The replacements were made  as part of the mechanical and electrical upgradation programme initiated by Ontario Hydro, the State-owned power utility of the Canadian province of Ontario running the power stations at the Niagara Falls.

The first of the generating station on Canadian side of Niagara river was built in 1905 by the Ontario Power Company. (A small generating station had started operation on the American side of the Niagara as back as in 1882). This station with nine units is now being operated by the Ontario Hydro.*

Ontario Hydro's predecessor, the Hydro-electric Power Commission, built the second station on the Niagara with ten generating units. These units, situated ten km down stream from the Falls, were commissioned in 1922. The station, which was for many years the largest in the World, has been carefully maintained. Its capacity was raised from 400 MW to 470 MW through installation of more efficient generating equipment. A 13 km canal was built from Welland River to the station's fore bay to provide sufficient flow.

Another 16 units were set up near to that in 1954-58 period. Water was diverted for these units from upstream of Niagara Falls through twin nine kilometre long tunnels built under the City of Niagara Falls. The tailrace water flows back into the river downstream of the Falls. Together the three stations produce, on an average, about 12 billion units of energy a year. The last two are named after Sir Adam Beck.

The older units at Niagara (built by Ontario Power) were characterised by their comparatively larger size. There are separate transformers for each phase, which are cylindrical and several metres high. They are now getting replaced with sleek and more efficient generating units.

According to engineers of Ontario Hydro, efficiencies could be improved by 15 per cent. There are also plans to construct a fourth generating station. This would be built almost entirely underground, below the Niagara city, with minimal disruption to residents and tourists.

Ontario Hydro is an international partner in conserving Niagara Falls as a scenic tourist destination by maintaining the flow of water over the falls in accordance with a treaty signed in 1950. As per terms of the treaty, water flow is regulated to ensure that at least 100000 cubic feet flows over the 675 metre wide Horseshoe Falls (height 52 metres) and the 320 metre American Falls during day light hours of the tourist season (May to October). A flow of at least 50000 cubic feet is to be ensured at night and during the winter.

The flow is managed using a river control structure that extends half way across the river from the Canadian shore above the Falls. This has 18 gates that open and close to regulate the flow of water or ice. It spreads water over various parts of the Falls to enhance the view. In winter, the treaty requires Ontario Hydro and the New York Power Authority (which has its generating units on the other side of the river) to manage the ice formation. If ragged ice packs build up over the river, that could damage the facilities along the river.