Italy

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.

Among the numerous envisioned applications for hydrogen in the decarbonization of the energy system seasonal energy storage is usually regarded as one of the most likely options. Although long-term energy storage is usually considered at grid-scale level given the increasing diffusion of distributed energy systems and the expected cost reduction in hydrogen related components some companies are starting to offer residential systems with PV modules and batteries that rely on hydrogen for seasonal storage of electrical energy. Such hydrogen storage systems are generally composed by water electrolysers hydrogen storage vessels and fuel cells.<br/>The aim of this work is to investigate such systems and their possible applications for different geographical conditions in Italy. On-grid and off-grid systems are considered and compared to systems without hydrogen in terms of self-consumption ratio size of components and economic investment. Each different option has been assessed from a techno-economic point of view via MESS (Multi Energy Systems Simulator) an analytical programming tool for the analysis of local energy systems.<br/>Results have identified the optimal sizing of the system's components and have shown how such systems are not in general economically competitive for a single dwelling although they can in some cases ensure energy independence.

This paper presents two different scenarios for the energy system of the Netherlands that achieve the Dutch government’s national target of near net-zero greenhouse gas emissions in 2050. Using the system optimisation model OPERA the authors have analysed the technology sector and cost implications of the assumptions underlying these scenarios. While the roles of a number of key energy technology and emission mitigation options are strongly dependent on the scenario and cost assumptions the analysis yields several common elements that appear in both scenarios and that consistently appear under differing cost assumptions. For example one of the main options for the decarbonisation of the Dutch energy system is electrification of energy use in end-use sectors and for the production of renewable hydrogen with electrolysers. As a result the level of electricity generation in 2050 will be three to four times higher than present generation levels. Ultimately renewable energy – particularly from wind turbines and solar panels – is projected to account for the vast majority of electricity generation around 99% in 2050. Imbalances between supply and demand resulting from this variable renewable electricity production can be managed via flexibility options including demand response and energy storage. Hydrogen also becomes an important energy carrier notably for transportation and in industry. If import prices are lower than costs of domestic production from natural gas with CCS or through electrolysis from renewable electricity (2.4–2.7 €/kgH2) the use of hydrogen increases especially in the built environment.

New technological solutions are required to control the impact of the increasing presence of renewable energy sources connected to the electric grid that are characterized by unpredictable production (i.e. wind and solar energy). Energy storage is becoming essential to stabilize the grid when a mismatch between production and demand occurs. Among the available solutions Power to Hydrogen (P2H) is one of the most attractive options. However despite the potential many barriers currently hinder P2H market development. The literature reports general barriers and strategies to overcome them but a specific analysis is fundamental to identifying how these barriers concretely arise in national and regional frameworks since tailored solutions are needed to foster the development of P2H local market. The paper aims to identify and to analyze the existing barriers for P2H market uptake in Italy. The paper shows how several technical regulatory and economic issues are still unsolved resulting in a source of uncertainty for P2H investment. The paper also suggests possible approaches and solutions to address the Italian barriers and to support politics and decision-makers in the definition and implementation of the national hydrogen strategy.

A larger adoption of hydrogen fuel-cell electric vehicles (FCEVs) is typically included in the strategies to decarbonize the transportation sector. This inclusion is supported by life-cycle assessments (LCAs) which show the potential greenhouse gas (GHG) emission benefit of replacing internal combustion engine vehicles with their fuel cell counterpart. However the literature review performed in this study shows that the effects of durability and performance losses of fuel cells on the life-cycle environmental impact of the vehicle have rarely been assessed. Most of the LCAs assume a constant fuel consumption (ranging from 0.58 to 1.15 kgH2/100 km) for the vehicles throughout their service life which ranges in the assessments from 120000 to 225000 km. In this study the effect of performance losses on the life-cycle GHG emissions of the vehicles was assessed based on laboratory experiments. Losses have the effect of increasing the life-cycle GHG emissions of the vehicle up to 13%. Moreover this study attempted for the first time to investigate via laboratory analyses the GHG implications of replacing the hydrophobic polymer for the gas diffusion medium (GDM) of fuel cells to increase their durability. LCA showed that when the service life of the vehicle was fixed at 150000 km the GHG emission savings of using an FC with lower performance losses (i.e. FC coated with fluorinated ethylene propylene (FEP) instead of polytetrafluoroethylene (PTFE)) are negligible compared to the overall life-cycle impact of the vehicle. Both the GDM coating and the amount of hydrogen saved account for less than 2% of the GHG emissions arising during vehicle operation. On the other hand when the service life of the vehicle depends on the operability of the fuel cell the global warming potential per driven km of the FEP-based FCEV reduces by 7 to 32%. The range of results depends on several variables such as the GHG emissions from hydrogen production and the initial fuel consumption of the vehicle. Higher GHG savings are expected from an FC vehicle with high consumption of hydrogen produced with fossil fuels. Based on the results we recommend the inclusion of fuel-cell durability in future LCAs of FCEVs. We also advocate for more research on the real-life performance of fuel cells employing alternative materials.

The current greatest challenge that all gas turbine manufactures and users have in front of them for the years to come is the energy transition while reducing CO2 footprint and to contrast climate change. To this aim the introduction of hydrogen as fuel gas (or its blend) is playing a very important role. The benefit from an environmental point of view is undisputed but the presence of hydrogen introduces a series of safety related aspects to be considered for the design of all systems of a gas turbine package. Most of the design standards developed and adopted in the past are based on conventional natural gas however physical properties of hydrogen require to analyze additional aspects or revise the current ones. In this context the design for safety is paramount as it is strongly impacted by the low energy ignition of hydrogen blend fuels. Baker Hughes has built its experience on several sites different Customers and applications currently installed. These gas turbines run with a variety of hydrogen blends with concentration as high as 100% hydrogen. Baker Hughes has achieved several milestones moving from design to experimental set up leveraging the internal infrastructures consolidating design assumptions. In this work the critical aspects such as material selection instrumentation electrical devices and components are discussed in the framework of package safety with the aim to evolve conventional design minimizing the impacts on package configurations.

Lamination-like defects in pipeline steels can be of both metallurgical and operational origin. In pipelines transporting hydrocarbon usually such defects are not a big challenge since they do not propagate under operating conditions. Nonetheless in presence of a corrosion phenomenon and sour gas (H2S) it is possible to observe blisters and cracks which may propagate in the steel. The observed damage mechanisms is Hydrogen Embrittlement and in spite of a huge amount of study and publications available it is quite difficult for a pipeline owner to get practical data (crack propagation rate for instance) allowing a reliable estimate of the fitness for service of a pipeline. Taking advantage of a pipeline spool containing internal defects that was in service for more than 10 years and recently removed a comprehensive study is underway to obtain a complete assessment of the pipeline future integrity. The program is comprehensive of study and comparison of ILI reports of the pipeline to determine the optimum interval between inspections assessment of inspection results via an accurate nondestructive (UT) and destructive examination of the removed section to verify ILI results lab tests program on specimens from the removed spool at operating conditions (75-80 bar and 30°-36° C) in presence of a small quantity of water H2S (5%) and CO2 (7%) in order to assess defect propagation and to obtain an estimate of crack growth rate and test in field of available methods to monitor the presence of Hydrogen and/or the growth of defects in in-service pipelines. This quite ambitious program is also expected to be able of offering a small contribution toward a better understanding of HE mechanisms and the engineering application of such complex often mainly academic studies.

Decarbonization of energy economy is nowadays a topical theme and several pathways are under discussion. Gaseous fuels have a fundamental role for this transition and the production of low carbon-impact fuels is necessary to deal with this challenge. The generation of renewable hydrogen is a trusted solution since this energy vector can be promptly produced from electricity and injected into the existing natural gas infrastructure granting storage capacity and easy transportation. This scenario will lead in the near future to hydrogen enrichment of natural gas whose impact on the infrastructures is being actively studied. The effect on end-user devices such as domestic gas boilers instead is still little analyzed and tested but is fundamental to be assessed. The aim of this research is to generate knowledge on the effect of hydrogen enrichment on the widely used premixed boilers: the investigations include pollutant emissions efficiency flashback and explosion hazard control system and materials selection. A model for calculating several parameters related to combustion of hydrogen enriched natural gas is presented. Guidelines for the design of new components are provided and an insight is given on the maximum hydrogen blending bearable by the current boilers.

The framework for life cycle sustainability analysis (LCSA) developed within the project CALCAS (Co-ordination Action for innovation in Life-Cycle Analysis for Sustainability) is introducing a truly integrated approach for sustainability studies. However it needs to be further conceptually refined and to be made operational. In particular one of the gaps still hindering the adoption of integrated analytic tools for sustainability studies is the lack of a clear link between the goal and scope definition and the modeling phase. This paper presents an approach to structure the goal and scope phase of LCSA so as to identify the relevant mechanisms to be further detailed and analyzed in the modeling phase. The approach is illustrated with an on-going study on a new technology for the production of high purity hydrogen from biomass to be used in automotive fuel cells.

The main objective of the article is to provide a thorough review of currently used AC-DC converters for alkaline and proton exchange membrane (PEM) electrolyzers in power grid or wind energy conversion systems. Based on the current literature this article aims at emphasizing the advantages and drawbacks of AC-DC converters mainly based on thyristor rectifier bridges and chopper-rectifiers. The analysis is mainly focused on the current issues for these converters in terms of specific energy consumption current ripple reliability efficiency and power quality. From this analysis it is shown that thyristors-based rectifiers are particularly fit for high-power applications but require the use of active and passive filters to enhance the power quality. By comparison the association combination of the chopper-rectifier can avoid the use of bulky active and passive filters since it can improve power quality. However the use of a basic chopper (i.e. buck converter) presents several disadvantages from the reliability energy efficiency voltage ratio and current ripple point of view. For this reason new emerging DC-DC converters must be employed to meet these important issues according to the availability of new power switching devices. Finally based on the authors’ experience in power conversion for PEM electrolyzers a discussion is provided regarding the future challenges that must face power electronics for green hydrogen production based on renewable energy sources.