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 which facilitate this movement are known as 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.
Electric power distribution is the final stage in the delivery of electric power; it carries electricity from the transmission system to individual consumers. Distribution substations connect to the transmission system and lower the transmission voltage to medium voltage ranging between 2 kV and 35 kV with the use of transformers. Primary distribution lines carry this medium voltage power to distribution transformers located near the customer's premises. Distribution transformers again lower the voltage to the utilization voltage used by lighting, industrial equipment and household appliances. Often several customers are supplied from one transformer through secondary distribution lines. Commercial and residential customers are connected to the secondary distribution lines through service drops. Customers demanding a much larger amount of power may be connected directly to the primary distribution level or the subtransmission level.
The electric power industry covers the generation, transmission, distribution and sale of electric power to the general public and industry. The commercial distribution of electric power started in 1882 when electricity was produced for electric lighting. In the 1880s and 1890s, growing economic and safety concerns lead to the regulation of the industry. What was once an expensive novelty limited to the most densely populated areas, reliable and economical electric power has become an essential aspect for normal operation of all elements of developed economies.
The British Columbia Hydro and Power Authority, operating as BC Hydro, is a Canadian electric utility in the province of British Columbia. It is the main electricity distributor, serving 1.8 million customers in most areas, with the exception of the City of New Westminster, where the city runs its own electrical department and portions of the West Kootenay, Okanagan, the Boundary Country and Similkameen regions, where FortisBC, a subsidiary of Fortis Inc. directly provides electric service to 213,000 customers and supplies municipally owned utilities in the same area. As a provincial Crown corporation, BC Hydro reports to the BC Ministry of Energy, Mines and Low Carbon Innovation, and is regulated by the British Columbia Utilities Commission (BCUC). Its mandate is to generate, purchase, distribute and sell electricity.
The Manitoba Hydro-Electric Board, operating as Manitoba Hydro, is the electric power and natural gas utility in the province of Manitoba, Canada. Founded in 1961, it is a provincial Crown Corporation, governed by the Manitoba Hydro-Electric Board and the Manitoba Hydro Act. Today the company operates 15 interconnected generating stations. It has more than 527,000 electric power customers and more than 263,000 natural gas customers. Since most of the electrical energy is provided by hydroelectric power, the utility has low electricity rates. Stations in Northern Manitoba are connected by a HVDC system, the Nelson River Bipole, to customers in the south. The internal staff are members of the Canadian Union of Public Employees Local 998 while the outside workers are members of the International Brotherhood of Electrical Workers Local 2034.
Hydro One Limited is an electricity transmission and distribution utility serving the Canadian province of Ontario. Hydro One traces its history to the early 20th century and the establishment of the Hydro-Electric Power Commission of Ontario. In October 1998, the provincial legislature passed the Energy Competition Act which restructured Ontario Hydro into separate entities responsible for electrical generation, transmission/delivery, and price management with a final goal of total privatization.
The electricity sector in Canada has played a significant role in the economic and political life of the country since the late 19th century. The sector is organized along provincial and territorial lines. In a majority of provinces, large government-owned integrated public utilities play a leading role in the generation, transmission, and distribution of electricity. Ontario and Alberta have created electricity markets in the last decade in order to increase investment and competition in this sector of the economy.
National Grid, Malaysia is the high-voltage electric power transmission network in Peninsular Malaysia. It is operated and owned by Tenaga Nasional Berhad (TNB) by its Transmission Division. There are two other electrical grids in Sabah and Sarawak operated by Sabah Electricity Sdn Bhd (SESB) and Sarawak Energy Berhad (SEB) respectively.
FortisBC is an electricity and natural gas distribution utility in the Canadian province of British Columbia, a subsidiary of Newfoundland-based Fortis Inc., Canada’s largest private utility company. In March 2011, Terasen Gas, British Columbia's largest natural gas distributor, was renamed FortisBC Energy Inc., as both companies are owned by Fortis Inc.
ITC Transmission was founded in 1999 as International Transmission Co., a subsidiary of Detroit Edison, charged in the ownership, operation and maintenance of Detroit Edison's transmission system. In 2003, DTE sold the subsidiary to ITC Holdings Corp. In 2004, ITC Transmission became the first, fully independent electricity transmission company in the United States following the 2003 transfer of ownership from DTE Energy to ITC Transmission’s parent company, ITC Holdings Corp. ITC Transmission owns a fully regulated, high-voltage system that transmits electricity to local electricity distribution facilities. ITC Holdings Corp. became a publicly traded company in 2005 and is headquartered in Novi, Michigan. Today it owns transmission systems in several states under a unique independent business model.
The electricity sector in New Zealand uses mainly renewable energy; such as hydropower, geothermal power and increasingly wind energy. As of 2019, 82% of electricity is generated from renewable sources, making New Zealand one of the countries with the lowest carbon dioxide emissions from electricity generation. Electricity demand grew by an average of 2.1% per year from 1974 to 2010 but decreased by 1.2% from 2010 to 2013.
Hydro-Québec's electricity transmission system is an international electric power transmission system centred in Quebec, Canada. The system pioneered the use of very high voltage 735-kilovolt (kV) alternating current (AC) power lines that link the population centres of Montreal and Quebec City to distant hydroelectric power stations like the Daniel-Johnson Dam and the James Bay Project in northwestern Quebec and the Churchill Falls Generating Station in Labrador.
The Jordan River Dam, officially the Jordan River Diversion Dam, and known locally simply as Diversion Dam, is a dam located in Jordan River, British Columbia, Canada. It is part of the second hydroelectric development on Vancouver Island.
An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids vary in size and can cover whole countries or continents. It consists of:
Whakamaru Power Station is a hydroelectric power station on the Waikato River, in the North Island of New Zealand. It is the fourth hydroelectric power station on the Waikato River.
The National Grid is the nationwide system of electric power transmission in New Zealand. The national electricity transmission grid is owned, operated, and maintained by state-owned enterprise Transpower New Zealand, although some lines are owned by local distribution companies and leased to Transpower. In total, the national grid contains 11,803 kilometres (7,334 mi) of high-voltage lines and 178 substations.
The provision of electricity in Queensland required a considerable degree of pioneering, innovation, and commitment. Queensland proved to be a pioneer in the supply of electricity in Australia, with the first public demonstration in Australia, the first recorded use for public purposes in the country, the first Parliament House in Australia and the first commercial operations in Australia all occurring in Brisbane.
Electricity sector in Hong Kong ranges from generation, transmission, distribution and sales of electricity covering Hong Kong. There are two main providers of electricity in Hong Kong.
The Juan de Fuca Cable Project is a proposed 550 MW, 150 kV high-voltage direct current (HVDC) submarine power cable connection running 19 miles (31 km) under the Strait of Juan de Fuca between Port Angeles, Washington, and Victoria, British Columbia. The project's final environmental impact statement was completed in October 2007, and a presidential permit issued in June 2008.
Scottish and Southern Electricity Networks is one of two energy companies in the UK to be involved both in electricity transmission and distribution.
