Contact Wind and Contact Energy counsel, Trevor Robinson, admitted as much under questioning on the opening day of a six-week board of inquiry hearing into the $1 billion proposal in Tuakau yesterday.

In his opening submissions Mr Robinson said the wind farm on 34km of isolated coastline from Te Akau, 8km north of Raglan, to 4km south of Port Waikato and colloquially dubbed "HMR'' was unlikely to proceed immediately after consents were granted.

That was because the dollar cost per unit of electricity from the turbines was greater than from geothermal developments or other wind farms, which could generate more efficiently.

And that was why Contact was seeking a 10-year lapse period for the project.

Board chairman Judge Jeffrey Smith presiding alongside Dr Diane Menzies, John Lumsden and Hamilton's Gina Rangi asked Mr Robinson if the wind farm would be constructed at all.

''There is no certainty HMR will be built,'' Mr Robinson replied. ''But Contact is looking for certainty it can be built, if and when it is needed.''

It was "critically important to have consents that are able to be exercised when market conditions are favourable''.

And that was not necessarily just pricing issues.

''If there are delays in upgrading the transmission grid, a number of other wind farm developments are unlikely to proceed and the security of electricity supply issues for the greater Auckland area might come even more into focus as a priority.

But he said Contact would not proceed with such a massive investment unless it was economic to do so.

''However it is very important that if and when HMR is required as signalled by the electricity market that it should be able to proceed.''

The wind farm is substantially larger- both in terms of footprint and capacity- than any existing wind farm in New Zealand, with a maximum of 180 turbines producing up to 1600GW hours of electricity each year.

The proposal attracted 96 submissions, 31 in support, seven neutral, 43 opposing, 13 mixed, and two unstated.

An analysis of likely economic benefits estimated additional income of $159 million for the Waikato region over the construction period and an additional 399 jobs.

Mr Robinson stressed the need for flexibility in structuring the application for resource consent, saying there was a reluctance to commit substantial resources required for detailed engineering design before consents were obtained.

Despite Mr Robinson's opening running to 66 pages, Judge Smith flagged early his concern at the lack of detail and discussion in some of Contact's evidence.

He warned much more clarity was needed to understand the effects of turbine consent.

''There is huge tension between the flexibility you desire and the effects we need to consider,'' he said.

More detailed plans were suggested.

"We don't have the power to consent for what is not specified.''

Judge Smith was also unimpressed with Mr Robinson's assertion that one of the most attractive features of the HMR proposal was that it would inject electricity into the national grid north of Huntly, and thus avoid transmission constraints to the south in feeding directly into Auckland.

But Judge Smith said he understood that transmission system constraints would not be avoided because wind power was generally substituted for hydro loading, in which case constraints to the south would still be a major issue.

He welcomed Contact's evidence on this point.

Among those due to make opposing submissions over the next six weeks are former National Party energy minister Sir William Birch, who ironically for one of National's former Think Big architects is concerned at the impact and enormity of the project.

Other opponents include the Maori Party's Hauraki Waikato candidate at the last election, the Ravensdown Fertiliser Collective, the Waikeretu School board of trustees, and the Raglan Point Boardriders Club.

Principal aspects of the project include:

-New substations at Te Akau, Matira, and Limestone Downs;
-A 25km 22kV line to a switching station at orton and 33kV lines fro each turbine;
- Re-establishment of the disused whitford Quarry to supply construction needs;
- Public viewing plants and Concrete batching plants
-The board of inquiry is likely to convene in Raglan during the week of May 18.