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Topic Review
Gas/Oil-Relative Permeabilities
Thermal recovery processes for heavy oil exploitation involve three-phase flow at elevated temperatures. The mathematical modeling of such processes necessitates the account of changes in the rock–fluid system’s flow behavior as the temperature rises. To this end, numerous studies on effects of the temperature on relative permeabilities have been reported in the literature. Compared to studies on the temperature effects on oil/water-relative permeabilities, studies (and hence, data) on gas/oil-relative permeabilities are limited. However, the role of temperature on both gas/oil and oil/water-relative permeabilities has been a topic of much discussion, contradiction and debate. The jury is still out, without a consensus, with several contradictory hypotheses, even for the limited number of studies on gas/oil-relative permeabilities. This study presents a critical analysis of studies on gas/oil-relative permeabilities as reported in the literature, and puts forward an undeniable argument that the temperature does indeed impact gas/oil-relative permeabilities and the other fluid–fluid properties contributing to flow in the reservoir, particularly in a thermal recovery process. It further concludes that such thermal effects on relative permeabilities must be accounted for, properly and adequately, in reservoir simulation studies using numerical models. The paper presents a review of most cited studies since the 1940s and identifies the possible primary causes that contribute to contradictory results among them, such as differences in experimental methodologies, experimental difficulties in flow data acquisition, impact of flow instabilities during flooding, and the differences in the specific impact of temperature on different rock–fluid systems. We first examined the experimental techniques used in measurements of oil/gas-relative permeabilities and identified the challenges involved in obtaining reliable results. Then, the effect of temperature on other rock–fluid properties that may affect the relative permeability was examined. Finally, we assessed the effect of temperature on parameters that characterized the two-phase oil/gas-relative permeability data, including the irreducible water saturation, residual oil saturation and critical gas saturation. Through this critical review of the existing literature on the effect of temperature on gas/oil-relative permeabilities, we conclude that it is an important area that suffers profoundly from a lack of a comprehensive understanding of the degree and extent of how the temperature affects relative permeabilities in thermal recovery processes, and therefore, it is an area that needs further focused research to address various contradictory hypotheses and to describe the flow in the reservoir more reliably.
  • 2.9K
  • 14 Jul 2020
Topic Review
Digital Applications in Energy Sector
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 provides a structured overview of potential digital applications in the German energy (electricity) sector on the basis of a literature review.
  • 2.9K
  • 14 Apr 2021
Topic Review
Agrivoltaic Systems Design
An agrivoltaic system is a complex system, being, at least, a spatial, an energy and an agronomic system. Its design and assessment must adhere to requirements set depending on the project’s needs in order to meet desired performance quality objectives. Different dimensions of performance need to be taken into account.
  • 2.9K
  • 18 Nov 2021
Topic Review
Optimal Configuration of Solar Panel
In solar photovoltaic (PV) energy generation system, the term “photovoltaic” refers to a semiconductor-based device used to convert solar energy (sunlight) into electrical DC energy. To generate electricity, the solar PV generation system has become a mainstream option, especially for the communities who live in rural areas. Its market has vastly expanded in a short period, where according to Parikh, 70% of solar PV module manufacturing is accounted for by China.
  • 2.9K
  • 24 May 2021
Topic Review
IoT and the Energy Sector
Integration of renewable energy and optimization of energy use are key enablers of sustainable energy transitions and mitigating climate change. Modern technologies such the Internet of Things (IoT) offer a wide number of applications in the energy sector, i.e, in energy supply, transmission and distribution, and demand. IoT can be employed for improving energy efficiency, increasing the share of renewable energy, and reducing environmental impacts of the energy use.
  • 2.9K
  • 26 Sep 2021
Topic Review
Biomass Feedstocks Thermochemical Conversion Processes
An effective analytical technique for biomass characterisation is inevitable for biomass utilisation in energy production. To improve biomass processing, various thermal conversion methods such as torrefaction, pyrolysis, combustion, hydrothermal liquefaction, and gasification have been widely used to improve biomass processing. Thermogravimetric analysers (TG) and gas chromatography (GC) are among the most fundamental analytical techniques utilised in biomass thermal analysis. Thus, GC and TG, in combination with MS, FTIR, or two-dimensional analysis, were used to examine the key parameters of biomass feedstock and increase the productivity of energy crops. We can also determine the optimal ratio for combining two separate biomass or coals during co-pyrolysis and co-gasification to achieve the best synergetic relationship. 
  • 2.9K
  • 18 Sep 2021
Topic Review
Solar-Powered Plant Protection Equipment
Solar photovoltaic (PV) devices present a positive approach to sustainable crop production by reducing crop loss in various ways. This might result in the extensive use of PV devices in the near future. PV-based plant protection equipment/devices are primarily utilized in protecting crops from birds, weeds, or insects. The utilization of PV systems for different applications constitutes a new era in agriculture, horticulture, and forest sectors. A PV system is a potential alternative, offering more opportunities in operating different types of electricity-based agricultural equipment. The development of devices with simple construction/operation for plant protection may work well on small-scale farms.
  • 2.9K
  • 28 Nov 2022
Topic Review
Gel Fuels Preparation
Gel fuels can become an alternative energy resource within the framework of the implementation of the program for developments in rocket and space technology. These propellants combine the advantages of solid and liquid rocket propellants, of which the main ones are related to safety aspects, energy efficiency and storage. The components range and gel fuels compositions are diverse, so the method of their preparation in each specific case can be quite different, especially when using thickeners of various origins.
  • 2.8K
  • 10 Jan 2023
Topic Review
Pressure Wave Supercharger
One main direction in improving the efficiency of an internal combustion engine, together with lowering the emissions, is supercharging, i.e., creating a considerable amount of boost for the inlet combustion air. Turbochargers are the most commonly used for this task, but another advantageous alternative exploiting the energy within exhaust gases is the pressure wave supercharger (PWS).
  • 2.8K
  • 19 Apr 2022
Topic Review
Modeling Approaches of Biogas Production
Biogas production is a relevant component in renewable energy systems. Model approaches of biogas production show different levels of detail. They can be classified as white, gray, and black box, or bottom-up and top-down approaches. On the one hand, biogas modeling can supply dynamic information on the anaerobic digestion process, e.g., to predict biogas yields or to optimize the anaerobic digestion process. These models are characterized by a bottom-up approach with different levels of detail: the comprehensive ADM1 (white box), simplifications and abstractions of AD models (gray box), or highly simplified process descriptions (black box). On the other hand, biogas production is included in energy system models. These models usually supply aggregated information on regional biogas potentials and greenhouse gas emissions. They are characterized by a top-down approach with a low level of detail. Most energy system models reported in literature are based on black box approaches. Considering the strengths and weaknesses of the integration of detailed and deeply investigated process models in energy system models reveals the opportunity to develop dynamic and fluctuating business models of biogas usage. 
  • 2.8K
  • 29 Jul 2021
Topic Review
Peer-to-Peer Energy Trading
Peer-to-peer energy trading (P2P-ET) provides an online marketplace where direct energy exchange can occur between its participants, namely, prosumers and consumers. P2P-ET offers techno-economical benefits to its participants and brings savings to them.
  • 2.8K
  • 08 Dec 2022
Topic Review
Power Generation Using Dielectric Elastomers
Power generation using dielectric elastomer (DE) artificial muscle is attracting attention because of its light weight, low cost, and high-efficiency. Since this method is a system that produces electricity without emitting carbon dioxide nor using rare earths, it would contribute to the goal of environmental sustainability. 
  • 2.8K
  • 30 Jun 2021
Topic Review
Energy Return on Investment
Energy Return on Energy Invested (EROEI) (also Energy Return on Investment (EROI)) is a dimensionless ratio that compares the output over the life of an energy generating system—such as a power plant—to the energy inputs to the system. EROEI thus has the potential to filter out unsuitable projects, and to rank surviving projects according to their energy return. EROEI is therefore an important adjunct to conventional monetary project assessments.
  • 2.8K
  • 14 Dec 2020
Topic Review
Vanadium Redox Flow Battery
Large-scale energy storage systems (ESS) are nowadays growing in popularity due to the increase in energy production by renewable energy sources, which in general have a random intermittent nature. Currently, several redox flow batteries have been presented as an alternative of the classical ESS; the scalability, design flexibility and long life cycle of the vanadium redox flow battery (VRFB) have made it to stand out. In a VRFB cell, which consists of two electrodes and an ion exchange membrane, the electrolyte flows through the electrodes where the electrochemical reactions take place. Computational Fluid Dynamics (CFD) simulations are a very powerful tool to develop feasible numerical models to enhance the performance and lifetime of VRFBs. 
  • 2.8K
  • 20 Jan 2021
Topic Review
Asphaltene
Asphaltenes is the heaviest and most polar fraction of petroleum not yet wery well characterized and only presently define by they solubility.
  • 2.8K
  • 29 Aug 2021
Topic Review
Vulnerabilities and Challenges in IoT-Enabled Smart Grids
Internet of Things (IoT) has appeared as one of the enabling technologies for smart energy grids by delivering abundant cutting-edge solutions in various domains, including critical infrastructures. As IoT-enabled devices continue to flourish, one of the major challenges is security issues, since IoT devices are connected through the Internet, thus making the smart grids vulnerable to a diverse range of cyberattacks. 
  • 2.7K
  • 25 Oct 2022
Topic Review
Renewable Energy in Algeria
Algeria—being the largest county in Africa—has experienced a rapid growth in energy demand over the past decade due to the significant increase in residential, commercial, and industry sectors.
  • 2.7K
  • 07 Jun 2021
Topic Review
Hydrogen Production in Arctic Region
The development of markets for low-carbon energy sources requires reconsideration of issues related to extraction and use of oil and gas. Significant reserves of hydrocarbons are concentrated in Arctic territories, e.g., 30% of the world’s undiscovered natural gas reserves and 13% of oil. Associated petroleum gas, natural gas and gas condensate could be able to expand the scope of their applications. Natural gas is the main raw material for the production of hydrogen and ammonia, which are considered promising primary energy resources of the future, the oxidation of which does not release CO2. Complex components contained in associated petroleum gas and gas condensate are valuable chemical raw materials to be used in a wide range of applications.
  • 2.7K
  • 17 Apr 2024
Topic Review
Liquid-Organic Hydrogen Carrier
Molecular liquid that can accommodate and release hydrogen molecules via chemical hydrogenation and dehydrogenation.
  • 2.7K
  • 04 Dec 2020
Topic Review
Thermochemical Recycling of Plastic Wastes to Alternative Fuels
Due to its resistance to natural degradation and decomposition, plastic debris perseveres in the environment for centuries. As a lucrative material for packing industries and consumer products, plastics have become one of the major components of municipal solid waste today. The recycling of plastics is becoming difficult due to a lack of resource recovery facilities and a lack of efficient technologies to separate plastics from mixed solid waste streams. This has made oceans the hotspot for the dispersion and accumulation of plastic residues beyond landfills. 
  • 2.7K
  • 27 Jun 2023
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