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Long delayed upgrades to begin soon

By Moana Moeka’a

RAROTONGA, Cook Islands (Cook Islands News, Oct. 28, 2009) - Four years after the first report was done on Aitutaki’s power needs, the island’s new power station was commissioned on October 15.

After a number of reports written in 2005 and 2006 -- including a wind resource assessment – government committed capital expenditure of NZ$1.65 million [US$1.2 million] in 2006-07 for the power station upgrade.

NZAID chipped in with NZ$1.1 million, while Cook Islands Investment Corporation and the Aitutaki Power Supply (APS) put NZ$150,000 towards the project.

CIIC’s Lloyd Miles says registrations of interest were advertised in June 2007, with 19 entities signing up, and 10 being shortlisted in August.

Unfortunately, the project was suspended by government shortly after and it wasn’t until June 2008 that the 10 entities were invited to tender. The five tenders received were evaluated in August last year.

Miles says because there was a shortfall of NZ$1.3m for the preferred tender, an application was made to NZAID for additional funding. The sum of NZ$1.1m was given the okay on October 1 and the government tender committee approved the tender later that month. Cummins South Pacific New Zealand Limited accepted the tender to construct, procure, supply, install and commission plant and equipment for the Aitutaki station on October 30.

The project was completed on September 21 and the period of defects liability will expire on September 20 next year.

Miles says approximately NZ$2.9m has been spent on the project, with NZ$377,142 going on building renovations and improvements, and NZ$2,522,858 being spent on plant and equipment.

Building renovations include construction of a new switch room and control room, new cladding and insulation of main station building including a new roof, as well as construction and installation of acoustic louvers and fans, concrete work, and repainting.

While all three generators are online at all times and are synchronized for automatic switch on/off, Miles says only one engine operates for most of the time.

"However a second generator will be required at times, and will automatically switch on, to meet peak demand and then automatically switch off when demand falls away."

Miles says during the night and even a large part of the day the load is fairly consistent and can be met, for the most part, by only one engine.

"However there are periods during a 24 hour day where demand is increased, namely the first three or four hours of each morning, and three or four hours in the evening where load increases."

Miles says ideally a generator should operate at about 75 to 80 percent load for the most part because that is when it is most efficient.

"If the generator operates efficiently then fuel consumption and consumables and wear and tear are down. All good things as those efficiencies save costs and the engines last longer."

The equipment at the station includes three Cummins C900D5 generators units with engine QSK23-G3, prime rated at 668 kWe, 835kVA/continuous rated at 514kWe, 643kVA; skid mounted generators; Cummins PCC 2100 digital controller; AC controls with meters; PMG 3 phase sensing voltage regulator; AMP sentry protection; electronic governors; air cleaners; low coolant level shutdown; anti vibration mountings; remote mounted radiators; stainless steel and acoustic upgrade exhausts; double skinned fuel tanks and fuel lines; new control panel and switch boards; ancillary and auxiliary equipment.

The commissioning was attended by deputy prime minister Sir Terepai Maoate, the island’s MPs, CIIC chairman Tapi Taio and NZAID representative Julie Affleck.

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