Italy

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.

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.

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.

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.

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.

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.

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.

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 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.

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.