulty it affects the operating parameters and in particular the ecological parameters of the modern engine such as the emission of toxic substances into the environment. Additionally a hydrogen reactor has been installed in the Common Rail (CR) system the task of which is to produce hydrogen. As a result of the temperature prevailing in the operating environment of the injection equipment various types of wear occur inside the system including hydrogen degradation. The types of degradation processes of precision pairs of modern fuel injectors have been analyzed and classified. Microscopic tests were performed to analyze the contamination in the fuel system and to compare the ecological parameters of the engine operating on efficient and worn fuel injectors. The emission of nitrogen oxides carbon monoxide and soot has been analyzed as a key ecological parameter. It has been established that the loss of precision of pairs of elements of a damaged fuel injector significantly affects the size of the injection doses of the fuel mixture containing hydrogen.

This paper presents a novel literature survey on leveraging electrolysis for grid frequency stabilization in power systems with high penetration of renewable energy sources (RESs) uniquely integrating global research findings with specific insights into the Polish energy context—a region facing acute grid challenges due to rapid RES growth and infrastructure limitations. The intermittent nature of wind and solar power exacerbates frequency fluctuations necessitating dynamic demand-side management solutions like hydrogen production via electrolysis. By synthesizing over 30 studies the survey reveals key results: electrolysis systems particularly PEM and alkaline electrolyzers can reduce frequency deviations by up to 50% through fast frequency response (FFR) and primary reserve provision as demonstrated in simulations and real-world pilots (e.g. in France and the Netherlands); however economic viability requires enhanced compensation schemes with current models showing unprofitability without subsidies. Technological advancements such as transistor-based rectifiers improve efficiency under partial loads while integration with RES farms mitigates overproduction issues as evidenced by Polish cases where 44 GWh of solar energy was curtailed in March 2024. The survey contributes actionable insights for policymakers and engineers including recommendations for deploying electrolyzers to enhance grid resilience support hydrogen-based transportation and facilitate Poland’s target of 50.1% RESs by 2030 thereby advancing the green energy transition amid rising instability risks like blackouts in RES-heavy systems.

According to the European Hydrogen Strategy hydrogen will solve many of the problems with energy storage for balancing variable renewable energy sources (RES) supply and demand. At the same time we can see increasing popularity of the so-called energy communities (e.g. cooperatives) which (i) enable groups of entities to invest in manage and benefit from shared RES energy infrastructure; (ii) are expected to increase the energy independence of local communities from large energy corporations and increase the share of RES. Analyses were conducted on 2000 randomly selected energy cooperatives and four energy cooperatives formed on the basis of actual data. The hypotheses assumed in the research and positively verified in this paper are as follows: (i) there is a relationship between hydrogen storage capacity and the power of RES which allows an energy community to build energy independence; (ii) the type of RES generating source is meaningful when optimizing hydrogen storage capacity. The paper proves it is possible to build “island energy independence” at the local level using hydrogen storage and the efficiency of the power-to-power chain. The results presented are based on simulations carried out using a dedicated optimization model implemented by mixed integer programming. The authors’ next research projects will focus on optimizing capital expenditures and operating costs using the Levelized Cost of Electricity and Levelized Cost of Hydrogen methodologies.

Adverse climate change has forced a deeper reflection on the scale of pollution related to human activity including in the aviation industry. As a result fundamental questions have arisen about the characteristics of these pollutants the mechanisms of their formation and potential strategies for reducing them. This paper provides a comprehensive overview of key technical solutions to minimize the environmental impact of aircraft engines. The solutions presented range from fuel innovations to advanced design changes and drive concepts. Particular attention was paid to sustainable aviation fuels (SAFs) which are currently an important element of the environmental strategy regulated by the European Union. It also discusses the potential use of hydrogen as a potential alternative fuel to replace traditional aviation fuels in the long term. The analysis in the article made it possible to characterize in detail possible modifications in the functioning of aircraft engines based both on the current state of technical knowledge and on the anticipated directions of its development which has not been a frequent issue in comprehensive research so far. The analysis shows that the type of raw material used to create SAF has a strong impact on its physical and chemical parameters and the degree of greenhouse gas emissions. This necessitates a broader analysis of the legitimacy of using a given type of fuel from the SAF group in the direction of selected air operations and areas with a higher risk of severe atmospheric pollution. These results provide the basis for further research into sustainable solutions in the aviation sector that can contribute to significantly reducing its impact on climate change.

The subject of this study is the analysis of influence of capillary threshold pressure and injection well location on the dynamic CO2 and H2 storage capacity for the Lower Jurassic reservoir of the Sierpc structure from central Poland. The results of injection modeling allowed us to compare the amount of CO2 and H2 that the considered structure can store safely over a given time interval. The modeling was performed using a single well for 30 different locations considering that the minimum capillary pressure of the cap rock and the fracturing pressure should not be exceeded for each gas separately. Other values of capillary threshold pressure for CO2 and H2 significantly affect the amount of a given gas that can be injected into the reservoir. The structure under consideration can store approximately 1 Mt CO2 in 31 years while in the case of H2 it is slightly above 4000 tons. The determined CO2 storage capacity is limited; the structure seems to be more prospective for underground H2 storage. The CO2 and H2 dynamic storage capacity maps are an important element of the analysis of the use of gas storage structures. A much higher fingering effect was observed for H2 than for CO2 which may affect the withdrawal of hydrogen. It is recommended to determine the optimum storage depth particularly for hydrogen. The presented results important for the assessment of the capacity of geological structures also relate to the safety of use of CO2 and H2 underground storage space.

This article presents a novel approach to the analysis of heat release in a hydrogen-fueled internal combustion spark-ignition engine with exhaust gas recirculation (EGR). It also discusses aspects of thermodynamic analysis common to modeling and empirical analysis. This new approach concerns a novel method of calculating the specific heat ratio (cp/cv) and takes into account the reduction in the number of moles during combustion which is characteristic of hydrogen combustion. This reduction in the number of moles was designated as a molar contraction. This is particularly crucial when calculating the average temperature during combustion. Subsequently the outcomes of experimental tests including the heat-release rate the initial combustion phase (denoted CA0- 10) and the main combustion phase (CA10-90) are presented. Furthermore the impact of exhaust gas recirculation on the combustion process in the engine is also discussed. The efficacy of the proposed measures was validated by analyzing the heat-release rate and calculating the mean combustion temperature in the engine. The application of EGR in the range 0-40% resulted in a notable prolongation of both the initial and main combustion phases which consequently influenced the mean combustion temperature.

In Poland hydrogen production should be carried out using renewable energy sources particularly wind energy (as this is the most efficient zero-emission technology available). According to hydrogen demand in Poland and to ensure stability as well as security of energy supply and also the realization of energy policy for the EU it is necessary to use offshore wind energy for direct hydrogen production. In this study a centralized offshore hydrogen production system in the Baltic Sea area was presented. The goal of our research was to explore the possibility of producing hydrogen using offshore wind energy. After analyzing wind conditions and calculating the capacity of the proposed wind farm a 600 MW offshore hydrogen platform was designed along with a pipeline to transport hydrogen to onshore storage facilities. Taking into account Poland’s Baltic Sea area wind conditions with capacity factor between 45 and 50% and having obtained results with highest monthly average output of 3508.85 t of hydrogen it should be assumed that green hydrogen production will reach profitability most quickly with electricity from offshore wind farms.

Green hydrogen production is expected to play a major role in the context of the shift towards sustainable energy stipulated in the Fit for 55 package. Green hydrogen and its derivatives have the capacity to act as effective energy storage vectors while fuel cell-powered vehicles will foster net-zero emission mobility. This study evaluates the potential of green hydrogen production in Power-to-Gas (P2G) systems operated in former mining sites where sand and gravel aggregate has been extracted from lakes and rivers under wet conditions (below the water table). The potential of hydrogen production was assessed for the selected administrative unit in Poland the West Pomerania province. Attention is given to the legal and organisational aspects of operating mining companies to identify the sites suitable for the installation of floating photovoltaic facilities by 2050. The method relies on the use of GIS tools which utilise geospatial data to identify potential sites for investments. Basing on the geospatial model and considering technical and organisational constraints the schedule was developed showing the potential availability of the site over time. Knowing the surface area of the water reservoir the installed power of the floating photovoltaic plant and the production capacity of the power generation facility and electrolysers the capacity of hydrogen production in the P2G system can be evaluated. It appears that by 2050 it should be feasible to produce green fuel in the P2G system to support a fleet of city buses for two of the largest urban agglomerations in the West Pomerania province. Simulations revealed that with a water coverage ratio increase and the planned growth of green hydrogen generation it should be feasible to produce fuel for net-zero emission urban mobility systems to power 200 buses by 2030 550 buses by 2040 and 900 buses by 2050 (for the bus models Maxi (40 seats) and Mega (60 seats)). The results of the research can significantly contribute to the development of projects focused on the production of green hydrogen in a decentralised system. The disclosure of potential and available locations over time can be compared with competitive solutions in terms of spatial planning environmental and societal impact and the economics of the undertaking.

This article presents the results of a comparative scenario analysis of the “green hydrogen” development pathways in Poland and the EU in the 2050 perspective. We prepared the scenarios by linking three models: two sectoral models for the power and transport sectors and a Computable General Equilibrium model (d-Place). The basic precondition for the large-scale use of hydrogen in both Poland and in European Union countries is the pursuit of ambitious greenhouse gas reduction targets. The EU plans indicate that the main source of hydrogen will be renewable energy (RES). “Green hydrogen” is seen as one of the main methods with which to balance energy supply from intermittent RES such as solar and wind. The questions that arise concern the amount of hydrogen required to meet the energy needs in Poland and Europe in decarbonized sectors of the economy and to what extent can demand be covered by internal production. In the article we estimated the potential of the production of “green hydrogen” derived from electrolysis for different scenarios of the development of the electricity sector in Poland and the EU. For 2050 it ranges from 76 to 206 PJ/y (Poland) and from 4449 to 5985 PJ/y (EU+). The role of hydrogen as an energy storage was also emphasized highlighting its use in the process of stabilizing the electric power system. Hydrogen usage in the energy sector is projected to range from 67 to 76 PJ/y for Poland and from 1066 to 1601 PJ/y for EU+ by 2050. Depending on the scenario this implies that between 25% and 35% of green hydrogen will be used in the power sector as a long-term energy storage.

The utilization of hydrogen for reciprocating internal combustion engines remains a subject that necessitates thorough research and careful analysis. This paper presents a study on the co-combustion of hydrogen with diesel fuel and biodiesel (RME) in a compression-ignition piston engine operating at maximum load with a hydrogen content of up to 34%. The research employed engine indication and exhaust emissions measurement to assess the engine’s performance. Engine indication allowed for the determination of key combustion stages including ignition delay combustion time and the angle of 50% heat release. Furthermore important operational parameters such as indicated pressure thermal efficiency and specific energy consumption were determined. The evaluation of dual-fuel engine stability was conducted by analyzing variations in the coefficient of variation in indicated mean effective pressure. The increase in the proportion of hydrogen co-combusted with diesel fuel and biodiesel had a negligible impact on ignition delay and led to a reduction in combustion time. This effect was more pronounced when using biodiesel (RME). In terms of energy efficiency a 12% hydrogen content resulted in the highest efficiency for the dual-fuel engine. However greater efficiency gains were observed when the engine was powered by RME. It should be noted that the hydrogen-powered engine using RME exhibited slightly less stable operation as measured by the COVIMEP value. Regarding emissions hydrogen as a fuel in compression ignition engines demonstrated favorable outcomes for CO CO2 and soot emissions while NO and HC emissions increased.

This review synthesizes recent research on alternative fuels for piston-engine aircraft and related propulsion technologies. Biofuels show substantial promise but face technological economic and regulatory barriers to widespread adoption. Among liquid options biodiesel offers a high cetane number and strong lubricity yet suffers from poor low-temperature flow and reduced combustion efficiency. Alcohol fuels (bioethanol biomethanol) provide high octane numbers suited to high-compression engines but are limited by hygroscopicity and phase-separation risks. Higher-alcohols (biobutanol biopropanol) combine favorable heating values with stable combustion and emerge as particularly promising candidates. Biokerosene closely matches conventional aviation kerosene and can function as a drop-in fuel with minimal engine modifications. Emissions outcomes are mixed across studies: certain biofuels reduce NOx or CO while others elevate CO2 and HC underscoring the need to optimize combustion and advance second- to fourth-generation biofuel production pathways. Beyond biofuels hydrogen engines and hybrid-electric systems offer compelling routes to lower emissions and improved efficiency though they require new infrastructure certification frameworks and cost reductions. Demonstrated test flights with biofuels synthetic fuels and hydrogen confirm technical feasibility. Overall no single option fully replaces aviation gasoline today; instead a combined trajectory—biofuels alongside hydrogen and hybrid-electric propulsion—defines a pragmatic medium- to long-term pathway for decarbonizing general aviation.

This article provides an overview of current hydrogen technologies used in road transport with particular emphasis on their potential for decarbonizing the mobility sector. The author analyzes both fuel cells and hydrogen combustion in internal combustion engines as two competing approaches to using hydrogen as a fuel. He points out that although fuel cells offer higher efficiency hydrogen combustion technologies can be implemented more quickly because of their compatibility with existing drive systems. The article emphasizes the importance of hydrogen’s source—so-called green hydrogen produced from renewable energy sources has the greatest ecological potential. Issues related to the storage distribution and safety of hydrogen use in transport are also analyzed. The author also presents the current state of refueling infrastructure and forecasts for its development in selected countries until 2030. He points to the need to harmonize legal regulations and to support the development of hydrogen technologies at the national and international levels. He also highlights the need to integrate the energy and transport sectors to effectively utilize hydrogen as an energy carrier. The article presents a comprehensive analysis of technologies policies and markets identifying hydrogen as a key link in the energy transition. In conclusion the author emphasizes that the future of hydrogen transport depends not only on technical innovations but above all on coherent strategic actions and infrastructure investments.

In the coming years as a result of changing climate policies and finite fossil fuel resources energy producers will be compelled to introduce new fuels with lower carbon footprints. One of the solutions is hydrogen which can be burned or co-fired with methane in energy generation systems. Therefore this study presents a thermodynamic and emission analysis of a gas turbine fueled by a mixture of CH4 and H2 as well as pure hydrogen. Numerical studies were conducted for the actual operating parameters of the LM6000 gas turbine in both simple and combined cycles. Aspen Hysys and Chemkin-Pro 2023R1 commercial software were used for the calculations. It was demonstrated that with a constant turbine inlet temperature set at 1723 K the thermal efficiency increased from 39.4% to 40.2% for the gas turbine cycle and from 49% to 49.4% for the combined cycle gas turbine. Nitrogen oxides emissions were calculated using the reactor network revealing that an increase in H2 content above 20%vol. in the fuel leads to a significant rise in nitric oxides emissions. In the case of pure H2 emissions are more than three times higher than for CH4 . The main reason for this increase in emissions was identified as the greater presence of H O and OH radicals in the reaction zone causing an acceleration in the formation of nitric oxides.

The energy production market based on hydrogen technologies is an innovative solution that will allow the industry to achieve climate neutrality in the future in Poland and in the world. The paper presents the idea of using hydrogen as a modern energy carrier and devices that in cooperation with renewable energy sources produce the so-called green hydrogen and the applicable legal acts that allow for the implementation of the new technology were analyzed. Energy transformation is inevitable and according to reports on good practices in European Union countries hydrogen and the hydrogen value chain (production transport and transmission storage use in transport and energy) have wide potential. Thanks to joint projects and subsidies from the EU initiatives supporting hydrogen technologies are created such as hydrogen clusters and hydrogen valleys and EU and national strategic programs set the main goals. Poland is one of the leaders in hydrogen production both in the world and in Europe. Domestic tycoons from the energy refining and chemical industries are involved in the projects. Eight hydrogen valleys that have recently been created in Poland successfully implement the assumptions of the “Polish Hydrogen Strategy until 2030 with a perspective until 2040” and “Energy Policy of Poland until 2040” which are in line with the assumptions of the most important legal acts of the EU including the European Union’s energy and climate policy the Green Deal and the Fit for 55 Package. The review of the analysis of the development of hydrogen technologies in Poland shows that Poland does not differ from other European countries. As part of the assumptions of the European Hydrogen Strategy and the trend related to the management of energy surpluses electrolyzers with a capacity of at least 6 GW will be installed in Poland in 2020–2024. It is also assumed that in the next phase planned for 2025–2030 hydrogen will be a carrier in the energy system in Poland. Poland as a member of the EU is the creator of documents that take into account the assumptions of the European Union Commission and systematically implement the assumed goals. The strategy of activities supporting the development of hydrogen technologies in Poland and the value chain includes very extensive activities related to among others obtaining hydrogen using hydrogen in transport energy and industry developing human resources for the new economy supporting the activities of hydrogen valley stakeholders building hydrogen refueling stations and cooperation among Poland Slovakia and the Czech Republic as part of the HydrogenEagle project.