NIWA’s energy projects are turning the tide


Harnessing tidal power for electricity generation will be a landmark in broadening New Zealand’s already impressive renewable energy portfolio, a marine energy conference is to be told.

“In the drive to replace non-renewable fossil fuels with renewable energy sources, marine energy is emerging as a viable option in the near-future and a real complement to wind, geothermal and hydro resources,” says NIWA oceanographer, Dr Craig Stevens.

Dr Stevens is a presenter at the AWATEA conference to be held in Wellington next week 19/20th April. It will include a report on the state of marine energy in New Zealand and includes keynote speakers from the United States, the United Kingdom among many international delegates.

“High speed flows in the coastal ocean are very complicated and not surprisingly carry vast amounts of energy.  We are starting with the basics, looking at the oceanography and getting a handle on variability.  This will provide us with real knowledge when it comes to both picking the best sites for energy extraction and understanding how the environment will be impacted,” says Dr Stevens.

Questions around the environmental impact of new electricity generation have maintained a high profile with the public. In order to facilitate environmental consenting, Dr Stevens is investigating the impact of tidal turbines on coastal waters.

This is made difficult because there are only a handful of tidal turbines operating in the world and no tidal turbine farms at all.  This is likely to change rapidly in the next five years – but for now we have very little to go on in terms of real data on their effect and operation, says Dr Stevens.

New Zealand’s first marine energy tidal stream turbine development is likely to be in the conditionally approved Kaipara Harbour Crest Energy project with an experimental device consented for Cook Strait (Neptune Energy) and a project looking at the fast flows in Tory Channel (Energy Pacifica).

Stevens believes “we could see a few turbines in Cook Strait within 2-5 years, and building on this experience within ten years our first turbine farm should be operational providing predictable and relatively unobtrusive power that is again relatively low in carbon emissions.”

The aim of Stevens’ group’s work is to gain a stronger understanding of tidal stream energy issues like turbulence, weather, waves, and climate.  The group is building on experience with assessing the environmental impact of aquaculture developments. Stevens believes good quality impact assessments require an understanding of the underpinning physical science. “We are bringing this knowledge to the point where the economic benefits are clear and the integration of marine energy into the New Zealand energy systems can become reality.”

This research is funded by The Foundation for Research Science and Technology.


Principal Scientist - Marine Physics
Brett Grant Craig Stewart and Tim Divett looking at a map of the sea floor of the Cook Strait.