unit 8 on 1 June 1962. The commissioning of Roxburgh removed the need for power restrictions in the South Island and ensure a surplus of power for many years. Project cost In December 1947 the government expected the project to cost a total of £11,500,000. By September 1949 when the final location and type of dam had been chosen the cost had increased to £17,000,000. A contract of £8,620,074 was awarded to Hannen, Holland & Cubitts in association with Conrad Zschokke. This was a target estimate contract with a 'no loss clause'. In May 1954 the contract was re-negotiated to include Downer & Co as the principal. The new contract was based upon 'a schedule of rates' at a value of £10,120,000. The final total cost of the project was £24,102, 800 of which £19,151,700 was for civil engineering, £445,000 on the bulkhead caissons and stage 2 civil works, £4,506,100 on the purchase and installation and commissioning of the eight generators and outdoor switchyard. Included in the civil engineering cost was £900,000 for the early completion bonus and £35,900 on expediting the programme. A total of 3,500 drawings were produced between the Ministry of Works, the State Hydro-Electric Department and contractors to build the power station. Service In December 1965 a generator coil failed on unit 2, followed by a series of further failures between 1971 and 1973, which in an effort to correct, the windings were reversed. Units 1, 3 and 4 had their stators rewound in 1975 to 1976. The sluice gate No. 3 in 1996 and gate No. 2 in 2001 were modified to enable the power station to pass an increased maximum design flood of . Gate No. 1 was also plugged with concrete. To improve the structure's ability to withstand seismic events the original heavy chain and counterweight spillway gate operating system was replaced with a hydraulic system while the dam's top bridge was strengthened and the gantry towers were lowered. In the 1990s the power station's control systems were automated with new control and protection systems which allowed it to be de-manned. Control of the power station is now undertaken from a control centre at Clyde Power Station. Ownership changes In 1987 the assets of the NZED (including Roxburgh) were transferred to the Electricity Corporation of New Zealand (ECNZ). On 1 April 1996 ownership of Roxburgh was transferred from the Electricity Corporation of New