Publications

Enhancing system durability and fuel economy stands as a crucial factor in the energy management of fuel cell hybrid vehicles. This paper proposes an Equivalent Consumption Minimization Strategy (ECMS) based on the Genetic Algorithm (GA) aiming to minimize the overall operating cost of the system. First this study establishes a dynamic model of the hydrogen–electric hybrid vehicle a static input–output model of the hybrid power system and an aging model. Next a speed prediction method based on an Autoregressive Integrated Moving Average (ARIMA) model is designed. This method fits a predictive model by collecting historical speed data in real time ensuring the robustness of speed prediction. Finally based on the speed prediction results an adaptive Equivalence Factor (EF) method using a GA is proposed. This method comprehensively considers fuel consumption and the economic costs associated with the aging of the hydrogen–electric hybrid system forming a total operating cost function. The GA is then employed to dynamically search for the optimal EF within the cost function optimizing the system’s economic performance while ensuring real-time feasibility. Simulation outcomes demonstrate that the proposed energy management strategy significantly enhances both the durability and fuel economy of the fuel cell hybrid vehicle.

The integration of water electrolyzers and photovoltaic (PV) solar technology is a potential development in renewable energy systems offering new avenues for sustainable energy generation and storage. This coupling consists of using PV-generated electricity to power water electrolysis breaking down water molecules into hydrogen and oxygen. While oxygen is a useful byproduct the created hydrogen is used as a clean storable energy carrier or feedstock for numerous businesses. It is possible to operate the device with or without battery storage. When solar energy is combined with batteries excess solar energy may be stored for later use maximizing energy efficiency and guaranteeing a steady supply of electricity even in the absence of direct sunlight. On the other hand battery-free systems depend on the electrolyzer’s continuous power generation to convert solar energy into hydrogen during the day. In addition to allowing for the production of renewable hydrogenthis hybrid PV-solar and water electrolyzer setup contributes to grid stability by offering demand-side flexibility. Moreover the modularity of these systems enables scalability to meet diverse energy requirements spanning from residential to industrial applications thereby fostering a cleaner and more sustainable energy landscape. This review delves into various topologies for PV-driven electrolysis and conducts a thorough exploration of the dynamics of low-temperature water electrolyzers. Specifically it examines their integration with three primary technologies: Proton Exchange Membrane Alkaline and Anion Exchange Membrane shedding light on their implications for the broader integration landscape. Through detailed analysis and insights this study enriches the understanding of the potential and challenges inherent in the convergence of PV solar water electrolysis and renewable energy systems.

We present an optimization model of an energy district in South Italy that supplies baseload electricity and hydrogen services. The district is sized such that a nuclear reactor could provide these services. We define scenarios for 2050 to explore the system effects of discount rate sensitivity vetoes on technologies and cost uncertainties. We address the following issues relevant to decarbonization in South Italy: land-based wind and solar vs. exclusive solar rooftop extra cost of a veto on nuclear conservative assumptions on future storage technology and the role of pumped hydro storage lack of low-cost geological storage of hydrogen and the industrial competitiveness of this carrier and the methanation synergy with the agroforestry sector. Our results quantify the high system cost of vetoes on land-based wind and solar. Nuclear may enter the optimal mix only with a veto against onshore wind and a hypothesis of equal project risk hence an equal discount rate with renewables. Scenarios with land-based wind and solar obtain low-cost hydrogen and thus allow industrial uses for this carrier. The methanation synergy with the agroforestry sector does not offer a system cost advantage but improves the district’s configuration. The extra cost of full decarbonization relative to unregulated fossil gas is small with land-based wind and solar and significant with vetoes to these technologies.

This report is an output of the Clean Energy Technology Observatory (CETO). CETO's objective is to provide an evidence-based analysis feeding the policy making process and hence increasing the effectiveness of R&I policies for clean energy technologies and solutions. It monitors EU research and innovation activities on clean energy technologies needed for the delivery of the European Green Deal; and assesses the competitiveness of the EU clean energy sector and its positioning in the global energy market. CETO is being implemented by the Joint Research Centre for DG Research and Innovation in coordination with DG Energy.

Hydrogen produced from renewable sources has the potential to tackle various energy challenges from allowing cost-effective transportation of renewable energy from production to consumption regions to decarbonizing intensive energy consumption industries. Due to its application versatility and non-greenhouse gaseous emissions characteristics it is expected that hydrogen will play an important role in the decarbonization strategies set out for 2050. Currently there are some barriers and challenges that need to be addressed to fully take advantage of the opportunities associated with hydrogen. The present work aims to characterize the state of the art of different hydrogen production storage transport and distribution technologies which compose the hydrogen value chain. Based on the information collected it was possible to conclude the following: (i) Electrolysis is the frontrunner to produce green hydrogen at a large scale (efficiency up to 80%) since some of the production technologies under this category have already achieved a commercially available state; (ii) in the storage phase various technologies may be suitable based on specific conditions and purposes. Technologies of the physical-based type are the ones mostly used in real applications; (iii) transportation and distribution options should be viewed as complementary rather than competitive as the most suitable option varies based on transportation distance and hydrogen quantity; and (iv) a single value chain configuration cannot be universally applied. Therefore each case requires a comprehensive analysis of the entire value chain. Methodologies like life cycle assessment should be utilized to support the decision-making process.

Green hydrogen obtained from renewable electricity can play an essential role in the decarbonization of different sectors. The reliability of the data used to model the entire supply chain is a crucial parameter in Life Cycle Assessment. In this study the authors show how photovoltaic and wind electricity supply chains influence the carbon footprint of green H2. While most published studies rely on default datasets from commercial libraries the current work exploits the actual supply chain of the PV panels and builds an updated average European wind turbine supply chain. The updated values for PV-based H2 experiencing a 40–60% reduction are 2.7 and 1.8 kg CO2 eq./kg H2 for the UK and Italy. The carbon footprint of UK offshore wind-based H2 can be reduced up to 24% and get close to 0.6 kg CO2 eq./kg H2. The findings emphasize the sensitivity of the final climate profile generated by the processes upstream of the electrolysis system.

The existing gas transmission pipeline network can be a convenient and cost-effective way to transport hydrogen. However hydrogen can cause hydrogen embrittlement (HE) of the steels used in pipeline construction. HE is typically manifested as a reduction in fracture toughness and ductility. To ensure structural integrity it is thus important to understand the fracture toughness of pipeline steels in hydrogen gas at pipeline pressures. This paper reviews (i) the influence of hydrogen on the fracture toughness of pipeline steels and (ii) the phenomena that occurs during fracture toughness tests of pipeline steel in air and hydrogen. Also reviewed are (i) the in fluence of hydrogen on tensile properties and (ii) the diffusion and solubility of hydrogen in pipeline steels under conditions relevant to hydrogen transport in gas transmission pipelines.

Proton exchange membrane electrolyzers are an attractive technology for hydrogen production due to their high efficiency low maintenance cost and scalability. To receive these benefits however electrolyzers require high power reliability and have relatively high demand. Due to their intermittent nature integrating renewable energy sources like solar and wind has traditionally resulted in a supply too sporadic to consistently power a proton exchange membrane electrolyzer. This study develops an electrolyzer model operating with renewable energy sources at a highly instrumented university site. The simulation uses dynamic models of photovoltaic solar and wind systems to develop models capable of responding to changing climatic and seasonal conditions. The aim therefore is to observe the feasibility of operating a proton exchange membrane system fuel cell yearround at optimal efficiency. To address the problem of feasibility with dynamic renewable generation a case study demonstrates the proposed energy management system. A site with a river onsite is chosen to ensure sufficient wind resources. Aside from assessing the feasibility of pairing renewable generation with proton exchange membrane systems this project shows a reduction in the intermittency plaguing previous designs. Finally the study quantifies the performance and effectiveness of the PEM energy management system design. Overall this study highlights the potential of proton exchange membrane electrolysis as a critical technology for sustainable hydrogen production and the importance of modeling and simulation techniques in achieving its full potential.

This article presents a study on the distributed optimization operation method for micro-energy grid clusters within an electric thermal and hydrogen integrated energy system. The research focuses on precisely modeling the Power-toHydrogen (P2H) conversion process in electrolytic cells by considering their startup characteristics. An optimization operation model is established with each micro-energy grid as the principal entity to cater to their individual interests and demands. The Alternating Direction Method of Multipliers (ADMM) algorithm is adopted for distributed solution. Case studies demonstrate that the connection topology between micro-energy grids significantly impacts the total operating cost and the effectiveness of the ADMM algorithm is validated through a comparison with centralized optimization approaches.

Compression ignition engines will still be predominant in the naval sector: their high efficiency high torque and heavy weight perfectly suit the demands and architecture of ships. Nevertheless recent emission legislations impose limitations to the pollutant emissions levels in this sector as well. In addition to post-treatment systems it is necessary to reduce some pollutant species and therefore the study of combustion strategies and new fuels can represent valid paths for limiting environmental harmful emissions such as CO2 . The use of methane in dual fuel mode has already been implemented on existent vessels but the progressive decarbonization will lead to the utilization of carbon-neutral or carbon-free fuels such as in the last case hydrogen. Thanks to its high reactivity nature it can be helpful in the reduction of exhaust CH4 . On the contrary together with the high temperatures achieved by its oxidation hydrogen could cause uncontrolled ignition of the premixed charge and high emissions of NOx. As a matter of fact a source of ignition is still necessary to have better control on the whole combustion development. To this end an optimal and specific injection strategy can help to overcome all the before-mentioned issues. In this study three-dimensional numerical simulations have been performed with the ANSYS Forte® software (version 19.2) in an 8.8 L dual fuel engine cylinder supplied with methane hydrogen or hydrogen–methane blends with reference to experimental tests from the literature. A new kinetic mechanism has been used for the description of diesel fuel surrogate oxidation with a set of reactions specifically addressed for the low temperatures together with the GRIMECH 3.0 for CH4 and H2 . This kinetics scheme allowed for the adequate reproduction of the ignition timing for the various mixtures used. Preliminary calculations with a one-dimensional commercial code were performed to retrieve the initial conditions of CFD calculations in the cylinder. The used approach demonstrated to be quite a reliable tool to predict the performance of a marine engine working under dual fuel mode with hydrogen-based blends at medium load. As a result the system modelling shows that using hydrogen as fuel in the engine can achieve the same performance as diesel/natural gas but when hydrogen totally replaces methane CO2 is decreased up to 54% at the expense of the increase of about 76% of NOx emissions.