Reheating as an option to increase the efficiency of a novel power generation system based on ammonia oxy-combustion

Ammonia is a promising hydrogen-based energy vector. In the HiPowAR project, an innovative system is developed, based on oxy-combustion of ammonia in a membrane reactor and expansion of the obtained nitrogen-steam mixture. The system combines high temperature and pressure (typical of gas turbines) and large expansion ratio (typical of steam cycles). This work studies the impact of reheating, which proves advantageous, with stronger benefits at lower temperature

Techno-economic assessment of enhanced Biogas&Power-to-SNG processes with high-temperature electrolysis integration

Biogenic energy sources are essential elements of the decarbonization pathways, but are strongly constrained by the limited availability. In this context, Biogas&Power-to-X technologies are strongly supported as a promising solution to foster renewable power generation and drive sector coupling opportunities. This work investigates enhanced Synthetic Natural Gas (SNG) production processes for the repurposing of biogas plants. As an alternative to combined heat and power applications via internal combustion engines, the Italian legislation is supporting biogas-to-biomethane upgrading, focusing on the transport market. The proposed integrated plant scheme is a flexible solution based on Power-to-Hydrogen and methanation, able to exploit both electric and gas grid connections, enhancing biomethane production. Advanced process schemes are studied combining solid oxide electrolysers that exploit the methanation waste heat as input thermal energy and flexible PEM electrolysers that improve the part-load operation. The calculated efficiency at max load is about 55% for the Power-to-Methane block and nearly 75% for the overall integrated plant. Results show limited sensitivity of efficiency to input power variations, making the system suitable for the recovery of surplus renewable power generation

Development of diagnostic instrumentations for fuel cells based on consumer electronics

The decarbonization process is pushing the energy sector into a transition towards clean energy vectors. In the hard-to-abate sectors, such as heavy-duty transport and industry, hydrogen can act as an energy carrier and a sector coupler. Key devices for hydrogen exploitation are fuel cells. Diagnostic is a crucial element for safety and efficiency during operation. This work regards the development process – from the conception to the validation and use – of an acquisition system made of consumer electronic components. By measuring differential voltage at high frequency, it enables to perform Electrochemical Impedance Spectroscopy (EIS). The system consists of an Arduino board running a self-developed circuit composed of an operational amplifier, an analog-to-digital converter, and a buffer memory. The system is designed to be expanded with multiple synchronized modules to monitor several cells at once. The module can be applied to a single cell or a group of cells (e.g., a stack) by tuning the operational amplifier. A dedicated software has also been developed, involving assembly language to achieve the required speed performance. The circuit has been validated using a function generator to apply sinusoids with frequencies between 100 Hz and 10 kHz and amplitudes of 10-500 mV (reflecting the EIS requirements on a single cell). An oscilloscope is used to double-check the generated signal. The results proved that the system features errors below 3% on amplitude and below 0.3% on frequency. Finally, the developed system has been tested against a commercial device performing EIS measurements. The obtained impedance values generally differ by less than 3% in the range of interest, while a few specific frequencies are affected by external disturbances

A Mathematical Tool for Optimising Carbon Capture, Utilisation and Sequestration Plants for e-MeOH Production

Carbon capture, utilisation, and sequestration is key for the decarbonisation of hard-to-abate industries, as it allows avoiding the direct release of CO2 to the atmosphere and generating carbon-based products. However, for these products to be truly carbon-neutral, intermittent renewable electricity must be deployed at scale, leading to the necessity of optimising flexible plants with potential for local buffer storages, geological sequestration, and conversion units. The scope of this work is to provide a mathematical framework for the economic optimisation of a carbon capture, utilisation, and sequestration system, to decarbonise a cement plant located in the Puglia region (Italy), via CO2 geological confinement and/or power and CO2-to-methanol conversion. The final aim is to determine the optimal sizing and cost of the process units of the plant, depending on economic conditions such as the methanol sale price and different perspective costs scenarios. The main outcome is an economic convenience of geological sequestration, as opposed to utilisation, while a long-term scenario would allow for a cost-effective production of methanol when the sale price is above 550 EUR/t

Sizing of integrated solar photovoltaic and electrolysis systems for clean hydrogen production

This work presents a method to design an optimised system that combines electrolysers and solar photovoltaic panels for sustainable hydrogen production. Given the daily and seasonal variations of the electricity output vs. a stable hydrogen demand, power exchange to/from the electric grid and hydrogen storage systems are considered. The aim is to determine the optimal size of the PV field, the electrolyser, and the storage, for a given hydrogen demand, by minimising the cost of the hydrogen produced

Impact of Detailed Hydropower Representation in National Energy System Modelling

Renewables are becoming more and more important due to the ambitious decarbonization targets. In this scenario, the improved integration of hydropower can play a crucial role thanks to its programmable operation, which is a valuable feature. In some countries it is a primary alternative to fossil resources, for example Italy, where hydro currently covers roughly half of the renewable power generation. Hydropower flexibility poses considerable modelling challenges due to the scarce availability of data. This work aims at addressing this research gap, by analysing the impact of hydropower details on energy system models. Using open-source information, a detailed dataset of Italian hydroelectric programmable plants (pumped hydro and reservoirs) is created. For each plant, storage capacity, geographical location, and nominal power are available. The multiannual historical operational data are exploited to derive a precipitation inflow timeseries for each electricity market bidding zone, which is then distributed on power plants aggregated by administrative region. This new set of data is applied to a multi-node, multi-sector, and multi-vector energy system model, which optimises the design and operation of a carbon-neutral Italian energy system, looking at a 2050 framework with assigned energy vectors demand. Results are compared to those of a fixed-hydropower operation case, thus being able to assess how the modelled flexibility impacts the optimal solution. The analysis favours an improved understanding of future energy systems, helping to shape properly integrated systems with a great amount of non-programmable sources

Techno-economic study of chimneyless electric arc furnace plants for the coproduction of steel and of electricity, hydrogen, or methanol

Electric arc furnace (EAF) is the most common technology for steel production from steel scrap. Although the input energy is mostly constituted by electricity, significant amounts of carbon dioxide are emitted with the exhaust gases, most of which are classifiable as process-related. The main goal of this study is to perform a techno-economic analysis of chimneyless electric arc furnace plants, fed by either scrap or direct reduced iron (DRI), and able to coproduce steel as well as electricity, hydrogen, or methanol. Several plant configurations are investigated, featuring different combinations of oxy-postcombustion, carbon capture, carbon monoxide-rich gas recovery, hydrogen or syngas production by high-temperature electrolysis or coelectrolysis, and methanol synthesis. These configurations are also characterized by decreased false air leakage and by heat recovery for steam production. Results show that all cases allow achieving a substantial reduction of direct carbon dioxide emissions, close to 99% compared to the unabated conditions. From an economic perspective, in a long-term scenario, the internal rate of return is always above 8%, and up to 73% for the DRI-fed case. However, in a short-term scenario, only cases with sole power production are economically viable. Hydrogen and methanol are competitive with market prices only for low electricity costs. In a higher electricity cost scenario, the case of carbon capture and storage is more competitive than the case of carbon capture and utilization. With an electricity cost of 100 €/MWh, a steel premium of 10-40 €/t allows to reach economic feasibility if methanol or hydrogen selling prices are in line with current market conditions. In general, the configurations with DRI-fed furnaces obtain more favorable economic performance than scrap-fed ones. The competitiveness of sole electricity, hydrogen or methanol production configurations depends on the case study and on the future market prices

A Mathematical Tool for Optimising Carbon Capture, Utilisation and Sequestration Plants for e-MeOH Production

Carbon capture, utilisation, and sequestration is key for the decarbonisation of hard-to-abate industries, as it allows avoiding the direct release of CO2 to the atmosphere and generating carbon-based products. However, for these products to be truly carbon-neutral, intermittent renewable electricity must be deployed at scale, leading to the necessity of optimising flexible plants with potential for local buffer storages, geological sequestration, and conversion units. The scope of this work is to provide a mathematical framework for the economic optimisation of a carbon capture, utilisation, and sequestration system, to decarbonise a cement plant located in the Puglia region (Italy), via CO2 geological confinement and/or power and CO2-to-methanol conversion. The final aim is to determine the optimal sizing and cost of the process units of the plant, depending on economic conditions such as the methanol sale price and different perspective costs scenarios. The main outcome is an economic convenience of geological sequestration, as opposed to utilisation, while a long-term scenario would allow for a cost-effective production of methanol when the sale price is above 550 €/t

On the active deformations of hybrid specimens

Purpose – The purpose of this study concerns numerical studies and experimental validation of the mechanical behavior of hybrid specimens. These kinds of composite specimens are made up of thin carbon and glass substrates on which some Macro Fiber Composite ® (MFC) piezoelectric patches are glued. A proper design and manufacturing of the hybrid specimens as well as testing activities have been performed. The research activity has been carried out under the FutureWings project, funded by the European Commission within the 7th Framework. Design/methodology/approach – The paper describes the basic assumptions made to define specimen geometries and to carry out experimental tests. Finite element (FE) results and experimental data (laser technique measurements) have been compared: it shows very good agreement for the displacements’ distribution along the specimens. Findings – Within the objectives of the project, the study of passive and active deformation characteristics of the hybrid composite material has provided reference technical data and has allowed for the correct adaptation of the FE models. More in particular, using the hybrid specimens, both the bending deformations and the torsion deformations have been studied. Practical implications – The deformation capability of the hybrid specimens will be used in the development of prototypical three-dimensional structures, that, through the electrical control of the MFC patches, will be able to change the curvature of their cross section or will be able to change the angle of torsion along their longitudinal axis. Originality/value – The design of nonstandard specimens and the tests executed represent a novelty in the field of structures using piezoelectric actuators. The numerical and experimental data of the present research constitute a small step forward in the field of smart materials technology

14.5: Ricerche geologico petrografiche sul settore orientale dell'Adamello fra Val di Genova e Val di Breguzzo

44 p., 3 carte di tavol