Issue 3, Volume 2 – 5 articles

Cover Story (View full-size image):
The global energy revolution is accelerating, and hydrogen stands at its forefront. As industries move away from fossil fuels, hydrogen promises to decarbonize key sectors, from energy generation to heavy industry. The development of advanced Mixed Matrix Membranes (MMMs-polymer and metal-organic framwork (MOFs)) for CO2/H2 separation, highlighted in this issue, plays a pivotal role in making hydrogen production cleaner and more efficient. These technologies not only boost sustainability but also integrate hydrogen into existing systems, enabling a low-carbon economy. As we harness hydrogen's potential, we're driving a transformative shift toward a sustainable, clean energy future.
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Perspective

24 June 2024

High Entropy Oxides: Next-Generation Air Electrodes for Reversible Protonic Solid Oxide Cells

Reversible protonic solid oxide cell (P-SOC) operating at intermediate-temperature exhibits excellent potential as a power generation and green hydrogen production device in fuel cell and electrolysis cell modes because of the high conversion efficiency. However, the lack of efficient air electrodes is the main challenge to obtain P-SOC with remarkable performance. Typically, air electrodes should possess high proton, oxygen ion and electron conductivity, outstanding catalytic ability for oxygen reduction reaction and H2O splitting, and also long-term durability. Recently, high entropy oxides (HEO) have become popular due to their various potential applications in terms of outstanding properties, including catalysis ability, conductivity, thermal stability, etc. HEO air electrodes have been confirmed to show good electrochemical performance in P-SOC, but the complex compositions and structure make it difficult to study HEO by traditional experimental methods. Machine learning (ML) has been regarded as a powerful tool in materials research and can solve the drawbacks in the discovery of HEO in a traditional way. In this perspective, we not only discuss the current utilization of HEO in P-SOC but also provide a possible process to use ML to guide the development of HEO.

Article

26 July 2024

Current and Future Costs of Storage for Electricity in a Decarbonized Electricity System

As power systems globally are transitioning from fossil fuels to renewable sources, integrating energy storage becomes imperative to balance variable renewable electricity generation. The core objective of this paper is to conduct a comprehensive cost assessment of selected energy storage technologies from 2023 to 2050, focusing on the Austrian electricity market. Our method combines techno-economic assessment with the technological learning method to integrate various storage technologies into a renewable electricity system, using scenarios that account for decarbonization goals. Results indicate that pumped storage hydro exhibits none or negative learning effects, while lithium-ion batteries demonstrate significant investment cost decreases. Despite investment cost reductions, underground hydrogen storage continues to incur high total costs per kWh discharged due to low roundtrip efficiency, suggesting its future outlook depends on seasonal storage needs in fossil-free power systems. An important finding of this analysis underscores the importance of optimizing the ratio of electricity demand, renewable generation expansion and storage deployment for cost-effectiveness. Excessive storage deployment leads to lower utilization and higher costs, emphasizing the necessity of at least 1500 full-load hours for profitable operation across all storage systems. Strategic planning for optimal storage deployment is emphasized to optimize utilization and minimize costs.

Article

06 August 2024

Evaluation of a Present-Day Thermal Activity on the Constitutive Minerals of a Granite and of Its Impact on the Whole-Rock Sealing Potentials

Mineralogical and chemical analyses of the major constitutive minerals from granite des Crêtes collected near the thermal site of Plombières-les-Bains (Vosges Mountains, eastern France) clearly show that recently circulating thermal waters up to 90 °C do not impact them. Even the constitutive minerals smaller than 2 microns are not affected. As a result, all minerals reflect the entire complex tectonic-thermal history of the granitic massif rather than just the recent thermal impact. Only the open faults and natural drains contain calcite from recent thermal waters. This is confirmed by similar calcite deposits with the same elemental contents sampled in the pipes of thermal installations. As a complementary conclusion, storage of containers of nuclear waste that diffuse an overall temperature up to 100 °C will not alter the potential sealing properties of a plutonic host massif, of course, without any recent thermal drainage that could potentially spread radioactive waste. This conclusion was already obtained on a moderately faulted sedimentary environment after a one-year in-situ heating experiment at about 100 °C. Calcium is a key indicator of low thermal impact. After an initial decrease, its levels rose significantly in the most "altered" granite samples, inducing calcite precipitation, even in the water pipes at the thermal site. The negligible impact of a hydro-thermal activity at a maximum of about 100 °C in a granitic material represents, indeed, a piece of useful information, as deep sites for nuclear waste in plutonic host rocks appear to act, also, as potential isolated host systems.

Article

15 August 2024

Hazardous Gas Monitoring with IoT Enabled Drone in Underground Tunnels and Cavities

Considering the healthiness of the atmosphere in mining activities (e.g., tunnelling), two of the most important parameters to be monitored are the concentration of oxygen and the presence of harmful gases such as CO2. Traditional methods for their measurement are fixed platforms and portable gas detectors carried by miners; they are incapable of recognizing sudden or short-term pollution events or correctly accounting for the spatial scarcity of gases. A UAV (Unmanned Aerial Vehicle) device capable of guaranteeing the measurement and continuous monitoring of concentrations has been designed. By using innovative technologies, it promotes digitization in the mining sector. This approach replaces current methods that, while effective at detecting and measuring environmental parameters, are slow, routine, and heavily reliant on human input. It saves productive expenses in the sector since it reduces costs compared to hiring a field technician for activities such as analysis of environmental conditions. This saving is about 110 euros daily, representing a 32% saving per working day for each mining technical responsible for environmental control. It also obtains a 3D spatial distribution of contaminants, a high sample resolution and a high sample resolution.. It reduces inspection time in mining works and the data collection time by more than 50%. The ECODRONE project constitutes a contribution to the MINE THE GAP challenge is a project financed with European funds whose line of desire aims to combine the innovation and development of SMEs or business groups from different regions of the mining, raw materials and materials sector. This program is aimed at strengthening the existing value chains and developing new industrial ones while designing new procedures, automated technologies, information and communication flows, which increase efficiency in the consumption of resources. All of the above implies integration with a circular economy and respect for European and global efficiency policies aimed at sustainability, industrial modernization, human health and the environment.

Communication

22 August 2024

Mixed Matrix Membranes Produced from a Fluorinated MOF and Pebax for CO2/H2 Separation

Hydrogen (H2) emerges as a promising clean energy source, but its efficient purification from various sources needs advanced separation technologies. This study explores the use of CO2-selective membranes, especially mixed matrix membranes (MMM) incorporating KAUST-7 metal-organic framework (MOF), for hydrogen purification. The MMM was fabricated with various KAUST-7 content in a polymer matrix (Pebax 1657) and characterized via Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and gas permeation tests. The XRD analysis confirms the incorporation of KAUST-7 into the MMM, while SEM reveals a homogeneous particle distribution at low content (below 10%) but agglomeration at higher ones (above 10%). FTIR confirms good interfacial interactions between the MOF and polymer matrix. TGA results show that the MMM thermal stability slightly decreases with increasing MOF content. Gas permeation results reveal improved CO2 permeability (79%) and CO2/H2 selectivity (19%) for MMM compared to neat Pebax membranes, with an optimal performance observed at 10 wt.% KAUST-7. Beyond this threshold, the performance deteriorates, possibly due to polymer rigidity and MOF agglomeration. Overall, the study highlights the potential of KAUST-7/Pebax MMM for enhanced hydrogen purification.

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