Modeling and optimization of renewable hydrogen systems:A systematic methodological review and machine learning integration

The renewable hydrogen economy is recognized as an integral solution for decarbonizing energy sectors.However,high costs have hindered widespread deployment.One promising way of reducing the costs is optimization.Optimization generally involves finding the configuration of the renewable generation and hydrogen system components that maximizes return on investment.Previous studies have included many aspects into their optimizations,including technical parameters and different costs/socio-economic objective functions,however there is no clear best-practice framework for model development.To address these gaps,this critical review examines the latest development in renewable hydrogen microgrid models and summarizes the best modeling practice.The findings show that advances in machine learning integration are improving solar electricity generation forecasting,hydrogen system simulations,and load profile development,particularly in data-scarce regions.Additionally,it is important to account for electrolyzer and fuel cell dynamics,rather than utilizing fixed performance values.This review also demonstrates that typical meteorological year datasets are better for modeling solar irradiation than first-principle calculations.The practicability of socio-economic objective functions is also assessed,proposing that the more comprehensive Levelized Value Addition(LVA)is best suited for inclusion into models.Best practices for creating load profiles in regions like the Global South are discussed,along with an evaluation of AI-based and traditional optimization methods and software tools.Finally,a new evidence-based multi-criteria decision-making framework integrated with machine learning insights,is proposed to guide decision-makers in selecting optimal solutions based on multiple attributes,offering a more comprehensive and adaptive approach to renewable hydrogen system optimization.

A coordinated operation method of wind-PV-hydrogenstorage multi-agent energy system

Wind-photovoltaic(PV)-hydrogen-storage multi-agent energy systems are expected to play an important role in promoting renewable power utilization and decarbonization.In this study,a coordinated operation method was proposed for a wind-PVhydrogen-storage multi-agent energy system.First,a coordinated operation model was formulated for each agent considering peer-to-peer power trading.Second,a coordinated operation interactive framework for a multi-agent energy system was proposed based on the theory of the alternating direction method of multipliers.Third,a distributed interactive algorithm was proposed to protect the privacy of each agent and solve coordinated operation strategies.Finally,the effectiveness of the proposed coordinated operation method was tested on multi-agent energy systems with different structures,and the operational revenues of the wind power,PV,hydrogen,and energy storage agents of the proposed coordinated operation model were improved by approximately 59.19%,233.28%,16.75%,and 145.56%,respectively,compared with the independent operation model.

Forward perspective on the development and strategic pathway of green hydrogen in China

Fundamental transformations are taking place in the areas of energy structure on the supply side and on the energy-consumption side towards clean,low-carbon and safe energy.Furthermore,a new energy system is being constructed with renewable energy as its core in China with energy transition and‘carbon peak and carbon neutral’as the overall goal.China’s hydrogen-industry plan,‘Mid-to-long term hydrogen industry development plan(2021-2035)’,has an emphasis on hydrogen generation by using renewable energies as the centre piece,which points in the right direction for hydrogen’s green development.In this paper,the current status of China’s hydrogen industry is analysed;strategic needs for green hydrogen’s development and its hurdles in its paths are sorted out.Integrated demonstration at provincial levels,development of a‘great hydrogen base’and the green-hydrogen development path by gradual substitution with renewable hydrogen are proposed.Scaled-up hydrogen production,expanded consumer hydrogen usage and established hydrogen commodity exchange are recommended to safeguard its development and promote its high-quality development in China.

Chemical storage of hydrogen in synthetic liquid fuels:building block for CO_(2)-neutral mobility

Green hydrogen is anticipated to play a major role in the decarbonization of the mobility sector.Its chemical storage in CO_(2)-neutral synthetic liquid fuels is advantageous in terms of safety and reliability compared to other hydrogen storage developments,and thus represents a complementary building block to developments in electric and hydrogen mobility for the low-carbon transition in the mobility sector.Its development is especially relevant for transport sectors which will have no alternatives to liquid fuels in the foreseeable future.In this paper,three alternative technological routes for the chemical storage of hydrogen in CO_(2)-neutral synthetic liquid fuels are identified and comparatively evaluated in terms of feedstock potential,product potential,demand for renewable electricity and associated costs,efficiency as well as expected market relevance.While all three routes exhibited similar levels of overall efficiencies,electricity-based liquid fuels in Germany are currently limited by the high cost and limited supply of renewable electricity.In contrast,liquid fuels generated from biogenic waste have a constant supply of biogenic feedstock and are largely independent from the supply and cost of renewable electricity.

Reversed configuration of photocatalyst to exhibit improved properties of basic processes compared to conventional one

Performances of semiconductor photocatalysts are integrally determined by efficiencies of basic processes such as light absorption,charge separation and surface catalysis,but conventional configurations of photocatalysts normally suffers from the competition of light absorption originating from cocatalyst deposition and limited interface charge separation between the photocatalyst and cocatalyst.Herein we give the first proof-of-concept illustration that a reversed configuration of photocatalysts with a core/shell structure of microsized Mo2N cocatalysts and nanosized CdS photocatalysts,which exhibits superior solar hydrogen production to the conventional configuration with nanosized Mo2N cocatalysts deposited on the surface of CdS photocatalysts.It is revealed that the reversed configuration outperforms the conventional one in all areas of light absorption,charge separation and surface catalysis.Strikingly,the special core/shell structure introduced here can well avoid the competition of light absorption by cocatalysts and make an effective confinement effect to promote the surface catalysis of Mo2N.Our finding provides an alternative strategy to improve performances of photocatalysts.

Integrated Energy Production Unit: An Innovative Concept and Design for Energy Transition Toward Low-carbon Development

To achieve the goals of emission peak and carbon neutrality,significant effort is invested to accelerate the energy transition,with a focus on the development and utilization of renewable energy,as well as the upgrading of conventional units.Within this context,this paper proposes an innovative concept,known as the integrated energy production unit(IEPU),providing a variety of energy products and flexible adjustment functions for power systems with high penetration of non-hydro renewable energy.In the IEPU framework,a photovoltaic(PV)power plant is installed to produce electricity;CO_(2) capture technology is applied to the existing coal-fired power plant with biomass co-combustion.The generated CO_(2) is used to synthesize methane or methanol with hydrogen through electrolysis.First,the operational principle and advantages of this concept are illustrated.Then,a simplified model is built to provide an optimal configuration scheme of equipment capacity.Finally,the potential contribution of IEPU to the operational flexibility of the power system is also analyzed.