Poland

In this study a theoretical–experimental methodology for determining the stress–strain state in pipeline systems taking into account the hydrogen environment was developed. A complex of theoretical and experimental studies was conducted to determine the specific energy of destruction as an invariant characteristic of the material’s resistance to strain at different hydrogen concentrations. The technique is based on the construction of complete diagrams of the destruction of the material based on the determination of true strains and stresses in the local volume using the method involving the optical–digital correlation of speckle images. A complex of research was carried out and true diagrams of material destruction were constructed depending on the previous elastic–plastic strain and the action of the hydrogen environment. The change in the concentration of hydrogen absorbed by the material was estimated depending on the value of the specific energy of destruction. A study was conducted on tubular samples and the degree of damage to the material of the inner wall under the action of hydrogen and stress from the internal pressure was evaluated according to the change in specific energy depending on the value of the true strain established with the help of an optical–digital correlator on the outer surface and the degree of damage was determined. It has been established that the specific fracture energy of 17G1S steel decreases by 70–90% under the influence of hydrogen. The effect of the change in the amount of strain energy on the thickness of the pipe wall is illustrated.

The main purpose of this paper is the techno-economic analysis of hydrogen production from biogas via steam reforming in a pilot plant. Process flow modeling based on mass and energy balance is used to estimate the total equipment purchase and operating costs of hydrogen production. The pilot plant installation produced 250.67 kg/h hydrogen from 1260 kg/h biomethane obtained after purification of 4208 m3/h biogas using a heat and mass integration process. Despite the high investment cost the plant shows a great potential for biomethane reduction and conversion to hydrogen an attractive economic path with ecological possibilities. The conversion of waste into hydrogen is a possibility of increasing importance in the global energy economy. In the future such a plant will be expanded with a CO2 reduction module to increase economic efficiency and further reduce greenhouse gases in an economically viable manner.

Building a hydrogen economy is perceived as a way to achieve the decarbonization goals set out in the Paris Agreement to limit global warming as well as to meet the goals resulting from the European Green Deal for the decarbonization of Europe. This article presents a literature review of various aspects of this economy. The full added value chain of hydrogen was analyzed from its production through to storage transport distribution and use in various economic sectors. The current state of knowledge about hydrogen is presented with particular emphasis on its features that may determine the positives and negatives of its development. It was noted that although hydrogen has been known for many years its production methods are mainly related to fossil fuels which result in greenhouse gas emissions. The area of interest of modern science is limited to green hydrogen produced as a result of electrolysis from electricity produced from renewable energy sources. The development of a clean hydrogen economy is limited by many factors the most important of which are the excessive costs of producing clean hydrogen. Research and development on all elements of the hydrogen production and use chain is necessary to contribute to increasing the scale of production and use of this raw material and thus reducing costs as a result of the efficiencies of scale and experience gained. The development of the hydrogen economy will be related to the development of the hydrogen trade and the centers of this trade will differ significantly from the current centers of energy carrier trade.

This study conducted a Life Cycle Assessment (LCA) of alternative (electric and hydrogen) and conventional diesel buses in a large metropolitan area. The primary focus was on hydrogen derived from coke oven gas a byproduct of the coking process which is a crucial step in the steel production value chain. The functional unit was 1000000 km traveled over 15 years. LCA analysis using SimaPro v9.3 revealed significant environmental differences between the bus types. Hydrogen buses outperformed electric buses in all 11 environmental impact categories and in 5 of 11 categories compared to conventional diesel buses. The most substantial improvements for hydrogen buses were observed in ozone depletion (8.6% of diesel buses) and global warming (29.9% of diesel buses). As a bridge to a future dominated by green hydrogen employing grey hydrogen from coke oven gas in buses provides a practical way to decrease environmental harm in regions abundant with this resource. This interim solution can significantly contribute to climate policy goals.

The main purpose of this work is to investigate the influence of methane addition in methane-hydrogen-air mixture (φ = 0.8 – 1.6) on the critical conditions for transition to detonation in a 90-deg wedge corner. Similar to hydrogen-air mixtures investigated previously [1] methane-hydrogen-air mixtures results showed three ignition modes weak ignition followed by deflagration with ignition delay time higher than 1 μs strong ignition with instantaneous transition to detonation and third with deflagrative ignition and delayed transition to detonation. Methane addition caused an increase in the range of 3.25 – 5.03% in the critical shock wave velocity necessary for transition to detonation for all mixtures considered. For example in stoichiometric mixture with 5% methane in fuel (95% hydrogen in fuel) in air the transition to detonation velocity was approx. 752 m/s (an increase of 37 m/s from hydrogen-air) corresponding to M = 1.89 (an increase of 0.14 from hydrogen-air) and 75.7% (an increase of 4.7% from hydrogen-air) of speed of sound in products. Also similar to hydrogen-air mixture the transition to detonation velocity increased for leaner and richer mixture. Moreover it was observed that methane addition in general increased the pressure limit at the corner necessary for transition to detonation.

Geological structures in deep aquifers and salt caverns can play an important role in large-scale hydrogen storage. However more work needs to be done to address the hydrogen storage demand for zero-emission energy systems. Thus the aim of the article is to present the demand for hydrogen storage expressed in the number of salt caverns in bedded rock salt deposits and salt domes or the number of structures in deep aquifers. The analysis considers minimum and maximum hydrogen demand cases depending on future energy system configurations in 2050. The method used included the estimation of the storage capacity of salt caverns in bedded rock salt deposits and salt domes and selected structures in deep aquifers. An estimation showed a large hydrogen storage potential of geological structures. In the case of analyzed bedded rock salt deposits and salt domes the average storage capacity per cavern is 0.05–0.09 TWhH2 and 0.06–0.20 TWhH2 respectively. Hydrogen storage capacity in analyzed deep aquifers ranges from 0.016 to 4.46 TWhH2. These values indicate that in the case of the upper bound for storage demand there is a need for the 62 to 514 caverns depending on considered bedded rock salt deposits and salt domes or the 9 largest analyzed structures in deep aquifers. The results obtained are relevant to the discussion on the global hydrogen economy and the methodology can be used for similar considerations in other countries.

This article presents a 3D model of a yellow hydrogen generation system that uses the electricity produced by a photovoltaic carport. The 3D models of all key system components were collected and their characteristics were described. Based on the design of the 3D model of the photovoltaic carport the amount of energy produced monthly was determined. These quantities were then applied to determine the production of low-emission hydrogen. In order to increase the amount of low-emission hydrogen produced the usage of a stationary energy storage facility was proposed. The Metalog family of probability distributions was adopted to develop a strategic model for low-emission hydrogen production. The hydrogen economy of a company that uses small amounts of hydrogen can be based on such a model. The 3D modeling and calculations show that it is possible to design a compact low-emission hydrogen generation system using rapid prototyping tools including the photovoltaic carport with an electrolyzer placed in the container and an energy storage facility. This is an effective solution for the climate and energy transition of companies with low hydrogen demand. In the analytical part the Metalog probability distribution family was employed to determine the amount of monthly energy produced by 6.3 kWp photovoltaic systems located in two European countries: Poland and Italy. Calculating the probability of producing specific amounts of hydrogen in two European countries is an answer to a frequently asked question: In which European countries will the production of low-emission hydrogen from photovoltaic systems be the most profitable? As a result of the calculations for the analyzed year 2023 in Poland and Italy specific answers were obtained regarding the probability of monthly energy generation and monthly hydrogen production. Many companies from Poland and Italy are taking part in the European competition to create hydrogen banks. Only those that offer low-emission hydrogen at the lowest prices will receive EU funding.

To inject green hydrogen (H2) into the existing natural gas (NG) infrastructure is one way to decarbonize the European energy system. However asset readiness is necessary to be successful. Preliminary analysis and experimental results about the compatibility of hydrogen and natural gas mixtures (H2NG) with the actual gas grids make the scientific community confident about the feasibility. Nevertheless specific technical questions need more research. A significant topic of debate is the impact of H2NG mixtures on the performance of state-ofthe-art fiscal measuring devices which are essential for accurate billing. Identifying and addressing any potential degradation in their metrological performance due to H2NG is critical for decision-making. However the literature lacks data about the gas meters’ technologies currently installed in the NG grids such as a comprehensive overview of their readiness at different concentrations while data are fragmented among different sources. This paper addresses these gaps by analyzing the main characteristics and categorizing more than 20000 gas meters installed in THOTH2 project partners’ grids and by summarizing the performance of traditional technologies with H2NG mixtures and pure H2 based on literature review operators experience and manufacturers knowledge. Based on these insights recommendations are given to stakeholders on overcoming the identified barriers to facilitate a smooth transition.

Hydrogen-fueled engines require large values of the excess air ratio in order to achieve high thermal efficiency. A low value of this coefficient promotes knocking combustion. This paper analyzes the conditions for the occurrence of knocking combustion in an engine with a turbulent jet ignition (TJI) system with a passive pre-chamber. A single-cylinder engine equipped with a TJI system was running with an air-to-fuel equivalence ratio λ in the range of 1.25–2.00 and the center of combustion (CoC) was regulated in the range of 2–14 deg aTDC (top dead center). Such process conditions made it possible to fully analyze the ascension of knock combustion until its disappearance with the increase in lambda and CoC. Measures of knock in the form of maximum amplitude pressure oscillation (MAPO) and integral modulus of pressure oscillation (IMPO) were used. The absolute values of these indices were pointed out which can provide the basis for the definition of knock combustion. Based on our own work the MAPO index > 1 bar was defined determining the occurrence of knocking (without indicating its quality). In addition taking into account MAPO it was concluded that IMPO > 0.13 bar·deg is the quantity responsible for knocking combustion.

The paper discusses potential hazards at hydrogen refueling stations for transportation vehicles: cars and trucks. The main hazard analyzed here is an uncontrolled gas release due to a failure in one of the structures in the station: storage tanks of different pressure levels or a dispenser. This may lead to a hydrogen cloud occurring near the source of the release or at a given distance. The range of the cloud was analyzed in connection to the amount of the released gas and the wind velocity. The results of the calculations were compared for chosen structures in the station. Then potential fires and explosions were investigated. The hazard zones were calculated with respect to heat fluxes generated in the fires and the overpressure generated in explosions. The maximum ranges of these zones vary from about 14 to 30 m and from about 9 to 14 m for a fires and an explosions of hydrogen respectively. Finally human death probabilities are presented as functions of the distance from the sources of the uncontrolled hydrogen releases. These are shown for different amounts and pressures of the released gas. In addition the risk of human death is determined along with the area where it reaches the highest value in the whole station. The risk of human death in this area is 1.63 × 10−5 [1/year]. The area is approximately 8 square meters.