Wind and solar power generation will continue to grow in the energy supply of the future, but its inherent variability (intermittency) requires appropriate energy systems for storing and using power. Storage of possibly temporary excess of power as methane from hydrogen gas and carbon dioxide is a promising option. With electrolysis hydrogen gas can be generated from (renewable) power. The combination of such hydrogen with carbon dioxide results in the energy carrier methane that can be handled well and may may serve as carbon feedstock of the future. Biogas from biomass delivers both methane and carbon dioxide. Anaerobic microorganisms can make additional methane from hydrogen and carbon dioxide in a biomethanation process that compares favourably with its chemical counterpart. Biomethanation for renewable power storage and use makes appropriate use of the existing infrastructure and knowledge base for natural gas. Addition of hydrogen to a dedicated biogas reactor after fermentation optimizes the biomethanation conditions and gives maximum flexibility. The low water solubility of hydrogen gas limits the methane production rate. The use of hollow fibers, nano-bubbles or better-tailored methane-forming microorganisms may overcome this bottleneck. Analyses of patent applications on biomethanation suggest a lot of freedom to operate. Assessment of biomethanation for economic feasibility and environmental value is extremely challenging and will require future data and experiences. Currently biomethanation is not yet economically feasible, but this may be different in the energy systems of the near future.
DOCUMENT
Within the Flexnode Plus project the long-term degradation characteristics of a proton exchange membrane (PEM) electrolyzer (5.5 kW, AC, 1 Nm3/h H2) and fuel cell (1.0 kW, DC, 0.9 Nm3/h) was experimentally tested. The electrolyzer unit was operated at various loads and pressures for approximately 750 hours in total, while the fuel cell was operated at a constant load of 1 Ω resistance for approximately 1120 hours in total. The efficiency of the hydrogen production in the electrolyzer and the electricity production in the fuel cell was expressed using the hourly average system efficiency and average cell efficiency. Inorder to predict the state of health and remaining lifetime of the electrolyzer cell and fuel cell, the decay of the cell voltage over time was monitored and the direct mapping from aging data method was used.The electrolyzer cell showed a stable cell voltage and cell efficiency in the studied time period, with an average cell voltage decay rate of 0.5 μV/h. The average cell voltage of the fuel cell dropped with a rate of 2 μV/h during the studied time period.
DOCUMENT
This paper proposes a Hybrid Microgrid (HμG) model including distributed generation (DG) and a hydrogen-based storage system, controlled through a tailored control strategy. The HμG is composed of three DG units, two of them supplied by solar and wind sources, and the latter one based on the exploitation of theProton Exchange Membrane (PEM) technology. Furthermore, the system includes an alkaline electrolyser, which is used as a responsive load to balance the excess of Variable Renewable Energy Sources (VRES) production, and to produce the hydrogen that will be stored into the hydrogen tank and that will be used to supply the fuel cell in case of lack of generation. The main objectives of this work are to present a validated dynamic model for every component of the HμG and to provide a strategy to reduce as much as possible the power absorption from the grid by exploiting the VRES production. The alkaline electrolyser and PEM fuel cell models are validated through real measurements. The State of Charge (SoC) of the hydrogen tank is adjusted through an adaptive scheme. Furthermore, the designed supervisor power control allows reducing the power exchange and improving the system stability. Finally, a case, considering a summer load profile measured in an electrical substation of Politecnico di Torino, is presented. The results demonstrates the advantages of a hydrogen-based micro-grid, where the hydrogen is used as medium to store the energy produced by photovoltaic and wind systems, with the aim to improve the self-sufficiency of the system
MULTIFILE
In the course of the “energie transitie” hydrogen is likely to become a very important energy carrier. The production of hydrogen (and oxygen) by water electrolysis using electricity from sun or wind is the only sustainable option. Water electrolysis is a well-developed technique, however the production costs of hydrogen by electrolysis are still more expensive than the conventional (not sustainable) production by steam reforming. One challenge towards the large scale application of water electrolysis is the fabrication of stable and cheap (noble metal free) electrodes. In this project we propose to develop fabrication methods for working electrodes and membrane electrode stack (MEAs) that can be used to implement new (noble metal free) electrocatalysts in water electrolysers.
The growing energy demand and environmental impact of traditional sources highlight the need for sustainable solutions. Hydrogen produced through water electrolysis, is a flexible and clean energy carrier capable of addressing large-electricity storage needs of the renewable but intermittent energy sources. Among various technologies, Proton Exchange Membrane Water Electrolysis (PEMWE) stands out for its efficiency and rapid response, making it ideal for grid stabilization. In its core, PEMWEs are composed of membrane electrode assemblies (MEA), which consist of a proton-conducting membrane sandwiched between two catalyst-coated electrodes, forming a single PEMWE cell unit. Despite the high efficiency and low emissions, a principal drawback of PEMWE is the capital cost due to high loading of precious metal catalysts and protective coatings. Traditional MEA catalyst coating methods are complex, inefficient, and costly to scale. To circumvent these challenges, VSParticle developed a technology for nanoparticle film production using spark ablation, which generates nanoparticles through high-voltage discharges between electrodes followed by an impaction printing module. However, the absence of liquids poses challenges, such as integrating polymeric solutions (e.g., Nafion®) for uniform, thicker catalyst coatings. Electrohydrodynamic atomization (EHDA) stands out as a promising technique thanks to its strong electric fields used to generate micro- and nanometric droplets with a narrow size distribution. Co-axial EHDA, a variation of this technique, utilizes two concentric needles to spray different fluids simultaneously.The ESPRESSO-NANO project combines co-axial EHDA with spark ablation to improve catalyst uniformity and performance at the nanometer scale by integrating electrosprayed ionomer nanoparticles with dry metal nanoparticles, ensuring better distribution of the catalyst within the nanoporous layer. This novel approach streamlines numerous steps in traditional synthesis and electrocatalyst film production which will address material waste and energy consumption, while simultaneously improve the electrochemical efficiency of PEMWEs, offering a sustainable solution to the global energy crisis.
