Engineer and Neptune Power director Chris Bathurst, of Christchurch, was called to give evidence by appellant John Douglas, on the logistics of marine energy generation.
During cross-examination by Meridian counsel Andrew Beatson, Dr Bathurst acknowledged he had made a submission opposing Project Hayes, asking for the application to be "thrown out".
Neptune Power has been granted resource consent for an experimental turbine capable of producing 1MW of power in 80m of water 4.5km off the south coast of Wellington.
Dr Bathurst said marine generation was known to be consistent and regular, and would be more useful to the New Zealand transmission network than an irregular and inconsistent resource such as wind.
He said marine generation would require two to three hours of backup energy to be stored for use between incoming and outgoing tides, which would not be difficult because tidal behaviour could be accurately plotted in advance.
Such a system was in place in England, he said.
Dr Bathurst said a storage reservoir on top of a Wellington hill would be an ideal location, to which seawater could be pumped for use in between tides.
In response to a question from commissioner Heather McConachy, Dr Bathurst said such technology was within the country's reach, and much closer to fruition than was commonly thought.
"I think we can get a [1MW] turbine [in the Cook Strait] up and running within one year without too many hold-ups such as finance.
We believe we could develop a 30MW turbine in about three years and are expecting to get a 900MW turbine in about 10 or 15 years," he said.
Dr Bathurst said the "simple" technology for successful marine-energy generation was known and available in New Zealand, and it was a matter of putting technology together in a "good engineering fashion".
He said arguing about a development such as Project Hayes, which would not solve the country's electricity-demand problems, was a waste of time and resources better spent on developing marine generation.
In response to a question from commissioner Alex Sutherland, Dr Bathurst said marine technology was already working both in Norway and Hawaii.
Project Hayes appeal
Day 31
Panel: Environment Court Judge Jon Jackson, commissioner Alex Sutherland, commissioner Heather McConachy, and deputy commissioner Ken Fletcher.
Yesterday's witnesses: Engineer and Neptune Power director Chris Bathurst, of Christchurch; photographer Mike Langford, of Queenstown.
Coming up: The hearing will resume on Monday.
Quote of the day: "In some of the TrueView images, I would say the turbines are diminished by as much as 300%." -Queenstown photographer Mike Langford
