Power consumers will bear the brunt of a $158 million planned upgrade to the national grid.
Transpower is seeking approval from the Electricity Commission for grid upgrades which would see it squeeze as much as it can out of existing lines in the North and South Islands.
While Transpower will
pay for the project, the cost will be passed on to lines and generation companies, forcing up the price of power.
Transpower spokesman Chris Roberts said the proposed upgrades would happen over the next three to four years and customers may see increases in transmission charges but they were likely to be in cents rather than dollars.
Mr Roberts said it would be up to the commission to decide how the costs of the project would be spread between lines and generation companies.
Transpower's announcement yesterday follows a decision last week that the planned 400kV line from Whakamaru to Otahuhu would be put back a year.
It will be the first time Transpower has had to take a proposal to the newly formed Electricity Commission headed by commissioner Roy Hemmingway.
Transpower chief executive Ralph Craven said the plans were "tactical upgrades" which would secure supply mainly into Christchurch and the upper South Island.
Work in the North Island predominantly involved looking at what lines it could "run hotter" or pump more electricity through.
The upgrades also involve changes to substations to improve voltage flow, installing more lines on towers which currently only have lines on one side, putting in an additional set of conductors along the Livingstone to Islington line in Canterbury and working to reduce line outages.
Mr Craven said it was the most significant investment in the national grid for some time.
"We expect the Electricity Commission to consider and approve these important projects under the appropriate provisions of the Electricity Governance Rules," Mr Craven said.
