Fuel-based Technologies Research Articles

(Invited) Degradation Mechanisms and Mitigation Strategies for High-Temperature Solid Oxide Cells

Solid oxide cell technology represents one of the most efficient methods for energy conversion and has been the subject of extensive research over the past few decades. With significant technological progress, solid oxide fuel cells (SOFCs) have made their way into the market, steadily increasing their market share across various sectors for power generation. Additionally, solid oxide electrolysis cells (SOECs) have attracted substantial interest recently as a highly promising method for the clean production of hydrogen and various chemicals. However, the economic competitiveness of SOFCs and SOECs against conventional fossil fuel-based technologies remains a challenge, with cell and stack lifetimes being a critical factor. Operating at high temperatures, both SOFCs and SOECs are prone to various degradation phenomena, which have been a focal point in their development. SOECs operate under an even harsher environment, leading to additional degradation mechanisms beyond those observed in SOFCs. Studying the degradation mechanisms of SOFCs and SOECs is challenging, primarily due to limitations in characterization techniques. However, recent advancements in characterization techniques for high-temperature phenomena, coupled with theoretical modeling tools, have significantly enhanced our understanding. This progress has provided valuable insights into strategies to prolong the lifetime of SOFC/SOEC cells and stacks. This presentation will review recent advancements in degradation studies and discuss mitigation strategies for major degradation issues, including Cr poisoning, electrode delamination, and Ni agglomeration.

Numerical Estimation of Potable Water Production for Single-Slope Solar Stills in the Caspian Region

This study provides a detailed numerical assessment of the productivity of single-slope solar stills across key cities in the Caspian region, including Aktau, Atyrau, Astrakhan, Makhachkala, Baku, Tehran, and Turkmenbashi. Employing a mathematical model based on heat balance equations and the Fourth Order Runge–Kutta method, we simulated the distillation process under various climatic conditions. The results reveal that productivity is significantly influenced by geographic location and local meteorological conditions. Tehran demonstrated the highest productivity across all seasons, with values of 1.75 × 103 kg/(m2·year) and an efficiency of 0.53, due to its optimal solar irradiation and ambient temperature. In contrast, Atyrau and Makhachkala exhibited lower productivity, particularly in colder months, highlighting the effect of ambient temperature on solar still efficiency. The analysis identified the optimal water depth at 2 cm and insulation thickness between 4 and 9 cm for enhancing productivity in continental climates like Aktau. Additionally, the lowest cost of distilled water was USD 0.024 per kilogram in Baku. These findings align with the existing literature, validating the numerical model’s accuracy. Future research will explore integrating solar stills with other renewable and fossil fuel-based technologies.

Post mortem Study of Catalyst Degradations Occurring in High-Temperature Proton Exchange Membrane Fuel Cells Upon Start-Stop Operation

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) could replace fossil fuel-based technologies for applications which cannot involve bulky/heavy cooling systems, such as aeronautics. However, severe materials degradations upon operation prevent performance retention for acceptable lifetimes. While others have already reported degradations in HT-PEMFC, post mortem characterizations of used HT-PEMFC membrane electrode assemblies (MEAs) remain scarce. Herein, HT-PEMFC performance degradation is studied by applying a startup/shutdown protocol to a short-stack operated at 160 °C; one MEA is characterized using complementary physicochemical/electrochemical techniques to identify/understand the degradation mechanisms and their origin. This start/stop operation mode (co-flow gas reactants) leads to substantial degradation inhomogeneity. For the anode, migration, coalescence, and detachment of Pt nanoparticles are witnessed induced by high-surface-area carbon support functionalization and corrosion. The anode electrochemical surface area (ECSA) remains constant at the inlet and increases significantly at the outlet, following inhomogeneous degradation of the cathode catalyst: the Ptz+ ions formed at high potential/oxidizing conditions concentrate towards the outlet, where they redeposit locally or at the anode, after diffusion/migration across the PBI membrane. Hence, the cathode ECSA decreases significantly at the inlet. Furthermore, intense Ni-leaching from the initial PtNi alloy catalyst is reported as a result of O2 mass-transport and phosphoric acid dilution inhomogeneity.

Uncovering Reduction Mechanisms of Fluoroethylene Carbonate

Energy storage plays an integral role in climate change mitigation, given that many promising alternatives to fossil fuel-based technologies rely on intermittent energy sources like the sun or wind. Particularly, lithium metal batteries (LMBs) are a promising technology due to lithium’s high theoretical specific capacity and low reduction potential, which can result in batteries with energy densities surpassing current state of the art lithium-ion batteries.1 Electrolyte design is a key strategy to improve the cycling stability and Coulombic efficiency of LMBs, where the highly reductive lithium metal anode reacts with the electrolyte during cycling, resulting in capacity loss. These reactions form a solid electrolyte interphase (SEI), and many successful electrolyte engineering strategies have involved tuning the SEI to be mechanically and chemically stable to prevent further reactions.In this research, we focus on fluoroethylene carbonate (FEC), a highly effective electrolyte solvent in LMBs.2 Although prior research has illuminated key reduction products of FEC2,3, including lithium fluoride (LiF), there remains a gap in understanding regarding the mechanism by which FEC and other similar fluorinated solvents are reduced to form an SEI. Furthermore, recent research has demonstrated that a preformed SEI comprised solely of LiF breaks down during cycling, illustrating that bulk chemical and mechanical properties of SEI components may not translate to their function within the SEI.4 In this work, we employ electron paramagnetic resonance (EPR) spectroscopy to study intermediate generation during FEC reduction. We pursued both a chemical reduction using lithium naphthalenide and an electrochemical approach to reduce FEC. The use of EPR with spin traps enables insight into the radical species formed during FEC reduction, which we hypothesize are precursors to cross-linked polymer networks that are key to a high performing SEI. Here, we employed conventional post-mortem SEI analysis like X-ray Photoelectron Spectroscopy (XPS) in addition to EPR to clarify reduction mechanisms of FEC and form a framework for studying electrolyte reduction intermediates. Ultimately, this approach affords insight into electrolyte breakdown mechanisms to form an effective SEI which can both accommodate volume expansion and inhibit parasitic electrolyte consumption. This will guide electrolyte design for high Coulombic efficiency LMBs in the future.References K. G. Gallagher et al., Energy Environ. Sci., 7, 1555–1563 (2014).X.-Q. Zhang, X.-B. Cheng, X. Chen, C. Yan, and Q. Zhang, Advanced Functional Materials, 27, 1605989 (2017).Y. Jin et al., J. Am. Chem. Soc., 139, 14992–15004 (2017).M. He, R. Guo, G. M. Hobold, H. Gao, and B. M. Gallant, Proceedings of the National Academy of Sciences, 117, 73–79 (2020).

Intermetallic Compounds Mo2 TMB2 (TM: Fe, Co, Ni) for Hydrogen Evolution Reaction

Due to rising energy demand, renewable energy sources integrated processes have gained great interest in the recent years. Water electrolysis powered with renewable energy have potential to contribute to the development of sustainable hydrogen economy enormously. Despite the fact that “green” hydrogen is produced in the water electrolyzers with eco-friendly product O2, the excess energy input still hinders this technology to replace the fossil fuel-based technologies. Even with tremendous attempts and considerable contribution to the electrocatalyst development/optimization/improvement over last decades, there is a continued massive endeavor on the way of noble-metal based catalyst replacement for oxygen evolution reaction (OER) as well as for hydrogen evolution reaction (HER). From this point of view, transition metal-containing intermetallic compounds with well-defined electronic and crystal structures, are considered as promising electrocatalysts or precursors for them [1, 3]. Up to now, Mo-Ni and Mo-B systems have been explored for the hydrogen evolution reaction, and noticeable HER activities have been demonstrated for the binary compounds in these systems [4-6].The chemical behavior of ternary borides Mo2FeB2, Mo2CoB2 and Mo2NiB2 under hydrogen evolution (HER) reactions is investigated. Material synthesis and electrode manufacturing include the arc melting of elements in 2:1:2 atomic ratio, homogenization annealing at 1300-1400 °C and densification of grinded powder into cylindrically shaped electrodes via spark plasma sintering (SPS). The electrochemical measurements are carried out in 1M KOH and ambient conditions. Electrocatalytic activity and stability are monitored with cyclic voltammetry (CV) and 2-hour chronopotentiometry (CP) measurements performed at reducing current density of 10 mA cm-2, which are considered as conditions of standard benchmarking HER experiment. Furthermore, long-term stability of HER activity at elevated reducing current densities such as 50, 100, 200 mA cm-2 are essential to prove the preserved catalytic performance under harsh reaction conditions. For the comprehensive pre- and post-characterization of the electrode materials, bulk and surface-sensitive techniques are utilized.The pristine Mo2FeB2, Mo2CoB2 and Mo2NiB2 in HER region outperform their constituent TM components and indeed, their HER activity is close to that of the state-of-art Pt catalyst (Figure). During short-term CP experiment, Mo2NiB2 and Mo2FeB2 show continuing activation during the measurement, whereas Mo2CoB2 maintained its stability. Energy dispersive X-ray analysis (EDXS) of electrochemically treated areas indicate an enrichment in Fe, Co and Ni due to the noticeable leaching of Mo into electrolyte. Also, chemical analysis via ICP-OES reveals only Mo among all three constituent elements in the exploited electrolyte solution.As a conclusion, Mo2 TMB2 intermetallic compounds show outstanding HER activity and its stability over 2h of CP with respect to corresponding reference materials. Long-term chronopotentiometry in alkaline media were carried out and will be extensively presented. Figure. HER activity of Mo2 TMB2 (TM: Fe, Co, Ni) with respect to elemental references Fe, Co, Ni and state-of-art Pt. Inlets: Backscattered secondary electron images after 2h CP, including energy dispersive X-ray (EDXS) analysis results.

Carbon-Coated Mesoporous Silica Nano-Quills from Bioderived Cellulosic Templates for Low-Cost Anodes

The escalating global energy demands, driven by population growth and the electrification of transportation, have positioned rechargeable lithium-ion batteries (LIBs) as critical components in phasing out traditional fuel-based technologies. To date, several high-capacity active materials have been developed to replace current graphite-based anodes for boosting the energy density of LIBs. Silicon dioxide (SiO2, or silica) has emerged as a promising alternative, with a high theoretical capacity of 1965 mAh g-1, five times higher than conventional graphite, along with a comparatively smaller volume change than elemental Si during battery cycling. In this study, we report a patented synthesis process that harnesses wood-derived cellulose nanocrystals (CNCs) to craft a unique three-dimensional (3D) silica architecture for developing low-cost LIB anodes. Our cost-effective method yields a mesoporous silica material, termed silica nano-quill (SilicaNQ), with distinctive hollow 1D arms. In addition, we propose a direct annealing strategy for transforming CNC templates into a conformal carbon coating to fabricate SilicaNQ@C powder material. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) provided a detailed exploration of the elemental composition and the bonding states at the atomic level. Anodes comprising SilicaNQ@C active material delivered a stable reversible capacity of 1030 mAh g-1 after cycling at 200 mA g-1 for 200 cycles. We performed X-ray diffraction (XRD) measurements on SilicaNQ@C half cells to identify phase changes at various state-of-charge levels and explore the evolution of interface components over cycling.

Green hydrogen exports in New Zealand and Chile can improve electricity supply security if configured as local energy insurance

Extreme weather events, for example, prolonged droughts, are increasingly stressing electricity systems and threatening the achievement of energy transition goals. At the same time, countries such as Chile and New Zealand are developing strategies to export renewable energy through green hydrogen. This paper economically evaluates the use of future green hydrogen exports as strategic storage under the logic of energy insurance, based on the assumption that Chile and New Zealand will adopt a hydrogen economy. Our first contribution is to compare the marginal costs of re-electrified green hydrogen, for different scenarios, to the value of lost load in New Zealand and Chile. We then determine the marginal cost of energy produced from green hydrogen based on projected production, transportation, and re-electrification costs for the year 2030. Finally, we estimate the eventual penalties that exporters would incur in the case of breaking their contracts and the overall resulting system costs of using hydrogen for system security. We found that re-electrifying hydrogen can be competitive with conventional technologies at 3 USD/kg. At 1.5 USD/kg, hydrogen is more competitive than fossil fuel-based technologies, for both New Zealand and Chile. Thus, in 2030, it could make economic sense for New Zealand and Chile to use hydrogen as a strategic reserve. The system cost of the proposed insurance scheme in 2030 ranges from 0.53 to 1.76 USD/MWh, which is small compared to total electricity costs. These values can be used for power system expansion and operation planning.

Firming Technologies to Reach 100% Renewable Energy Production in Australia’s National Electricity Market (NEM)

Australia has committed to reducing its greenhouse gas emissions in a manner consistent with limiting anthropogenic climate change to no more than 2 degrees Celsius. One of the ways in which this commitment is being realised is through a shift towards variable renewable energy (VRE) within Australia’s National Electricity Market (NEM). Substituting existing dispatchable thermal plant with VRE requires consideration of long-term energy resource adequacy given the unpredictability of solar and wind resources. While pumped hydro and battery storage are key technologies for addressing short-term mismatches between resource availability and demand, they may be unable to cost effectively address ‘energy droughts’. In this article, we present a time sequential solver model of the NEM and an optimal firming technology plant mix to allow the system to be supplied by 100% VRE. Our conclusion is that some form of fuel-based technology (most likely hydrogen) will probably be required. This has important implications for Australian energy policy.

Waste Tire Derived Carbon Support for Non-Platinum-Group Metal Catalyst Materials for Oxygen Reduction Reaction in Alkaline Medium

Extensive use of non-renewable energy sources and excessive accumulation of hard-to-recycle waste, such as end-of-life tires, are among the most significant environmental problems today. For a more sustainable future, it is essential to find alternative solutions to energy and special waste management. For example, waste tires can be used to synthesize high-tech porous carbon materials, which can be used as a carbon support in fuel cell catalysts. [1] While fuel cells offer a promising alternative to some fossil fuel-based technologies, low temperature fuel cell catalysts rely on expensive platinum. Non-platinum-group metal (NPGM) catalysts, such as iron and nitrogen co-doped carbon materials are good contenders to platinum-based catalysts for the oxygen reduction reaction. Synthesizing porous carbon materials for more economically viable NPGM fuel cell catalysts could provide one way to use waste tires more sustainably and lower the cost of efficient fuel cell catalysts.For this work, a carbon material was synthesized by pyrolyzing tire granules (Imdex A/S) at 1000 °C for three hours in Ar [2]. Based on this carbon material, several iron and nitrogen co-doped catalyst materials were synthesized using Fe(NO3)3 as the iron source, dicyandiamide or guanidine as the nitrogen source, and ZnCl2 as a pore modifier. All synthesized materials were acid washed overnight to remove redundant elements such as Zn from the pore modifier and various impurities originating from the tire granules (mainly Si, S, Ca, and Zn). Finally, the materials pyrolyzed for a second time. The pyrolysis temperature, choice of nitrogen compound, and precursor ratios were varied for the syntheses described in this work.The NPGM catalyst materials were characterized by various physical and electrochemical methods to describe the relationship between the catalyst structure and the activity of the oxygen reduction reaction. SEM and SEM-EDX were used to evaluate the morphology and composition of the catalyst materials. N2 sorption data suggested that the specific surface area ranged from 77 to 194 m2 g-1 for all materials. Electrochemical characterization was performed in 0.1M KOH solution using the rotating disk electrode method. The highest onset potential (Eon = 920 mV vs RHE) was reached by a material using guanidine as the nitrogen source pyrolyzed at 900 °C, which is comparable to other recently described NPGM materials [3], including waste-tire derived NPGM catalysts [4]. Acknowledgements: This work was supported by the following projects: PRG676 “ Development of express analysis methods for micro-mesoporous materials for Estonian peat derived carbon supercapacitors” (1.01.2020- 31.12.2024)"Advanced materials and high-technology devices for sustainable energetics, sensorics and nanoelectronics” (TK141) (1.01.2016−1.03.2023) References [1] J. S. Gnanaraj et al., Sustainability 10(8), 2840 (2018)[2] J. Laanemäe, R. Jäger, P. Teppor, O. Volobujeva, and Enn Lust, ECS Transactions, 108, p. 39 (2022)[3] R. Gutru et al., International Journal of Hydrogen Energy, 47 (2022)[4] M. Muhyuddin et al., Electrochemica Acta, 433, 141254 (2022)

Modelling the linkage between fossil fuel usage and organizational sustainability

In today's competitive business environment, ensuring the sustainability in long-run remains a key challenge for business organizations. Using fossil fuel-based technologies for in carrying out operating activities may put organizational sustainability at stake. Until now, researcher have not paid much attention to explore these issues. Consequently, following the recommendations of natural-resource-based view current study attempts to identify the issues & sub-issues concerning fossil-fuel usage by businesses and solutions to mitigate the effect of these. To understand the priority order of these identified issues and respective sub-issues, BWM (Best Worst Method) is employed. Further, current work uses VIKOR (VlseKriterijumska Optimizacija I Kompromisno Resenje) to explore the ranks of the proposed solutions considering the issues under consideration. Current analysis indicates “Legislation” to remain the most important issue followed by “Environment.” Further, ‘Sensitising and training employees towards usage of fossil fuel-based technologies with no wastage or minimum wastage’ is observed as the most workable solution in the short-term. The solution “Switching to renewable energy sources” is ranked on the second position. Findings of current study carry significant informational content that may assist organizations in developing the strategic framework to achieving long-term sustainability.

Quantifying agricultural productive use of energy load in Sub-Saharan Africa and its impact on microgrid configurations and costs

The use of advanced energy technologies for agricultural purposes—such as irrigation, refrigeration, crop processing, and egg incubation—has the potential to increase crop yield, reduce vulnerability to changing precipitation patterns, increase shelf life, strengthen income and employment opportunities in rural areas, and reduce emissions by displacing fossil fuel-based technologies. These productive uses of energy (PUE) in remote areas could potentially be powered by microgrids that additionally serve otherwise unelectrified communities, most of which are located in rural Sub-Saharan Africa. In this paper, we use high-resolution geospatial data to estimate the end-use electricity demand for a range of agricultural PUE across Sub-Saharan Africa, and we share these data in an open-access mapping tool. Next, we use REopt®, a techno-economic optimization model of energy systems, to determine the cost and system sizing implications of incorporating agricultural PUE into microgrid designs in Kenya and Zambia. We estimate the upper bound of agricultural PUE demand for irrigation, milling, shelling, refrigeration, and egg incubation across Sub-Saharan to be 16.8 TWh/yr. We find that incorporating local agricultural PUE into microgrid system designs increases the required system sizing while having minimal impact on the levelized cost of energy of these systems. Our analysis is the first to demonstrate the PUE potential in the agricultural sector at a 10x10-kilometer resolution across Sub-Saharan Africa and to show, at scale, how site-specific PUE can impact the cost and sizing of microgrids that are otherwise deployed to serve local household and community load.

A Study on Linkage between Global Warming Indicators and Climate Change Expenditure

Purpose: The emissions of greenhouse gases (GHGs) have a critical influence on sustainable development and cause global warming, therefore contributing to climate change. National and international governments prioritize measures to mitigate global warming by funding green projects. The study aims to assess the relationship between global warming indicators (emission level of carbon dioxide, methane and greenhouse gas) and India’s climate change expenses incurred for employing renewable energy sources avenues nuclear power plants, efficient waste management, and transforming fuel-based technology with electricity-based to meet the extending electricity need. Methodology: The secondary data is taken from the World Bank to establish the causality between climate change expenditure and global warming indicators. The augmented dickey-fuller (unit root) test is performed to check the stationarity of the data series. Based on the validated data, the quantum of discharge of CO2, CH4 and GHGs is used to gauge the impact on climate change expenditure through Engle and Granger technique on e-views software. Findings: The results indicate a positive relationship between CO2, CH4, GHGs emissions and expenditure incurred to implement the mitigation strategies for climate change. The stationarity of the series is established at the first difference. Then regression model is determined through Engle-Granger Test, which depicts the model as a good fit with a 76% prediction level. Managerial implications: The study provides insight into the successive increase in climate change expenditure which requires the government to frame a more stringent policy to preserve the environment with proper implementation to reduce greenhouse gas emissions.

A Review of the Life Cycle Analysis Results for Different Energy Conversion Technologies

Technologies that use renewable energy sources (RES) are crucial to achieving decarbonization goals, but a significant number of studies show their relatively high environmental impact during the production phase. Therefore, technologies need to be compared in terms of their life-cycle environmental impact. The life cycle analysis (LCA) methodology is well known and widely employed. However, problems related to the methodological choices prevent taking full advantage of the LCA, as the results of numerous studies are often incomparable. The presented review aims to critically compare the impact of different energy generation technologies—RES (as well as non-RES) energy generators and co-generators. The numeric results are structured and analyzed in terms of the global warming potential (GWP) and non-RES primary energy consumption. The results show that RES technologies are superior compared to conventional fossil-fuel-based systems in most cases, and the high impact during the production and installation phases is compensated in the operational phase. The high variations in GWP from similar technologies result from different methodological choices, but they also show that the wrong choice of the technology in a certain location might cause serious environmental drawbacks when the impact of the RES technology exceeds the impact of fossil fuel-based technologies. Cogeneration technologies using waste as a fuel may even have a negative GWP impact, thus showing even higher potential for decarbonization than RES technologies.

Porous Silicon Nano-Quill Anodes for Lithium-Ion Batteries

The growing population and increasing demands for energy are overwhelming our supply of fossil fuels and limiting the availability for future generations. Technologies for energy storage devices are emerging to replace conventional fuel-based technologies to meet emissions goals set by world governments and the rapid electrification of the transportation sector. Lithium-ion batteries (LIBs) are widely used for energy storage in devices across many commercial applications. LIB electrodes are continuously evolving due to demands for higher energy density and long cycling life. Among the recent developments in anode electrode materials, silicon (Si) is regarded as the most promising replacement for graphite due to its high theoretical specific capacity (~4200 mAh g-1), which is over 10 times greater than that of conventional graphite anodes (~372 mAh g-1). Despite the advancements, persisting challenges hinder the commercialization of Si for LIB anodes. Si-based electrodes are susceptible to rapid degradation due to the large volume change (approx. 400%) of Si particles during lithium insertion and extraction. The repeated volume change leads to the pulverization of the Si material, ultimately leading to decreased cycling stability from the loss of contact with the current collector. To overcome this obstacle, 3-dimensional porous and hollow nanostructures have been employed to provide sufficient void space to accommodate the volume change during electrochemical cycling. However, with the demands for material cost-reduction from industry, Si structures' strategic engineering must be cost-effective for commercial viability.Our team has developed a patent-pending cost-effective, scalable, and green methodology to use bio-renewable templates to synthesize a 3-dimensional Si architecture, called Si nano-quills (SiNQs). We innovated a two-step, cost-effective process that yields SiNQs with a porous morphology and hollow interior structure. First, in a scalable sol-gel process, silica gel particles were prepared using commonly available low-cost chemicals. The unique mesoporous SiNQ morphology was engineered using surfactant-modified cellulose nanocrystals as a bio-renewable sacrificial template. The templates were removed via thermal treatment to form silica nanoparticles. These particles, called silica nano-quills (SilicaNQs), possess a 3-dimensional bulk structure comprised of hollow quill-like arms and a high degree of porosity. In the second step, we employed a low-temperature magnesiothermic reduction method to convert SilicaNQs into SiNQs with a relatively large surface area. Anode electrodes were fabricated using SiNQs as the active material for electrochemical testing. The slurry was prepared using the active material, carbon black, and PVDF with a mass ratio of 60:20:20 coated onto an ion-permeable Bucky Paper (BP, a flexible and conductive paper made of carbon nanotubes). The 2032-type coin cells were assembled for battery testing using SiNQ electrodes (with an active mass loading of 1 mg cm-2) and a lithium metal chip as the counter electrode. The coin cells were cycled at a current rate of 0.1C (420 mA g-1) over the potential range of 0.01 – 1.0 V at room temperature. The SiNQ anode offered superior battery capacity retention of 73% of the initial reversible capacity of 963 mAh g-1 after 220 cycles. In comparison, batteries fabricated from the Mg reduction of commercially available mesoporous silica, SBA-15, offer capacity retention of only 52.6% after 100 cycles. The SiNQ precursor is engineered to possess porous walls with a superior BET surface area (1265 m2 g-1) compared to SBA-15 (550 m2 g-1). After Mg reduction, the SiNQs retain a BET surface area of 232 m2 g-1, whereas the surface area of reduced SBA-15 is 74 m2 g-1. The superior performance of SiNQs is due to their unique morphology that offers high surface area and porosity for effective diffusion of lithium ions and more sites for interactions with lithium ions, leading to a higher reversible capacity. Moreover, the porous architecture of SiNQs can effectively mitigate the volume change issue during lithiation and delithiation processes, thus providing a good cycling performance.

Exploring energy storage methods for grid-connected clean power plants in case of repetitive outages

Inadequate access and unstable grid service are among the most severe difficulties developing communities face. As a result, these communities depend on fossil fuel-based technology to supply their electrical demands, which has significant socioeconomic consequences for society. The objective of this paper was to investigate greener, more sustainable technologies, such as solar battery storage systems. This research proposed a sizing technique for grid-connected photovoltaic systems with different battery technologies through techno-economic feasibility analysis. In the suggested method, the techno-economic performance of photovoltaic energy systems with five different battery technologies was compared: lead-acid battery, lithium-ion battery, vanadium redox battery, and nickel-iron battery. For different grid outage frequencies, this investigation was conducted (0 to 500 interruptions per year. The key comparison indices considered are the investment cost, renewable energy fraction, and surplus electricity. The grid-connected photovoltaic/nickel-iron battery system was shown to be the most efficient at high main grid failure frequencies.

(Digital Presentation) Ternary Nifetiooh Catalyst for the Oxygen Evolution Reaction: Study of the Effect of the Addition of Ti at Different Loadings

Ternary NiFeTiOOH Catalyst for the Oxygen Evolution Reaction: Study of the Effect of the Addition of Ti at Different Loadings Wenjamin Moschkowitsch and Lior Elbaz Chemistry Department, Bar-Ilan University, Ramat-Gan 5290002, IsraelThe demand for energy is expected to grow rapidly in the next decades, but it cannot be solely fulfilled with fossil fuel-based technologies without having a huge impact on the environment. The shift to production of clean energy from alternative sources, such as wind and sun, raise the importance of energy storage technologies. One of the most prominent solutions is storing surplus energy, harvested at peak production times and seasons, in hydrogen. However, the production of hydrogen with methods that require as little energy as possible, as well as being sustainable, environmentally friendly and cheap, are still considered to be a big challenge.Water electrolysis is the simplest industrial process for hydrogen production, and can be linked to fuel cells technology. Among the available electrolyzers, alkaline electrolyzers (ALE) are considered state-of-the-art. Although they can work with platinum-group metal-free (PGM-free) catalysts, unfortunately, this technology still requires the use of PGM catalysts in order to increase the current density, and lower the reaction activation energy.In electrolyzers, water splits into oxygen and hydrogen in two separate reactions, taking place at the anode and cathode. The cathodic reaction is the Hydrogen Evolution Reaction (HER), which is considered to be relatively facile. The anodic, Oxygen Evolution Reaction (OER), is considered to be much more difficult, since it is a four-electron process with very sluggish kinetics. The best known catalysts for this reaction in acidic medium are IrO2 and RuO2, oxides of very rare and precious metals (Ir is the scarcest metal on earth’s crust). In addition, in acidic medium, most PGM-free catalysts, based on earth abundant elements, are considered unstable (these conditions have also shown to be detrimental for Ir and Ru-based catalysts). In contrast, in ALEs, PGM-free catalysts have shown to be a good alternative to PGM catalysts. The most common OER PGM-free catalysts are first-row transition metals in their oxide, hydroxide and oxyhydroxide forms.One such catalyst is nickel oxyhydroxide (NiOOH). The structure of this specific catalyst has been studied in great detail by many different research groups, yet there are several open questions regarding the OER mechanism, i.e. the exact catalytic center and active phase.Recent studies suggest that pure NiOOH is not very active at all, and that all of the activity can be attributed to iron impurities.Indeed, NiFeOOH with iron content of 15-25 %at, has a much higher activity and a much lower overpotential compared to other PGM-free catalysts. It can thus be regarded as a benchmark for this class of OER catalysts.It is well accepted by now that the bimetallic catalyst further increases the intrinsic catalytic activity, and that addition of other transition metals,can further increase it.

Electrolyte Effects on CO2 Electrochemical Reduction to CO.

ConspectusThe electrochemical reduction of CO2 (CO2RR) constitutes an alternative to fossil fuel-based technologies for the production of fuels and commodity chemicals. Yet the application of CO2RR electrolyzers is hampered by low energy and Faradaic efficiencies. Concomitant electrochemical reactions, like hydrogen evolution (HER), lower the selectivity, while the conversion of CO2 into (bi)carbonate through solution acid–base reactions induces an additional concentration overpotential. During CO2RR in aqueous media, the local pH becomes more alkaline than the bulk causing an additional consumption of CO2 by the homogeneous reactions. The latter effect, in combination with the low solubility of CO2 in aqueous electrolytes (33 mM), leads to a significant depletion in CO2 concentration at the electrode surface.The nature of the electrolyte, in terms of pH and cation identity, has recently emerged as an important factor to tune both the energy and Faradaic efficiency. In this Account, we summarize the recent advances in understanding electrolyte effects on CO2RR to CO in aqueous solutions, which is the first, and crucial, step to further reduced products. To compare literature findings in a meaningful way, we focus on results reported under well-defined mass transport conditions and using online analytical techniques. The discussion covers the molecular-level understanding of the effects of the proton donor, in terms of the suppression of the CO2 gradient vs enhancement of HER at a given mass transport rate and of the cation, which is crucial in enabling both CO2RR and HER. These mechanistic insights are then translated into possible implications for industrially relevant cell geometries and current densities.

NiO nanowire-containing heat transfer nanofluids for CSP plants: Experiments and simulations to promote their application

Concentrating solar power (CSP) is considered a clean, renewable and sustainable energy with a significant potential to become an alternative to polluting fossil fuel-based technologies. Among CSP collectors, parabolic-trough collectors (PTC) are the most mature technology, representing nearly 90% of the currently installed collectors in CSP plants worldwide. In this technology, a heat transfer fluid (HTF) carries the thermal energy absorbed to a power block to produce electricity. Improving the thermal properties of the conventional HTF could lead to an improvement of the efficiency of CSP plants. In this sense, the use of nanofluids as the HTF in these plants can be a promising choice. Here, polycrystalline NiO nanowire-containing nanofluids have been prepared using the conventional HTF used in CSP plants as the base fluid; that is, the eutectic and azeotropic mixture of biphenyl (26.5%) and diphenyl oxide (73.5%). The stability, rheological and thermal properties have been characterized, and an analysis of the performance of the nanofluids prepared in standard and volumetric absorbers have been carried out. The overall CSP system performance can be increased up to 34.8% using the nanofluid in a surface collector or up to 34.3% using the nanofluid in a volumetric collector, which are better than the predicted 28.5% using the conventional HTF in a standard surface collector, thanks to the improvements in thermal properties, both specific heat and thermal conductivity. Finally, from molecular dynamics simulations we determined that the mean free path of thermal vibrations is longer for monocrystalline NiO nanowires. Thus, the development of strategies for obtaining this kind of nanostructures is of great interest because they can further improve the efficiency of these nanofluids.

Risk-Calibrated conventional-renewable generation mix using master-slave portfolio approach guided by flexible investor preferencing

This paper proposes a master-slave approach to quantify, combine and balance energy-risk and cost-risk involved in a generation portfolio with renewable and fuel-based technologies. Subjective preferences of the investor on risk, cost and emission are traded-off using pareto-optimization and quantified using multi-criteria decision-making techniques. Temporal variations in renewable energy production led to ‘energy-risk’ (kWh), characterized by energy-return-risk Efficient Frontier (EF). The uncertainty in the energy production cost of the fuel-based sources (FBS) results in ‘cost-risk’ ($/kWh), represented by cost-risk EF. These efficient frontiers are combined using the concepts of Sharpe ratio and tangency portfolio. The master portfolio (MP) gives a percentage share for the total renewable and total conventional generation. The slave portfolio (SP) assigns internal weights within the renewable (solar and wind) and within the fuel-based (coal, natural gas, and oil) generations. The best solution is selected from the pareto-front by calibrating the investor preferences using Analytic Hierarchy Process (AHP) and then verified using Elimination and Choice Translating Reality (ELECTRE). It is understood that a completely customizable multi-criteria portfolio selection can be achieved by incorporating subjective views of the investors, eliminating one-sided energy portfolios.

Valorisation of lignocellulosic biomass to value-added products: Paving the pathway towards low-carbon footprint

Biofuel is the presently needed potential energy reservoir as an alternative to wearying fossil fuel-based technology. Second generation lignocellulose is considered to be the most abundant source of renewable feedstock among the biomaterials. Lignocellulose biomass (LCB) is the effective feed stock for bio-based chemicals for carbon neutrality, which paves critical prospect for significant sustainable and renewable development. This review discusses the types of biomass, characterization, and value-added products developed. Integrating the biological funnelling pathway in the bio-refinery concept and explaining the genetic modification of lignocellulosic biomass for enhanced yield is also discussed. The outlook on lowering the carbon footprint by discussing in detail the life cycle carbon balance, process development tools, supply chain description, and circular economy.