‘Unlimited resource’: NZ’s offshore energy revolution
An energy revolution is just taking off in New Zealand, with offshore wind potentially doubling our renewable electricity output in just a few decades, Marc Daalder reports

Special report: They may not be in place for another decade, but offshore wind farms have the potential to remake New Zealand's energy economy and spearhead our path to net zero emissions.

Transpower estimates New Zealand will need to increase its electricity generation by 68 percent by 2050 in order to keep up with population growth and the electrification of transport and industry. Given we'll also need to retire our fossil fuelled power stations, meeting demand in 2050 could require the country to double its current renewable generation.

In just 28 years' time, the grid operator says, there will need to be nine times more electricity generated from wind. Offshore turbines could play a crucial role in that. They're bigger, meaning they generate more power, and wind speeds offshore are higher and more consistent.



If New Zealand wanted to fill the wind gap with land-based turbines alone, we'd need to build 25 percent more onshore generation, compared to an all-offshore strategy.

There's still a long way to go before offshore wind becomes a reality in New Zealand, experts warn. We have no regulatory regime to enable exploration or consenting of wind farms and the Government expects it will have to play a role in guaranteeing off-take of the electricity. But the opportunity it provides for New Zealand - and for regions like Taranaki that are expected to be hard hit by the transition to a low-emissions economy - could be invaluable.

There is no shortage of energy in New Zealand’s marine environment. A current discussion document (calling for public submissions by April 14) signals that offshore wind is poised to build a beachhead in a renewables market historically dominated by hydro power and underpinned by coal.

The technical and environmental challenges of offshore wind power are complex and expensive. Countries such as China, Denmark, Ireland and the UK currently lead the way, but New Zealand’s position in the southwest Pacific Ocean means there’s plenty of wind energy, both on land and at sea.

A shift in energy supply
Ara Ake, an energy innovation centre with a mission to assist New Zealand’s decarbonisation, recently held a forum on offshore renewable energy in New Plymouth, the country’s centre for the natural gas sector.

The discussions centred around upcoming changes to the Resource Management Act, which will affect how development in the environment proceeds, and the recognition that any new initiatives need to engage with Te Tiriti and Māori perspectives on how resources are used and who benefits.

The discussion document highlights two regions: the Taranaki Bight and Foveaux Strait. Both locations are relatively shallow and well suited to installations of current technology.

A NZ$4 billion project to build the country’s first 65-turbine offshore wind farm off the Taranaki coast could be completed within a decade, but the document also identifies some potential future regions that are deeper and more exposed to the Southern Ocean.

Potential impacts of offshore wind farms
New Zealand is watching developments at a large Australian offshore wind farm off the coast of Gippsland, which aims to supply 20% of the electricity for the state of Victoria.

But offshore wind generation presents environmental challenges, including possible impacts of large arrays of wind turbines on seabirds and marine mammals. The seas around Aotearoa are home to a greater proportion of seabirds than almost any other populated centre, including many seabird species that breed nowhere else.

one set of impacts has so far received little consideration. As tides push water past turbine pylons, the resultant wakes affect ocean stirring. This effect can be seen from space.

A recent study for UK offshore wind farms identified how large arrays are affecting the biological functioning of coastal seas.

With growing impacts from a changing climate, we need to ask more nuanced questions. For example, when considering environmental impacts, what baseline should we consider? Will the impacts of any particular development exceed the projected impacts of climate-driven extremes for that region?

Another compound question is how offshore renewables infrastructure will cope with . . . increasing future storminess and stronger or more frequent tropical cyclones. These will be challenging for all infrastructure, not just marine.

A notable aspect of the current discussions in [NZ] is the use of the term “offshore renewables” rather than “offshore wind”. This allows the focus to . . .including next-generation ocean renewables such as wave and tidal energy.