Otara Gas Turbine Station By Doug St George, Assistant Engineer with NZ Electricity Dept 1967 to 1969.

This power station was built with 4 Stal-Laval gas turbines, each of 50 Megawatts, or about 67,000 horsepower. The first turbine was dual-fuel, to run on either Kapuni natural gas, or diesel and was cooled by fresh water with cooling towers. Units 2,3 and 4 were cooled by salt water from the Otara creek nearby. This power station was built with 4 Stal-Laval gas turbines, each of 50 Megawatts, or about 67,000 horsepower. The first turbine was dual-fuel, to run on either Kapuni natural gas, or diesel and was cooled by fresh water with cooling towers. Units 2,3 and 4 were cooled by salt water from the Otara creek nearby.

The turbine unit comprised a gas generator, on the left, with separate low and high pressure compressors, twin vertical combustion chambers, with piping above and below the floor leading to the power turbine, driving the generator. Starting was by compressed air blowing into the low pressure compressor. The turbine unit comprised a gas generator, on the left, with separate low and high pressure compressors, twin vertical combustion chambers, with piping above and below the floor leading to the power turbine, driving the generator. Starting was by compressed air blowing into the low pressure compressor.

The generator shaft had a free-wheel coupling to allow the generator to be run at 3000 RPM on its own, as a synchronous condensor, for voltage control. The generator shaft had a free-wheel coupling to allow the generator to be run at 3000 RPM on its own, as a synchronous condensor, for voltage control.

Some views follow, taken from the top of one of the exhaust stacks. The Otahuhu Sub-Station building can be seen, where remote start switches were fitted. The turbines could be generating full power in a few minutes after pressing start. Some views follow, taken from the top of one of the exhaust stacks. The Otahuhu Sub-Station building can be seen, where remote start switches were fitted. The turbines could be generating full power in a few minutes after pressing start.

A view of the Otara Creek, used for salt water cooling, and the salt-water pumphouse. A view of the Otara Creek, used for salt water cooling, and the salt-water pumphouse.

A view of the cooling towers for turbine # 1. A view of the cooling towers for turbine # 1.

The control room for the Otara Turbine Station. In 1969, the equipment included relay control panels and solid-state turbine governors, made of discrete components (before integrated circuits, silicon chips and computers were invented) The control room for the Otara Turbine Station. In 1969, the equipment included relay control panels and solid-state turbine governors, made of discrete components (before integrated circuits, silicon chips and computers were invented)

The NZEDs 1946 Bedford truck for use by the Assistant Engineers, Bob Eagle and Doug St George. We had use of it when it was not being used for blocking a hedge in Henderson. The NZEDs 1946 Bedford truck for use by the Assistant Engineers, Bob Eagle and Doug St George. We had use of it when it was not being used for blocking a hedge in Henderson.

After leaving the NZED in 1969 I worked for Stal-Laval in Sweden. This is a picture of the same type of turbine installed in Hämeenlinna, in Finland. Others were installed in China and Västervik, Sweden. After leaving the NZED in 1969 I worked for Stal-Laval in Sweden. This is a picture of the same type of turbine installed in Hämeenlinna, in Finland. Others were installed in China and Västervik, Sweden.

And now in 2007? In the 1970s two more gas turbine units were installed, but the Government chose aero- engine types as they had found the Stal-Laval units did not start up reliably when needed. Two more chimneys were added to the western end of the station. The chimneys for the Stal-Laval units have since been removed. And now in 2007? In the 1970s two more gas turbine units were installed, but the Government chose aero- engine types as they had found the Stal-Laval units did not start up reliably when needed. Two more chimneys were added to the western end of the station. The chimneys for the Stal-Laval units have since been removed. Otahuhu B combined cycle power station has been built nearby. Otahuhu B combined cycle power station has been built nearby.