Residents Conway Powell and Rudi Sanders, submitting individually, agreed with Aurora Energy Ltd's evidence yesterday that a higher voltage electricity supply was needed to meet rising power demands in the valley.
However, Aurora had not recognised or offered to mitigate any detrimental effects the proposed upgrade's 11m high poles and three extra lines would have on the two landowners.
Independent commissioners Jane Taylor and Sally Middleton heard the arguments during the one-day resource consent hearing at Crowne Plaza Queenstown yesterday.
Aurora applied for consent to upgrade the 11kV feed up the Cardrona Valley with a 33/66kV overbuild for most of its length and replace 191 poles between the Orchard and Riverbank Rd intersection and the Cardrona Valley Rd substation.
Mr Powell asked why Aurora did not offer to put cables underground through his property, as the firm had proposed to put 1.2km of 11kV lines underground on road reserve up Riverbank Rd.
But Delta engineering services manager Nigel Harwood said putting a 66kV cable underground would cost eight to 10 times the cost of the overhead option.
"This would turn a $2.3 million project into a $18.4 million to $23 million project, again with the costs ultimately being borne by the Wanaka community.
This would be over twice the cost of upgrading the lines to Wanaka and the Wanaka substation in 2002 to 2004."
Mr Sanders asked commissioners to approve the upgrade on one of two conditions: underground lines, or the line to follow Cardrona Valley Rd further upstream and cross the Cardrona River as "a cheap alternative"."
Aurora is making a long-term business investment and is able to recoup cost over a very long time and through increased line usage.
The disadvantages for us are huge."
Delta projects manager David Paterson said power demand in the Cardrona Valley was near the limit.
Some consumers had already experienced problems because of dips during the start-ups of the Cardrona ski lifts, despite two regulators inserted on the 11kV line to boost voltage.
He said Aurora's policy was to place power lines overhead in rural areas, and landowners were asked to pay for the extra work if they wanted lines underground.
In his summary, Aurora counsel Christopher Thomsen told commissioners there was a "question of balance, when you consider the effects on the submitters versus economic effects on both the applicant and the public".
The commissioners reserved their decision.