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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. • Design of control algorithms for islanded and grid-connected microgrids. • Development of hierarchical MPCs to target long-term and short-term operations. • Tracking the load demand and maximizing the revenue via electricity markets. • Minimization of the HESS operational costs. [ABSTRACT FROM AUTHOR]

Hydrogen supplying to industrial users is currently the major hydrogen business worldwide and the demand for hydrogen is almost entirely supplied from fossil fuels. In the last years a widespread interest on hydrogen has grown as energy vector for the decarbonization of multiple sectors, including industry, transport and buildings. Nevertheless, the impact of natural gas and other fossil fuels substitution with hydrogen is highly affected by the mix of different technologies and energy sources applied for hydrogen generation. The paper aims to investigate current CO 2 emissions related with hydrogen generation in Australia and Italy by means of PEM and alkaline technologies; and to evaluate the potential impact considering cell characteristics variation and 3 scenarios based on energy mix. A sensitivity analysis is performed to identify the critical parameters. Based on experimental data, the energy consumption for hydrogen production using PEM technology is more sensitive to cell voltage compared to current density, which indicates the importance of cell manufacturing and electrolyte resistance. In addition, by performing sensitivity analysis regarding energy sources scenarios it is found that carbon dioxide emission in Australia is more sensitive to renewable energy sources rather than Italy. [Display omitted] • Importance of manufacturing and electrolyte resistance because of high PEM energy consumption sensitivity to cell voltage. • Predicted emission in 2030 is 5–10 kg CO 2 using PEM/alkaline technology in Italy. • 18% reduction of national electricity grid CO 2 emission in Australia is predicted. (In 2030 in comparison to 2019). [ABSTRACT FROM AUTHOR]

The literature lacks a systematic analysis of HRS equipment and operating standards. Researchers, policymakers, and HRS operators could find this information relevant for planning the network's future expansion. This study is intended to address this information need by providing a comprehensive strategic overview of the regulations currently in place for the construction and maintenance of hydrogen fueling stations. A quick introduction to fundamental hydrogen precautions and hydrogen design is offered. The paper, therefore, provides a quick overview of hydrogen's safety to emphasize HRS standards, rules, and regulations. Both gaseous and liquid safety issues are detailed, including possible threats and installation and operating expertise. After the safety evaluation, layouts, equipment, and operating strategies for HRSs are presented, followed by a review of in-force regulations: internationally, by presenting ISO, IEC, and SAE standards, and Europeanly, by reviewing the CEN/CENELEC standards. A brief and concise analysis of Italy's HRS regulations is conducted, with the goal of identifying potential insights for strategic development and more convenient technology deployment. [ABSTRACT FROM AUTHOR]

Hydrogen storage can help achieve climate change and reduce greenhouse gas emissions. This paper presents a first assessment of the suitability of northeastern Italy for underground hydrogen storage (UHS). The study focuses on the analysis of publicly available well data, which allowed identifying geological formations potentially suitable for UHS. The most promising area, known as the "Treviso Area" consists of both saline aquifers and depleted gas fields. One of the key petrophysical properties, i.e. porosity, was calculated for each of the five wells revealing conditions potentially suitable for UHS by applying empirical formulas to geophysical log data. For the two depleted gas fields, a hydrogen injection simulation was also performed. This work is a pioneer study and lays the foundation for hopeful further analyses, which could help implement the recently launched "North Adriatic Hydrogen Valley" initiative. [Display omitted] • A first assessment of underground hydrogen storage (UHS) in Italy is provided. • In NE Italy, saline aquifers and depleted gas fields are potentially suitable for UHS. • A key petrophysical property for UHS, porosity, is calculated from geophysical logs. • A simulation of hydrogen injection and production is provided. [ABSTRACT FROM AUTHOR]

Remote areas usually do not have access to electricity from the national grid. The energy demand is often covered by diesel generators, resulting in high operating costs and significant environmental impacts. With reference to the case study of Ginostra (a village on a small island in the south of Italy), this paper analyses the environmental sustainability of an innovative solution based on Renewable Energy Sources (RES) integrated with a hybrid hydrogen-battery energy storage system. A comparative Life Cycle Assessment (LCA) has been carried out to evaluate if and to what extent the RES-based system could bring environmental improvements compared to the current diesel-based configuration. The results show that the impact of the RES-based system is less than 10% of that of the current diesel-based solution for almost all impact categories (climate change, ozone depletion, photochemical ozone formation, acidification, marine and terrestrial eutrophication and fossil resource use). The renewable solution has slightly higher values only for the following indicators: use of mineral and metal resources, water use and freshwater eutrophication. The climate change category accounts for 0.197 kg CO 2 eq./kWh in the renewable scenario and 1.73 kg CO 2 eq./kWh in the diesel-based scenario, which corresponds to a reduction in GHG emissions of 89%. By shifting to the RES-based solution, about 6570 t of CO 2 equivalent can be saved in 25 years (lifetime of the plant). In conclusion, the hydrogen-battery system could provide a sustainable and reliable alternative for power supply in remote areas. • An LCA of an off-grid hybrid battery-hydrogen system is performed. • A comparison with the current scenario based on a diesel generator is performed. • Low impact on climate change for the Renewable scenario (0.197 kg CO 2 eq./MWh). • The Renewable scenario can save more than 260 t of CO 2 eq. per year. • The impact due to transport by helicopter to the remote site is negligible. [ABSTRACT FROM AUTHOR]

Abstract Industry is one of the highest energy consumption sector: some facilities like steelworks, foundries, or paper mills are highly energy-intensive activities. Many countries have already implemented subsidies on energy efficiency in generation and utilisation, with the aim of decreasing overall consumption and energy intensity of gross domestic product. Meanwhile, researchers have increased interest into alternative energy systems to decrease pollution and use of fossil fuels. Hydrogen, in particular, is proposed as a clean alternative energy vector, as it can be used as energy storage mean or to replace fossil fuels, e.g. for transport. This work analyses the re-vamping of the energy generation system of a paper mill by means of reversible solid oxide cells (RSOCs). The aim is not only to increase efficiency on energy generation, but also to create a polygeneration system where hydrogen is produced. Application on a real industrial facility, based in Italy with a production capacity of 60000 t/y of paper, is analysed. First, the current energy system is studied. Then, a novel system based on RSOC is proposed. Each component of the systems (both existing and novel) is defined using operational data, technical datasheet, or models defined with thermodynamic tools. Then, the interaction between them is studied. Primary energy analysis on the novel system is performed, and saving with respect to the current configuration is evaluated. Even if the complexity of the system increases, results show that saving occurs between 2 and 6%. Hydrogen generation is assessed, comparing the RSOC integrated system with proton exchange membrane (PEM) electrolysis, in terms of both primary energy and economics. Results exhibit significant primary energy and good economic performance on hydrogen production with the novel system proposed (hydrogen cost decreases from 10 €/kg to at least 8 €/kg). Highlights • The re-vamping of the energy generation system of a paper mill is analysed. • Reversible solid oxide cells are used increasing efficiency on energy generation. • A polygeneration system where hydrogen is produced is also created. • Primary energy saving on energy facility generation occurs between 2 and 6%. • Significant primary energy and good economic performance on hydrogen production are performed. [ABSTRACT FROM AUTHOR]

This paper aims to investigate a system for large size hydrogen production, storage and distribution to refueling stations for its employment in land transportation. Hydrogen is produced by pressurized alkaline electrolysers, employing time-dependent renewable electricity produced by a large size hydroelectric plant (100 MW); the hydrogen is stored into pressurized tanks and delivered by trucks to the refueling stations. Since the technologies related to hydrogen vehicles still present high costs, an alternative solution is investigated: the hydrogen produced by water electrolysis is converted into Hydro-methane (a blend of methane and hydrogen, where H 2 maximum volume content is 30%), which is easier to be stored and transported to the refueling stations, considering its higher energy content in volume terms. Since electricity available from the hydroelectric plant varies widely throughout the year, a time-dependent hierarchical thermo-economic analysis is performed in order to investigate both the optimal size of the whole plant and the management of the alkaline electrolysers. The analysis is carried out for the H 2 and Hydro-methane plant lay-outs, comparing the results from energetic, strategic and economic point of view in a typical European economic scenario (Italy). For the different plant lay-outs, two energy scenarios are considered: (i) to feed the electrolysers only with renewable hydroelectricity during the year, keeping them off when it is not available; (ii) to purchase electricity from the national grid in shortage periods, in order to increase the utilization factor of the electrolysers and the production of H 2 and Hydro-methane for the refueling stations. [ABSTRACT FROM AUTHOR]

In the challenge of mitigating greenhouse gases produced mainly by fossil fuels, the recovery of agricultural and food waste to produce biohydrogen by dark fermentation is considered a promising source for the future. However, industrial-scale production remains challenging and several parameters significantly influencing the application of the technology need to be finely tuned. In the present study, an evaluation of the production of biohydrogen from cassava and pineapple waste, widely available in many African countries, was carried out using different microbial consortia originating from industrial biogas plants in Italy. The production of biohydrogen was defined both by screening the most appropriate inoculum and by using a "centered composite design" to optimize the inoculum pretreatment time and the pH. From cassava waste, which is abundant of starch (43%), the highest hydrogen levels (62.32 mL H 2 /gVS) were obtained at pH 7.72 adopting a 4-h heat treated inoculum originating from an anaerobic digester fed with corn and barley silage. Higher hydrogen yields (75.50 mL H 2 /gVS) were achieved at pH 6 once pineapple, which has a high content of hemicellulose, was converted by another selected inoculum, isolated from an olive pomace treating plant, where hemicellulose is one of the most common polysaccharide. The correlation coefficients R2 and adjusted R2 are close to unity, proving the model to be appropriate to express the concentration of hydrogen produced. This combined approach performed successfully and represents a strong strategy to optimize the production of biohydrogen from agricultural residues even in African contexts. [Display omitted] • African residues are good candidates for biohydrogen production. • Response surface methodology optimized bio-H 2 yields. • The selection of proper inoculum is decisive for bio-H 2 production. • Inoculum treatment and pH are major factors for bio-H 2 production. • Cassava and pineapple were converted up to 62 and 75 mL H 2 /gVS, respectively. [ABSTRACT FROM AUTHOR]