The Public Works Department wanted to source major equipment from outside the usual United Kingdom because of tight delivery dates, and British firms' lack of experience in constructing large turbines, generators and 220 kV equipment. Eventually, contracts were let to Canada for the generators and the United States for the turbines, both being more experienced and the price being 40% less than the British equivalent. For the spillway gates and frames, a tender from West Germany only five years after the Second World War was quite surprisingly accepted by Cabinet, being one-third lower and one year faster than the lowest British offer. By mid-1951, the penstocks had been installed and the first three machines had been installed. On 31 October 1952, Maraetai generated its first electricity, producing on a reduced load and half head. Temporary flumes transported water through the powerhouse from the two remaining penstocks. The reduced head was maintained while the diversion tunnel was stopped with a huge long concrete plug. The head was raised to in April 1953, and the station was officially opened on 5 September 1953 - two years after the target completion date. The fourth machine was installed in January 1954, followed by the fifth and final machine in April. The lake was then raised to its full height of head. Maraetai II The construction of the Maraetai II powerhouse, the last powerhouse to be built on the Waikato River began in 1959, with a 500-metre long canal taking water down the south side of the gorge to the powerhouse. In 1961, work on Maraetai II was suspended when the newly elected National government, led by Sir Keith Holyoake, shifted priority to building the HVDC Inter-Island ("Cook Strait cable") between the North and South Islands, following a significant increase in electricity demand. With the inter-island link completed in 1965, work recommenced on Maraetai II, with the first two turbines and generators were finally commissioned in July 1970. The last turbine and generator, and the last on the Waikato River, being commissioned in February 1971 - almost 25 years after construction of Maraetai began. Dam Maraetai's dam is a concrete arch dam which impounds the Waikato River behind the Maraetai I powerhouse, and creates Lake Maraetai. The dam is long, high, and is wide at the base and at the crest. At one time, the dam was the largest hydroelectric dam in the Southern Hemisphere.