Publications

Energy transition will reshape the power sector and hydrogen is a key energy carrier that could contribute to energy security. The inclusion of sustainability criteria is crucial for the adequate design/deployment of resilient hydrogen networks. While cost and environmental metrics are commonly included in hydrogen models social aspects are rarely considered. This paper aims to identify the social criteria related to the hydrogen economy by using a systematic hybrid literature review. The main contribution is the identification of twelve social aspects which are described ranked and discussed. “Accessibility” “Information” “H2 markets” and “Acceptability” are now emerging as the main themes of hydrogen-related social research. Identified gaps are e.g. lack of the definition of the value of H2 for society insufficient research for “socio-political” aspects (e.g. geopolitics wellbeing) scarce application of social lifecycle assessment and the low amount of works with a focus on social practices and cultural issues.

Hydrogen energy represents a crucial pathway towards achieving carbon neutrality and is a pivotal facet of future strategic emerging industries. The safe and efficient transportation of hydrogen is a key link in the entire chain development of the hydrogen energy industry’s “production storage and transportation”. Mixing hydrogen into natural gas pipelines for transportation is the potential best way to achieve large-scale long-distance safe and efficient hydrogen transportation. Welds are identified as the vulnerable points in natural gas pipelines and compatibility between hydrogen-doped natural gas and existing pipeline welds is a critical technical challenge that affects the global-scale transportation of hydrogen energy. Therefore this article systematically discusses the construction and weld characteristics of hydrogen-doped natural gas pipelines the research status of hydrogen damage mechanism and mechanical property strengthening methods of hydrogen-doped natural gas pipeline welds and points out the future development direction of hydrogen damage mechanism research in hydrogen-doped natural gas pipeline welds. The research results show that: 1 Currently there is a need for comprehensive research on the degradation of mechanical properties in welds made from typical pipe materials on a global scale. It is imperative to systematically elucidate the mechanism of mechanical property degradation due to conventional and hydrogeninduced damage in welds of high-pressure hydrogen-doped natural gas pipelines worldwide. 2 The deterioration of mechanical properties in welds of hydrogen-doped natural gas pipelines is influenced by various components including hydrogen carbon dioxide and nitrogen. It is necessary to reveal the mechanism of mechanical property deterioration of pipeline welds under the joint participation of multiple damage mechanisms under multi-component gas conditions. 3 Establishing a fundamental database of mechanical properties for typical pipeline steel materials under hydrogen-doped natural gas conditions globally is imperative to form a method for strengthening the mechanical properties of typical high-pressure hydrogen-doped natural gas pipeline welds. 4 It is essential to promptly develop relevant standards for hydrogen blending transportation welding technology as well as weld evaluation testing and repair procedures for natural gas pipelines.

This paper presents a Linear Joule Engine Generator (LJEG) powered by ammonia and hydrogen co-combustion to tackle decarbonisation in the electrification of transport propulsion systems. A dynamic model of the LJEG which integrates mechanics thermodynamics and electromagnetics sub-models as well as detailed combustion chemistry analysis for emissions is presented. The dynamic model is integrated and validated and the LJEG performance is optimised for improved performance and reduced emissions. At optimal conditions the engine could generate 1.96 kWe at a thermal efficiency of 34.3% and an electrical efficiency of 91%. It is found that the electromagnetic force of the linear alternator and heat addition from the external combustor and engine valve timing have the most significant influences on performance whereas the piston stroke has a lesser impact. The impacts of hydrogen ratio oxygen concentration inlet pressure and equivalence ratio of ammonia-air on nitric oxide (NO) formation and reduction are revealed using a detailed chemical kinetic analysis. Results indicated that rich combustion and elevated pressure are beneficial for NO reduction. The rate of production analysis indicates that the equivalence ratio significantly changes the relative contribution among the critical NO formation and reduction reaction pathways.

Decarbonising energy is fundamental in the transition towards a sustainable future. Our Future Energy Scenarios aim to stimulate debate to inform the decisions that will help move us towards achieving carbon reduction targets and ultimately shape the energy system of the future.

Dihydrogen (H2) commonly named ‘hydrogen’ is increasingly recognised as a clean and reliable energy vector for decarbonisation and defossilisation by various sectors. The global hydrogen demand is projected to increase from 70 million tonnes in 2019 to 120 million tonnes by 2024. Hydrogen development should also meet the seventh goal of ‘affordable and clean energy’ of the United Nations. Here we review hydrogen production and life cycle analysis hydrogen geological storage and hydrogen utilisation. Hydrogen is produced by water electrolysis steam methane reforming methane pyrolysis and coal gasification. We compare the environmental impact of hydrogen production routes by life cycle analysis. Hydrogen is used in power systems transportation hydrocarbon and ammonia production and metallugical industries. Overall combining electrolysis-generated hydrogen with hydrogen storage in underground porous media such as geological reservoirs and salt caverns is well suited for shifting excess of-peak energy to meet dispatchable on-peak demand.

In order to enhance the durability of fuel cell systems in fuel cell hybrid electric vehicles (FCHEVs) researchers have been dedicated to studying the degradation monitoring models of fuel cells under driving conditions. To predict the actual degradation factors and lifespan of fuel cell systems a semi-empirical and semi-physical degradation model suitable for automotive was proposed and developed. This degradation model is based on reference degradation rates obtained from experiments under known conditions which are then adjusted using coefficients based on the electrochemical model. By integrating the degradation model into the vehicle simulation model of FCHEVs the impact of different fuel cell sizes and dynamic limitations on the efficiency and durability of FCHEVs was analyzed. The results indicate that increasing the fuel cell stack power improves durability while reducing hydrogen consumption but this effect plateaus after a certain point. Increasing the dynamic limitations of the fuel cell leads to higher hydrogen consumption but also improves durability. When considering only the rated power of the fuel cell a comparison between 160 kW and 100 kW resulted in a 6% reduction in hydrogen consumption and a 10% increase in durability. However when considering dynamic limitation factors comparing the maximum and minimum limitations of a 160 kW fuel cell hydrogen consumption increased by 10% while durability increased by 83%.

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).

This paper looks at the possible role of ‘green gas’ in the decarbonisation of heat in the United Kingdom.  The option is under active discussion at the moment because of the UK’s rigorous carbon reduction targets and the growing realisation that there are problems with the ‘default’ option of electrifying heat. Green gas appears to be technically and economically feasible.  However as the paper discusses there are major practical and policy obstacles which make it unlikely that the government will commit itself to developing ‘green gas’ in the foreseeable future.

Hydrogen energy is regarded as an important way to achieve carbon emission reduction. This paper focuses on the combination of the design of the hydrogen supply chain network and the location of hydrogen refueling stations on the expressway. Based on the cost analysis of the hydrogen supply chain a multi-objective model is developed to determine the optimal scale and location of hydrogen refueling stations on the hydrogen expressway. The proposed model considers the hydrogen demand forecast hydrogen source selection hydrogen production and storage and transportation hydrogen station refueling mode etc. Taking Dalian City China as an example with offshore wind power as a reliable green hydrogen supply to select the location and capacity of hydrogen refueling stations for the hydrogen energy demonstration section of a certain expressway under multiple scenarios. The results of the case show that 4 and 5 stations are optimized on the expressway section respectively and the unit hydrogen cost is $14.3 /kg H2 and $11.8 /kg H2 respectively which are equal to the average hydrogen price in the international range. The optimization results verify the feasibility and effectiveness of the model.

Hydrogen is an attractive clean sustainable energy source primarily produced via industry. At present most reviews on hydrogen mainly focus on the preparation and storage of hydrogen while the development and utilization of natural hydrogen will greatly reduce its cost. Natural hydrogen has been discovered in many geological environments. Therefore based on extensive literature research in this study the distribution and sources of natural hydrogen were systematically sorted and the identification method and occurrence state of natural hydrogen were examined and summarized. The results of this research show that hydrogen has been discovered in oceanic spreading centers transform faults passive margins convergent margins and intraplate settings. The primary sources of the hydrogen include alterations in Fe(II)-containing rocks the radiolysis of water degassed magma and the reaction of water- and silica-containing rocks during the mechanical fracturing. Hydrogen can appear in free gas it can be adsorbed and trapped in inclusions. Currently natural hydrogen exploration is in its infancy. This systematic review helps to understand the origin distribution and occurrence pattern of natural hydrogen. In addition it facilitates the exploration and development of natural hydrogen deposits thus enabling the production of low-cost hydrogen.