Italy

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; Read More

Given the global effort to embrace research actions and technology enhancement for the energy transition innovative sustainable systems are needed both for energy production and for those sectors that are responsible for high pollution and CO2 emissions. In this context electrolytic cells and fuel cells in their variety and flexibility are energy systems characterized by high efficiency and important performance guaranteeing a sustainable solution for futu Read More

In the sustainability context the performance of energy-producing technologies using different energy sources needs to be scored and compared. The selective criterion of a higher level of useful energy to feed an ever-increasing demand of energy to satisfy a wide range of endo- and exosomatic human needs seems adequate. In fact surplus energy is able to cover energy services only after compensating for the energy expenses incurred to build Read More

Within integrated steelmaking industries significant research efforts are devoted to the efficient use of resources and the reduction of CO2 emissions. Integrated steelworks consume a considerable quantity of raw materials and produce a high amount of by-products such as off-gases currently used for the internal production of heat steam or electricity. These off-gases can be further valorized as feedstock for methane and methanol syntheses but th Read More

Supporting policies to achieve a green revolution and ecological transition is a global trend. Although the maritime transport of goods and people can rightly be counted among the least polluting sectors much can be done to further reduce its environmental footprint. Moreover to boost the ecological transition of vessels a whole series of international regulations and national laws have been promulgated. Among these the most impactful on both design and Read More

A numerical study of the energy conversion process occurring in a lean-charge cogenerative engine designed to be powered by natural gas is here conducted to analyze its performances when fueled with mixtures of natural gas and several percentages of hydrogen. The suitability of these blends to ensure engine operations is proven through a zero–one-dimensional engine schematization where an original combustion model is employed to ac Read More

The author discusses in this paper the potential of a micro gas turbine (MGT) combustor when operated under unconventional fuel supplied. The combustor of C30 gas turbine is a reverse flow annular combustor. The CFD analysis of the reacting flow is performed with the 3D ANSYS-FLUENT solver. Specific computational experiments refer to the use of hydrogen – natural gas mixtures in order to define the optimal conditions for pilot and main injectio Read More

The multi-generation systems with simultaneous production of power by renewable energy in addition to polymer electrolyte membrane electrolyzer and fuel cell (PEMFC-PEMEC) energy storage have become more and more popular over the past few years. The fresh water provision for PEMECs in such systems is taken into account as one of the main challenges for them where conventional desalination technologies such as reverse osmosis (RO) and mecha Read More

In recent years growing awareness about environmental issues is pushing humankind to explore innovative technologies to reduce the anthropogenic sources of pollutants. Among these sources internal combustion engines in non-road mobile machinery (NRMM) such as agricultural tractors are one of the most important. The aim of this work is to explore the possibility of replacing the conventional diesel engine with an electric powertrain powered by a hy Read More

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 isolat Read More

Globally the increasing share of renewables prominently driven by intermittent sources such as solar and wind power poses significant challenges to the reliability of current electrical infrastructures leading to the adoption of extreme measures such as generation curtailment to preserve grid security. Within this framework it is essential to develop energy storage systems that contribute to reinforce the flexibility and security of power grids while simult Read More

The share of electrical energy hailing from renewable sources in the European electricity mix is increasing. The match between renewable power supply and demand has become the greatest challenge to cope with. Gas infrastructure can accommodate large volumes of electricity converted into gas whenever this supply of renewable power is larger than the grid capacity or than the electricity demand. The Power-to-Gas (P2G) process chain could play a signi Read More

In the pathway towards decarbonization hydrogen can provide valid support in different sectors such as transportation iron and steel industries and domestic heating concurrently reducing air pollution. Thanks to its versatility hydrogen can be produced in different ways among which steam reforming of natural gas is still the most commonly used method. Today less than 0.7% of global hydrogen production can be considered low-carbon-emission. Among the Read More

Hydrogen is the energy vector that will lead us toward a more sustainable future. It could be the fuel of both fuel cells and internal combustion engines. Internal combustion engines are today the only motors characterized by high reliability duration and specific power and low cost per power unit. The most immediate solution for the near future could be the application of hydrogen as a fuel in modern internal combustion engines. This solution has adv Read More

Green hydrogen produced using renewable energy is nowadays one of the most promising alternatives to fossil fuels for reducing pollutant emissions and in turn global warming. In particular the use of hydrogen as fuel for internal combustion engines has been widely analyzed over the past few years. In this paper the authors show the results of some experimental tests performed on a hydrogen-fueled CFR (Cooperative Fuel Research) engine with particular Read More

The freight sector is expected to keep or even increase its fundamental role for the major modern economies and therefore actions to limit the growing pressure on the environment are urgent. The use of electricity is a major option for the decarbonization of transports; in the heavy-duty segment it can be implemented in different ways: besides full electric-battery powertrains electricity can be used to supply catenary roads or can be chemically stor Read More

The conversion to renewable energy can be achieved when cities and communities start to depend on sustainable resources capable of providing for the basic needs of the community along with a reduction in the daily problems and issues that people face. These issues such as poverty hunger sanitation and economic difficulties are highlighted in the Sustainable Development Goals (SDGs) which aim to limit and eradicate these problems along with oth Read More

The interest in hybrid polymer electrolyte membrane fuel cells (PEMFC) fuelled by hydrogen in shipping has seen an unprecedented growth in the last years as it could allow zero-emission navigation. However technical safety and regulatory barriers in PEMFC ship design and operation are hampering the use of such systems on a large scale. While several studies analyse these aspects a comprehensive and up-to-date overview on hydrogen PEMFCs for shi Read More

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 po Read More

This article investigates the potential of renewable and low-carbon fuel production for the maritime shipping sector using Sweden as a case in focus. Techno-economic modelling and socio-technical transition studies are combined to explore the conditions opportunities and barriers to decarbonising the maritime shipping industry. A set of scenarios have been developed considering demand assumptions and potential instruments such as carbon price energ Read More

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 th Read More

Underground Hydrogen Storage (UHS) provides a large-scale and safe solution to balance the fluctuations in energy production from renewable sources and energy consumption but requires a proper and detailed characterization of the candidate reservoirs. The scope of this study was to estimate the hydrogen diffusion coefficient for real caprock samples from two natural gas storage reservoirs that are candidates for underground hydrogen storage. A si Read More

This paper presents a comparative analysis of two hydrogen station configurations during the refueling process: the conventional “directly pressurized refueling process” and the innovative “cascade refueling process.” The objective of the cascade process is to refuel vehicles without the need for booster compressors. The experiments were conducted at the Hydrogen Research and Fueling Facility located at California State University Los Angeles. In Read More

Hydrogen is seen as a prime choice for complete replacement of gasoline so as to achieve zero-emissions energy and mobility. Combining the use of this alternative fuel with a circular economy approach for giving new life to the existing fleet of passenger cars ensures further benefits in terms of cost competitiveness. Transforming spark ignition (SI) engines to H2 power requires relatively minor changes and limited added components. Within thi Read More

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 spec Read More

Fuel cell electric buses (FCBs) have proven to be a technically viable solution for transportation owing to various advantages such as reliability simplicity better energy efficiency and quietness of operation. However largescale adoption of FCBs is hindered by the lack of extensive and structured infrastructure and the high cost of clean hydrogen. Many studies agree that one of the significant contributors to the lack of competitiveness of green hydrogen Read More

In the last few decades the problem of pollution resulting from human activities has pushed research toward zero or net-zero carbon solutions for transportation. The main objective of this paper is to perform a preliminary performance assessment of the use of hydrogen in conventional turbine engines for aeronautical applications. A 0-D dynamic model of the Allison 250 C-18 turboshaft engine was designed and validated using conventional aviati Read More

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 sta Read More

Hydrogen is an important raw material in chemical industries and the steam reforming of light hydrocarbons (such as methane) is the most used process for its production. In this process the use of a catalyst is mandatory and if compared to precious metal-based catalysts Ni-based catalysts assure an acceptable high activity and a lower cost. The aim of a distributed hydrogen production for example through an on-site type hydrogen station is only reachabl Read More

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 fu Read More

High fluctuations in the combustion process from one cycle to another referred to as cycle-by-cycle variations can have adverse effects on internal combustion engine performances particularly in spark ignition (SI) engines. These effects encompass incomplete combustion the potential for misfires and adverse impacts on fuel economy. Furthermore the cycle-by-cycle variations can also affect a vehicle’s drivability and overall comfort especially w Read More

In recent years there has been a significant increase in research on hydrogen due to the urgent need to move away from carbon-intensive energy sources. This transition highlights the critical role of hydrogen storage technology where hydrogen tanks are crucial for achieving cleaner energy solutions. This paper aims to provide a general overview of hydrogen treatment from a mechanical viewpoint and to create a comprehensive review that integrates th Read More

The carbon-neutrality target set by the European Union for 2050 drives the increasing relevance of green hydrogen as key player in the energy transition. This work uses the JRC-EU-TIMES energy system model to assess opportunities and challenges for green hydrogen trade from North Africa to Europe analysing to what extent it can support its decarbonization. An important novelty is addressing uncertainty regarding hydrogen economy develop Read More

This paper deals with the optimal scheduling of the resources of a renewable energy community whose coordination is aimed at providing flexibility services to the electrical distribution network. The available resources are renewable generation units battery energy storage systems dispatchable loads and power-to-hydrogen systems. The main purposes behind the proposed strategy are enhancement of self-consumption and hydrogen production from loca Read More

The Italian National Recovery and Resilience Plan (NRRP) includes among other measures investments in hydrogen vehicle refuelling stations intending to promote the use of fuel cell electric vehicles (FCEVs) for long-haul freight transport. This paper evaluates the impact that this action could have on CO2 emissions and fuel consumption focusing on a case study of the Campania region. The proposed approach which can also be transferred to other Read More

Decarbonizing road transportation is vital for addressing climate change given that the sector currently contributes to 16% of global GHG emissions. This paper presents a comparative analysis of electric and hydrogen mobility infrastructures in a remote context i.e. an off-grid island. The assessment includes resource assessment and sizing of renewable energy power plants to facilitate on-site self-production. We introduce a comprehensive methodolog Read More

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 t Read More

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 Read More

A surging demand for sustainable energy and the urgency to lower greenhouse gas emissions is driving industrial systems towards more eco-friendly and cost-effective models. Biogas from agricultural and municipal organic waste is gaining momentum as a renewable energy source. Concurrently the European Hydrogen Strategy focuses on green hydrogen for decarbonising the industrial and transportation sectors. This paper presents a multi-objective n Read More

A gas turbine is usually installed inside an acoustic enclosure where the fuel gas supply system is also placed. It is common practice using CFD analysis to simulate the accidental fuel gas release inside the enclosure and the consequent dispersion. These numerical studies are used to properly design the gas detection system according to specific safety criteria which are well defined when the fuel gas is a conventional natural gas. Package design is do Read More

The maritime transportation sector is a large and growing contributor of greenhouse gas and other emissions. Therefore stringent measures have been taken by the International Maritime Organization to mitigate the environmental impact of the international shipping. These lead to the adoption of new technical solutions involving clean fuels such as hydrogen and high efficiency propulsion technologies that is fuel cells. In this framework this paper Read More

Among the different hydrogen premixed combustion concepts direct injection (DI) is one of the most promising for internal combustion engine (ICE) applications. However to fully exploit the benefits of this solution the optimization of the mixture preparation process is a crucial factor. In the present work a study of the hydrogenair mixture formation process in a DI H2-ICE for off-road applications was performed through 3D-CFD simulations. First a sen Read More

Hydrogen production and storage in hybrid systems is a promising solution for sustainable energy transition decoupling the energy generation from its end use and boosting the deployment of renewable energy. Nonetheless the optimal and cost-effective design of hybrid hydrogen-based systems is crucial to tackle existing limitations in diffusion of these systems. The present study explores net-zero energy management via a multi-objective optimizatio Read More

Direct solar hydrogen generation via a combination of photovoltaics (PV) andwater electrolysis can potentially ensure a sustainable energy supply whileminimizing greenhouse emissions. The PECSYS project aims at demonstrating asolar-driven electrochemical hydrogen generation system with an area >10 m 2with high efficiency and at reasonable cost. Thermally integrated PV electrolyzers(ECs) using thin-film silicon undoped and silver-doped Cu Read More

The road transport sector is one of the major contributors to greenhouse gas emissions as it still largely relies on traditional powertrain solutions. While some progress has been made in the passenger car sector with the diffusion of battery electric vehicles heavy-duty transport remains predominantly dependent on diesel internal combustion engines. This research aims to evaluate and compare three potential solutions for the decarbonisation of heavy-duty fr Read More

Multi-energy systems that combine different energy sources and carriers to improve the overall technical economic and environmental performance can boost the energy transition. In this paper we posit an innovative multi-energy system for green hydrogen production that achieves negative carbon emissions by combining bio-fuel membraneintegrated steam reforming and renewable electricity electrolysis. The system produces green hydrogen and car Read More

In recent years the use of alternative fuels in thermal engine power plants has gained more and more attention becoming of paramount importance to overcome the use of fuels from fossil sources and to reduce polluting emissions. The present work deals with the analysis of the response to two different gas fuels—i.e. hydrogen and a syngas from agriculture product—of a 30 kW micro gas turbine integrated with a solar field. The solar field included a t Read More

Studies estimating the production cost of hydrogen-based fuels known as e-fuels often use renewable power profile time series obtained from open-source simulation tools that rely on meteorological reanalysis and satellite data such as Renewables.ninja or PVGIS. These simulated time series contain errors compared to real on-site measured data which are reflected in e-fuels cost estimates plant design and operational performance increasing the ris Read More

Fuel cell-based systems are emerging as the future focus for global adaptation and hydrogen compressors and turbines as economically critical versions are at the technological edge of product development of hydrogen-based energy systems in sustainable energy initiatives. As a novelty the paper deals with the issues behind implementing hydrogen machinery technologies to bring about a resilient hydrogen infrastructure also powered by fuel cells and it a Read More

The growing demand for air travel in the commercial sector leads to an increase in global emissions whose mitigation entails transitioning from the current fossil-fuel based generation of aircrafts to a cleaner one within a short timeframe. The use of hydrogen and fuel cells has the potential to reach zero emissions in the aerospace sector provided that required innovation and research efforts are substantially accomplished. Development programs i Read More