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Topic Review
Solar Energy
As an essential source of renewable energy, solar energy systems are broadly characterized as either passive solar or active solar depending on how they capture and distribute solar energy.
  • 1.9K
  • 03 Apr 2023
Topic Review
Hazards of the Ammonia Bunkering Process
Ammonia is thought to be a potential alternative for hydrogen storage in the future, allowing for CO2-free energy systems. Ammonia’s beneficial characteristics with regard to hydrogen storage include its high volumetric hydrogen density, low storage pressure, and long-term stability. However, ammonia is characterized by toxicity, flammability, and corrosiveness, making safety a challenge compared to other alternative fuels. In specific circumstances, leakage from ammonia bunkering can cause risks, dispersion, and unsafe areas due to its flammability and toxicity. To avoid dispersion, fire, and explosion hazards on ships, it is crucial to conduct thorough risk analyses.
  • 1.9K
  • 30 May 2023
Topic Review
Whey for Bioethanol Production by Yeast
Concerns about fossil fuel depletion and the environmental effects of greenhouse gas emissions have led to widespread fermentation-based production of bioethanol from corn starch or sugarcane. However, competition for arable land with food production has led to the extensive investigation of lignocellulosic sources and waste products of the food industry as alternative sources of fermentable sugars. In particular, whey, a lactose-rich, inexpensive byproduct of dairy production, is available in stable, high quantities worldwide. Therefore, whey is indeed an ideal alternative feedstock for fuel ethanol feedstock because it can provide a remarkable 6–10 million tons of lactose annually. However, despite the availability of this massive, underutilized resource, it faces challenges in being adopted at a commercial scale since S. cerevisiae, the most common fermentative species for transforming sugars to ethanol, lacks the enzyme required for lactose utilization and thus cannot ferment whey into ethanol without further metabolic engineering. 
  • 1.9K
  • 27 Apr 2022
Topic Review
Evaluation of Digital Applications
Digitalization is a transformation process which has already affected many parts of industry and society and is expected to yet increase its transformative speed and impact. In the energy sector, many digital applications have already been implemented. However, a more drastic change is expected during the next decades. Good understanding of which digital applications are possible and what are the associated benefits as well as risks from the different perspectives of the impacted stakeholders is of high importance. On the one hand, it is the basis for a broad societal and political discussion about general targets and guidelines of digitalization. On the other hand, it is an important piece of information for companies in order to develop and sustainably implement digital applications. This entry suggests a methodology to holistically analyze digital applications in the energy sector. The intended purpose of the suggested methodology is to provide a complexity-reduced fact base as input for societal and political discussions and for the development of new digital products, services, or business models. While the methodology is outlined in this entry, in a follow-up article the application of the methodology will be presented and the use of the approach reflected.
  • 1.9K
  • 05 Nov 2020
Topic Review
Technical and Economic Viability of Underground Hydrogen Storage
The concept of underground hydrogen storage (UHS) is less known than its natural gas counterpart, which is expected due to its less significant role in the past. Despite this, the insights gained with natural gas can be applied to hydrogen storage due to the shared cavern design and operation.
  • 1.9K
  • 11 Dec 2023
Topic Review
Fuel Cells
Fast start-up, high efficiency, no toxic emissions into the atmosphere and good modularity are the key advantages of fuel cell applications. Despite the merits associated with fuel cells, the high cost of the technology remains a key factor impeding its widespread commercialization.
  • 1.9K
  • 13 Jan 2021
Topic Review
Lignin/Cellulose Nanofibers for Supercapacitor Applications
Supercapacitors are energy storage devices with high power density, rapid charge/discharge rate, and excellent cycle stability. Carbon-based supercapacitors are increasingly attracting attention because of their large surface area and high porosity. Carbon-based materials research has been recently centered on biomass-based materials due to the rising need to maintain a sustainable environment. Cellulose and lignin constitute the major components of lignocellulose biomass. Since they are renewable, sustainable, and readily accessible, lignin and cellulose-based supercapacitors are economically viable and environmentally friendly.
  • 1.9K
  • 07 Mar 2022
Topic Review
LHTES
Latent heat thermal energy storage systems (LHTES) are useful for solar energy storage and many other applications, but there is an issue with phase change materials (PCMs) having low thermal conductivity. This can be enhanced with fins, metal foam, heat pipes, multiple PCMs, and nanoparticles (NPs). This entry focuses on nano-enhanced PCM (NePCM) alone and with additional enhancements. Low, middle, and high temperature PCM are classified, and the achievements and limitations of works are assessed. The review is categorized based upon enhancements: solely NPs, NPs and fins, NPs and heat pipes, NPs with highly conductive porous materials, NPs and multiple PCMs, and nano-encapsulated PCMs. Both experimental and numerical methods are considered, focusing on how well NPs enhanced the system. Generally, NPs have been proven to enhance PCM, with some types more effective than others. Middle and high temperatures are lacking compared to low temperature, as well as combined enhancement studies. Al2O3, copper, and carbon are some of the most studied NP materials, and paraffin PCM is the most common by far.
  • 1.9K
  • 07 Jul 2021
Topic Review
Perovskite Solar Cell
Organic-inorganic hybrid perovskite materials have attracted tremendous attention as a key material in various optoelectronic devices. Distinctive optoelectronic properties, such as a tunable energy band position, long carrier diffusion lengths, and high charge carrier mobility, have allowed rapid progress in various perovskite-based optoelectronic devices (solar cells, photodetectors, light emitting diodes (LEDs), and lasers). Interestingly, the developments of each field are based on different characteristics of perovskite materials which are suitable for their own applications. 
  • 1.8K
  • 20 Jan 2021
Topic Review
Microbial Technologies Applied Biofuel Production
The use of fossil energy sources has a negative impact on the economic and socio-political stability of specific regions and countries, causing environmental changes due to the emission of greenhouse gases. Moreover, the stocks of mineral energy are limited, causing the demand for new types and forms of energy. Biomass is a renewable energy source and represents an alternative to fossil energy sources. Microorganisms produce energy from the substrate and biomass, i.e., from substances in the microenvironment, to maintain their metabolism and life. However, specialized microorganisms also produce specific metabolites under almost abiotic circumstances that often do not have the immediate task of sustaining their own lives. Microorganisms can change the current paradigm, energy–environment, and open up countless opportunities for producing new energy sources, especially hydrogen, which is an ideal energy source for all systems (biological, physical, technological). Developing such energy production technologies can significantly change the already achieved critical level of greenhouse gases that significantly affect the climate.
  • 1.8K
  • 20 Sep 2022
Topic Review
Exploration and Use of Lithium in Oman
Oman has huge potential for lithium exploitation and production, considering the enormous quantities of spodumene and seawater salt with high-grade lithium available, developing efficient regulations and rules to protect investors’ rights, and reducing the environmental risks associated with the production and recycling of lithium-ion batteries. 
  • 1.8K
  • 29 Jan 2024
Topic Review
Hydrogen Production by Wastewater Alkaline Electro-Oxidation
The electro-oxidation of olive mill and biodiesel wastewaters in an alkaline medium with the aim of hydrogen production and simultaneous reduction in the organic pollution content are presented. The process is performed, at laboratory scale, in an own-design single cavity electrolyzer with graphite electrodes and no membrane. The system and the procedures to generate hydrogen under ambient conditions are described. The gas flow generated is analyzed through gas chromatography. The wastewater balance in the liquid electrolyte shows a reduction in the chemical oxygen demand (COD) pointing to a decrease in the organic content. The experimental results confirm the production of hydrogen with different purity levels and the simultaneous reduction in organic contaminants. This wastewater treatment appears as a feasible process to obtain hydrogen at ambient conditions powered with renewable energy sources, resulting in a more competitive hydrogen cost.
  • 1.8K
  • 15 Sep 2022
Topic Review
Produced Water Treatment
Flowback-produced water (FP) is a waste fluid associated with hydraulic fracturing in unconventional oil and gas development (UOG). Initially, FP reflects the composition of the hydraulic fracturing fluid, which is referred as flowback water (FBW). After the initial months of well production, the waste fluid is predominantly representative of the formation and is known as produced water (PW). 
  • 1.8K
  • 08 Jul 2022
Topic Review
Hybrid Renewable Energy System
The HRES is a cyber–physical system that can be divided into two layers: the power infrastructure and the communication infrastructure layers, as shown in Figure 1. The power infrastructure layer consists of different energy sources (e.g., wind turbines, photovoltaics, diesel generators, and batteries), transformers, feeders, converters, and electrical connections. The communication infrastructure layer supports the physical infrastructure by an underlying communication network, linking between sensors and actuators nodes. This enables the local control center to manage the system operation. In this integration, ICTs play an essential role in allowing the transition from the conventional power grid to the future smart grid by supporting the integration of HRES.
  • 1.8K
  • 06 Sep 2021
Topic Review
Time Series Aggregation for ESMs
Due to the high degree of intermittency of renewable energy sources and the growing interdependences amongst formerly separated energy pathways, the modeling of adequate energy systems is crucial to evaluate existing energy systems and to forecast viable future ones. However, this corresponds to the rising complexity of energy system models (ESMs) and often results in computationally intractable programs. To overcome this problem, time series aggregation is frequently used to reduce ESM complexity. As these methods aim at the reduction of input data and preserving the main information about the time series, but are not based on mathematically equivalent transformations, the performance of each method depends on the justifiability of its assumptions.
  • 1.8K
  • 29 Sep 2021
Topic Review
Effect of Wettability Parameters on Enhanced OIl Recovery
Modifying reservoir surface wetting properties is an appealing topic to the upstream oil and gas industry for enhancing hydrocarbon recovery, as the shifting of reservoir rock surface wetting from oil-wet to water-wet has enhanced the oil recovery (EOR) by as much as 70–80%. Wettability is defined as the ability of a fluid to stay in contact with a solid surface preferentially to another immiscible fluid present due to intermolecular interactions. The cohesive and adhesive forces describe the intermolecular interaction between solids and liquids. Cohesive force attracts similar molecules; adhesive force attracts different molecules. The balance of adhesive and cohesive forces of the oil–water–rock phase defines the wettability conditions of reservoir rocks. The wettability condition of reservoir rocks is one of the most critical factors influencing fluid flow in porous media, subsequently impacting the overall hydrocarbon recovery efficiency. Based on their wettability characteristics, oil reservoirs are divided into water-wet, oil-wet, mixed-wet, and intermediate-wet. Many experimental studies have contributed to the understanding of the wettability alteration mechanism. Despite the extensive research, concerns about a lack of understanding of the wettability alteration mechanisms in various reservoir conditions still exist. Microfluidic technologies, with microfabrication and reservoir micromodels, revolutionize researchers'  understanding of wettability alteration during enhanced oil recovery, surpassing traditional core-based experiments and offering real-time insights into geochemical changes.
  • 1.8K
  • 11 Mar 2024
Topic Review
Iron Ore Reduction with Hydrogen
The steel industry represents about 7% of the world’s anthropogenic CO2 emissions due to the high use of fossil fuels. The CO2-lean direct reduction of iron ore with hydrogen is considered to offer a high potential to reduce CO2 emissions, and this direct reduction of Fe2O3 powder is investigated in this research.
  • 1.8K
  • 18 Sep 2021
Topic Review
Power Battery Thermal Management System
The battery thermal management system is a key skill that has been widely used in power battery cooling and preheating. It can ensure that the power battery operates safely and stably at a suitable temperature.
  • 1.8K
  • 28 Mar 2022
Topic Review
The Lean Blowout Prediction Techniques
The lean blowout is the most critical issue in lean premixed gas turbine combustion. Decades of research into LBO prediction methods have yielded promising results. Predictions can be classified into five categories based on methodology: semi-empirical model, numerical simulation, hybrid, experimental, and data-driven model.
  • 1.8K
  • 30 Nov 2022
Topic Review
Failures of the Photovoltaic Module Components
With the global increase in the deployment of photovoltaic (PV) modules, the need to explore and understand their reported failure mechanisms has become crucial. Despite PV modules being considered reliable devices, failures and extreme degradations often occur. Some degradations and failures within the normal range may be minor and not cause significant harm. Others may initially be mild but can rapidly deteriorate, leading to catastrophic accidents, particularly in harsh environments.
  • 1.8K
  • 12 Mar 2024
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