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Topic Review
Electrically Excited Doubly Salient Variable Reluctance Machine
The Electrically Excited Doubly Salient Variable Reluctance Machine (EEDSVRM) is a new type of brushless machine designed according to the principle of air gap reluctance change.
  • 802
  • 14 Jan 2022
Topic Review
Electrically Powered Spacecraft Propulsion
An electrically powered spacecraft propulsion system uses electrical, and possibly also magnetic fields, to change the velocity of a spacecraft. Most of these kinds of spacecraft propulsion systems work by electrically expelling propellant (reaction mass) at high speed. Electric thrusters typically use much less propellant than chemical rockets because they have a higher exhaust speed (operate at a higher specific impulse) than chemical rockets. Due to limited electric power the thrust is much weaker compared to chemical rockets, but electric propulsion can provide thrust for a longer time. Electric propulsion is now a mature and widely used technology on spacecraft. Russia n satellites have used electric propulsion for decades. (As of 2019), over 500 spacecraft operated throughout the Solar System use electric propulsion for station keeping, orbit raising, or primary propulsion. In the future, the most advanced electric thrusters may be able to impart a delta-v of 100 km/s, which is enough to take a spacecraft to the outer planets of the Solar System (with nuclear power), but is insufficient for interstellar travel. An electric rocket with an external power source (transmissible through laser on the photovoltaic panels) has a theoretical possibility for interstellar flight. However, electric propulsion is not suitable for launches from the Earth's surface, as it offers too little thrust. On a journey to Mars, an electrically powered ship might be able to carry 70% of its initial mass to the destination, while a chemical rocket could carry only a few percent.
  • 589
  • 23 Nov 2022
Topic Review
Electrically Tunable Phase Gratings
Electrically tunable phase gratings are able to steer an incoming light beam without employing movable parts. Here, we present the design and implementation of a 2D beam steering device by cascading two orthogonal 1D liquid crystal (LC) based phase gratings, each having an array of 72 rectangular individually controlled pixels and driven by a custom 12-bit Pulse-Width Modulation (PWM) electrical driver.
  • 642
  • 01 Jul 2021
Topic Review
Electricity Consumption in China
China’s electricity consumption presents a significant spatial spill over effect, and the spatial agglomeration of electricity consumption in local regions is mainly HH clusters. A 1% positive change in financial development causes an increase of 0.089% in electricity consumption, but a 1% rise in financial development reduces electricity consumption of neighboring regions by 0.051%. A 1% positive change in trade openness decreases electricity consumption by 0.051%, while the spatial spillover effect of trade openness is not significant. It is also found that financial development has a long-term promoting effect on electricity consumption, while trade openness has a long-term inhibiting effect on electricity consumption. 
  • 471
  • 16 Sep 2021
Topic Review
Electricity Day-Ahead Market Conditions and Market Price Forecasting
Participants in deregulated electricity markets face risks from price volatility due to various factors, including fuel prices, renewable energy production, electricity demand, and crises such as COVID-19 and energy-related issues. Price forecasting is used to mitigate risk in markets trading goods which have high price volatility. Forecasting in electricity markets is difficult and challenging as volatility is attributed to many unpredictable factors.
  • 287
  • 21 Jun 2023
Topic Review
Electricity Demand Forecasting
With the globally increasing electricity demand, its related uncertainties are on the rise as well. Therefore, a deeper insight into load forecasting techniques for projecting future electricity demands becomes imperative for business entities and policymakers. The electricity demand is governed by a set of different variables or “electricity demand determinants”. These demand determinants depend on forecasting horizons (long term, medium term, and short term), the load aggregation level, climate, and socio-economic activities. In this paper, a review of different electricity demand forecasting methodologies is provided in the context of a group of low and middle-income countries. The article presents a comprehensive literature review by tabulating the di fferent demand determinants used in di fferent countries and forecasting the trends and techniques used in these countries. A comparative review of these forecasting methodologies over di fferent time horizons reveal that the time series modeling approach has been extensively used while forecasting for long and medium terms. For short term forecasts, artificial intelligence-based techniques remain prevalent in the literature. Furthermore, a comparative analysis of the demand determinants in these countries indicates frequent use of determinants like the population, GDP, weather, and load data over di fferent time horizons.
  • 1.7K
  • 05 Aug 2020
Topic Review
Electricity Energy Storage
The mass deployment of energy storage and distributed energy resources has become a major goal across several states in the United States. However, the viability and reality of such a goal in New York City has been put in question as possible financial burdens and execution risks are still unclear, while policies and regulations are still not fully settled. This entry provides a foundational overview of the Lazard LCOS study with emphasis on forward states which have successfully implemented mass deployment of energy storage technologies. “Adders” are related to the practicality in deploying these systems in a highly regulated and densely populated urban area such as New York City. It also discusses details on the typical financial structure/incentives that support the policies and regulations that allow for achieving these clean energy goals. 
  • 453
  • 08 Apr 2022
Topic Review
Electricity Generation Forecasting and Transfer Learning
Accurate forecasting is one of the keys to the efficient use of the limited existing energy resources and plays an important role in sustainable development. The existing research related to power forecasting can be grouped into three categories: (1) statistical models, (2) deep learning models, and (3) hybrid models. Statistical approaches are often based on autoregressive linear regression models. Deep learning models are based on various types of neural networks that employ a fixed lookback window to produce forecasts. Hybrid models combine two or more methods to create a single forecast. 
  • 141
  • 08 Feb 2024
Topic Review
Electricity Market in Brazil
With the current worsening of climate change-associated risks, the transition to low-carbon energy sources has become a global priority. In this context, the advances in the implementation of smart grids, which, in addition to greater efficiency and resilience, also allow greater penetration of renewable distributed energy resources, are becoming increasingly important. However, the necessary investments will be colossal. Many specialists see the process of opening up the electric energy markets as essential to boosting these new technologies. Greater decentralization of the decision-making process can potentially promote greater scalability. However, not all liberalization reforms have led to good results. Several researchers have been evaluating experiences in different countries. Brazil, a country with continental dimensions and peculiar characteristics, already counts with a mostly renewable electric energy generation mix. In recent decades, however, it has become increasingly dependent on fossil fuel sources. Brazil has been conducting a process of opening the electric energy market since the 1990s. This process has faced a series of barriers. This article presents a critical bibliographic review of the Brazilian Power System history and its ongoing opening process, its possible successes and errors, as well as its perspectives and challenges.
  • 1.1K
  • 18 Jun 2021
Topic Review
Electricity Tariffs and Solutions for Optimal Energy Management
Today, electricity tariffs play an essential role in the electricity retail market as they are the key factor for the decision-making of end-users. Additionally, tariffs are necessary for increasing competition in the electricity market. They have a great impact on load energy management. Moreover, tariffs are not taken as a fixed approach to expense calculations only but are influenced by many other factors, such as electricity generation, transmission, distribution costs, and governmental taxation. Thus, electricity pricing differs significantly between countries or between regions within a country. Improper tariff calculation methodologies in some areas have led to high-power losses, unnecessary investments, increased operational expenses, and environmental pollution due to the non-use of available sustainable energy resources.
  • 1.6K
  • 25 Nov 2022
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