Hazelwood Power Station was approved in 1959, and was to consist of six generating units, giving a total of 1,200 MW of generating capacity. The first unit was to enter service in 1964, and the sixth in 1971. Growing electricity demand saw a review carried out by the SECV in 1963, with commissioning of the generating units moved forward to 1969. Additional capacity was provided when in 1965 two additional generating units at Hazelwood were approved, to be commissioned in 1970 and 1971 respectively.