Publications

This paper investigates the challenges and solutions associated with integrating a hydrogen-generating nuclear-renewable integrated energy system (NR-IES) under a transactive energy framework. The proposed system directs excess nuclear power to hydrogen production during periods of low grid demand while utilizing renewables to maintain grid stability. Using digital real-time simulation (DRTS) in the Typhoon HIL 404 model the dynamic interactions between nuclear power plants electrolyzers and power grids are analyzed to mitigate issues such as harmonic distortion power quality degradation and low power factor caused by large non-linear loads. A three-phase power conversion system is modeled using the Typhoon HIL 404 model and includes a generator a variable load an electrolyzer and power filters. Active harmonic filters (AHFs) and hybrid active power filters (HAPFs) are implemented to address harmonic mitigation and reactive power compensation. The results reveal that the HAPF topology effectively balances cost efficiency and performance and significantly reduces active filter current requirements compared to AHF-only systems. During maximum electrolyzer operation at 4 MW the grid frequency dropped below 59.3 Hz without filtering; however the implementation of power filters successfully restored the frequency to 59.9 Hz demonstrating its effectiveness in maintaining grid stability. Future work will focus on integrating a deep reinforcement learning (DRL) framework with real-time simulation and optimizing real-time power dispatch thus enabling a scalable efficient NR-IES for sustainable energy markets.

Fuel cell hybrid systems due to their combination of the high energy density of fuel cells and the rapid response capability of power batteries have become an important category of new energy vehicles. This paper discusses energy management strategies in hydrogen fuel cell vehicles. Firstly a detailed comparative analysis of existing PID control strategies and Adaptive Equivalent Consumption Minimization Strategies (A-ECMSs) is conducted. It was found that although A-ECMS can balance the energy utilization of the fuel cell and power battery well the power fluctuations of the fuel cell are significant leading to increased hydrogen consumption. Therefore this paper proposes an improved Adaptive Low-Pass Filter Equivalent Consumption Minimization Strategy (A-LPF-ECMS). By introducing low-pass filtering technology transient changes in fuel cell power are smoothed effectively reducing fuel consumption. Simulation results show that under the 6*FTP75 cycle the energy loss of A-LPF-ECMS is reduced by 10.89% (compared to the PID strategy) and the equivalent hydrogen consumption is reduced by 7.1%; under the 5*WLTC cycle energy loss is reduced by 5.58% and equivalent hydrogen consumption is reduced by 3.18%. The research results indicate that A-LPF-ECMS performs excellently in suppressing fuel cell power fluctuations under idling conditions significantly enhancing the operational efficiency of the fuel cell and showing high application value.

Background: This study applied levelized cost of hydrogen (LCOH) and environmental cost accounting techniques to evaluate the feasibility of producing green hydrogen (GH2) via alkaline electrolysis for use in a bus fleet in Fortaleza Brazil. Methods: A GH2 plant with a 3 MW wind tower was considered in this financial project. A sensitivity analysis was conducted to assess the economic viability of the project considering the influence of production volume the number of electrolysis kits financing time and other kay economic indices. Revenue was derived from the sale of by-products including green hospital oxygen (GHO2) and excess wind energy. A life cycle assessment (LCA) was performed to quantify material and emission flows throughout the H2 production chain. A zero-net hydrogen price scenario was tested to evaluate the feasibility of its use in urban transportation. Results: The production of GH2 in Brazil using alkaline electrolysis powered by wind energy proved to be economically viable for fueling a hydrogen-powered bus fleet. For production volumes ranging from 8.89 to 88.9 kg H2/h the sensitivity analysis revealed high economic performance achieving a net present value (NPV) between USD 19.4 million and USD 21.8 million a payback period of 1–4 years an internal rate of return (IRR) of 24–90% and a return on investment (ROI) of 300–1400%. The LCOH decreased with increased production ranging from 56 to 25 USD/MWh. Over the project timeline GH2 production and use in the bus fleet reduced CO2 emissions by 53000–287000 t CO2 eq. The fuel cell bus fleet project demonstrated viability through fuel cost savings and revenue from carbon credit sales highlighting the economic social and environmental sustainability of GH2 use in urban transportation in Brazil.

The combustion and emission characteristics of a hydrogen engine were investigated through experimental analysis using a GDI engine. To enable hydrogen in-cylinder direct injection a specialized hydrogen gas injector was employed. A comparative analysis of the combustion performance between gasoline and hydrogen fuels in a spark-ignited engine was conducted. Additionally the study experimentally explored the thermal efficiency and emission reduction potential of hydrogen engines in lean combustion modes. The results indicated a significant improvement in the combustion rate when hydrogen fuel was utilized in the spark-ignited engine. However the effective thermal efficiency was found to be lower than that of gasoline fuel due to the delayed MBF50 under stoichiometric conditions. Furthermore when compared to gasoline fuel the reduction of CO and THC emissions was accompanied by an increase in NOx emissions. Nevertheless optimizing the air dilution ratio in hydrogen engines led to an improvement in the effective thermal efficiency. Specifically under medium load conditions a Lambda value of 2.7 resulted in an effective thermal efficiency of 43.5%. Additionally under ultra-lean conditions (Lambda > 2.3) NOx emissions could be reduced to below 50 ppm reaching as low as 44 ppm. This study highlights the potential of improving combustion efficiency and reducing emissions by utilizing hydrogen fuel particularly in lean combustion modes. It contributes to the continuous development of hydrogen engine technology and promotes the implementation of cleaner and more efficient energy solutions.

Hydrogen-Integrated energy systems (HIESs) are pivotal in driving the transition to a low-carbon energy structure in China. This paper proposes a low-carbon economic scheduling strategy to improve the operational efficiency and reduce the carbon emissions of HIESs. The approach begins with the implementation of a stepwise carbon trading framework to limit the carbon output of the system. This is followed by the development of a joint operational model that combines hydrogen energy use and carbon capture. To improve the energy supply flexibility of HIESs modifications to the conventional combined heat and power (CHP) unit are made by incorporating a waste heat boiler and an organic Rankine cycle. This results in a flexible CHP response model capable of adjusting both electricity and heat outputs. Furthermore a comprehensive demand response model is designed to optimize the flexible capacities of electric and thermal loads thereby enhancing demand-side responsiveness. The integration of electric vehicles (EVs) into the system is analyzed with respect to their energy consumption patterns and dispatch capabilities which improves their potential for flexible scheduling and enables an optimized synergy between the demand-side flexibility and system operations. Finally a low-carbon economic scheduling model for the HIES is developed with the objective of minimizing system costs. The results show that the proposed scheduling method effectively enhances the economy low-carbon performance and flexibility of HIES operation while promoting clean energy consumption deep decarbonization of the system and the synergistic complementarity of flexible supply–demand resources. In the broader context of expanding clean energy and growing EV adoption this study demonstrates the potential of energy-saving emissionreduction systems and vehicle-to-grid (V2G) strategies to contribute to the sustainable and green development of the energy sector.

Combining electrolytic hydrogen production with wind–photovoltaic power can effectively smooth the fluctuation of power and enhance the schedulable wind–photovoltaic power which provides an effective solution to solve the problem of wind–photovoltaic power accommodation. In this paper the optimization operation strategy is studied for the wind–photovoltaic power-based hydrogen production system. Firstly to make up for the deficiency of the existing research on the multi-state and nonlinear characteristics of electrolyzers the three-state and power-current nonlinear characteristics of the electrolyzer cell are modeled. The model reflects the difference between the cold and hot starting time of the electrolyzer and the linear decoupling model is easy to apply in the optimization model. On this basis considering the operation constraints of the electrolyzer hydrogen storage tank battery and other equipment the optimization operation model of the wind–photovoltaic power-based hydrogen production system is developed based on the typical scenario approach. It also considers the cold and hot starting time of the electrolyzer with the daily operation cost as the goal. The results show that the operational benefits of the system can be improved through the proposed strategy. The hydrogen storage tank capacity will have an impact on the operation income of the wind–solar hydrogen coupling system and the daily operation income will increase by 0.32% for every 10% (300 kg) increase in the hydrogen storage tank capacity.

Solar energy is the largest energy source on Earth. In contrast to the limited andgreenhouse gases-emitting fossil fuels solar energy is inexhaustible carbonneutral and nonpolluting. The conversion of this most abundant but highlydiffused source into hydrogen is increasingly attractive. In nature photosyntheticmicroorganisms exploit solar energy to produce hydrogen via photosynthesiswhich is also known as photobiological hydrogen production. More recentlyvarious types of artificial materials have been developed to hybrid microorgan-isms for converting solar energy into hydrogen namely semiartificial photo-synthesis hydrogen production. Herein the strategies for converting solar energyinto hydrogen with whole-cell biocatalyst are summarized and their potentials forfuture social sustainable development are discussed.

Hydrogen is the most environmentally friendly and cleanest fuel that has the potential to supply most of the world's energy in the future replacing the present fossil fuel-based energy infrastructure. Hydrogen is expected to solve the problem of energy shortages in the near future especially in complex geographical areas (hills arid plateaus etc.) and harsh climates (desert ice etc.). Thus in this report we present a current status of achievable hydrogen fuel based on various scopes including production methods storage and transportation techniques the global market and the future outlook. Its objectives include analyzing the effectiveness of various hydrogen generation processes and their effects on the economy society and environment. These techniques are contrasted in terms of their effects on the environment manufacturing costs energy use and energy efficiency. In addition hydrogen energy market trends over the next decade are also discussed. According to numerous encouraging recent advancements in the field this review offers an overview of hydrogen as the ideal renewable energy for the future society its production methods the most recent storage technologies and transportation strategies which suggest a potential breakthrough towards a hydrogen economy. All these changes show that this is really a profound revolution in the development process of human society and has been assessed as having the same significance as the previous industrial revolution.

The road transport sector is one of the major contributors to greenhouse gas emissions as it still largely relies on traditional powertrain solutions. While some progress has been made in the passenger car sector with the diffusion of battery electric vehicles heavy-duty transport remains predominantly dependent on diesel internal combustion engines. This research aims to evaluate and compare three potential solutions for the decarbonisation of heavy-duty freight transport from an economic perspective: Battery Electric Trucks (BETs) Fuel Cell Electric Trucks (FCETs) and Hydrogen-fuelled Internal Combustion Engine Trucks (H2ICETs). The study focuses on the Finnish market and road network where affordable and low-carbon electricity creates an ideal environment for the development of alternative powertrain vehicles. The analysis employs the Total Cost of Ownership (TCO) method which allows for a comprehensive assessment of all cost components associated with the vehicles throughout their entire lifecycle encompassing both initial expenses and operational costs. Among the several factors affecting the results the impact of the three powertrain technologies on the admissible payloads has been taken into account. The study specifically focuses on the costs directly incurred by the truck owner. Additionally to evaluate the cost effectiveness of the proposed powertrain technologies under different scenarios a sensitivity analysis on electricity and hydrogen prices is conducted. The outcomes of this study reveal that no single powertrain solution emerges as universally optimal as the most cost-effective choice depends strongly on the truck type and its use (i.e. daily mileage). For relatively small trucks (18 t) covering short driving distances (approximately 100 to 200 km/day) BETs prove to be the best solution due to their higher efficiency and lower vehicle costs compared to FCETs. Conversely for larger trucks (42 and 76 t) engaged in longer hauls (>300 km/day) H2ICETs exhibit larger cost benefits due to their lower vehicle costs among the three options under investigation. Finally for small trucks (18 t) travelling long distances (200 km/day or more) FCETs represent a competitive choice due to their high efficiency and costeffective energy storage system. Considering future advancements in FCETs and BETs in terms of improved performance and reduced investment cost the fuel cell-based solution is expected to emerge as the best option across various combinations of truck sizes and daily mileages.

Direct hydrogen production from inexhaustible seawater using abundant offshore wind power offers a promising pathway for achieving a sustainable energy industry and fuel economy. Various direct seawater electrolysis methods have been demonstrated to be effective at the laboratory scale. However larger-scale in situ demonstrations that are completely free of corrosion and side reactions in fluctuating oceans are lacking. Here fluctuating conditions of the ocean were considered for the first time and seawater electrolysis in wave motion environment was achieved. We present the successful scaling of a floating seawater electrolysis system that employed wind power in Xinghua Bay and the integration of a 1.2 Nm3 h−1 -scale pilot system. Stable electrolysis operation was achieved for over 240 h with an electrolytic energy consumption of 5 kWh Nm−3 H2 and a high purity (>99.9%) of hydrogen under fluctuating ocean conditions (0~0.9 m wave height 0~15 m s−1 wind speed) which is comparable to that during onshore water electrolysis. The concentration of impurity ions in the electrolyte was low and stable over a long period of time under complex and changing scenarios. We identified the technological challenges and performances of the key system components and examined the future outlook for this emerging technology.