Institution of Gas Engineers & Managers

Hydrogen offers an effective pathway for the large‑scale storage of renewable energy. For a tourist city located in a plateau region rich in renewable energy hydrogen shows great potential for reducing carbon emissions and utilizing uncertain renewable energy. Herein the wind–solar–hydrogen stand‑alone and grid‑connected systems in the plateau tourist city of Lijiang City in Yunnan Province are modeled and techno‑economically evaluated by using the HOMER Pro software (version 3.14.2) with the multi‑criteria decision anal‑ ysis models. The system is composed of 5588 kW solar photovoltaic panels an 800 kW wind turbine a 1600 kW electrolyzer a 421 kWh battery and a 50 kW fuel cell. In addi‑ tion to meeting the power requirements for system operation the system has the capacity to provide daily electricity for 200 households in a neighborhood and supply 240 kg of hydrogen per day to local hydrogen‑fueled buses. The stand‑alone system can produce 10.15 × 106 kWh of electricity and 93.44 t of hydrogen per year with an NPC of USD 8.15 million an LCOE of USD 0.43/kWh and an LCOH of USD 5.26/kg. The grid‑connected system can generate 10.10 × 106 kWh of electricity and 103.01 ton of hydrogen annually. Its NPC is USD 7.34 million its LCOE is USD 0.11/kWh and its LCOH is USD 3.42/kg. This study provides a new solution for optimizing the configuration of hybrid renewable en‑ ergy systems which will develop the hydrogen economy and create low‑carbon‑emission energy systems.

Population growth and economic development have significantly increased global energy demand. Hence it has raised concerns about the increase in the consumption of fossil fuels and climate change. The present work introduced a new approach to using carbon-free energy sources such as nuclear and renewable to meet energy demand. The idea of using the Nuclear-Renewable Hybrid Energy System (N-R HES) is suggested as a leading solution that couples a nuclear power plant with renewable energy and hydrogen-based storage systems. For this purpose using a meta-heuristic method based on Newton’s laws the configuration of the N-R HES is optimized from an economic and reliability point of view. The optimal system is selected from among six cases with different subsystems such as wind turbine photovoltaic panel nuclear reactor electrolysis fuel cell and hydrogen storage tank. Furthermore the performance of hydrogen-based energy storage systems such as hightemperature electrolysis (HTE) and low-temperature electrolysis (LTE) is evaluated from technical and economic aspects. The results of this work showed that using nuclear energy to supply the base load increases the reliability of the system and reduces the loss of power supply probability to zero. More than 70 % of the power is produced by nuclear reactors which includes more than 80 % of the system costs. The key findings showed that despite HTE’s higher efficiency using LTE as a storage system in N-R HES is more cost-effective. Finally due to recent developments and the safer design of nuclear reactors they can play an important role in combination with renewable energies to support carbon-free energy sectors especially in remote areas for decades to come.

Methanol reforming is considered to be one of the most promising hydrogen production technologies for hydrogen fuel cells. It is expected to solve the problem of hydrogen storage and transportation because of its high hydrogen production rate low cost and good safety. However the strong nonlinearity and slow response of the pressure and temperature subsystems pose challenges to the tracking control of the methanol reforming hydrogen production system. In this paper two internal model-based temperature and pressure controllers are proposed in which the temperature is adjusted by controlling the air flow and the pressure is adjusted by controlling the opening of the backpressure valve. Firstly a lumped parameter model of the methanol reforming hydrogen production system is constructed using MATLAB/Simulink® (produced by MathWorks in Natick Massachusetts USA). In addition the transfer function model of the system is obtained by system identification at the equilibrium point and the internal model controller is further designed. The simulation results show that the control method achieves the robustness of the system and the temperature and pressure of the reforming reactor can quickly and accurately track the target value when the load changes. Small-load step tests indicate stable tracking of the temperature and pressure for the reforming reactor without steady-state errors. Under large-temperature step signal testing the response time for the reforming temperature is about 148 s while the large-pressure step signal test shows that the response time for the reforming pressure is about 8 s. Compared to the PID controller the internal model controller exhibits faster response zero steady-state error and no overshoot. The results show that the internal model control method has strong robustness and dynamic characteristics.

Sustainability goals include the utilization of renewable energy resources to supply the energy needs in addition to wastewater treatment to satisfy the water demand. Moreover hydrogen has become a promising energy carrier and green fuel to decarbonize the industrial and transportation sectors. In this context this research investigates a wind-photovoltaic power plant to produce green hydrogen for hydrogen refueling station and to operate an electrocoagulation water treatment unit in Ostrava Czech Republic’s northeast region. The study conducts a techno-economic analysis through HOMER Pro® software for optimal sizing of the power station components and to investigate the economic indices of the plant. The power station employs photovoltaic panels and wind turbines to supply the required electricity for electrolyzers and electrocoagulation reactors. As an offgrid system lead acid batteries are utilized to store the surplus electricity. Wind speed and solar irradiation are the key role site dependent parameters that determine the cost of hydrogen electricity and wastewater treatment. The simulated model considers the capital operating and replacement costs for system components. In the proposed system 240 kg of hydrogen as well as 720 kWh electrical energy are daily required for the hydrogen refueling station and the electrocoagulation unit respectively. Accordingly the power station annually generates 6997990 kWh of electrical energy in addition to 85595 kg of green hydrogen. Based on the economic analysis the project’s NPC is determined to be €5.49 M and the levelized cost of Hydrogen (LCH) is 2.89 €/kg excluding compressor unit costs. This value proves the effectiveness of this power system which encourages the utilization of green hydrogen for fuel-cell electric vehicles (FCVs). Furthermore emerging electrocoagulation studies produce hydrogen through wastewater treatment increasing hydrogen production and lowering LCH. Therefore this study is able to provide practicable methodology support for optimal sizing of the power station components which is beneficial for industrialization and economic development as well as transition toward sustainability and autonomous energy systems.

The present work demonstrates a comparative study of hydrogen fuel cells and combustion aircraft to investigate the potential of fuel cells as a visionary propulsion system for radically more sustainable medium- to long-range commercial aircraft. The study which considered future airframe and propulsion technologies under the Se2A project was conducted to quantify potential emissions and costs associated with such aircraft and to determine the benefits and drawbacks of each energy system option for different market segments. Future technologies considered in the present work include laminar flow control active load alleviation new materials and structures ultra-high bypass ratio turbofan engines more efficient thermal management systems and superconducting electric motors. A multi-fidelity initial sizing framework with coupled constraint and mission analysis blocks was used for parametric airplane sizing and calculations of all necessary characteristics. Analyses performed for three reference aircraft of different sizes and ranges concluded that fuel-cell aircraft could have operating cost increases in the order of 30% compared to hydrogen combustion configurations and were caused by substantial weight and fuel burn increases. In-flight changes in emissions of fuel cell configurations at high altitudes were progressively reduced from medium-range to long-range segments from being similar to hydrogen combustion for medium-range to 24% for large long-range aircraft although fuel cell aircraft consume 22–30% more fuel than combustion aircraft. Results demonstrate a positive environmental impact of fuel cell propulsion for longrange applications the possibilities of being a more emission-universal solution if desired optimistic technology performance metrics are satisfied. The study also demonstrates progressively increasing technology requirements for larger aircraft making the long-range application’s feasibility more challenging. Therefore substantial development of fuel cell technologies for long-range aircraft is imperative. The article also emphasizes the importance of airframe and propulsion technologies and the necessity of green hydrogen production to achieve desired emissions.

Hydrogen is considered a promising solution for global decarbonisation as an alternative to fossil fuels. However it can interact with and brittle most metallic materials and is highly flammable. These properties call for a systematic investigation of physical and chemical hazards and for the definition of a comprehensive risk management and monitoring framework including proper maintenance planning. This study aims at establishing a hydrogen monitoring scheme and it provides a descriptive bibliometric and interpretative review of the current state-of-the-art of suitable techniques to ensure the safe handling of hydrogen systems. The descriptive analysis outlines the technologies available to supervise the hydrogen-material interactions and detect hydrogen leaks and flames. The bibliometric analysis shows quantitative data to identify the most relevant research groups. The interpretative study discusses the findings and examines the possibility of combining the identified techniques with maintenance programs to prevent catastrophic events.

Integrating coal-to-hydrogen production with Carbon Capture Utilization and Storage (CCUS) is essential for reducing greenhouse gas emissions and facilitating a shift towards a more sustainable energy paradigm. This paper explores the diffusion of CCUS technology within the coal-to-hydrogen sector against the dynamic backdrop of the carbon trading market. An evolutionary game-theoretic approach is utilized within a smallworld network framework to analyze the spread of CCUS technology among coal-tohydrogen enterprises. The simulation reveals that current market dynamics along with technological market and policy-related uncertainties do not robustly encourage the adoption of CCUS. As the carbon trading market continues to mature carbon prices become a significant factor influencing the diffusion of CCUS technology in coal-to-hydrogen processes. Furthermore investment costs hydrogen market prices and governmental policies are identified as pivotal elements in the propagation of CCUS technology. This study contributes valuable insights into the sustainable development of the hydrogen industry and the broader implications for low-carbon energy transition strategies.

Demand response (DR) is a crucial element in the optimization of integrated energy systems (IESs) that incor porate distributed generation (DG). However its inherent uncertainty poses significant challenges to the eco nomic viability of IESs. This research presents a novel economic dispatch model for IESs utilizing information gap decision theory (IGDT). The model integrates various components to improve IES performance and dispatch efficiency. With a focus on hydrogen energy the model considers users’ energy consumption patterns thereby improving system flexibility. By applying IGDT the model effectively addresses the uncertainty associated with DR and DG overcoming the limitations of traditional methods. The research findings indicate that in relation to the baseline method the proposed model has the potential to reduce operating costs by 6.3 % and carbon emissions by 4.2 %. The integration of a stepwise carbon trading mechanism helps boost both economic and environmental advantages achieving a 100 % wind power consumption rate in the optimized plan. In addition the daily operating costs are minimized to 23758.99 ¥ while carbon emissions are significantly reduced to 34192 kg. These findings provide quantitative decision support for IES dispatch planners to help them develop effective dispatch strategies that are consistent with low-carbon economic initiatives.

This study introduces a multi-period integrated optimization model for designing a strategic hydrogen supply chain (HSC) network concentrating on the post-production stages of conditioning storage transportation and post-conditioning. Qatar serves as the case study for evaluating three HSC pathways—ammonia (as a hydrogen carrier) liquefied hydrogen and compressed hydrogen—across pre-conditioning storage shipping and postconditioning stages. The optimization framework spans a 20-year plan supporting strategic long-term hydrogen export infrastructure planning. Economic and environmental factors are incorporated to analyze HSC performance under various scenarios accounting for realistic constraints such as investment limits and emission caps. Key findings reveal trade-offs between pathways and design strategies that must account for balancing costs with environmental impacts. Results indicate that the ammonia pathway is preferred in scenarios without emission penalties but becomes less favorable with increased penalties shifting preference toward the liquified hydrogen pathway. With stringent emission limits short- and mid-range markets are prioritized underscoring the importance of emissions-conscious strategies. This study demonstrates the utility of optimi zation tools in balancing economic and environmental objectives offering policymakers and industry stake holders a robust framework for developing sustainable and efficient HSC networks.

Solid oxide cells (SOC) play a major role in strategic visions to achieve decarbonization and climate-neutrality. With its multifuel capability this technology has received rapidly growing amount of attention from researchers worldwide. Due to the great flexibility of SOCs with respect to the fuels that can be used not only hydrogen but also biogas natural gas diesel reformates and many other conventional and alternative fuels can be used. This makes it possible to couple SOCs with diverse sustainable fuel sources to generate electricity or to generate valuable fuels such as syngas when utilizing renewable electricity. In this paper the reader is provided with a review of the existing knowledge about solid oxide fuel cell (SOFC) and solid oxide electrolysis (SOE) systems and how to safely operate them over the long-term placing a special focus on real-world operating environments. Both the utilization and generation of real commercially available fuels are taken into consideration. Different failure modes can appear during the system operation under real-world conditions and reduce the SOC lifetime an aspect that is extensively discussed in this review. Firstly a detailed discussion of the difference between carbon-free and carbon-containing fuels is presented considering different impurities and their impacts on the SOC performance stability and lifetime. Secondly unfavorable operating conditions are presented and possibilities for the early identification of different failure modes are explored. An overview of available conventional and non-conventional diagnostic tools and their applications is provided here. Overall this review paper presents a guideline for all relevant degradation issues related to SOCs operated in a real-world environment describing (i) how these issues appear and how to understand them (ii) how to predict them (iii) how to identify them and (iv) how to prevent them as well as if required how to reverse them. To achieve this goal individual chapters specifically address failure modes degradation prediction degradation prevention and performance regeneration. The reader is provided with necessary knowledge about the long-term and short-term operating stability and the degradation provoked in a compact summary. The available knowledge about specific process frequencies is summarized in one diagram which is a novel contribution of this review. This enables researchers to rapidly identify all occurring process mechanisms with SOFCs and SOECs. Moreover suggestions for how to accelerate degradation and how to regenerate performance are summarized in several tables.