Electrical energy in the context of "Alternating current"

Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. The interconnected lines that facilitate this movement form a transmission network. This is distinct from the local wiring between high-voltage substations and customers, which is typically referred to as electric power distribution. The combined transmission and distribution network is part of electricity delivery, known as the electrical grid.

Efficient long-distance transmission of electric power requires high voltages. This reduces the losses produced by strong currents. Transmission lines use either alternating current (AC) or direct current (DC). The voltage level is changed with transformers. The voltage is stepped up for transmission, then reduced for local distribution.

In electronics, a capacitor is a device that stores electrical energy by accumulating electric charges on two closely spaced surfaces that are insulated from each other. It is a passive electronic component with two terminals. A capacitor was originally known as a condenser, a term still encountered in a few compound names, such as the condenser microphone. Colloquially, a capacitor may be called a cap.

The utility of a capacitor depends on its capacitance. While some capacitance exists between any two electrical conductors in proximity in a circuit, a capacitor is a component designed specifically to add capacitance to some part of the circuit.

A heat engine is a system that transfers thermal energy to do mechanical or electrical work. While originally conceived in the context of mechanical energy, the concept of the heat engine has been applied to various other kinds of energy, particularly electrical, since at least the late 19th century. The heat engine does this by bringing a working substance from a higher state temperature to a lower state temperature. A heat source generates thermal energy that brings the working substance to the higher temperature state. The working substance generates work in the working body of the engine while transferring heat to the colder sink until it reaches a lower temperature state. During this process some of the thermal energy is converted into work by exploiting the properties of the working substance. The working substance can be any system with a non-zero heat capacity, but it usually is a gas or liquid. During this process, some heat is normally lost to the surroundings and is not converted to work. Also, some energy is unusable because of friction and drag.

In general, an engine is any machine that converts energy to mechanical work. Heat engines distinguish themselves from other types of engines by the fact that their efficiency is fundamentally limited by Carnot's theorem of thermodynamics. Although this efficiency limitation can be a drawback, an advantage of heat engines is that most forms of energy can be easily converted to heat by processes like exothermic reactions (such as combustion), nuclear fission, absorption of light or energetic particles, friction, dissipation and resistance. Since the heat source that supplies thermal energy to the engine can thus be powered by virtually any kind of energy, heat engines cover a wide range of applications.

In electricity generation, a generator, also called an electric generator, electrical generator, and electromagnetic generator is an electromechanical device that converts mechanical energy to electrical energy for use in an external circuit. In most generators which are rotating machines, a source of kinetic power rotates the generator's shaft, and the generator produces an electric current at its output terminals which flows through an external circuit, powering electrical loads. Sources of mechanical energy used to drive generators include steam turbines, gas turbines, water turbines, internal combustion engines, wind turbines and even hand cranks. Generators produce nearly all of the electric power for worldwide electric power grids. The first electromagnetic generator, the Faraday disk, was invented in 1831 by British scientist Michael Faraday.

The reverse conversion of electrical energy into mechanical energy is done by an electric motor, and motors and generators are very similar. Some motors can be used in a "backward" sense as generators, if their shaft is rotated they will generate electric power.

A thermal power station, also known as a thermal power plant, is a type of power station in which the heat energy generated from various fuel sources (e.g., coal, natural gas, nuclear fuel, etc.) is converted to electrical energy. The heat from the source is converted into mechanical energy using a thermodynamic power cycle (such as a Diesel cycle, Rankine cycle, Brayton cycle, etc.). The most common cycle involves a working fluid (often water) heated and boiled under high pressure in a pressure vessel to produce high-pressure steam. This high pressure-steam is then directed to a turbine, where it rotates the turbine's blades. The rotating turbine is mechanically connected to an electric generator which converts rotary motion into electricity. Fuels such as natural gas or oil can also be burnt directly in gas turbines (internal combustion), skipping the steam generation step. These plants can be of the open cycle or the more efficient combined cycle type.

The majority of the world's thermal power stations are driven by steam turbines, gas turbines, or a combination of the two. The efficiency of a thermal power station is determined by how effectively it converts heat energy into electrical energy, specifically the ratio of saleable electricity to the heating value of the fuel used. Different thermodynamic cycles have varying efficiencies, with the Rankine cycle generally being more efficient than the Otto or Diesel cycles. In the Rankine cycle, the low-pressure exhaust from the turbine enters a steam condenser where it is cooled to produce hot condensate which is recycled to the heating process to generate even more high pressure steam.

A fossil fuel power station is a thermal power station that burns fossil fuel, such as coal, oil, or natural gas, to produce electricity. Fossil fuel power stations have machines that convert the heat energy of combustion into mechanical energy, which then powers an electrical generator. The prime mover may be a steam turbine, a gas turbine or, in small plants, a reciprocating gas engine. All plants use the energy extracted from the expansion of a hot gas, either steam or combustion gases. Although different energy conversion methods exist, all thermal power station conversion methods have their efficiency limited by the Carnot efficiency and therefore produce waste heat.

Fossil fuel power stations provide most of the electrical energy used in the world. Some fossil-fired power stations are designed for continuous operation as baseload power plants, while others are used as peaker plants. However, starting from the 2010s, in many countries plants designed for baseload supply are being operated as dispatchable generation to balance increasing generation by variable renewable energy.

The energy efficiency in transport is the useful travelled distance, of passengers, goods or any type of load; divided by the total energy put into the transport propulsion means. The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in liquid fuels, electrical energy or food energy. The energy efficiency is also occasionally known as energy intensity. The inverse of the energy efficiency in transport is the energy consumption in transport.

Energy efficiency in transport is often described in terms of fuel consumption, fuel consumption being the reciprocal of fuel economy. Nonetheless, fuel consumption is linked with a means of propulsion which uses liquid fuels, whilst energy efficiency is applicable to any sort of propulsion. To avoid said confusion, and to be able to compare the energy efficiency in any type of vehicle, experts tend to measure the energy in the International System of Units, i.e., joules.

Energy consumption is the amount of energy used. In physics, energy consumption refers to the transformation of energy from one form to another, rather than its complete disappearance. According to the law of conservation of energy, energy cannot be created or destroyed, only converted. For instance, when a light bulb "consumes" electricity, it is not destroying the electrical energy but rather converting it into light and heat. Similarly, a car "consumes" gasoline by converting its chemical energy into kinetic energy (motion) and heat. Understanding energy consumption is crucial for analyzing the efficiency of various systems and processes, as the ultimate goal is often to minimize the conversion of useful energy into less desirable forms, such as waste heat.

From a societal and economic perspective, "energy consumption" often refers to the use of energy resources by human civilization to power homes, industries, transportation, and other activities. This typically involves drawing upon various primary energy sources, including fossil fuels (coal, oil, natural gas), nuclear power, and renewable sources (solar, wind, hydro, geothermal). The scale and patterns of this consumption have significant implications for environmental sustainability, economic development, and geopolitical stability. Analyzing trends in global and regional energy consumption helps policymakers and researchers understand resource availability, greenhouse gas emissions, and the potential for transitioning to more sustainable energy systems.

An electricity market is a system that enables the exchange of electrical energy through an electrical grid. Historically, electricity has been primarily sold by companies that operate electric generators, purchased by electricity retailers, and sold to customers.

The electric power industry began in the late 19th and early 20th centuries in the United States and United Kingdom. Throughout the 20th century, and up to the present, many countries have made changes to their system of supplying and/or purchasing electricity. Change has been driven by many factors, ranging from technological advances (on both the supply and demand side) to politics and ideology.