Italy
Numerical Redesign of 100kw MGT Combustor for 100% H2 Fueling
Jan 2014
Publication
The use of hydrogen as energy carrier in a low emission microturbine could be an interesting option for renewable energy storage distributed generation and combined heat & power. However the hydrogen using in gas turbine is limited by the NOx emissions and the difficulty to operate safely. CFD simulations represent a powerful and mature tool to perform detailed 3-D investigation for the development of a prototype before carrying out an experimental analysis. This paper describes the CFD supported redesign of the Turbec T100 microturbine combustion chamber natural gas-fired to allow the operation on 100% hydrogen.
Solid State Hydrogen Storage in Alanates and Alanate-Based Compounds: A Review
Jul 2018
Publication
The safest way to store hydrogen is in solid form physically entrapped in molecular form in highly porous materials or chemically bound in atomic form in hydrides. Among the different families of these compounds alkaline and alkaline earth metals alumino-hydrides (alanates) have been regarded as promising storing media and have been extensively studied since 1997 when Bogdanovic and Schwickardi reported that Ti-doped sodium alanate could be reversibly dehydrogenated under moderate conditions. In this review the preparative methods; the crystal structure; the physico-chemical and hydrogen absorption-desorption properties of the alanates of Li Na K Ca Mg Y Eu and Sr; and of some of the most interesting multi-cation alanates will be summarized and discussed. The most promising alanate-based reactive hydride composite (RHC) systems developed in the last few years will also be described and commented on concerning their hydrogen absorption and desorption performance.
Hazard Footprint of Alternative Fuel Storage Concepts for Hydrogen-powered Urban Buses
Nov 2023
Publication
Hydrogen mobility is a powerful strategy to fight climate change promoting the decarbonization of the transportation sector. However the higher flammability of hydrogen in comparison with traditional fuels raises issues concerning the safety of hydrogen-powered vehicles in particular when urban mobility in crowded areas is concerned. In the present study a comparative analysis of alternative hydrogen storage concepts for buses is carried out. A specific inherent safety assessment methodology providing a hazard footprint of alternative hydrogen storage technologies was developed. The approach provides a set of ex-ante safety performance indicators and integrates a sensitivity analysis performed by a Monte Carlo method. Integral models for consequence analysis and a set of baseline frequencies are used to provide a preliminary identification of the worstcase credible fire and explosion scenarios and to rank the inherent safety of alternative concepts. Cryocompressed storage in the supercritical phase resulted as the more hazardous storage concept while cryogenic storage in the liquid phase at ambient pressure scored the highest safety performance. The results obtained support risk-informed decision-making in the shift towards the promotion of sustainable mobility in urban areas.
Flashback Propensity due to Hydrogen Blending in Natural Gas: Sensitivity to Operating and Geometrical Parameters
Jan 2024
Publication
Hydrogen has emerged as a promising option for promoting decarbonization in various sectors by serving as a replacement for natural gas while retaining the combustion-based conversion system. However its higher reactivity compared to natural gas introduces a significant risk of flashback. This study investigates the impact of operating and geometry parameters on flashback phenomena in multi-slit burners fed with hydrogenmethane-air mixtures. For this purpose transient numerical simulations which take into account conjugate heat transfer between the fluid and the solid walls are coupled with stochastic sensitivity analysis based on Generalized Polynomial Chaos. This allows deriving comprehensive maps of flashback velocities and burner temperatures within the parameter space of hydrogen content equivalence ratio and slit width using a limited number of numerical simulations. Moreover we assess the influence of different parameters and their interactions on flashback propensity. The ranges we investigate encompass highly H2 -enriched lean mixtures ranging from 80% to 100% H2 by volume with equivalence ratios ranging from 0.5 to 1.0. We also consider slit widths that are typically encountered in burners for end-user devices ranging from 0.5 mm to 1.2 mm. The study highlights the dominant role of preferential diffusion in affecting flashback physics and propensity as parameters vary including significant enrichment close to the burner plate due to the Soret effect. These findings hold promise for driving the design and optimization of perforated burners enabling their safe and efficient operation in practical end-user applications.
Addressing Environmental Challenges: The Role of Hydrogen Technologies in a Sustainable Future
Dec 2023
Publication
Energy and environmental issues are of great importance in the present era. The transition to renewable energy sources necessitates technological political and behavioral transformations. Hydrogen is a promising solution and many countries are investing in the hydrogen economy. Global demand for hydrogen is expected to reach 120 million tonnes by 2024. The incorporation of hydrogen for efficient energy transport and storage and its integration into the transport sector are crucial measures. However to fully develop a hydrogen-based economy the sustainability and safety of hydrogen in all its applications must be ensured. This work describes and compares different technologies for hydrogen production storage and utilization (especially in fuel cell applications) with focus on the research activities under study at SaRAH group of the University of Naples Federico II. More precisely the focus is on the production of hydrogen from bio-alcohols and its storage in formate solutions produced from renewable sources such as biomass or carbon dioxide. In addition the use of materials inspired by nature including biowaste as feedstock to produce porous electrodes for fuel cell applications is presented. We hope that this review can be useful to stimulate more focused and fruitful research in this area and that it can open new avenues for the development of sustainable hydrogen technologies.
Analysis of a Distributed Green Hydrogen Infrastructure Designed to Support the Sustainable Mobility of a Heavy-duty Fleet
Aug 2023
Publication
Clean hydrogen is a key pillar for the net zero economy which can be deployed by consistent utilization on heavy-duty transport. This study investigates a distributed green hydrogen infrastructure (DHI) for heavy-duty transportation consisting of on-site hydrogen production storage compression and refueling systems in Italy. Two options for energy supply are analyzed: grid connection using green energy via Power Purchasing Agreements (PPAs) and direct connection to the photovoltaic field respectively. Radiation data are representative of the three main Italian areas namely South (Catania) Center (Roma) and North (Milano). The sensitivity analysis varies the PPA value between 50 V/MWh and 200 V/MWh and the water electrolysis capacity factor between 20% and 100%. The study finds that the LCOH ranges from 7.4 V/kgH2 to 67.8 V/kgH2 for the first option and 5.5 V/kgH2 to 27.5 V/kgH2 for the second option with Southern Italy having the lowest LCOH due to higher solar irradiation. The research shows that a DHI can offer economic and technical benefits for heavy-duty mobility. However the performance is highly influenced by external conditions such as hydrogen demand and electricity prices. This study provides valuable insights into designing and operating a DHI for heavy-duty mobility promoting a carbon-free society.
Hydrogen Consumption and Durability Assessment of Fuel Cell Vehicles in Realistic Driving
Jan 2024
Publication
This study proposes a predictive equivalent consumption minimization strategy (P-ECMS) that utilizes velocity prediction and considers various dynamic constraints to mitigate fuel cell degradation assessed using a dedicated sub-model. The objective is to reduce fuel consumption in real-world conditions without prior knowledge of the driving mission. The P-ECMS incorporates a velocity prediction layer into the Energy Management System. Comparative evaluations with a conventional adaptive-ECMS (A-ECMS) a standard ECMS with a well-tuned constant equivalence factor and a rule-based strategy (RBS) are conducted across two driving cycles and three fuel cell dynamic restrictions (|∕| ≤ 0.1 0.01 and 0.001 A∕cm2 ). The proposed strategy achieves H2 consumption reductions ranging from 1.4% to 3.0% compared to A-ECMS and fuel consumption reductions of up to 6.1% when compared to RBS. Increasing dynamic limitations lead to increased H2 consumption and durability by up to 200% for all tested strategies.
The Use of Hydrogen as Alternative Fuel for Ship Propulsion: A Case Study of Full and Partial Retrofitting of Roll-on/Roll-off Vessels for Short Distance Routes
Oct 2023
Publication
Roll-on/Roll-Off (Ro-Ro) vessels including those without and with passenger accommodation Roll-on/roll-off passenger (Ro-Pax) can be totally or partially retrofitted to reduce the greenhouse gas (GHG) emissions in maritime transport not only during hoteling operation at the dock but also during service. This study is based on data of the vessel routes connecting the Port of Piombino to the Elba Island in Italy. Three retrofitting scenarios have been considered: replacement of the main and auxiliary engines with fuel cells (FC) (full retrofitting) replacement of the auxiliary engines with FCs (partial retrofitting) and replacement of the auxiliary engines with FCs and hoteling only with auxiliary engines for one specific vessel. The amount of hydrogen the filling time and the energy needed for production compression and pre-cooling of hydrogen have been calculated for the different scenarios.
The Potential of Hydrogen-battery Storage Systems for a Sustainable Renewable-based Electrification of Remote Islands in Norway
Oct 2023
Publication
Remote locations and off-grid regions still rely mainly on diesel generators despite the high operating costs and greenhouse gas emissions. The exploitation of local renewable energy sources (RES) in combination with energy storage technologies can be a promising solution for the sustainable electrification of these areas. The aim of this work is to investigate the potential for decarbonizing remote islands in Norway by installing RES-based energy systems with hydrogen-battery storage. A national scale assessment is presented: first Norwegian islands are characterized and classified according to geographical location number of inhabitants key services and current electrification system. Then 138 suitable installation sites are pinpointed through a multiple-step sorting procedure and finally 10 reference islands are identified as representative case studies. A site-specific methodology is applied to estimate the electrical load profiles of all the selected reference islands. An optimization framework is then developed to determine the optimal system configuration that minimizes the levelized cost of electricity (LCOE) while ensuring a reliable 100% renewable power supply. The LCOE of the RES-based energy systems range from 0.21 to 0.63 €/kWh and a clear linear correlation with the wind farm capacity factor is observed (R2 equal to 0.87). Hydrogen is found to be crucial to prevent the oversizing of the RES generators and batteries and ensure long-term storage capacity. The techno-economic feasibility of alternative electrification strategies is also investigated: the use of diesel generators is not economically viable (0.87–1.04 €/kWh) while the profitability of submarine cable connections is highly dependent on the cable length and the annual electricity consumption (0.14–1.47 €/kWh). Overall the cost-effectiveness of RES-based energy systems for off-grid locations in Northern Europe can be easily assessed using the correlations derived in this analysis.
A New Generation of Hydrogen-Fueled Hybrid Propulsion Systems for the Urban Mobility of the Future
Dec 2023
Publication
The H2-ICE project aims at developing through numerical simulation a new generation of hybrid powertrains featuring a hydrogen-fueled Internal Combustion Engine (ICE) suitable for 12 m urban buses in order to provide a reliable and cost-effective solution for the abatement of both CO2 and criteria pollutant emissions. The full exploitation of the potential of such a traction system requires a substantial enhancement of the state of the art since several issues have to be addressed. In particular the choice of a more suitable fuel injection system and the control of the combustion process are extremely challenging. Firstly a high-fidelity 3D-CFD model will be exploited to analyze the in-cylinder H2 fuel injection through supersonic flows. Then after the optimization of the injection and combustion process a 1D model of the whole engine system will be built and calibrated allowing the identification of a “sweet spot” in the ultra-lean combustion region characterized by extremely low NOx emissions and at the same time high combustion efficiencies. Moreover to further enhance the engine efficiency well above 40% different Waste Heat Recovery (WHR) systems will be carefully scrutinized including both Organic Rankine Cycle (ORC)-based recovery units as well as electric turbo-compounding. A Selective Catalytic Reduction (SCR) aftertreatment system will be developed to further reduce NOx emissions to near-zero levels. Finally a dedicated torque-based control strategy for the ICE coupled with the Energy Management Systems (EMSs) of the hybrid powertrain both optimized by exploiting Vehicle-To-Everything (V2X) connection allows targeting H2 consumption of 0.1 kg/km. Technologies developed in the H2-ICE project will enhance the know-how necessary to design and build engines and aftertreatment systems for the efficient exploitation of H2 as a fuel as well as for their integration into hybrid powertrains.
Carbon Footprint Enhancement of an Agricultural Telehandler through the Application of a Fuel Cell Powertrain
Mar 2024
Publication
The growing awareness about climate change and environmental pollution is pushing the industrial and academic world to investigate more sustainable solutions to reduce the impact of anthropic activities. As a consequence a process of electrification is involving all kind of vehicles with a view to gradually substitute traditional powertrains that emit several pollutants in the exhaust due to the combustion process. In this context fuel cell powertrains are a more promising strategy with respect to battery electric alternatives where productivity and endurance are crucial. It is important to replace internal combustion engines in those vehicles such as the those in the sector of NonRoad Mobile Machinery. In the present paper a preliminary analysis of a fuel cell powertrain for a telehandler is proposed. The analysis focused on performance fuel economy durability applicability and environmental impact of the vehicle. Numerical models were built in MATLAB/Simulink and a simple power follower strategy was developed with the aim of reducing components degradation and to guarantee a charge sustaining operation. Simulations were carried out regarding both peak power conditions and a typical real work scenario. The simulations’ results showed that the fuel cell powertrain was able to achieve almost the same performances without excessive stress on its components. Indeed a degradation analysis was conducted showing that the fuel cell system can achieve satisfactory durability. Moreover a Well-to-Wheel approach was adopted to evaluate the benefits in terms of greenhouse gases of adopting the fuel cell system. The results of the analysis demonstrated that even if considering grey hydrogen to feed the fuel cell system the proposed powertrain can reduce the equivalent CO2 emissions of 69%. This reduction can be further enhanced using hydrogen from cleaner production processes. The proposed preliminary analysis demonstrated that fuel cell powertrains can be a feasible solution to substitute traditional systems on off-road vehicles even if a higher investment cost might be required.
Energy Performance Assessment of a Solar-driven Thermochemical Cycle Device for Green Hydrogen Production
Sep 2023
Publication
This paper presents a novel dynamic simulation model for assessing the energy performance of solar-driven systems employed in green hydrogen production. The system consists of a parabolic dish collector that focuses solar radiation on two cerium-based thermochemical reactors. The model is based on a transient finitedifference method to simulate the thermal behaviour of the system and it integrates a theoretical analysis of materials and operating principles. Different empirical data were considered for experimentally validating it: a good agreement between experimental and simulated results was obtained for the temperatures calculated inside the thermochemical reactor (R2 = 0.99 MAPE = 6.3%) and the hourly flow rates of hydrogen oxygen and carbon monoxide (R2 = 0.96 MAPE = 10%) inside the thermochemical reactor. The model was implemented in a MatLab tool for the system dynamic analysis under different boundary conditions. Subsequently to explore the capability of this approach the developed tool was used for analysing the examined device operating in twelve different weather zones. The obtained results comprise heat maps of specific crucial instants and hourly dynamic trends showing redox reaction cycles occurring into the thermochemical reactors. The yearly hydrogen production ranges from 1.19 m3 /y to 1.64 m3 /y according to the hourly incident solar radiations outdoor air temperatures and wind speeds. New graphic tools for rapid feasibility studies are presented. The developed tools and the obtained results can be useful to the basic design of this technology and for the multi-objective optimization of its layout and main design/operating parameters.
Optimal Decarbonization Strategies for an Industrial Port Area by Using Hydrogen as Energy Carrier
Jul 2023
Publication
This article discusses possible strategies for decarbonizing the energy systems of an existing port. The approach consists in creating a complete superstructure that includes the use of renewable and fossil energy sources the import or local production of hydrogen vehicles and other equipment powered by Diesel electricity or hydrogen and the associated refuelling and storage units. Two substructures are then identified one including all these options the other considering also the addition of the energy demand of an adjacent steel industry. The goal is to select from each of these two substructures the most cost-effective configurations for 2030 and 2050 that meet the emission targets for those years under different cost scenarios for the energy sources and conversion/storage units obtained from the most reliable forecasts found in the literature. To this end the minimum total cost of all the energy conversion and storage units plus the associated infrastructures is sought by setting up a Mixed Integer Linear Programming optimization problem where integer variables handle the inclusion of the different generation and storage units and their activation in the operational phases. The comprehensive picture of possible solutions set allows identifying which options can most realistically be realized in the years to come in relation to the different assumed cost scenarios. Optimization results related to the scenario projected to 2030 indicate the key role played by Diesel hybrid and electric systems while considering the most stringent or much more stringent scenarios for emissions in 2050 almost all vehicles energy demand and industry hydrogen demand is met by hydrogen imported as ammonia by ship.
Hydrogen Combustion: Features and Barriers to Its Exploitation in the Energy Transition
Oct 2023
Publication
The aim of this article is to review hydrogen combustion applications within the energy transition framework. Hydrogen blends are also included from the well-known hydrogen enriched natural gas (HENG) to the hydrogen and ammonia blends whose chemical kinetics is still not clearly defined. Hydrogen and hydrogen blends combustion characteristics will be firstly summarized in terms of standard properties like the laminar flame speed and the adiabatic flame temperature but also evidencing the critical role of hydrogen preferential diffusion in burning rate enhancement and the drastic reduction in radiative emission with respect to natural gas flames. Then combustion applications in both thermo-electric power generation (based on internal combustion engines i.e. gas turbines and piston engines) and hard-to-abate industry (requiring high-temperature kilns and furnaces) sectors will be considered highlighting the main issues due to hydrogen addition related to safety pollutant emissions and potentially negative effects on industrial products (e.g. glass cement and ceramic).
Hierarchical Model Predictive Control for Islanded and Grid-connected Microgrids with Wind Generation and Hydrogen Energy Storage Systems
Aug 2023
Publication
This paper presents a novel energy management strategy (EMS) to control a wind-hydrogen microgrid which includes a wind turbine paired with a hydrogen-based energy storage system (HESS) i.e. hydrogen production storage and re-electrification facilities and a local load. This complies with the mini-grid use case as per the IEA-HIA Task 24 Final Report where three different use cases and configurations of wind farms paired with HESS are proposed in order to promote the integration of wind energy into the grid. Hydrogen production surpluses by wind generation are stored and used to provide a demand-side management solution for energy supply to the local and contractual loads both in the grid-islanded and connected modes with corresponding different control objectives. The EMS is based on a hierarchical model predictive control (MPC) in which long-term and short-term operations are addressed. The long-term operations are managed by a high-level MPC in which power production by wind generation and load demand forecasts are considered in combination with day-ahead market participation. Accordingly the hydrogen production and re-electrification are scheduled so as to jointly track the load demand maximize the revenue through electricity market participation and minimize the HESS operating costs. Instead the management of the short-term operations is entrusted to a low-level MPC which compensates for any deviations of the actual conditions from the forecasts and refines the power production so as to address the real-time market participation and the short time-scale equipment dynamics and constraints. Both levels also take into account operation requirements and devices’ operating ranges through appropriate constraints. The mathematical modeling relies on the mixed-logic dynamic (MLD) framework so that the various logic states and corresponding continuous dynamics of the HESS are considered. This results in a mixed-integer linear program which is solved numerically. The effectiveness of the controller is analyzed by simulations which are carried out using wind forecasts and spot prices of a wind farm in center-south of Italy.
Assessment of Paper Industry Decarbonization Potential via Hydrogen in a Multi-energy System Scenario: A Case Study
Jul 2023
Publication
Green hydrogen is currently regarded as a key catalyst for the decarbonization of energy-intensive industries. In this context the pulp and paper industry stands out as one of the most demanding given the simultaneous need for large amounts of heat and electricity usually satisfied via cogeneration systems. Given the urgent need for cost-effective solutions in response to the climate crisis it is crucial to analyze the feasibility of retrofitting existing power plants to operate carbon-neutral. The aim of this work is to provide a techno-economic analysis for the conversion of a conventional cogeneration system to run on locally produced hydrogen. Building on the energy consumption of the paper mill the operation of a hydrogen-fuelled gas turbine is modelled in detail. Based on these results a multi-energy system model for the production of green fuel is presented considering production via solar-powered PEM electrolyzers storage in tanks and final use in the gas turbine. An optimal configuration for the system is defined leading to the definition of a solution that ensures a cost of 6.41 /kg for the production of green hydrogen. Finally a sensitivity analysis highlights the close dependence of the economic profitability of the Power-to-X system on the natural gas price. The results indicate that although positive performance is achieved the cost of investment remains still prohibitive for systems of this size and the high initial capital expenditure needs to be supported by incentive policies that facilitate the adoption of hydrogen in industrial applications making it competitive in the short term.
Numerical Analysis of Dual Fuel Combustion in a Medium Speed Marine Engine Supplied with Methane/Hydrogen Blends
Sep 2023
Publication
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.
Modelling Methodologies to Design and Control Renewables and Hydrogen-Based Telecom Towers Power Supply Systems
Aug 2023
Publication
Proton exchange membrane fuel cell (PEMFCS) and electrolyser (PEMELS) systems together with a hydrogen storage tank (HST) are suitable to be integrated with renewable microgrids to cover intermittency and fully exploit the excess of electrical energy. Such an integration perfectly fits telecom tower power supply needs both in off-grid and grid-connected sites. In this framework a model-based tool enabling both optimal sizing and proper year-through energy management of both the above applications is proposed. Respectively the islanded optimisation is performed considering two economic indices i.e. simple payback (SPB) and levelised cost of energy (LCOE) together with two strategies of hydrogen tank management charge sustaining and depleting and also accounting for the impact of grid extension distance. On the other hand the grid connection is addressed through the dynamic programming method while downsizing PEMELS and HST sizes to improve techno-economic effectiveness thanks to grid contribution towards renewables curtailment issues mitigation. For both the above introduced HST management strategies a reduction of more than 70% of the nominal PEMELS power and 90% of the HST size which will in turn lead to SPB and LCOE being reduced by 80% and 60% in comparison to the islanded case respectively is achieved. Furthermore the charge depleting strategy relying on possible hydrogen purchase interestingly provides an SPB and LCOE of 9% and 7% lower than the charge sustaining one.
Energy and Greenhouse Gases Life Cycle Assessment of Electric and Hydrogen Buses: A Real-world Case Study in Bolzano Italy
May 2023
Publication
The transportation sector plays an important role in the current effort towards the control of global warming. Against this backdrop electrification is currently attracting attention as the life cycle environmental performance of different powertrain technologies is critically assessed. In this study a life cycle analysis of the public transportation buses was performed. The scope of the analysis is to compare the energy and global warming performances of the different powertrain technologies in the city fleet: diesel full electric and hydrogen buses. Real world monitored data were used in the analysis for the energy consumptions of the buses and to produce hydrogen in Bolzano. Compared to the traditional diesel buses the electric vehicles showed a 43% reduction of the non-renewable primary energy demand and a 33% of the global warming potential even in the worst consequential scenario considered. The switch to hydrogen buses leads to very different environmental figures: from very positive if it contributes to a further penetration of renewable electricity to hardly any difference if hydrogen from steam-methane reforming is used to clearly negative ones (approximately doubling the impacts) if a predominantly fossil electricity mix is used in the electrolysis.
Assessing Sizing Optimality of OFF-GRID AC-Linked Solar PV-PEM Systems for Hydrogen Production
Jul 2023
Publication
Herein a novel methodology to perform optimal sizing of AC-linked solar PV-PEM systems is proposed. The novelty of this work is the proposition of the solar plant to electrolyzer capacity ratio (AC/AC ratio) as optimization variable. The impact of this AC/AC ratio on the Levelized Cost of Hydrogen (LCOH) and the deviation of the solar DC/AC ratio when optimized specifically for hydrogen production are quantified. Case studies covering a Global Horizontal Irradiation (GHI) range of 1400e2600 kWh/m2 -year are assessed. The obtained LCOHs range between 5.9 and 11.3 USD/kgH2 depending on sizing and location. The AC/AC ratio is found to strongly affect cost production and LCOH optimality while the optimal solar DC/AC ratio varies up to 54% when optimized to minimize the cost of hydrogen instead of the cost of energy only. Larger oversizing is required for low GHI locations; however H2 production is more sensitive to sizing ratios for high GHI locations.
Italian Offshore Platform and Depleted Reservoir Conversion in the Energy Transition Perspective
Aug 2023
Publication
New hypotheses for reusing platforms reaching their end-of-life have been investigated in several works discussing the potential conversions of these infrastructures from recreational tourism to fish farming. In this perspective paper we discuss the conversion options that could be of interest in the context of the current energy transition with reference to the off-shore Italian scenario. The study was developed in support of the development of a national strategy aimed at favoring a circular economy and the reuse of existing infrastructure for the implementation of the energy transition. Thus the investigated options include the onboard production of renewable energy hydrogen production from seawater through electrolyzers CO2 capture and valorization and platform reuse for underground fluid storage in depleted reservoirs once produced through platforms. Case histories are developed with reference to a typical fictitious platform in the Adriatic Sea Italy to provide an engineering-based approach to these different conversion options. The coupling of the platform with the underground storage to set the optimal operational conditions is managed through the forecast of the reservoir performance with advanced numerical models able to simulate the complexity of the phenomena occurring in the presence of coupled hydrodynamic geomechanical geochemical thermal and biological processes. The results of our study are very encouraging because they reveal that no technical environmental or safety issues prevent the conversion of offshore platforms into valuable infrastructure contributing to achieving the energy transition targets as long as the selection of the conversion option to deploy is designed taking into account the system specificity and including the depleted reservoir to which it is connected when relevant. Socio-economic issues were not investigated as they were out of the scope of the project.
Assessing Techno-economic Feasibility of Cogeneration and Power to Hydrogen Plants: A Novel Dynamic Simulation Model
Aug 2023
Publication
Green hydrogen technologies are crucial for decarbonization purposes while cogeneration offers efficient heat and power generation. Integrating green hydrogen and cogeneration brings numerous benefits optimizing energy utilization reducing emissions and supporting the transition to a sustainable future. While there are numerous studies examining the integration of combined heat and power with Power to Gas certain aspects still requires a more detailed analysis especially for internal combustion engines fuelled by natural gas due to their widespread adoption as one of the primary technologies in use. Therefore this paper presents a comprehensive numerical 0-D dynamic simulation model implemented within the TRNSYS environment considering internal combustion engines fuelled by natural gas. Specifically the study focuses on capturing CO2 from exhaust gases and producing green hydrogen from electrolysis. Based on these considerations two configurations are proposed: the first involves the methanation reaction while the second entails the production of a hydromethane mixture. The aim is to evaluate the technical and economic feasibility of these configurations and compare their performance within the Power to Gas framework. Self-sufficiency from the national electricity grid has been almost achieved for the two configurations considering an industrial case. The production of hydromethane allows smaller photovoltaic plant (81 kWp) compared to the production of synthetic methane (670 kWp) where a high quantity of hydrogen is required especially if all the carbon dioxide captured is used in the methanation process. Encouraging economic results with payback times below ten years have been obtained with the use of hydromethane. Moreover hydromethane shows potential residential applications with small required photovoltaic sizes.
Thermal Design and Heat Transfer Optimisation of a Liquid Organic Hydrogen Carrier Batch Reactor for Hydrogen Storage
Aug 2023
Publication
Liquid organic hydrogen carriers (LOHCs) are considered a promising hydrogen storage technology. Heat must be exchanged with an external medium such as a heat transfer fluid for the required chemical reactions to occur. Batch reactors are simple but useful solutions for small-scale storage applications which can be modelled with a lumped parameter approach adequately reproducing their dynamic performance. For such reactors power is consumed to circulate the external heat transfer fluid and stir the organic liquid inside the reactor and heat transfer performance and power consumption are two key parameters in reactor optimisation. Therefore with reference to the hydrogen release phase this paper describes a procedure to optimise the reactor thermal design based on a lumped-parameter model in terms of heat transfer performance and minimum power consumption. Two batch reactors are analysed: a conventional jacketed reactor with agitation nozzles and a half-pipe coil reactor. Heat transfer performance is evaluated by introducing a newly defined dimensionless parameter the Heat Transfer Ratio (HTR) whose value directly correlates to the heat rate required by the carrier's dehydrogenation reaction. The resulting model is a valid tool for adequately reproducing the hydrogen storage behaviour within dynamic models of complex and detailed energy systems.
Hydrogen Production from Renewable Energy Resources: A Case Study
May 2024
Publication
In the face of increasing demand for hydrogen a feasibility study is conducted on its production by using Renewable Energy Resources (RERs) especially from wind and solar sources with the latter preferring photovoltaic technology. The analysis performed is based on climate data for the Province of Brindisi Apulia Italy. The various types of electrolyzers will be analyzed ultimately choosing the one that best suits the case study under consideration. The technical aspect of the land consumption for RER exploitation until 2050 is analyzed for the Italian case of study and for the Apulia Region. For both the 200 MW and 100 MW RER Power Plants an economic analysis is carried out on the opportunities for using hydrogen. In the last part of the economic analysis the trade-off between the high specific investment cost and the Capacity Factor of Wind technologies is also investigated. The results show the affordability of building high-scale Wind Farms harnessing the existing scale economies. The lowest Hydrogen selling price is achieved by the 200 MW Wind Farms equal to 222 €/MWh against 232 €/MWh of the 200 MW Photovoltaic (PV) Farm. Finally the feasibility analysis considers also the greenhouse gas emission reduction by including in the economic analysis the carbon dioxide (CO2) Average Auction Clearing Price leading for the 200 MW Wind Farms to a hydrogen selling price equal to 191.2 €/MWh against 201 €/MWh of the 200 MW Photovoltaic Farm.
Assessing Opportunities and Weaknesses of Green Hydrogen Transport via LOHC through a Detailed Techno-economic Analysis
Aug 2023
Publication
In the transition towards a more sustainable energy system hydrogen is seen as the key low-emission energy source. However the limited H2 volumetric density hinders its transportation. To overcome this issue liquid organic hydrogen carriers (LOHCs) molecules that can be hydrogenated and upon arrival dehydrogenated for H2 release have been proposed as hydrogen transport media. Considering toluene and dibenzyltoluene as representative carriers this work offers a systematic methodology for the analysis and the comparison of LOHCs in view of identifying cost-drivers of the overall value-chain. A detailed Aspen Plus process simulation is provided for hydrogenation and dehydrogenation sections. Simulation results are used as input data for the economic assessment. The process economics reveals that dehydrogenation is the most impactful cost-item together with the carrier initial loading the latter related to the LOHC transport distance. The choice of the most suitable molecule as H2 carrier ultimately is a trade-off between its hydrogenation enthalpy and cost.
The Economic Impact and Carbon Footprint Dependence of Energy Management Strategies in Hydrogen-Based Microgrids
Sep 2023
Publication
This paper presents an economic impact analysis and carbon footprint study of a hydrogenbased microgrid. The economic impact is evaluated with respect to investment costs operation and maintenance (O&M) costs as well as savings taking into account two different energy management strategies (EMSs): a hydrogen-based priority strategy and a battery-based priority strategy. The research was carried out in a real microgrid located at the University of Huelva in southwestern Spain. The results (which can be extrapolated to microgrids with a similar architecture) show that although both strategies have the same initial investment costs (EUR 52339.78) at the end of the microgrid lifespan the hydrogen-based strategy requires higher replacement costs (EUR 74177.4 vs. 17537.88) and operation and maintenance costs (EUR 35254.03 vs. 34877.08) however it provides better annual savings (EUR 36753.05 vs. 36282.58) and a lower carbon footprint (98.15% vs. 95.73% CO2 savings) than the battery-based strategy. Furthermore in a scenario where CO2 emission prices are increasing the hydrogen-based strategy will bring even higher annual cost savings in the coming years.
Gas Turbine Combustion Technologies for Hydrogen Blends
Sep 2023
Publication
The article reviews gas turbine combustion technologies focusing on their current ability to operate with hydrogen enriched natural gas up to 100% H2. The aim is to provide a picture of the most promising fuel-flexible and clean combustion technologies the object of current research and development. The use of hydrogen in the gas turbine power generation sector is initially motivated highlighting both its decarbonisation and electric grid stability objectives; moreover the state-of-the-art of hydrogen-blend gas turbines and their 2024 and 2030 targets are reported in terms of some key performance indicators. Then the changes in combustion characteristics due to the hydrogen enrichment of natural gas blends are briefly described from their enhanced reactivity to their pollutant emissions. Finally gas turbine combustion strategies both already commercially available (mostly based on aerodynamic flame stabilisation self-ignition and staging) or still under development (like the micro-mixing and the exhaust gas recirculation concepts) are described.
Performance Analysis of a Diabatic Compressed Air Energy Storage System Fueled with Green Hydrogen
Oct 2023
Publication
The integration of an increasing share of Renewable Energy Sources (RES) requires the availability of suitable energy storage systems to improve the grid flexibility and Compressed Air Energy Storage (CAES) systems could be a promising option. In this study a CO2 -free Diabatic CAES system is proposed and analyzed. The plant configuration is derived from a down-scaled version of the McIntosh Diabatic CAES plant where the natural gas is replaced with green hydrogen produced on site by a Proton Exchange Membrane electrolyzer powered by a photovoltaic power plant. In this study the components of the hydrogen production system are sized to maximize the self-consumption share of PV energy generation and the effect of the design parameters on the H2 -CAES plant performance are analyzed on a yearly basis. Moreover a comparison between the use of natural gas and hydrogen in terms of energy consumption and CO2 emissions is discussed. The results show that the proposed hydrogen fueled CAES can effectively match the generation profile and the yearly production of the natural gas fueled plant by using all the PV energy production while producing zero CO2 emissions.
Suitability and Energy Sustainability of Atmospheric Water Generation Technology for Green Hydrogen Production
Sep 2023
Publication
This research investigated the suitability of air-to-water generator (AWG) technology to address one of the main concerns in green hydrogen production namely water supply. This study specifically addresses water quality and energy sustainability issues which are crucial research questions when AWG technology is intended for electrolysis. To this scope a reasoned summary of the main findings related to atmospheric water quality has been provided. Moreover several experimental chemical analyses specifically focused on meeting electrolysis process requirements on water produced using a real integrated AWG system equipped with certified materials for food contact were discussed. To assess the energy sustainability of AWGs in green hydrogen production a case study was presented regarding an electrolyzer plant intended to serve as energy storage for a 2 MW photovoltaic field on Iriomote Island. The integrated AWG used for the water quality analyses was studied in order to determine its performance in the specific island climate conditions. The production exceeded the needs of the electrolyzer; thus the overproduction was considered for the panels cleaning due to the high purity of the water. Due to such an operation the efficiency recovery was more than enough to cover the AWG energy consumption. This paper on the basis of the quantity results provides the first answers to the said research questions concerning water quality and energy consumption establishing the potential of AWG as a viable solution for addressing water scarcity and enhancing the sustainability of electrolysis processes in green hydrogen production.
The Role of Hydrogen in a Decarbonised Future Transport Sector: A Case Study of Mexico
Sep 2023
Publication
In recent years several approaches and pathways have been discussed to decarbonise the transport sector; however any effort to reduce emissions might be complex due to specific socio-economic and technical characteristics of different regions. In Mexico the transport sector is the highest energy consumer representing 38.9% of the national final energy demand with gasoline and diesel representing 90% of the sector´s total fuel consumption. Energy systems models are powerful tools to obtain insights into decarbonisation pathways to understand costs emissions and rate of deployment that could serve for energy policy development. This paper focuses on the modelling of the current Mexican transport system using the MUSE-MX multi-regional model with the aim to project a decarbonisation pathway through two different scenarios. The first approach being business as usual (BAU) which aims to analyse current policies implementation and the second being a goal of net zero carbon emissions by 2050. Under the considered net zero scenario results show potential deployment of hydrogen-based transport technologies especially for subsectors such as lorries (100% H2 by 2050) and freight train (25% H2 by 2050) while cars and buses tend to full electrification by 2050.
Modelling Large-scale Hydrogen Uptake in the Mexican Refinery and Power Sectors
Sep 2023
Publication
Due to the emissions reduction commitments that Mexico compromised in the Paris Agreement several clean fuel and renewable energy technologies need to penetrate the market to accomplish the environmental goals. Therefore there is a need to develop achievable and realistic policies for such technologies to ease the decision-making on national energy strategies. Several countries are starting to develop large-scale green hydrogen production projects to reduce the carbon footprint of the multiple sectors within the country. The conversion sectors namely power and refinery are fundamental sectors to decarbonise due to their energy supply role. Nowadays the highest energy consumables of the country are hydrocarbons (more than 90%) causing a particular challenge for deep decarbonisation. The purpose of this study is to use a multi-regional energy system model of Mexico to analyse a decarbonisation scenario in line with the latest National Energy System Development Program. Results show that if the country wants to succeed in reducing 22% of its GHG emissions and 51% of its short-lived climate pollutants emissions green hydrogen could play a role in power generation in regions with higher energy demand growth rates. These results show regarding the power sector that H2 could represent 13.8 GW or 5.1% of the total installed capacity by 2050 while for the refinery sector H2 could reach a capacity of 157 PJ/y which is around 31.8% of the total share and it is mainly driven by the increasing demands of the transport industry and power sectors. Nevertheless as oil would still represent the largest energy commodity CCS technologies would have to be deployed for new and retrofitted refinery facilities.
The Potential Role of Ammonia for Hydrogen Storage and Transport: A Critical Review of Challenges and Opportunities
Aug 2023
Publication
Hydrogen is being included in several decarbonization strategies as a potential contributor in some hard-to-abate applications. Among other challenges hydrogen storage represents a critical aspect to be addressed either for stationary storage or for transporting hydrogen over long distances. Ammonia is being proposed as a potential solution for hydrogen storage as it allows storing hydrogen as a liquid chemical component at mild conditions. Nevertheless the use of ammonia instead of pure hydrogen faces some challenges including the health and environmental issues of handling ammonia and the competition with other markets such as the fertilizer market. In addition the technical and economic efficiency of single steps such as ammonia production by means of the Haber–Bosch process ammonia distribution and storage and possibly the ammonia cracking process to hydrogen affects the overall supply chain. The main purpose of this review paper is to shed light on the main aspects related to the use of ammonia as a hydrogen energy carrier discussing technical economic and environmental perspectives with the aim of supporting the international debate on the potential role of ammonia in supporting the development of hydrogen pathways. The analysis also compares ammonia with alternative solutions for the long-distance transport of hydrogen including liquefied hydrogen and other liquid organic carriers such as methanol.
Dynamic Simulation and Thermoeconomic Analysis of a Power to Gas System
Sep 2023
Publication
Power to gas technology is an innovative solution to promote the use of renewable energy technologies also including e-fuels. This work presents a techno-economic analysis of a novel concept of a renewable power to gas plant. A 2.4 MW solid oxide electrolyzer fed by a 3.1 MW photovoltaic field is coupled with a biomethane production unit to produce synthetic methane by means of a 2.4 MW methanation unit. The hydrogen produced by the electrolyzer is used for the methanation reaction aiming at producing natural gas at net zero carbon emissions. The CO2 is obtained as a byproduct of the membrane separation in a biogas upgrading unit. The methanation unit and the electrolyzer models are developed in MatLab and integrated in TRNSYS to perform a dynamic simulation of all the components and the system as a whole. Dynamic simulation results show a 42% increase in the production of natural gas from renewable energy sources. The thermoeconomic analysis shows a remarkable primary energy saving index of 176% and a total amount of 896 tons of CO2 equivalent emissions saved. As expected the critical point is the economic feasibility since the simple payback is 9 years in case local incentives and subsidies are considered. The parametric analysis on the photovoltaic capacity shows that the simple payback dramatically depends on such design parameter varying from 6 years in the best case scenario to 92 years in the worst case scenario.
Life Cycle Assessments Use in Hydrogen-related Policies: The Case for a Harmonized Methodology Addressing Multifunctionality
May 2024
Publication
Legislation regulating the sustainability requirements for hydrogen technologies relies more and more on life cycle assessments (LCAs). Due to different scopes and development processes different pieces of EU legislation refer to different LCA methodologies with differences in the way multifunctional processes (i.e. co-productions recycling and energy recovery) are treated. These inconsistencies arise because incentive mechanisms are not standardized across sectors even though the end product hydrogen remains the same. The goal of this paper is to compare the life-cycle greenhouse gas (GHG) emissions of hydrogen from four production pathways depending on the multifunctional approach prescribed by the different EU policies (e.g. using substitution or allocation). The study reveals a large variation in the LCA results. For instance the life-cycle GHG emissions of hydrogen co-produced with methanol is found to vary from 1 kg CO2-equivalent/kg H2 (when mass allocation is considered) to 11 kg CO2-equivalent/kg H2 (when economic allocation is used). These inconsistencies could affect the market (e.g. hydrogen from a certain pathway could be considered sustainable or unsustainable depending on the approach) and the environment (e.g. pathways that do not lead to a global emission reduction could be promoted). To mitigate these potential negative effects we urge for harmonized and strict guidelines to assess the life-cycle GHG emissions of hydrogen technologies in an EU policy context. Harmonization should cover international policies too to avoid the same risks when hydrogen will be traded based on its GHG emissions. The appropriate methodological approach for each production pathway should be chosen by policymakers in collaboration with the LCA community and stakeholders from the industry based on the potential market and environmental consequences of such choice.
Proton Exchange Membrane Electrolyzer Modeling for Power Electronics Control: A Short Review
May 2020
Publication
The main purpose of this article is to provide a short review of proton exchange membrane electrolyzer (PEMEL) modeling used for power electronics control. So far three types of PEMEL modeling have been adopted in the literature: resistive load static load (including an equivalent resistance series-connected with a DC voltage generator representing the reversible voltage) and dynamic load (taking into consideration the dynamics both at the anode and the cathode). The modeling of the load is crucial for control purposes since it may have an impact on the performance of the system. This article aims at providing essential information and comparing the different load modeling.
Feasibility Assessment of Alternative Clean Power Systems onboard Passenger Short-Distance Ferry
Sep 2023
Publication
In order to promote low-carbon fuels such as hydrogen to decarbonize the maritime sector it is crucial to promote clean fuels and zero-emission propulsion systems in demonstrative projects and to showcase innovative technologies such as fuel cells in vessels operating in local public transport that could increase general audience acceptability thanks to their showcase potential. In this study a short sea journey ferry used in the port of Genova as a public transport vehicle is analyzed to evaluate a ”zero emission propulsion” retrofitting process. In the paper different types of solutions (batteries proton exchange membrane fuel cell (PEMFC) solid oxide fuel cell (SOFC)) and fuels (hydrogen ammonia natural gas and methanol) are investigated to identify the most feasible technology to be implemented onboard according to different aspects: ferry daily journey and scheduling available volumes and spaces propulsion power needs energy storage/fuel tank capacity needed economics etc. The paper presents a multi-aspect analysis that resulted in the identification of the hydrogen-powered PEMFC as the best clean power system to guarantee for this specific case study a suitable retrofitting of the vessel that could guarantee a zero-emission journey
Monitored Data and Social Perceptions Analysis of Battery Electric and Hydrogen Fuelled Buses in Urban and Suburban Areas
Jul 2023
Publication
Electrification of the transportation sector is one of the main drivers in the decarbonization of energy and mobility systems and it is a way to ensure security of energy supply. Public bus fleets can assist in achieving fast reduction of CO2 emissions. This article provides an analysis of a unique real-world dataset to support decision makers in the decarbonization of public fleets and interlink it with the social acceptance of drivers. Data was collected from 21 fuel cell and electric buses. The tank-to-wheel efficiency results of fuel cell electric buses (FCEB) are much lower than that of battery electric buses (BEB) and there is a higher variation in consumption for BEBs compared to FCEBs. Both technologies permit a strong reduction in CO2 emissions compared to conventional buses. There is a high level of acceptance of drivers which are likely to support the transition towards zero-emission buses introduced by the management.
A Review of the MSCA ITN ECOSTORE—Novel Complex Metal Hydrides for Efficient and Compact Storage of Renewable Energy as Hydrogen and Electricity
Mar 2020
Publication
Hydrogen as an energy carrier is very versatile in energy storage applications. Developments in novel sustainable technologies towards a CO2-free society are needed and the exploration of all-solid-state batteries (ASSBs) as well as solid-state hydrogen storage applications based on metal hydrides can provide solutions for such technologies. However there are still many technical challenges for both hydrogen storage material and ASSBs related to designing low-cost materials with low-environmental impact. The current materials considered for all-solid-state batteries should have high conductivities for Na+ Mg2+ and Ca2+ while Al3+-based compounds are often marginalised due to the lack of suitable electrode and electrolyte materials. In hydrogen storage materials the sluggish kinetic behaviour of solid-state hydride materials is one of the key constraints that limit their practical uses. Therefore it is necessary to overcome the kinetic issues of hydride materials before discussing and considering them on the system level. This review summarizes the achievements of the Marie Skłodowska-Curie Actions (MSCA) innovative training network (ITN) ECOSTORE the aim of which was the investigation of different aspects of (complex) metal hydride materials. Advances in battery and hydrogen storage materials for the efficient and compact storage of renewable energy production are discussed.
Hydrogen vs. Battery in the Long-term Operation. A Comparative Between Energy Management Strategies for Hybrid Renewable Microgrids
Apr 2020
Publication
The growth of the world’s energy demand over recent decades in relation to energy intensity and demography is clear. At the same time the use of renewable energy sources is pursued to address decarbonization targets but the stochasticity of renewable energy systems produces an increasing need for management systems to supply such energy volume while guaranteeing at the same time the security and reliability of the microgrids. Locally distributed energy storage systems (ESS) may provide the capacity to temporarily decouple production and demand. In this sense the most implemented ESS in local energy districts are small–medium-scale electrochemical batteries. However hydrogen systems are viable for storing larger energy quantities thanks to its intrinsic high mass-energy density. To match generation demand and storage energy management systems (EMSs) become crucial. This paper compares two strategies for an energy management system based on hydrogen-priority vs. battery-priority for the operation of a hybrid renewable microgrid. The overall performance of the two mentioned strategies is compared in the long-term operation via a set of evaluation parameters defined by the unmet load storage efficiency operating hours and cumulative energy. The results show that the hydrogen-priority strategy allows the microgrid to be led towards island operation because it saves a higher amount of energy while the battery-priority strategy reduces the energy efficiency in the storage round trip. The main contribution of this work lies in the demonstration that conventional EMS for microgrids’ operation based on battery-priority strategy should turn into hydrogen-priority to keep the reliability and independence of the microgrid in the long-term operation.
Potentialities of Hydrogen Enriched Natural Gas for Residential Heating Decarbonization and Impact Analysis on Premixed Boilers
Sep 2019
Publication
Nowadays decarbonization of energy economy is a topical theme and several pathways are under discussion. Gaseous fuels will play a primary role during this transition and the production of renewable or low carbon-impact gaseous fuels is necessary to deal with this challenge. Decarbonization will be sustained by an increasing share of renewables which production intermittency can be critical for the energy system. Renewable hydrogen generation is a viable solution since this energy vector can be produced from electricity with a fast response and injected in the existing natural gas infrastructures granting storage capacity and easy transport. Parallelly to the renewable-based energy production fossil-based energy can be exploited with a low carbon impact using methane from reservoirs to produce hydrogen capturing CO2. The mentioned scenarios will lead to hydrogen enrichment of natural gas which impact on the infrastructures is being actively studied. The effect on end-user devices instead is poorly analysed but is fundamental to be assessed. This paper highlights the impact on the widely used premixed condensing boilers which will be fired with hydrogen enriched natural gas in the near future and the changes required to components.
Economic Evaluation of Renewable Hydrogen Integration into Steelworks for the Production of Methanol and Methane
Jun 2022
Publication
This work investigates the cost-efficient integration of renewable hydrogen into steelworks for the production of methane and methanol as an efficient way to decarbonize the steel industry. Three case studies that utilize a mixture of steelworks off-gases (blast furnace gas coke oven gas and basic oxygen furnace gas) which differ on the amount of used off-gases as well as on the end product (methane and/or methanol) are analyzed and evaluated in terms of their economic performance. The most influential cost factors are identified and sensitivity analyses are conducted for different operating and economic parameters. Renewable hydrogen produced by PEM electrolysis is the most expensive component in this scheme and responsible for over 80% of the total costs. Progress in the hydrogen economy (lower electrolyzer capital costs improved electrolyzer efficiency and lower electricity prices) is necessary to establish this technology in the future.
Green Hydrogen Production from Raw Biogas: A Techno-Economic Investigation of Conventional Processes Using Pressure Swing Adsorption Unit
Feb 2018
Publication
This paper discusses the techno-economic assessment of hydrogen production from biogas with conventional systems. The work is part of the European project BIONICO whose purpose is to develop and test a membrane reactor (MR) for hydrogen production from biogas. Within the BIONICO project steam reforming (SR) and autothermal reforming (ATR) have been identified as well-known technologies for hydrogen production from biogas. Two biogases were examined: one produced by landfill and the other one by anaerobic digester. The purification unit required in the conventional plants has been studied and modeled in detail using Aspen Adsorption. A pressure swing adsorption system (PSA) with two and four beds and a vacuum PSA (VPSA) made of four beds are compared. VPSA operates at sub-atmospheric pressure thus increasing the recovery: results of the simulations show that the performances strongly depend on the design choices and on the gas feeding the purification unit. The best purity and recovery values were obtained with the VPSA system which achieves a recovery between 50% and 60% at a vacuum pressure of 0.1 bar and a hydrogen purity of 99.999%. The SR and ATR plants were designed in Aspen Plus integrating the studied VPSA model and analyzing the behavior of the systems at the variation of the pressure and the type of input biogas. The SR system achieves a maximum efficiency calculated on the LHV of 52% at 12 bar while the ATR of 28% at 18 bar. The economic analysis determined a hydrogen production cost of around 5 €/kg of hydrogen for the SR case.
Sizing and Performance Analysis of Hydrogen- and Battery-Based Powertrains, Integrated into a Passenger Train for a Regional Track, Located in Calabria (Italy)
Aug 2022
Publication
In order to decarbonize the rail industry the development of innovative locomotives with the ability to use multiple energy sources constituting hybrid powertrains plays a central role in transitioning from conventional diesel trains. In this paper four configurations based on suitable combinations of fuel cells and/or batteries are designed to replace or supplement a diesel/overhead line powertrain on a real passenger train (the Hitachi Blues) tested on an existing regional track the Catanzaro Lido–Reggio Calabria line (Italy) managed by Trenitalia SpA. (Italy). The configurations (namely battery–electrified line full-battery fuel cell–battery–electrified line and fuel cell–battery) are first sized with the intention of completing a round trip then integrated on board with diesel engine replacement in mind and finally occupy a portion of the passenger area within two locomotives. The achieved performance is thoroughly examined in terms of fuel cell efficiency (greater than 47%) hydrogen consumption (less than 72 kg) braking energy recovery (approximately 300 kWh) and battery interval SOC.
Review and Perspectives of Key Decarbonization Drivers to 2030
Jan 2023
Publication
Global climate policy commitments are encouraging the development of EU energy policies aimed at paving the way for cleaner energy systems. This article reviews key decarbonization drivers for Italy considering higher environmental targets from recent European Union climate policies. Energy efficiency the electrification of final consumption the development of green fuels increasing the share of renewable energy sources in the electric system and carbon capture and storage are reviewed. A 2030 scenario is designed to forecast the role of decarbonization drivers in future energy systems and to compare their implementation with that in the current situation. Energy efficiency measures will reduce final energy consumption by 15.6% as primary energy consumption will decrease by 19.8%. The electrification of final consumption is expected to increase by 6.08%. The use of green fuels is estimated to triple as innovative fuels may go to market at scale to uphold the ambitious decarbonization targets set in the transportation sector. The growing trajectory of renewable sources in the energy mix is confirmed as while power generation is projected to increase by 10% the share of renewables in that generation is expected to increase from 39.08% to 78.16%. Capture and storage technologies are also expected to play an increasingly important role. This article has policy implications and serves as a regulatory reference in the promotion of decarbonization investments.
The Route from Green H2 Production through Bioethanol Reforming to CO2 Catalytic Conversion: A Review
Mar 2022
Publication
Currently a progressively different approach to the generation of power and the production of fuels for the automotive sector as well as for domestic applications is being taken. As a result research on the feasibility of applying renewable energy sources to the present energy scenario has been progressively growing aiming to reduce greenhouse gas emissions. Following more than one approach the integration of renewables mainly involves the utilization of biomass-derived raw material and the combination of power generated via clean sources with conventional power generation systems. The aim of this review article is to provide a satisfactory overview of the most recent progress in the catalysis of hydrogen production through sustainable reforming and CO2 utilization. In particular attention is focused on the route that starting from bioethanol reforming for H2 production leads to the use of the produced CO2 for different purposes and by means of different catalytic processes passing through the water–gas shift stage. The newest approaches reported in the literature are reviewed showing that it is possible to successfully produce “green” and sustainable hydrogen which can represent a power storage technology and its utilization is a strategy for the integration of renewables into the power generation scenario. Moreover this hydrogen may be used for CO2 catalytic conversion to hydrocarbons thus giving CO2 added value.
Two-stage Model Predictive Control for a Hydrogen-based Storage System Paired to a Wind Farm Towards Green Hydrogen Production for Fuel Cell Electric Vehicles
Jul 2022
Publication
This study proposes a multi-level model predictive control (MPC) for a grid-connected wind farm paired to a hydrogen-based storage system (HESS) to produce hydrogen as a fuel for commercial road vehicles while meeting electric and contractual loads at the same time. In particular the integrated system (wind farm + HESS) should comply with the “fuel production” use case as per the IEA-HIA report where the hydrogen production for fuel cell electric vehicles (FCEVs) has the highest unconditional priority among all the objectives. Based on models adopting mixed-integer constraints and dynamics the problem of external hydrogen consumer requests optimal load demand tracking and electricity market participation is solved at different timescales to achieve a long-term plan based on forecasts that then are adjusted at real-time. The developed controller will be deployed onto the management platform of the HESS which is paired to a wind farm established in North Norway within the EU funded project HAEOLUS. Numerical analysis shows that the proposed controller efficiently manages the integrated system and commits the equipment so as to comply with the requirements of the addressed scenario. The operating costs of the devices are reduced by 5% which corresponds to roughly 300 commutations saved per year for devices.
Dynamic Electric Simulation Model of a Proton Exchange Membrane Electrolyzer System for Hydrogen Production
Sep 2022
Publication
An energy storage system based on a Proton Exchange Membrane (PEM) electrolyzer system which could be managed by a nanoGrid for Home Applications (nGfHA) is able to convert the surplus of electric energy produced by renewable sources into hydrogen which can be stored in pressurized tanks. The PEM electrolyzer system must be able to operate at variable feeding power for converting all the surplus of renewable electric energy into hydrogen in reasonable time. In this article the dynamic electric simulation model of a PEM electrolyzer system with its pressurized hydrogen tanks is developed in a proper calculation environment. Through the calculation code the stack voltage and current peaks to a supply power variation from the minimum value (about 56 W) to the maximum value (about 440 W) are controlled and zeroed to preserve the stack the best range of the operating stack current is evaluated and hydrogen production is monitored.
Development of a Hydrogen Valley for Exploitation of Green Hydrogen in Central Italy
Oct 2022
Publication
Green hydrogen exploitation plays a crucial role in achieving carbon neutrality by 2050. Hydrogen in fact provides a number of key benefits for the energy system due to its integrability with other clean technologies for energy production and consumption. This paper is aimed at presenting the project of recovery of an abandoned industrial area located in central Italy by developing a site for the production of green hydrogen. To this aim the analysis of the territorial and industrial context of the area allowed us to design the project phases and to define the sizing criteria of the hydrogen production plant. The results of a preliminary cost–benefit analysis show that a huge initial investment is required and that in the short term the project is sustainable only with a very large public grant. On the other hand in the long term the project is sustainable and the benefits significantly overcome the costs.
Dynamic Emulation of a PEM Electrolyzer by Time Constant Based Exponential Model
Feb 2019
Publication
The main objective of this paper is to develop a dynamic emulator of a proton exchange membrane (PEM) electrolyzer (EL) through an equivalent electrical model. Experimental investigations have highlighted the capacitive effect of EL when subjecting to dynamic current profiles which so far has not been reported in the literature. Thanks to a thorough experimental study the electrical domain of a PEM EL composed of 3 cells has been modeled under dynamic operating conditions. The dynamic emulator is based on an equivalent electrical scheme that takes into consideration the dynamic behavior of the EL in cases of sudden variation in the supply current. The model parameters were identified for a suitable current interval to consider them as constant and then tested with experimental data. The obtained results through the developed dynamic emulator have demonstrated its ability to accurately replicate the dynamic behavior of a PEM EL.
Macroeconomic Factors Influencing Public Policy Strategies for Blue and Green Hydrogen
Nov 2021
Publication
The aim of this paper is to analyze the factors affecting hydrogen and Carbon Capture and Storage Technologies (“CCS”) policies taking into consideration Fossil Fuel Consumption Oil Reserves the Debt/GDP Ratio the Trilemma Index and other variables with respect to OECD countries. STATA 17 was used for the analysis. The results confirm the hypothesis that countries with high fossil fuel consumption and oil reserves are investing in blue hydrogen and CCS towards a “zero-carbon-emission” perspective. Moreover countries with a good Debt/GDP ratio act most favorably to green policies by raising their Public Debt because Foreign Direct Investments are negatively correlated with those kinds of policies. Future research should exploit Green Finance policy decision criteria on green and blue hydrogen.
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