China, People’s Republic

The paper explores options for a 2050 carbon free energy future for India. Onshore wind and solar sources are projected as the dominant primary contributions to this objective. The analysis envisages an important role for so-called green hydrogen produced by electrolysis fueled by these carbon free energy sources. This hydrogen source can be used to accommodate for the intrinsic variability of wind and solar complementing opportunities for storage of power by batteries and pumped hydro. The green source of hydrogen can be used also to supplant current industrial uses of grey hydrogen produced in the Indian context largely from natural gas with important related emissions of CO2. The paper explores further options for use of green hydrogen to lower emissions from otherwise difficult to abate sectors of both industry and transport. The analysis is applied to identify the least cost options to meet India’s zero carbon future.

The development of a hydrogen energy-based society is becoming the solution for more and more countries. Fuel cell electric vehicles are the best carriers for developing a hydrogen energy-based society. The current research on hydrogen leakage and the diffusion of fuel cell electric vehicles has been sufficient. However the study of hydrogen safety has not reduced the safety concerns for society and government management departments concerning the large-scale promotion of fuel cell electric vehicles. Hydrogen safety is both a technical and psychological issue. This paper aims to provide a comprehensive overview of fuel cell electric vehicles’ hydrogen dispersion and the burning behavior and introduce the relevant work of international standardization and global technical regulations. The CFD simulations in tunnels underground car parks and multistory car parks show that the hydrogen escape performance is excellent. At the same time the research verifies that the flow the direction of leakage and the vehicle itself are the most critical factors affecting hydrogen distribution. The impact of the leakage location and leakage pore size is much smaller. The relevant studies also show that the risk is still controllable even if the hydrogen leakage rate is increased ten times the limit of GTR 13 to 1000 NL/min and then ignited. Multi-vehicle combustion tests of fuel cell electric vehicles showed that adjacent vehicles were not ignited by the hydrogen. This shows that as long as the appropriate measures are taken the risk of a hydrogen leak or the combustion of fuel cell electric vehicles is controllable. The introduction of relevant standards and regulations also indirectly proves this point. This paper will provide product design guidelines for R&D personnel offer the latest knowledge and guidance to the regulatory agencies and increase the public’s acceptance of fuel cell electric vehicles.

Solar-to-hydrogen plants are predominantly based on steam electrolysis. Steam electrolysis requires water electricity and heat. The excess electric energy is generally converted into hydrogen via an electrolyser. The use of waste heat in hydrogen generation process promises energy efficiency improvement and production fluctuation reductions. This work investigates the techno-economic performance of the proposed system which recovers the waste heat from molten carbonate fuel cell and uses solar energy to produce steam. Comparison of thermally assisted solar system with corresponding solar system is done. The fuel cell provides 80% of the required thermal energy. The solar PV array provides the required electricity. The thermally assisted solar-to-hydrogen system annual energy efficiency (38.5 %) is higher than that of solar- to- hydrogen system. The investment cost of the proposed system is 2.4 % higher than that using only solar parabolic trough collector for the same required amount of heat. The advantage is that the fuel cell simultaneously produces electricity and heat. The recovery of waste heat allows getting an annual overall efficiency of 63.2 % for the molten carbonate fuel cell. It yields 2152 MWh of electricity per year. The 1 MW electrolysers annually generates 74 tonnes of hydrogen.

With increasing concerns on transportation decarbonization fuel cell hybrid trains (FCHTs) attract many attentions due to their zero carbon emissions during operation. Since fuel cells alone cannot recover the regenerative braking energy (RBE) energy storage devices (ESDs) are commonly deployed for the recovery of RBE and provide extra traction power to improve the energy efficiency. This paper aims to minimize the net hydrogen consumption (NHC) by co-optimizing both train speed trajectory and onboard energy management using a time-based mixed integer linear programming (MILP) model. In the case with the constraints of speed limits and gradients the NHC of co-optimization reduces by 6.4% compared to the result obtained by the sequential optimization which optimizes train control strategies first and then the energy management. Additionally the relationship between NHC and employed ESD capacity is studied and it is found that with the increase of ESD capacity the NHC can be reduced by up to 30% in a typical route in urban railway transit. The study shows that ESDs play an important role for FCHTs in reducing NHC and the proposed time-based co-optimization model can maximize the energy-saving benefits for such emerging traction systems with hybrid energy sources including both fuel cells and ESD.

A proton exchange membrane fuel cell (PEMFC) system requires an adequate hydrogen supply and circulation to achieve its expected performance and operating life. An ejector-based hydrogen circulation system can reduce the operating and maintenance costs noise and parasitic power consumption by eliminating the recirculation pump. However the ejector’s hydrogen entrainment capability restricted by its geometric parameters and flow control variability can only operate properly within a relatively narrow range of fuel cell output power. This research introduced the optimal design and operation control methods of a dual-ejector hydrogen supply/circulation system to support the full range of PEMFC system operations. The technique was demonstrated on a 70 kW PEMFC stack with an effective hydrogen entrainment ratio covering 8% to 100% of its output power. The optimal geometry design ensured each ejector covered a specific output power range with maximized entrainment capability. Furthermore the optimal control of hydrogen flow and the two ejectors’ opening and closing times minimized the anode gas pressure fluctuation and reduced the potential harm to the PEMFC’s operation life. The optimizations were based on dedicated computational fluid dynamics (CFD) and system dynamics models and simulations. Bench tests of the resulting ejector-based hydrogen supply/circulation system verified the simulation and optimization results.

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.

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.

With the rapid development of hydrogen energy worldwide the number of hydrogen energy facilities such as hydrogen refueling stations has grown rapidly in recent years. However hydrogen is prone to leakage accidents during use which could lead to hazards such as fires and explosions. Therefore research on the safety of hydrogen energy facilities is crucial. In this paper a study of high-pressure hydrogen jet flame accidents is conducted for a proposed integrated hydrogen production and refueling station in China. The effects of leakage direction and leakage port diameter on the jet flame characteristics are analyzed and a risk assessment of the flame accident is conducted. The results showed that the death range perpendicular to the flame direction increased from 2.23 m to 5.5 m when the diameter of the leakage port increased from 4 mm to 10 mm. When the diameter of the leakage port is larger than 8 mm the equipment on the scene will be within the boundaries of the damage. The consequences of fire can be effectively mitigated by a reasonable firewall setup to ensure the overall safety of the integrated station.

The electrocatalytic seawater splitting has become an important and necessary way for large-scale hydrogen production with challenges ahead. In this review a brief introduction to the reaction mechanism of seawater electrocatalytic process is first provided including the cathodic hydrogen evolution reaction and the anodic oxygen evolution reaction as well as the competitive chloride evolution reaction. Recent progress in transition metal phosphides-based catalysts for seawater electrolysis such as phosphorus doped transition metals binary metal phosphides and structural engineering are then evaluated and discussed. Finally the challenges and opportunities of transition metal phosphides are proposed and discussed.

The application of hydrogen energy produced by proton exchange membrane electrolyzer (PEMEC) is conducive to the solution of the greenhouse effect and the energy crisis. In order to understand the development trends and research hotspot of PEMEC in recent years a total of 1874 research articles related to this field from 2003 to 2023 were obtained from the Web of Science Core Collection (WoS CC) database. The visualization software VOSviewer is used for bibliometric analysis and the research progress hotspots and trends in the PEMEC field are summarized. It was found that in the past two decades literature in the PEMEC field has shown a trend of stable increase at first and then rapidly increasing. And it is in a stage of rapid growth after 2021.Renewable Energy previously published research articles related to PEMEC with the highest frequency of citations. There are a total of 6128 researchers in this field but core authors only account for 4.5% of the total. Although China entered this field later than the United States and Canada it has the largest number of research articles. The research results provide a comprehensive overview of various aspects in the PEMEC field which is beneficial for researchers to grasp the development hotspots of PEMEC.