Wind turbines at sea could help meet high future demand: experts.
International experts say New Zealand is missing out on a renewable energy source that could be a game changer for our ambitious clean energy goals: wind.
New Zealand has plenty of it and, in recent years, has built onshore wind farms to generate electricity. But New Zealand has no turbines built out to sea, missing out on the huge potential of offshore wind developments, says Anant Prakash, Group Director, Environment and Energy, AECOM.
Prakash believes offshore wind can play a key part in assisting New Zealand to reach its goals of 50 per cent of total energy consumption from renewable sources by 2035 – and 100 per cent of electricity from renewable sources by 2030.
AECOM is a global infrastructure consulting firm partnering with clients to develop infrastructure across various sectors, including transportation and construction through to the environment. Over the years, AECOM has worked with developers around the world to build offshore wind farms, delivering services including planning, design, environmental surveys, permitting and construction.
This includes several vital offshore wind projects in the US designed to power 10 million homes by 2030, along with projects in the Hunter Coast and South Pacific offshore wind farms as well as the Star of the South in Australia. The latter will consist of 400 offshore wind turbines and essential electricity transmission infrastructure for grid integration.
“The goal [for New Zealand] is to have an electricity system able to meet demand and that can be leveraged through renewable sources, at low cost,” he says. “Offshore wind is a big player in that, especially as in New Zealand the wind blows harder and more regularly than anywhere else in the world.”
That’s thanks to the area of the Southern Ocean known as the Roaring Forties, where the prevailing westerly winds barrel across the sea. There are no nearby land masses to impede the flow of wind and in some places it is just about continuous and relatively high speed, making these areas particularly well-suited to offshore wind energy development.
Areas identified as good sources of offshore wind are the ocean off Taranaki and Waikato, plus Foveaux Strait; developers are currently looking into the feasibility of turbines in the water there.
One of the main benefits of offshore wind farms compared to onshore is the amount of energy they can produce. “You can have the capacity to undertake much larger-scale ventures than you can onshore,” points out Prakash. “New Zealand, being a long and skinny country, limits how much onshore development we can have.”
Offshore wind farms may be able to produce so much electricity that it exceeds demand, so not only would that make it cheaper for consumers, but that surplus could then be exported. Excess electricity could also be used to produce hydrogen, a clean alternative to carbon-emitting natural gas – which can be used in everything from manufacturing to heating. When hydrogen is created using renewable energy like electricity, it is also considered to be renewable.
“There is a market offshore for green hydrogen and in New Zealand we could produce it because of our ability to tap into renewable wind energy.”
Another bonus of offshore wind farms is that the turbines can’t usually be seen from the land. “Typically, they are about 20km offshore so they are not really visible, which can be a big benefit from a community perspective.”
So why haven’t we rushed to build wind farms at sea? “The cost,” says Prakash. “Offshore wind is more expensive compared to other technology, such as onshore or solar. But like other technologies, the cost is starting to come down, which makes offshore wind more palatable to developers.”
Another concern is the impact on marine and bird life: “You have to consider things like how the pylons affect the flow of the ocean and the marine ecosystem, and how the height of the blades affects flight paths of birds. Do they fly elsewhere, do they feed elsewhere?”
Because offshore wind development is relatively new, environmental effects are still being studied. However, AECOM has a team of experts who can use their skills to analyse New Zealand’s situation and the unique bird and marine life.
When it comes to offshore wind, Prakash says, there are several challenges: regulatory frameworks need to be developed to steamline project permitting and consenting; the country involved needs to have the skills and labour to carry out all construction and maintenance as sustainably as possible. Also required are the development of offshore infrastructure like ports and transmission lines to ensure the electricity generated is moved to where it’s needed.
But he says the country should be getting on with finding solutions so this type of energy can help meet an inevitable demand.
“It’s being forecast that the amount of electricity we will consume will more than double by 2050,” he says. “At the moment, demand is just under 10 gigawatts [a year] but it could go up to 20-25 gigawatts.”
The increasing use of electricity in transportation is one of the factors driving this demand, with more electric cars on the roads, along with electric buses and trains. “We could even see electric planes,” says Prakash.
“The other big component is electrification in the industrial sector. That means replacing things like coal-fired boilers with electric ones – and even if we do use green hydrogen in industry, it still needs to be produced using electricity.”
Despite the challenges, being part of the process to bring offshore wind energy to New Zealand is exciting, says Prakash, “and we feel very positive about our ability to help shape the local renewable energy industry.”
For more information visit aecom.com