|Industry||Electrical generation, distribution|
|Fate||Broken into five separate businesses|
|Successor(s)||Ontario Power Generation, Hydro One, Independent Electricity System Operator, Electrical Safety Authority, Ontario Electricity Financial Corporation|
Ontario Hydro was a publicly owned electricity utility in Ontario, Canada. It was established in 1906 as the Hydro-Electric Power Commission of Ontario by the provincial Power Commission Act to build transmission lines to supply municipal utilities with electricity generated by private companies already operating at Niagara Falls.
It soon developed its own generation resources by buying private generation stations and then becoming a major designer and builder of new stations. As most of the readily developed hydroelectric sites were exploited, the corporation expanded into building first coal fired generation and then nuclear power. It was renamed "Ontario Hydro" in 1974, and by the 1990s, it had become one of the largest, fully integrated electricity corporations in North America.
In 1999, Ontario Hydro was split up into five successor companies.
Power at cost 
Energy policy focused on hydro-electric power and the formation in 1906 of the Hydro-Electric Power Commission of Ontario (HEPC). HEPC was a unique hybrid of a government department, a crown corporation, and a municipal cooperative that coexisted with the existing private companies. It was a "politically rational" rather than a "technically efficient" solution that depended on the watershed election of 1905 that saw the Conservatives replace the Liberals. The first chairman was Adam Beck, minister without portfolio in the provincial government of Sir James P. Whitney. Beck had been a prominent advocate of a publicly owned electricity grid. In 1907, Toronto City Council approves the development and public control of hydro-electric power, thanks to the leadership and commitment of Adam Beck's ally, William Peyton Hubbard. The son of a freed slave from Virginia, Hubbard was first elected to Toronto City Council in 1894. Together Beck and Hubbard made a formidable team, Beck fighting for public ownership province-wide, and Hubbard taking the lead at the municipal level.
The first transmission lines began providing power to southwestern Ontario in 1910. Beck was knighted in 1914 for his work in electrifying Ontario.
In the 1920s the commission began generating and distributing its own power when it was given the mandate to electrify rural areas. Besides building its own generating stations, it bought the transmission lines and generators of the largest private electricity company. In 1948, HEPCO changed most of its system from 25 Hz to 60 Hz. However, the Fort Erie area south of Niagara Falls stayed on the remaining 25 Hz generators until 1966, and this area had electricity throughout the 1965 Eastern Seaboard Blackout.
By the 1950s the commission was operating as a single integrated system. As demand rose in the post-war period, Ontario Hydro started expanding its generation system bringing on line many new hydroelectric stations. In 1953, Ontario Hydro began to interconnect with other utilities, the first interconnection being the Keith-Waterman line in Windsor which crosses the Detroit River to Detroit, Michigan interconnecting with Detroit Edison in the United States. This line was originally constructed at 120,000 volts and was later upgraded to 230,000 volts in 1973. Shortly thereafter, other interconnections with New York State were built. The first coal fired generating stations in the system were also built in this period. The expansion of coal continued during the 1960s and 1970s but was overtaken by the development of nuclear power.
Nuclear Age 
By the late 1950s the corporation also started getting involved in development, design and construction of CANDU nuclear power stations, with the first commercial sized one coming on line in 1965 at Douglas Point.
In the 1960s, HEPCO was the first utility in North America to utilize ultra-high voltage transmission lines. Planning for the UHV lines began in 1960 and in 1967, HEPCO put into service transmission lines carrying 500,000 volts that carry power from hydroelectric sources in remote Northern Ontario to high load areas in southern Ontario such as Toronto, London, and Ottawa. During the 1970s and 1980s, Ontario Hydro gradually expanded the 500KV transmission system into what it is today.
During the 1960s and 1970s Ontario Hydro's nuclear generating program expanded with the building of the first four units of the Pickering Nuclear Generating Station followed by stations at Bruce Nuclear Generating Station and a second four units at Pickering. By the late 1980s, Ontario Hydro operated one of the largest fleets of nuclear-powered generating stations in the world.
By 1970 all but the most remote municipal power systems in Ontario were organized into a single grid.
In 1974 the Power Corporation Act reorganized the system as a crown corporation called Ontario Hydro, the name it was most usually known by. In many Canadian provinces, including Ontario, hydroelectric power is so common that "hydro" has become synonymous with electric power regardless of the actual source of the electricity.
In 1989, Ontario Hydro published a four-volume study, up to the year 2014, under the title "Providing the Balance of Power. Ontario Hydro's Plan to Serve Customers' Electricity Needs". with different scenarios attempting to solve the need for additional facilities to replace aging electricity generation stations. This was derailed when electricity growth rates declined due to the recession of the early 1990s.
The last nuclear plant to be built in Ontario, Darlington Nuclear Generating Station, was planned in the 1970s. Construction started in 1981, but due to a series of political decision to delay construction, construction took an inordinately long time. Costs continued to mount during the delay and the plant was completed in 1993. This delay in the schedule caused the projected costs to increase tremendously, from an initial projected cost of $7.0 billion to $14.5 billion. The delay accounted for seventy percent of the cost increase. Nonetheless, upon completion, Darlington has performed above expectations, with many reactors operating at 93-95% capacity. The plant produces around $1 billion worth of power every year, and produces 20% of Ontario's electricity.
Ontario has the largest nuclear plant in the world,. the Bruce Nuclear Generating Station. The roughly 60% of Ontario's electricity is accounted for by the three nuclear power plants: Pickering, Darlington and Bruce. No fatal accidents related to nuclear power have occurred in Ontario.
Following what had seemed to be excellent operation in the early years, increase in costs from the construction of the Darlington Nuclear Generating Station and less than adequate maintenance with the existing nuclear stations, led to extended shutdowns and large increases in the rates charged.
In 1998, the Progressive Conservative government of Mike Harris passed the Energy Competition Act which authorized the establishment of a market in electricity. Ontario Hydros 19.5$B debt was detached from the companies and paid down through the Debt Retirement charge by Ontario ratepayers. In April 1999, Ontario Hydro was re-organized into five companies: Ontario Power Generation (OPG), the Ontario Hydro Services Company (later renamed Hydro One), the Independent Electricity Market Operator (later renamed the Independent Electricity System Operator), the Electrical Safety Authority, and Ontario Electricity Financial Corporation. The two commercial companies, Ontario Power Generation and Hydro One, were intended to eventually operate as private businesses rather than as crown corporations.
OPG was incorporated on April 1, 1999.
See also 
- Neil Freeman, "Turn-of-the-Century State Intervention: Creating the Hydro-Electric Power Commission of Ontario, 1906," Ontario History, Sept 1992, Vol. 84 Issue 3, pp 171-194
- Canadian Nuclear FAQs
- 1999 OPG Annual Report