It could cost between $50 million and $70 million to upgrade the lower Waitaki electricity grid to cope with irrigation for the dairy boom and a new cement works, Transpower says.
The owner of New Zealand's high-voltage electricity transmission grid is investigating how to ensure North Otago and South Canterbury get the power they need to meet increasing demand.
Auckland-based consultant Covec has forecast seven major projects, including irrigation schemes, a dairy factory and Holcim's cement works, could increase the peak load to 190MW by 2020.
That would be 200% more than this year's peak load and would outstrip the capacity of the 110kV transmission network, Covec's latest forecast suggests.
Transpower grid development general manager John Clarke confirmed an upgrade proposal could be ready for the Commerce Commission by the end of the year.
If approved, the Lower Waitaki Reliability Project could be completed by 2015-16.
Mr Clarke said the project could cost between $50 million and $70 million, but that estimates were once as high as $90 million. It was originally expected to cost $10 million to $20 million, according to Transpower's website.
Transpower had been consulting stakeholders, including Network Waitaki and Alpine Energy, as it developed a shortlist of four options, Mr Clarke said.
He declined to discuss them, but options put to stakeholders in April were a mix of upgrading existing lines and building new ones between Timaru and Studholm, and Livingston and Oamaru.
Stakeholders were told lines upgrades would take two to three years and that it could take five to seven years for new lines to be approved and built.
They were also told Transpower would consult people whose land might house new lines.
Mr Clarke said the "preferred solution" had yet to be determined: "We are still looking at options that may include doing things to the existing lines; or there could be a limited amount of new line."
News of the Waitaki project came as Transpower received Electricity Commission approval for a $62.4 million project to improve transmission capacity and meet dairy and industry-fuelled demand in Southland.
Making better use of transmission lines installed to supply the proposed Aramoana aluminium smelter, installing additional equipment at the Three Mile Hill, Roxburgh and Invercargill substations and connecting existing transmission lines at Gore would also improve security of supply, Mr Clarke said.
Also this month, Transpower received final approval for a $170 million project to upgrade the existing lines to double the transmission capacity between Roxburgh and the Waitaki valleys.
