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.
The National Grid is the high-voltage electric power transmission network serving Great Britain, connecting power stations and major substations, and ensuring that electricity generated anywhere on the grid can be used to satisfy demand elsewhere. The network serves the majority of Great Britain and some of the surrounding islands. It does not cover Northern Ireland, which is part of the Irish single electricity market.
The State Grid Corporation of China (SGCC), commonly known as the State Grid, is a Chinese state-owned electric utility corporation. It is the largest utility company in the world. As of March 2024, State Grid is the world's fourth largest company overall by revenue, behind Walmart, Saudi Aramco, and Amazon. In 2022 it was reported as having 871,145 employees, 1.1 billion customers and revenue equivalent to US$460 billion. It is overseen by the State-owned Assets Supervision and Administration Commission of the State Council.
The Western Interconnection is a wide area synchronous grid and one of the two major alternating current (AC) power grids in the North American power transmission grid. The other major wide area synchronous grid is the Eastern Interconnection. The minor interconnections are the Québec Interconnection, the Texas Interconnection, and the Alaska Interconnections.
China is both the world's largest energy consumer and the largest industrial country, and ensuring adequate energy supply to sustain economic growth has been a core concern of the Chinese Government since the founding of the People's Republic of China in 1949. Since the country's industrialization in the 1960s, China is currently the world's largest emitter of greenhouse gases, and coal in China is a major cause of global warming. However, from 2010 to 2015 China reduced energy consumption per unit of GDP by 18%, and CO2 emissions per unit of GDP by 20%. On a per-capita basis, China was only the world's 51st largest emitter of greenhouse gases in 2016. China is also the world's largest renewable energy producer, and the largest producer of hydroelectricity, solar power and wind power in the world. The energy policy of China is connected to its industrial policy, where the goals of China's industrial production dictate its energy demand managements.
China is the world's leader in electricity production from renewable energy sources, with over triple the generation of the second-ranking country, the United States. China's renewable energy sector is growing faster than its fossil fuels and nuclear power capacity, and is expected to contribute 43% of global renewable capacity growth. China's total renewable energy capacity exceeded 1,000 GW in 2021, accounting for 43.5 per cent of the country's total power generation capacity, 10.2 percentage points higher than in 2015. The country aims to have 80 per cent of its total energy mix come from non-fossil fuel sources by 2060, and achieve a combined 1,200 GW of solar and wind capacity by 2030. In 2023, it was reported that China was on track to reach 1,371 gigawatts of wind and solar by 2025, five years ahead of target due to new renewables installations breaking records.
China is the world leader in wind power generation, with the largest installed capacity of any nation and continued rapid growth in new wind facilities. With its large land mass and long coastline, China has exceptional wind power resources: Wind power remained China's third-largest source of electricity at the end of 2021, accounting for 7.5% of total power generation.
China is the world's largest electricity producer, having overtaken the United States in 2011 after rapid growth since the early 1990s. In 2021, China produced 8.5 petawatt-hour (PWh) of electricity, approximately 30% of the world's electricity production.
An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids consist of power stations, electrical substations to step voltage up or down, electric power transmission to carry power over long distances, and finally electric power distribution to customers. In that last step, voltage is stepped down again to the required service voltage. Power stations are typically built close to energy sources and far from densely populated areas. Electrical grids vary in size and can cover whole countries or continents. From small to large there are microgrids, wide area synchronous grids, and super grids.
A wide area synchronous grid is a three-phase electric power grid that has regional scale or greater that operates at a synchronized utility frequency and is electrically tied together during normal system conditions. Also known as synchronous zones, the most powerful is the Northern Chinese State Grid with 1,700 gigawatts (GW) of generation capacity, while the widest region served is that of the IPS/UPS system serving most countries of the former Soviet Union. Synchronous grids with ample capacity facilitate electricity trading across wide areas. In the ENTSO-E in 2008, over 350,000 megawatt hours were sold per day on the European Energy Exchange (EEX).
Energy in Ethiopia includes energy and electricity production, consumption, transport, exportation, and importation in the country of Ethiopia.
There is a large array of stakeholders that provide services through electricity generation, transmission, distribution and marketing for industrial, commercial, public and residential customers in the United States. It also includes many public institutions that regulate the sector. In 1996, there were 3,195 electric utilities in the United States, of which fewer than 1,000 were engaged in power generation. This leaves a large number of mostly smaller utilities engaged only in power distribution. There were also 65 power marketers. Of all utilities, 2,020 were publicly owned, 932 were rural electric cooperatives, and 243 were investor-owned utilities. The electricity transmission network is controlled by Independent System Operators or Regional Transmission Organizations, which are not-for-profit organizations that are obliged to provide indiscriminate access to various suppliers to promote competition.
The term smart grid is most commonly defined as an electric grid that has been digitized to enable two way communication between producers and consumers. The objective of the smart grid is to update electricity infrastructure to include more advanced communication, control, and sensory technology with the hope of increasing communication between consumers and energy producers. The potential benefits from a smart grid include increased reliability, more efficient electricity use, better economics, and improved sustainability.
Denmark's western electrical grid is part of the Synchronous grid of Continental Europe whereas the eastern part is connected to the Synchronous grid of Northern Europe via Sweden.
The National Grid covers most of mainland Great Britain and several of the surrounding islands, and there are interconnectors to Northern Ireland and to other European countries. Power is supplied to consumers at 230 volts AC with a frequency of 50 Hz. In 2023 about a third of electricity used in Britain was generated from fossil gas and two-thirds was low-carbon power. Wind generates the most low-carbon power, followed by nuclear some of which is imported from France. The government is aiming for greenhouse gas emissions from electricity in Britain to be net zero by 2035.
Russia is the fourth largest generator and consumer of electricity in the world. Its 440 power stations have a combined installed generation capacity of 220 GW.
China is the world's largest consumer of electricity, and its demand is expected to double by the next decade, and triple by 2035. In 2010, 70 percent of the country's electricity generation came from coal-fired power plants, but the Chinese government is investing heavily in renewable energy technologies. As of 2013, 21 percent of China's electricity generation comes from renewable sources. This represents only 9 percent of overall primary energy consumption in the country. China's latest goal is to increase renewable energy to 9.5 percent of overall primary energy use by 2015. To implement China's new clean energy capacity into the national power grid, and to improve the reliability of the country's existing infrastructure, requires significant upgrades and ultimately, a smart grid.
The Southern Hami–Zhengzhou UHVDC is an ultra high-voltage direct current power transmission line from the north-west to central China.
The electricity sector in Taiwan ranges from generation, transmission, distribution and sales of electricity, covering Taiwan island and its offshore islands.
Electricity sector in Hong Kong ranges from generation, transmission, distribution and sales of electricity covering Hong Kong. The combustion of coal, natural gas and oil are the main sources of electricity in Hong Kong. The electricity sector contributes 60.4% of Hong Kong's total greenhouse gas emissions.
