Ports of Auckland has agreed to buy the world's first full size electric tugboat in an effort to fight climate change.
Port's chief executive Tony Gibson said urgent action was needed on climate change. The tug has the same capacity for work as the port's diesel tugboats, and will cost less over its lifetime.
Over the last three years the company has battled to find a manufacturer who would be willing to take the challenge on. Dutch company Damen Shipyards will build the tug, and expects to deliver it in 2021.
The Ports of Auckland has a goal of being zero emissions by 2040, and hopes it inspires other ports.
"We hope this is a catalyst for supporting climate change [action] - that everyone takes this seriously - and that a build of an electric tug can be done," Mr Gibson said.
"It was important to us that a new electric tug should be able to carry out normal port operations, just like our existing diesel tugs. Our new e-tug will be able to do three to four shipping moves on a full charge, or around three to four hours' work. A fast charge will take about two hours. This is just what we need."
The port would not reveal the cost, but Mr Gibson said it would be approximately double that of a diesel tug, which costs $8 million to $9m.
"One of the other hurdles we had to get over was cost. The purchase price of this tug is significant, at roughly double that of a diesel tug, and that is an important consideration for a business that needs to make a profit. However, we are prepared to wear that up-front cost because our commitment to reduce emissions has to be more than just words.
"Fortunately, the cost of operating an electric tug is less than a third of the cost of running a diesel tug. So while we pay more up front, over the life of the tug we'll save around $12 million in operating costs, making our electric tug cheaper in the long term," he said.
Mr Gibson said the port planned to replace all of its other tugs with electric ones.
Port's operations manager Allan D'Souza said when they started looking for a battery-powered tug in 2016, no-one was making them, and shipyards told them they were dreaming.
They kept contacting yards and problem solved, and eventually negotiated a contract with Damen Shipyards.
Climate Change Minister James Shaw said: "People who say we have to wait for the technology to emerge before we can set ourselves bold goals have got it round the wrong way.
"Many of the challenges we face with climate change will require solutions that aren't yet on the market.
"Ports of Auckland and an increasing number of other businesses across New Zealand are showing that won't stop them finding ways to meet our goals on greenhouse gas emission reductions."