Chief executive Murray Jackson told EnergyReview.Net today that Genesis Power was planning to effectively double the economic life of the duel-fuel station by the stage five-year program.

There would be a complete control system upgrade, as well as the refurbishment of the condensers and full inspections of the steam boilers, to ensure the station was capable of another 100,000 hours of operation.

This should ensure the station, which first ran on only coal but was later modified to run on natural gas, would be well capable of operating another 20 years until 2022.

The staged refurbishment would require the maintenance shutdown of each of the station's four 250MW units through to 2007.

Meanwhile, Jackson said that since last December Genesis had been evaluating tenders, involving long-term maintenance, warranties and other things, from four major manufacturers for its planned new 360MW combined cycle plant.

Genesis was now in discussion with Mitsubishi Heavy Industries and hoped to finalise negotiations soon.

Site works had already started for the new plant, as well as major upgrading of the necessary railway bridges needed to transport the heavy loads from next year.

The main contracts needed to be awarded by July next year to ensure the 30-month construction phase could be finished in time for the scheduled December, 2005, commissioning.

The existing duel-fuel Huntly station, New Zealand's largest thermal plant, had averaged over 98% efficiency during the past year and was running on an average mix of 70% natural gas, from many Taranaki fields, and 30% coal from nearby coal fields.

Gas consumption was scheduled to increase from about 40PJ a year to a total of 60PJ once the higher efficiency combined cycle plant was operational.