Italy
Recent Developments of Membranes and Electrocatalysts for the Hydrogen Production by Anion Exchange Membrane Water Electrolysers: A Review
Nov 2022
Publication
Hydrogen production using anion exchange membrane water electrolysis (AEMWE) offers hope to the energy crisis faced by humanity. AEM electrolysis can be coupled with intermittent and renewable energy sources as well as with the use of low-cost electrocatalysts and other low-cost stack components. In AEM water electrolysis one of the biggest advantages is the use of low-cost transition metal catalysts instead of traditional noble metal electrocatalysts. AEMWE is still in its infancy despite irregular research on catalysts and membranes. In order to generate commercially viable hydrogen AEM water electrolysis technology must be further developed including energy efficiency membrane stability stack feasibility robustness ion conductivity and cost reduction. An overview of studies that have been conducted on electrocatalysts membranes and ionomers used in the AEMWEs is here reported with the aim that AEMWE research may be made more practical by this review report by bridging technological gaps and providing practical research recommendations leading to the production of scalable hydrogen.
Dynamic Modeling of a PEM Fuel Cell Power Plant for Flexibility Optimization and Grid Support
Jun 2022
Publication
The transition toward high shares of non-programmable renewable energy sources in the power grid requires an increase in the grid flexibility to guarantee grid reliability and stability. This work developed within the EU project Grasshopper identifies hydrogen Fuel Cell (FC) power plants based on low temperature PEM cells as a source of flexibility for the power grid. A dynamic numerical model of the flexible FC system is developed and tested against experimental data from a 100-kW pilot plant built within the Grasshopper project. The model is then applied to assess the flexible performance of a 1 MW system in order to optimize the scale-up of the pilot plant to the MW-size. Simulations of load-following operation show the flexibility of the plant which can ramp up and down with a ramp rate depending only on an externally imposed limit. Warm-up simulations allow proposing solutions to limit the warm-up time. Of main importance are the minimization of the water inventory in the system and the construction of a compact system which minimizes the distance between the components.
Experimental Investigation on CO2 Methanation Process for Solar Energy Storage Compared to CO2-Based Methanol Synthesis
Jun 2017
Publication
The utilization of the captured CO2 as a carbon source for the production of energy storage media offers a technological solution for overcoming crucial issues in current energy systems. Solar energy production generally does not match with energy demand because of its intermittent and non-programmable nature entailing the adoption of storage technologies. Hydrogen constitutes a chemical storage for renewable electricity if it is produced by water electrolysis and is also the key reactant for CO2 methanation (Sabatier reaction). The utilization of CO2 as a feedstock for producing methane contributes to alleviate global climate changes and sequestration related problems. The produced methane is a carbon neutral gas that fits into existing infrastructure and allows issues related to the aforementioned intermittency and non-programmability of solar energy to be overcome. In this paper an experimental apparatus composed of an electrolyzer and a tubular fixed bed reactor is built and used to produce methane via Sabatier reaction. The objective of the experimental campaign is the evaluation of the process performance and a comparison with other CO2 valorization paths such as methanol production. The investigated pressure range was 2–20 bar obtaining a methane volume fraction in outlet gaseous mixture of 64.75% at 8 bar and 97.24% at 20 bar with conversion efficiencies of respectively 84.64% and 99.06%. The methanol and methane processes were compared on the basis of an energy parameter defined as the spent energy/stored energy. It is higher for the methanol process (0.45) with respect to the methane production process (0.41–0.43) which has a higher energy storage capability.
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.
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.
Modeling and Simulation of an Isolated Hybrid Micro-grid with Hydrogen Production and Storage
Jan 2014
Publication
This work relates the study of system performance in operational conditions for an isolated micro-grid powered by a photovoltaic system and a wind turbine. The electricity produced and not used by the user will be accumulated in two different storage systems: a battery bank and a hydrogen storage system composed of two PEM electrolyzers four pressurized tanks and a PEM fuel cell. One of the main problems to be solved in the development of isolated micro-grids is the management of the various devices and energy flows to optimize their functioning in particular in relation to the load profile and power produced by renewable energy systems depending on weather conditions. For this reason through the development and implementation of a specific simulation program three different energy management systems were studied to evaluate the best strategy for effectively satisfying user requirements and optimizing overall system efficiency.
Multi-model Assessment of Heat Decarbonisation Options in the UK Using Electricity and Hydrogen
May 2022
Publication
Delivering low-carbon heat will require the substitution of natural gas with low-carbon alternatives such as electricity and hydrogen. The objective of this paper is to develop a method to soft-link two advanced investment-optimising energy system models RTN (Resource-Technology Network) and WeSIM (Whole-electricity System Investment Model) in order to assess cost-efficient heat decarbonisation pathways for the UK while utilising the respective strengths of the two models. The linking procedure included passing on hourly electricity prices from WeSIM as input to RTN and returning capacities and locations of hydrogen generation and shares of electricity and hydrogen in heat supply from RTN to WeSIM. The outputs demonstrate that soft-linking can improve the quality of the solution while providing useful insights into the cost-efficient pathways for zero-carbon heating. Quantitative results point to the cost-effectiveness of using a mix of electricity and hydrogen technologies for delivering zero-carbon heat also demonstrating a high level of interaction between electricity and hydrogen infrastructure in a zero-carbon system. Hydrogen from gas reforming with carbon capture and storage can play a significant role in the medium term while remaining a cost-efficient option for supplying peak heat demand in the longer term with the bulk of heat demand being supplied by electric heat pumps.
Pressure Management in Smart Gas Networks for Increasing Hydrogen Blending
Jan 2022
Publication
The injection of hydrogen into existing gas grids is acknowledged as a promising option for decarbonizing gas systems and enhancing the integration among energy sectors. Nevertheless it affects the hydraulics and the quality management of networks. When the network is fed by multiple infeed sites and hydrogen is fed from a single injection point non-homogeneous hydrogen distribution throughout the grid happens to lead to a reduction of the possible amount of hydrogen to be safely injected within the grid. To mitigate these impacts novel operational schemes should therefore be implemented. In the present work the modulation of the outlet pressures of gas infeed sites is proposed as an effective strategy to accommodate larger hydrogen volumes into gas grids extending the area of the network reached by hydrogen while keeping compliance with quality and hydraulic restrictions. A distribution network operated at two cascading pressure tiers interfaced by pressure regulators constitutes the case study which is simulated by a fluid-dynamic and multi-component model for gas networks. Results suggest that higher shares of hydrogen and other green gases can be introduced into existing distribution systems by implementing novel asset management schemes with negligible impact on grid operations.
Review on the Status of the Research on Power‐to‐Gas Experimental Activities
Aug 2022
Publication
In recent years power‐to‐gas technologies have been gaining ground and are increasingly proving their reliability. The possibility of implementing long‐term energy storage and that of being able to capture and utilize carbon dioxide are currently too important to be ignored. However sys‐ tems of this type are not yet experiencing extensive realization in practice. In this study an overview of the experimental research projects and the research and development activities that are currently part of the power‐to‐gas research line is presented. By means of a bibliographical and sitographical analysis it was possible to identify the characteristics of these projects and their distinctive points. In addition the main research targets distinguishing these projects are presented. This provides an insight into the research direction in this regard where a certain technological maturity has been achieved and where there is still work to be done. The projects found and analyzed amount to 87 mostly at laboratory scale. From these what is most noticeable is that research is currently focusing heavily on improving system efficiency and integration between components.
Achieving Net Zero Emissions in Italy by 2050: Challenges and Opportunities
Dec 2021
Publication
This paper contributes to the climate policy discussion by focusing on the challenges and opportunities of reaching net zero emissions by 2050 in Italy. To support Italian energy planning we developed energy roadmaps towards national climate neutrality consistent with the Paris Agreement objectives and the IPCC goal of limiting the increase in global surface temperature to 1.5 ◦C. Starting from the Italian framework these scenarios identify the correlations among the main pillars for the change of the energy paradigm towards net emissions by 2050. The energy scenarios were developed using TIMES-RSE a partial equilibrium and technology-rich optimization model of the entire Italian energy system. Subsequently an in-depth analysis was developed with the sMTISIM a long-term simulator of power system and electricity markets. The results show that to achieve climate neutrality by 2050 the Italian energy system will have to experience profound transformations on multiple and strongly related dimensions. A predominantly renewable-based energy mix (at least 80–90% by 2050) is essential to decarbonize most of the final energy consumption. However the strong increase of non-programmable renewable sources requires particular attention to new flexibility resources needed for the power system such as Power-to-X. The green fuels produced from renewables via Power-to-X will be a vital energy source for those sectors where electrification faces technical and economic barriers. The paper’s findings also confirm that the European “energy efficiency first” principle represents the very first step on the road to climate neutrality.
CFD Study of Dual Fuel Combustion in a Research Diesel Engine Fueled by Hydrogen
Jul 2022
Publication
Superior fuel economy higher torque and durability have led to the diesel engine being widely used in a variety of fields of application such as road transport agricultural vehicles earth moving machines and marine propulsion as well as fixed installations for electrical power generation. However diesel engines are plagued by high emissions of nitrogen oxides (NOx) particulate matter (PM) and carbon dioxide when conventional fuel is used. One possible solution is to use low-carbon gaseous fuel alongside diesel fuel by operating in a dual-fuel (DF) configuration as this system provides a low implementation cost alternative for the improvement of combustion efficiency in the conventional diesel engine. An initial step in this direction involved the replacement of diesel fuel with natural gas. However the consequent high levels of unburned hydrocarbons produced due to non-optimized engines led to a shift to carbon-free fuels such as hydrogen. Hydrogen can be injected into the intake manifold where it premixes with air then the addition of a small amount of diesel fuel auto-igniting easily provides multiple ignition sources for the gas. To evaluate the efficiency and pollutant emissions in dual-fuel diesel-hydrogen combustion a numerical CFD analysis was conducted and validated with the aid of experimental measurements on a research engine acquired at the test bench. The process of ignition of diesel fuel and flame propagation through a premixed air-hydrogen charge was represented the Autoignition-Induced Flame Propagation model included ANSYS-Forte software. Because of the inefficient operating conditions associated with the combustion the methodology was significantly improved by evaluating the laminar flame speed as a function of pressure temperature and equivalence ratio using Chemkin-Pro software. A numerical comparison was carried out among full hydrogen full methane and different hydrogen-methane mixtures with the same energy input in each case. The use of full hydrogen was characterized by enhanced combustion higher thermal efficiency and lower carbon emissions. However the higher temperatures that occurred for hydrogen combustion led to higher NOx emissions.
Overview of First Outcomes of PNR Project HYTUNNEL-CS
Sep 2021
Publication
Dmitry Makarov,
Donatella Cirrone,
Volodymyr V. Shentsov,
Sergii Kashkarov,
Vladimir V. Molkov,
Z. Xu,
Mike Kuznetsov,
Alexandros G. Venetsanos,
Stella G. Giannissi,
Ilias C. Tolias,
Knut Vaagsaether,
André Vagner Gaathaug,
Mark R. Pursell,
W. M. Rattigan,
Frank Markert,
Luisa Giuliani,
L.S. Sørensen,
A. Bernad,
Mercedes Sanz Millán,
U. Kummer,
C. Brauner,
Paola Russo,
J. van den Berg,
F. de Jong,
Tom Van Esbroeck,
M. Van De Veire,
D. Bouix,
Gilles Bernard-Michel,
Sergey Kudriakov,
Etienne Studer,
Domenico Ferrero,
Joachim Grüne and
G. Stern
The paper presents the first outcomes of the experimental numerical and theoretical studies performed in the funded by Fuel Cell and Hydrogen Joint Undertaking (FCH2 JU) project HyTunnel-CS. The project aims to conduct pre-normative research (PNR) to close relevant knowledge gaps and technological bottlenecks in the provision of safety of hydrogen vehicles in underground transportation systems. Pre normative research performed in the project will ultimately result in three main outputs: harmonised recommendations on response to hydrogen accidents recommendations for inherently safer use of hydrogen vehicles in underground traffic systems and recommendations for RCS. The overall concept behind this project is to use inter-disciplinary and inter-sectoral prenormative research by bringing together theoretical modelling and experimental studies to maximise the impact. The originality of the overall project concept is the consideration of hydrogen vehicle and underground traffic structure as a single system with integrated safety approach. The project strives to develop and offer safety strategies reducing or completely excluding hydrogen-specific risks to drivers passengers public and first responders in case of hydrogen vehicle accidents within the currently available infrastructure.
Energy Saving in Public Transport Using Renewable Energy
Jan 2017
Publication
Hydrogen produced by renewable sources represents an interesting way to reduce the energetic dependence on fossil fuels in the transportation sector. This paper shows a feasibility study for the production storage and distribution of hydrogen in the western Sicilian context using three different renewable sources: wind biomass and sea wave. The objective of this study is the evaluation of the hydrogen demand needed to replace all diesel supplied buses with electrical buses equipped with fuel cells. An economic analysis is presented with the evaluation of the avoidable greenhouse gas emissions. Four different scenarios correlate the hydrogen demand for urban transport to the renewable energy resources present in the territories and to the modern technologies available for the production of hydrogen. The study focuses on the possibility of tapping into the potential of renewable energies (wind biomass and sea wave) for the production of hydrogen by electrolysis. The use of hydrogen would reduce significantly the emissions of particulate and greenhouse gases in the urban districts under analysis.
Experimental Study of Hydrogen Embrittlement in Maraging Steels
Feb 2018
Publication
This research activity aims at investigating the hydrogen embrittlement of Maraging steels in connection to real sudden failures of some of the suspension blades of the Virgo Project experimental apparatus. Some of them failed after 15 years of service in working conditions. Typically in the Virgo detector blades are loaded up to 50-60% of the material yield strength. For a deeper understanding of the failure the relationship between hydrogen concentration and mechanical properties of the material have been investigated with specimens prepared in order to simulate blade working conditions. A mechanical characterization of the material has been carried out by standard tensile testing in order to establish the effect of hydrogen content on the material strength. Further experimental activity was executed in order to characterize the fracture surface and to measure the hydrogen content. Finally some of the failed blades have been analyzed in DICI-UNIPI laboratory. The experimental results show that the blades failure can be related with the hydrogen embrittlement phenomenon.
Techno-Economic Evaluation of Deploying CCS in SMR Based Merchant H2 Production with NG as Feedstock and Fuel
Aug 2017
Publication
Hydrogen is a crucial raw materials to other industries. Globally nearly 90% of the hydrogen or HyCO gas produced is consumed by the ammonia methanol and oil refining industries. In the future hydrogen could play an important role in the decarbonisation of transport fuel (i.e. use of fuel cell vehicles) and space heating (i.e. industrial commercial building and residential heating). This paper summarizes the results of the feasibility study carried out by Amec Foster Wheeler for the IEA Greenhouse Gas R&D Programme (IEA GHG) with the purpose of evaluating the performance and costs of a modern steam methane reforming without and with CCS producing 100000 Nm3 /h H2 and operating as a merchant plant. This study focuses on the economic evaluation of five different alternatives to capture CO2 from SMR. This paper provides an up-to-date assessment of the performance and cost of producing hydrogen without and with CCS based on technologies that could be erected today. This study demonstrates that CO2 could be captured from an SMR plant with an overall capture rate ranging between 53 to 90%. The integration of CO2 capture plant could increase the NG consumption by -0.03 to 1.41 GJ per Nm3 /h of H2. The amount of electricity exported to the grid by the SMR plant is reduced. The levelised cost of H2 production could increase by 2.1 to 5.1 € cent per Nm3 H2 (depending on capture rate and technology selected). This translates to a CO2 avoidance cost of 47 to 70 €/t.
Recent Combustion Strategies in Gas Turbines for Propulsion and Power Generation toward a Zero-Emissions Future: Fuels, Burners, and Combustion Techniques
Oct 2021
Publication
The effects of climate change and global warming are arising a new awareness on the impact of our daily life. Power generation for transportation and mobility as well as in industry is the main responsible for the greenhouse gas emissions. Indeed currently 80% of the energy is still produced by combustion of fossil fuels; thus great efforts need to be spent to make combustion greener and safer than in the past. For this reason a review of the most recent gas turbines combustion strategy with a focus on fuels combustion techniques and burners is presented here. A new generation of fuels for gas turbines are currently under investigation by the academic community with a specific concern about production and storage. Among them biofuels represent a trustworthy and valuable solution in the next decades during the transition to zero carbon fuels (e.g. hydrogen and ammonia). Promising combustion techniques explored in the past and then abandoned due to their technological complexity are now receiving renewed attention (e.g. MILD PVC) thanks to their effectiveness in improving the efficiency and reducing emissions of standard gas turbine cycles. Finally many advances are illustrated in terms of new burners developed for both aviation and power generation. This overview points out promising solutions for the next generation combustion and opens the way to a fast transition toward zero emissions power generation.
Hydrogen Production via Steam Reforming: A Critical Analysis of MR and RMM Technologies
Jan 2020
Publication
Hydrogen as the energy carrier of the future’ has been a topic discussed for decades and is today the subject of a new revival especially driven by the investments in renewable electricity and the technological efforts done by high-developed industrial powers such as Northern Europe and Japan. Although hydrogen production from renewable resources is still limited to small scale local solutions and R&D projects; steam reforming (SR) of natural gas at industrial scale is the cheapest and most used technology and generates around 8 kg CO2 per kg H2. This paper is focused on the process optimization and decarbonization of H2 production from fossil fuels to promote more efficient approaches based on membrane separation. In this work two emerging configurations have been compared from the numerical point of view: the membrane reactor (MR) and the reformer and membrane module (RMM) proposed and tested by this research group. The rate of hydrogen production by SR has been calculated according to other literature works a one-dimensional model has been developed for mass heat and momentum balances. For the membrane modules the rate of hydrogen permeation has been estimated according to mass transfer correlation previously reported by this research group and based on previous experimental tests carried on in the first RMM Pilot Plant. The methane conversion carbon dioxide yield temperature and pressure profile are compared for each configuration: SR MR and RMM. By decoupling the reaction and separation section such as in the RMM the overall methane conversion can be increased of about 30% improving the efficiency of the system.
Life Cycle Assessment and Water Footprint of Hydrogen Production Methods: From Conventional to Emerging Technologies
Oct 2020
Publication
A common sustainability issue arising in production systems is the efficient use of resources for providing goods or services. With the increased interest in a hydrogen (H2) economy the life-cycle environmental performance of H2 production has special significance for assisting in identifying opportunities to improve environmental performance and to guide challenging decisions and select between technology paths. Life cycle impact assessment methods are rapidly evolving to analyze multiple environmental impacts of the production of products or processes. This study marks the first step in developing process-based streamlined life cycle analysis (LCA) of several H2 production pathways combining life cycle impacts at the midpoint (17 problem-oriented) and endpoint (3 damage-oriented) levels using the state-of-the-art impact assessment method ReCiPe 2016. Steam reforming of natural gas coal gasification water electrolysis via proton exchange membrane fuel cell (PEM) solid oxide electrolyzer cell (SOEC) biomass gasification and reforming and dark fermentation of lignocellulosic biomass were analyzed. An innovative aspect is developed in this study is an analysis of water consumption associated with H2 production pathways by life-cycle stage to provide a better understanding of the life cycle water-related impacts on human health and natural environment. For water-related scope Water scarcity footprint (WSF) quantified using Available Water Remaining (AWARE) method was applied as a stand-alone indicator. The paper discusses the strengths and weaknesses of each production pathway identify the drivers of environmental impact quantify midpoint environmental impact and its influence on the endpoint environmental performance. The findings of this study could serve as a useful theoretical reference and practical basis to decision-makers of potential environmental impacts of H2 production systems.
Hydrogen as an Energy Vector to Optimize the Energy Exploitation of a Self-consumption Solar Photovoltaic Facility in a Dwelling House
Nov 2019
Publication
Solar photovoltaic (PV) plants coupled with storage for domestic self-consumption purposes seem to be a promising technology in the next years as PV costs have decreased significantly and national regulations in many countries promote their installation in order to relax the energy requirements of power distribution grids. However electrochemical storage systems are still unaffordable for many domestic users and thus the advantages of self-consumption PV systems are reduced. Thus in this work the adoption of hydrogen systems as energy vectors between a PV plant and the energy user is proposed. As a preliminary study in this work the design of a PV and hydrogen-production self-consumption plant for a single dwelling is described. Then a technical and economic feasibility study conducted by modeling the facility within the Homer Energy Pro energy systems analysis tool is reported. The proposed system will be able to provide back not only electrical energy but also thermal energy through a fuel cell or refined water covering the fundamental needs of the householders (electricity heat or cooling and water). Results show that although the proposed system effectively increases the energy local use of the PV production and reduces significantly the energy injections or demands into/from the power grid avoiding power grid congestions and increasing the nano-grid resilience operation and maintenance costs may reduce its economic attractiveness for a single dwelling.
An Innovative and Comprehensive Approach for the Consequence Analysis of Liquid Hydrogen Vessel Explosions
Oct 2020
Publication
Hydrogen is one of the most suitable solutions to replace hydrocarbons in the future. Hydrogen consumption is expected to grow in the next years. Hydrogen liquefaction is one of the processes that allows for increase of hydrogen density and it is suggested when a large amount of substance must be stored or transported. Despite being a clean fuel its chemical and physical properties often arise concerns about the safety of the hydrogen technologies. A potentially critical scenario for the liquid hydrogen (LH2) tanks is the catastrophic rupture causing a consequent boiling liquid expanding vapour explosion (BLEVE) with consequent overpressure fragments projection and eventually a fireball. In this work all the BLEVE consequence typologies are evaluated through theoretical and analytical models. These models are validated with the experimental results provided by the BMW care manufacturer safety tests conducted during the 1990’s. After the validation the most suitable methods are selected to perform a blind prediction study of the forthcoming LH2 BLEVE experiments of the Safe Hydrogen fuel handling and Use for Efficient Implementation (SH2IFT) project. The models drawbacks together with the uncertainties and the knowledge gap in LH2 physical explosions are highlighted. Finally future works on the modelling activity of the LH2 BLEVE are suggested.
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