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Transpower's controversial 400kV line from the Waikato might not be justifiable, major energy users and business leaders warn.
The Major Electricity Users Group (MEUG), Business New Zealand and the Employers and Manufacturers Association (Northern) say Transpower has yet to establish that the new power generated is sufficient to justify the new line from Whakamaru to Pakuranga and Otahuhu.
"Since there is not a material difference between [power] prices just south of Whakamaru and Pakuranga or Otahuhu, there is not a prima facie case that the surplus generating capacity already exists south of Whakamaru," notes a report by commissioned by MEUG.
The report, part of a submission on the new line to the Electricity Commission, also notes the majority of planned supply will not be sent through the new line.
"We recommend the commission carefully considers whether Transpower has established there will be surplus generation capacity to utilise the amount of additional transmission capacity between Whakamaru and Auckland ... and whether the additional supply of generation in Auckland will require this level of transmission assets."
Transpower submitted a revised plan for the line in October after the electricity commission knocked back the national grid operator's first proposal in April.
The new $683 million line will first be built to carry 220kV lines on more than 400 pylons, some as tall as 70 metres. But it will later be upgraded to carry 440kV lines. At the South Auckland urban boundary, the overhead line will connect to underground cables, that run to the Pakuranga substation. A second underground cable section to Otahuhu substation will be added as demand increases.
The commission is due to make a decision to approve or reject the plan on December 19 and then ask for a new round of submissions on its decision the day after.
Echoing MEUG's concerns, the EMA said Transpower's proposal does not take account of possible generation that could be built in Auckland or north of Auckland.
"Such generation, should it be built, could reduce the need for the proposed level of transmission," the EMA said in its submission.
Transpower dismissed the groups' concerns. A spokeswoman said new generation capacity that could make use of the line could yet come on stream.
Meanwhile, it said generators were supportive of the plan.
