Adam Beck II contains 16 generators and first produced power in 1954. The water was first diverted from the
Niagara River by two five-mile (8 km) tunnels under the city of Niagara Falls, Ontario, that start above the falls. A reservoir was created that permits the holding of water, diverted during the night, for use during the day. Between 2007 and 2013, Adam Beck II underwent major civil engineering projects with the addition of a major underground water supply tunnel built by the
Niagara Tunnel Project in order to improve its generation output. Water delivered by the major new tunnel complemented other upgrades to the Sir Adam Beck generating complex, resulting in a significant increase to the efficient use of the
Niagara River's hydro power. The project's new diameter, long tunnel was officially placed into service on 21 March 2013, helping to increase the generating complex's
nameplate capacity by 150 MW, able to provide the power for about 160,000 homes. A
CAD 60 million refurbishment of the Pump Generating Station reservoir, built in 1957, was started in 2016. The major 1965
Northeast Blackout of Ontario and several U.S. states occurred on 9 November, after maintenance personnel incorrectly set a protective relay on one of the transmission lines from the Sir Adam Beck Station No. II. The faulty relay later tripped open causing a major blackout created by a series of
cascading failures which affected over 30 million people for up to 12 hours. ==Water diversion==