Otahuhu makeover

The upgrading of Contact Energy’s Otahuhu B Combined Cycle Power Plant in Auckland over the summer holiday period was an international effort.

For six weeks 300 contractors, including 80 specialists flown in from Germany by Siemens and an inspector from the US, worked 24/7 to pull apart and overhaul the 370 tonne generator and gas turbine at the combined cycle power plant.

Contact Energy says an additional 11.5 megawatts were achieved on the plant’s original 400MW capacity. “We also gained about five or six megawatts from other outage related improvements and equipment changes, and heat rate efficiency improved by about 0.5 percent,” says a spokesman.

Modifications also included upgrading the of the gas turbine inlet guide vanes drive resulting in an improved plant’s reserve response amongst other things.

Contact’s Otahuhu B CCGT 400MW plant was commissioned in 1999 while Otahuhu A is used for reactive power to support the stability of the grid.

The power generator has a consented site adjacent to it’s Otahuhu-B CCGT earmarked as an expansion project called Otahuhu C, but says this has been deferred while it concentrates on other developments.

“We don’t have sufficient certainty around domestic gas supplies or price and we are currently focused on geothermal generation.”