Publications

Hydrogen technologies are evolving to decarbonise the transport sector. The present work focuses on the technical design of a Hydrogen Refueling Station to supply hydrogen to five buses in the city of Valencia Spain. The study deals with the technical selection of the components from production to consumption setting an efficient standardisation method. Different calculation are used to size the storage systems for 70.8 kg of hydrogen produced by the elecrolyser daily. For the high-pressure storage system massive and cascade methods are proposed being the last one more efficient (1577.53 Nm3 non usable volume compared to 9948.95 Nm3 of the massive method).

This study addresses the challenge of decarbonizing highly energy-intensive Industrial Port Areas (IPA) focusing on emissions from various sources like ship traffic warehouses buildings cargo handling equipment and hardto-abate industry typically hosted in port areas. The analysis and proposal of technological solutions and their optimal integration in the context of IPA is a topic of growing scientific interest with considerable social and economic implications. Representing the main novelties of the work this study introduces (i) the development of a novel IPA energy and green hydrogen hub located in a tropical region (Singapore); (ii) a multi-objective optimization approach to analyse synthesize and optimize the design and operation of the hydrogen and energy hub with the aim of supporting decision-making for decarbonization investments. A sensitivity analysis identifies key parameters affecting optimization results indicating that for large hydrogen demands imported ammonia economically outperforms other green hydrogen carriers. Conversely local hydrogen production via electrolysis becomes economically viable when the capital cost of alkaline electrolyser drops by at least 30 %. Carbon tax influences the choice of green hydrogen but its price variation mainly impacts system operation rather than design. Fuel cells and batteries are not considered economically feasible solutions in any scenario.

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.

The transition towards clean and economically viable hydrogen production is crucial for ensuring energy sustainability and mitigating climate change. This transition can be effectively facilitated by using renewable energy sources and advanced hydrogen production methods. Methane pyrolysis and water electrolysis emerge as crucial techniques for achieving hydrogen production with minimal carbon intensity. Recognizing the unique opportunity presented by solar energy for both processes this study presents a comparative techno-economic analysis between solar-based molten salt methane pyrolysis (SMSMP) and solar-based solid oxide electrolyzer cell (SSOEC). This study offers a guideline for selecting SMSMP vs SSOEC for cities across theworld. In particular a comprehensive case study including five cities worldwide—San Antonio Edmonton Auckland Seville and Lyon—is conducted utilizing their dynamic solar data and localized prices of methane and electricity to provide a realistic comparison. The results indicate the superior economic feasibility of SMSMP across all case studies. Among different case studies San Antonio and Auckland have the lowest hydrogen costs for SMSMP (2.31 $/kgH2) and SSOEC (5.19 $/kgH2) respectively. It was also concluded that SMSMP is preferred over SSOEC in average to ideal solar conditions given its full dependency on solar thermal energy. However the SSOEC has the potential to achieve better economic feasibility by incorporating clean hydrogen tax incentives and reducing the costs associated with renewable energy infrastructure in the future.

The transition to green energy in the transport sector is becoming a priority in the context of global climate challenges and the European Green Deal. This paper investigates the development of alternative fuelling stations particularly electric vehicle (EV) charging infrastructure and hydrogen stations across EU countries with a focus on Poland. It combines a policy and technology overview with a quantitative scientific analysis offering a multidimensional perspective on green infrastructure deployment. A Pearson correlation analysis reveals significant links between charging station density and both GDP per capita and the share of renewable energy. The study introduces an original Infrastructure Accessibility Index (IAI) to compare infrastructure availability across EU member states and models Poland’s EV charging station demand up to 2030 under multiple growth scenarios. Furthermore the article provides a comprehensive overview of biofuels including first- second- and third-generation technologies and highlights recent advances in hydrogen and renewable electricity integration. Emphasis is placed on life cycle considerations energy source sustainability and economic implications. The findings support policy development toward zero-emission mobility and the decarbonisation of transport systems offering recommendations for infrastructure expansion and energy diversification strategies.

Until recently electrified aircraft propulsion (EAP) technology development has been driven by the dual objectives of reducing greenhouse gas (GHG) emissions and addressing the depletion of fossil fuels. However the increasing severity of climate change posing a significant threat to all life forms has resulted in the global consensus of achieving net-zero GHG emissions by 2050. This major shift has alerted the aviation electrification industry to consider the following: What is the clear path forward for EAP technology development to support the net-zero GHG goals for large commercial transport aviation? The purpose of this paper is to answer this question. After identifying four types of GHG emissions that should be used as metrics to measure the effectiveness of each technology for GHG reduction the paper presents three significant categories of GHG reduction efforts regarding the engine evaluates the potential of EAP technologies within each category as well as combinations of technologies among the different categories using the identified metrics and thus determines the path forward to support the net-zero GHG objective. Specifically the paper underscores the need for the aviation electrification industry to adapt adjust and integrate its EAP technology development into the emerging new engine classes. These innovations and collaborations are crucial to accelerate net-zero GHG efforts effectively.

A liquid air energy storage (LAES) system is a promising Carnot battery configuration capable of efficiently recovering waste heat and cold energy carriers. Among these liquid hydrogen (LH₂) regasification presents a significant opportunity due to its high exergy content and its regasification temperature which aligns well with the liquid air liquefaction process. While most existing studies focus on integrating LAES with liquid natural gas (LNG) regasification or improving hydrogen liquefaction via liquid air regasification this work takes a novel approach by enhancing liquid air liquefaction through the utilization of waste cold from LH₂ regasification. Additionally this study explores an economic innovation the valorization of clean dry air discharged by LAES which has not been extensively examined in prior literature. A novel LAES configuration is proposed and subjected to a techno-economic analysis comparing its performance with a stand-alone LAES system. Results show that the proposed integration increases round-trip efficiency by 15 % reduces the levelized cost of storage by 60 % and achieves a payback period of under 10 years. These findings provide valuable insights for both academia and industry advancing the development of more efficient and economically viable LAES systems.

Promoting the development of China’s hydrogen energy industry is crucial for achieving green energy transition. However existing research lacks systematic studies on the spatial layout of the hydrogen industry chain. This study constructed a comprehensive theoretical framework encompassing hardware infrastructure software systems and soft power. Using multi-source heterogeneous data GIS analysis and NVivo text coding methods the current regional layout and challenges of China’s hydrogen infrastructure industry chain were systematically evaluated. The findings determined that economically developed eastern regions lead in infrastructure and soft power while central and western regions leverage their resource and manufacturing advantages. Major challenges include regional imbalances in hardware infrastructure uneven distribution of soft power and misalignment between software systems and actual needs. Analysis of the “14th Five-Year Plan” of various regions elucidated deep insights into the diversity of local hydrogen energy development strategies identifying five types of hydrogen cities: resource-advantaged market-oriented regionally collaborative innovation-driven and policy-supported. Accordingly strategies to enhance industry chain synergy clarify city roles and optimize regional ecosystems were proposed. It is recommended to integrate hydrogen infrastructure with urban planning and incorporate environmental impact assessments into spatial optimization decisions. This study provides a systematic analytical framework and progressive policy recommendations for the efficient and green layout of China’s hydrogen infrastructure offering important implications for the sustainable development of the hydrogen industry and other rapidly developing economies.

The steel industry is one of the major sources of greenhouse gas emissions with significant energy demand. Currently 73% of the world’s steel is manufactured through the coal-coke-based blast furnace-basic oxygen furnace route (BF-BOF) emitting about two tonnes of CO2 per tonne of steel produced. This review reports the major technologies recent developments challenges and technoeconomic comparison of steelmaking technol ogies emphasising the integration of hydrogen in emerging and established ironmaking and steelmaking pro cesses. Significant trials are underway especially in Germany to replace coal injected in the tuyeres of the blast furnace with hydrogen. However it is not clear that this approach can be extended beyond 30% replacement of coke because of the associated technical challenges. Direct smelting and fluidised bed technologies can emit 20%–30% less CO2 without carbon capture and storage utilisation. The implications of hydrogen energy in these technologies as a substitute for natural gas and coal are yet to be fully explored. A hydrogen-based direct reduction of iron ore (DRI) and steel scrap melting in an electric arc furnace (EAF) appeared to be the most mature technological routes to date capable of reducing CO2 emission by 95% but rely on the availability of rich iron concentrates as feed materials. Shaft furnace technologies are the common DRI-making process with a share of over 72% of the total production. The technology has been developed with natural gas as the main fuel and reductant. However it is now being adapted to operate predominantly on hydrogen to produce a low-carbon DRI product. Plasma and electrolysis-based iron and steelmaking are some of the other potential technologies for the application of hydrogen with a CO2 reduction potential of over 95%. However these technologies are in the preliminary stage of development with a technology readiness level of below 6. There are many technological challenges for the application of hydrogen in steel manufacturing such as challenges in distributing heat due to the endothermic H2 reduction process balancing carbon content in the product steel (particularly using zerocarbon DRI) removal of gangue materials and sourcing of cost-competitive renewable hydrogen and highquality iron ore (65>Fe). As iron ore quality degrades worldwide several companies are considering melting DRI before steelmaking possibly using submerged arc technology to eliminate gangue materials. Hence sig nificant laboratory and pilot-scale demonstrations are required to test process parameters and product qualities. Our analysis anticipates that hydrogen will play an instrumental role in decarbonising steel industries by 2035.

The growing emphasis on renewable energy highlights hydrogen’s potential as a clean energy carrier. However traditional hydrogen production methods contribute significantly to carbon emissions. This review examines the integration of carbon capture and storage (CCS) technologies with hydrogen production processes focusing on their ability to mitigate carbon emissions. It evaluates various hydrogen production techniques including steam methane reforming electrolysis and biomass gasification and discusses how CCS can enhance environmental sustainability. Key challenges such as economic technical and regulatory obstacles are analyzed. Case studies and future trends offer insights into the feasibility of CCS–hydrogen integration providing pathways for reducing greenhouse gases and facilitating a clean energy transition.