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Topic Review
Biomass Pyrolysis
Pyrolysis process has been considered to be an efficient approach for valorization of lignocellulosic biomass into bio-oil and value-added chemicals. Bio-oil refers to biomass pyrolysis liquid, which contains alkanes, aromatic compounds, phenol derivatives, and small amounts of ketone, ester, ether, amine, and alcohol. Lignocellulosic biomass is a renewable and sustainable energy resource for carbon that is readily available in the environment. This review article provides an outline of the pyrolysis process including pretreatment of biomass, pyrolysis mechanism, and process products upgrading. The pretreatment processes for biomass are reviewed including physical and chemical processes. In addition, the gaps in research and recommendations for improving the pretreatment processes are highlighted. Furthermore, the effect of feedstock characterization, operating parameters, and types of biomass on the performance of the pyrolysis process are explained. Recent progress in the identification of the mechanism of the pyrolysis process is addressed with some recommendations for future work. In addition, the article critically provides insight into process upgrading via several approaches specifically using catalytic upgrading. In spite of the current catalytic achievements of catalytic pyrolysis for providing high-quality bio-oil, the production yield has simultaneously dropped. This article explains the current drawbacks of catalytic approaches while suggesting alternative methodologies that could possibly improve the deoxygenation of bio-oil while maintaining high production yield.
  • 2.3K
  • 21 Jul 2020
Topic Review
Energy Poverty
The term “energy poverty” usually refers to the lack of affordability or of access to basic energy services to meet one’s most common needs, such as lighting, cooking, heating and cooling.
  • 2.2K
  • 15 Oct 2021
Topic Review
Classification of Electric Vehicles
EVs have the ability to run solely on electric propulsion or in conjunction with an internal combustion engine (ICE). The simplest sort of EV relies just on batteries as its source of energy; however, there are many variants that make use of a variety of other types of energy sources. These automobiles are hybrid electric models (HEVs). The Technical Committee 69 Electric Road Vehicles (ERV) of the International Electrical Technical Commission proposes that vehicles with two or more forms of energy source, storage, or converters can be classified as HEVs as long as at least one of them provides electrical energy.
  • 2.2K
  • 19 Jun 2023
Topic Review
Relation between Energy Efficiency and Industry 4.0
The industrial sector is the most energy-consuming sector before the transport and residential sectors. It accounts for about 31% of the overall energy consumption. For this reason, manufacturers are placing increasing emphasis on energy efficiency through improvements in energy management, energy devices, and insulation. Energy efficiency improvement is the application of engineering principles and best practices to control the energy consumption of a facility. It is a continuous process that requires the full involvement of all stakeholders (managers, engineers, workers, etc.) to identify, formulate proposals, and implement energy efficiency technologies and practices to reduce energy consumption. Many technologies and practices are currently available and in development that could save energy if adopted by industry, classified into two main categories: energy management technologies and energy devices. In addition, various tools and methods are used, such as energy monitoring tools, process modeling and integration, optimization and simulation tools, energy analysis and decision support tools, etc. One of the recent innovations is the introduction of Industry 4.0 in manufacturing, in other words, the transition to the new industrial era.
  • 2.2K
  • 15 Jun 2022
Topic Review
CO2 Storage in Shale Reservoirs
As a new “sink” of CO2 permanent storage, the depleted shale reservoir is very promising compared to the deep saline aquifer. To provide a greater understanding of the benefits of CO2 storage in a shale reservoir, a comparative study is conducted by establishing the full-mechanism model, including the hydrodynamic trapping, adsorption trapping, residual trapping, solubility trapping as well as the mineral trapping corresponding to the typical shale and deep saline aquifer parameters from the Ordos basin in China. The results show that CO2 storage in the depleted shale reservoir has merits in storage safety by trapping more CO2 in stable immobile phase due to adsorption and having gentler and ephemeral pressure perturbation responding to CO2 injection. The effect of various CO2 injection schemes, namely the high-speed continuous injection, low-speed continuous injection, huff-n-puff injection and water alternative injection, on the phase transformation of CO2 in a shale reservoir and CO2-injection-induced perturbations in formation pressure are also examined. With the aim of increasing the fraction of immobile CO2 while maintaining a safe pressure-perturbation, it is shown that an intermittent injection procedure with multiple slugs of huff-n-puff injection can be employed and within the allowable range of pressure increase, and the CO2 injection rate can be maximized to increase the CO2 storage capacity and security in shale reservoir.
  • 2.2K
  • 11 Jan 2021
Topic Review
Hydrogen Economy
Environmental issues make the quest for better and cleaner energy sources a priority. Worldwide, researchers and companies are continuously working on this matter, taking one of two approaches: either finding new energy sources or improving the efficiency of existing ones. Hydrogen is a well-known energy carrier due to its high energy content, but a somewhat elusive one for being a gas with low molecular weight. The so-called "Hydrogen Economy" is based on the use of hydrogen as an energy source. This entry examines the current electrolysis processes for obtaining hydrogen, with an emphasis on alkaline water electrolysis.
  • 2.2K
  • 18 Sep 2021
Topic Review
Solar Energy in Argentina
A large gap exists between Argentina’s potential for solar energy utilization and the current solar energy deployment, despite advantages such as a high solar and land resources. This gap is, however, not static: different legal frameworks and governmental promotion programs have led to the deployment of large-scale and distributed off-grid photovoltaic installations, but they are at a volume (in terms of installed capacity) that lags years behind other countries with which Argentina shares relevant characteristics. For example, renewable energies Law 27424 and its implementations through the RenovAR promotion programs for RE led to a promising initial PV deployment, which nevertheless stagnated.
  • 2.2K
  • 15 Apr 2022
Topic Review
Energy Resources in Algeria
Algeria is a wealthy country with natural resources, namely, nuclear, renewable, and non-renewable sources. The non-renewable energy sources are considered the lion’s share for energy production (98%). Algeria’s efforts to ensure and strengthen its energy security will take an important step in the coming decades by commissioning new energy infrastructure based on intensive use of water, coal, nuclear, non-renewable, and renewable sources.
  • 2.2K
  • 06 Jul 2022
Topic Review
Multilevel Inverters for PV Systems
Over the last decade, energy demand from the power grid has increased significantly due to the increasing number of users and the emergence of high-power industries. This has led to a signifi-cant increase in global emissions with conventional energy generation. Therefore, the penetration of renewable energy resources into the power grid has increased significantly. Photovoltaic sys-tems have become the most popular resources as their protentional is enormous, thus, the world-wide installed PV capacity has increased to more than 635 gigawatts (GW), covering approxi-mately 2% of the global electricity demand. Power electronics are an essential part of photovoltaic generation; the drive for efficient power electronic converters is gaining more and more momen-tum. Presently, multilevel inverters (MLI) have become more attractive to researchers compared to two-level inverters due to their abilities to provide lower electromagnetic interference, higher efficiency, and larger DC link voltages. 
  • 2.2K
  • 23 Mar 2021
Topic Review
Photovoltaic Module Degradation
An evaluation of the degradation effects on photovoltaic modules is essential to minimise uncertainties in the system operation. Bifacial photovoltaic technology is attracting attention due to the capacity of generating energy from the front and rear sides. The term degradation is defined as a gradual deterioration of the characteristics of a material, component, or system. This deterioration may cause an impact on the system capacity to operate within the expected limits and therefore impact directly on their operating conditions.
  • 2.1K
  • 07 Dec 2021
Topic Review
Aerogel-Based Plasters
Aerogel has entered the construction field in the last two decades as a component of many insulation products, due to its high thermal performance. Aerogel-based plasters allow the matching of high thermal performance and limited thickness. This makes them suitable when retrofitting an existing building and also when restoring a heritage building. This entry presents the state of the art of the research on aerogel-based plasters as a part of the aerogel-products for the building sector.
  • 2.1K
  • 08 Dec 2020
Topic Review
Application of Ground Heat Exchangers
Geothermal energy is a widely available, constant source of renewable energy that has shown great potential as an alternative source of energy in achieving global energy sustainability and environment protection. When exploiting geothermal energy, whether is for heating or cooling of buildings, a ground heat exchanger (GHE) is the most important component, whose performance can be easily improved by following the latest design aspects. 
  • 2.1K
  • 26 May 2021
Topic Review
AEM for Alkali Metal–Air Batteries
Rechargeable alkali metal-air batteries have enormous potential in energy storage applications due to their high energy densities, low-cost and environment friendliness. Membrane separators determine the performance and economic viability of these batteries. Usually, porous membrane separators taken from lithium-based batteries are used. Moreover, composite and cation-exchange membranes have been tested. However, crossover of unwanted species (such as zincate ions in zinc-air flow batteries) and/or low hydroxide ions conductivity are major issues to be overcome. On the other hand, state-of-art Anion-Exchange Membranes (AEMs) have been applied to meet the current challenges with regard to rechargeable zinc-air batteries, which has received the most attention among alkali metal-air batteries. The recent advances and remaining challenges of AEMs for these batteries are critically discussed. Correlation between the properties of the AEMs and performance and cyclability of the batteries has been established.
  • 2.1K
  • 27 Oct 2020
Topic Review
Energetic Valorisation of Olive Biomass
The generation, composition, properties and potential energetic applications of the main three biomass obtained from the olive oil industry are illustrated.
  • 2.1K
  • 27 Oct 2020
Topic Review
Functional Polymer Materials for Energy Applications
This entry provides insight into the recent energy applications of polymers.
  • 2.1K
  • 15 Dec 2021
Topic Review
Hydrogen Storage in Activated Carbons
With the rising demand for H2 in the past decades and its favorable characteristics as an energy carrier, the escalating USA consumption of pure H2 can be projected to reach 63 million tons by 2050. Despite the tremendous potential of H2 generation and its widespread application, transportation and storage of H2 have remained the major challenges of a sustainable H2 economy. Recently, the literature has been stressing the need to develop biomass-based activated carbons as an effective H2 storage material, as these are inexpensive adsorbents with tunable chemical, mechanical, and morphological properties.  This article reviews the current research trends and perspectives on the role of various properties of biomass-based activated carbons on its H2 uptake capacity. The critical aspects of the governing factors of H2 storage, namely, the surface morphology (specific surface area, pore volume, and pore size distribution), surface functionality (heteroatom and functional groups), physical condition of H2 storage (temperature and pressure), and thermodynamic properties (heat of adsorption and desorption), are discussed. A comprehensive survey of the literature showed that an “ideal” biomass-based activated carbon sorbent with a micropore size typically below 10 Å, micropore volume greater than 1.5 cm3/g, and high surface area of 4000 m2/g or more may help in substantial gravimetric H2 uptake of >10 wt% at cryogenic conditions (−196 °C), as smaller pores benefit by stronger physisorption due to the high heat of adsorption.
  • 2.1K
  • 01 Apr 2021
Topic Review
Fuel Cell Hybrid Electric Vehicles
With the development of the global economy, the automobile industry is also developing constantly. In recent years, due to the shortage of environmental energy and other problems, seeking clean energy as the power source of vehicles to replace traditional fossil energy could be one of the measures to reduce environmental pollution. Among them, fuel cell hybrid electric vehicles (FCHEVs) have been widely studied by researchers for their advantages of high energy efficiency, environmental protection, and long driving range.
  • 2.1K
  • 08 Oct 2022
Topic Review
Containment Building
A containment building, in its most common usage, is a reinforced steel, concrete or lead structure enclosing a nuclear reactor. It is designed, in any emergency, to contain the escape of radioactive steam or gas to a maximum pressure in the range of 275 to 550 kPa (40 to 80 psi) . The containment is the fourth and final barrier to radioactive release (part of a nuclear reactor's defence in depth strategy), the first being the fuel ceramic itself, the second being the metal fuel cladding tubes, the third being the reactor vessel and coolant system. Each nuclear plant in the US is designed to withstand certain conditions which are spelled out as "Design Basis Accidents" in the Final Safety Analysis Report (FSAR). The FSAR is available for public viewing, usually at a public library near the nuclear plant. The containment building itself is typically an airtight steel structure enclosing the reactor normally sealed off from the outside atmosphere. The steel is either free-standing or attached to the concrete missile shield. In the United States , the design and thickness of the containment and the missile shield are governed by federal regulations (10 CFR 50.55a), and must be strong enough to withstand the impact of a fully loaded passenger airliner without rupture. While the containment plays a critical role in the most severe nuclear reactor accidents, it is only designed to contain or condense steam in the short term (for large break accidents) and long term heat removal still must be provided by other systems. In the Three Mile Island accident the containment pressure boundary was maintained, but due to insufficient cooling, some time after the accident, radioactive gas was intentionally let from containment by operators to prevent over pressurization. This, combined with further failures, caused the release of up to 13 million curies of radioactive gas to atmosphere during the accident. While the Fukushima Daiichi plant had operated safely since 1971, an earthquake and tsunami well beyond the design basis resulted in failure of AC power, backup generators and batteries which defeated all safety systems. These systems were necessary to keep the fuel cool after the reactor had been shut down. This resulted in partial or complete meltdown of fuel rods, damage to fuel storage pools and buildings, release of radioactive debris to surrounding area, air and sea, and resorting to the expedient use of fire engines and concrete pumps to deliver cooling water to spent fuel pools and containment. During the incident, pressure within the containments of reactors 1-3 rose to exceed design limits, which despite attempts to reduce pressure by venting radioactive gases, resulted in breach of containment. Hydrogen leaking from the containment mixed with air into an explosive mixture which resulted in explosions in Unit 1, 3 and 4, complicating attempts to stabilize the reactors.
  • 2.1K
  • 08 Nov 2022
Topic Review
Advantages and Disadvantages of Hydrogen Trains
Hydrogen and electric drives used in various means of transport is a leading topic in many respects.
  • 2.1K
  • 07 Oct 2023
Topic Review
Smart Grids（SG）
Smart grid (SG), an evolving concept in the modern power infrastructure, enables the two-way flow of electricity and data between the peers within the electricity system networks (ESN) and its clusters. The self-healing capabilities of SG allow the peers to become active partakers in ESN. In general, the SG is intended to replace the fossil fuel-rich conventional grid with the distributed energy resources (DER) and pools numerous existing and emerging know-hows like information and digital communications technologies together to manage countless operations.
  • 2.1K
  • 01 Jul 2021
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