A company hoping to win the contract to shift cars from Auckland's waterfront wharves says it is building a five-storey car storage facility with a giant solar-panelled roof.
And the transport company wants to use the electricity generated to power huge barges that will ferry the cars away from Auckland ports.
The bold plan is being pitched by PTS Group, which has submitted a proposal to Auckland Council and Ports of Auckland to move 230,000 cars each year.
It comes after mayor Phil Goff last month announced an opportunity to finally open up the "jewel" of Auckland's waterfront real estate - with longstanding calls to construct public facilities such as a waterfront stadium, parks or a museum on the space.
PTS is already building a five-storey, 1.6-hectare car storage facility at its Highbrook depot in South Auckland. Under the company's plan, diesel/electric barges will take cars from Captain Cook and Bledisloe wharves along the Tamaki estuary to the depot.
"We have working drawings and we are going to build that. That will be commissioned ready for operation by August 2021. We are doing that," PTS chief executive Ray Roberts said.
"We need to go up. The footprint and the cost of land is so expensive here, that we've made a decision that we need to go vertical on that site."
The new multi-storey facility will be able to store 5500 vehicles under cover, with solar panels spanning the entire top level. The panels will generate enough electricity to power 1000 homes for a year. PTS is working with Vector Powersmart's senior leadership on the proposal.
PTS is in negotiations to buy diesel-electric barges that could be converted to full electric.
"We haven't ruled out full electric barges but that would be expensive and we would need some government assistance for that," Roberts said.
"I do have vague costings but that's all confidential at the moment. It's eye-watering stuff."
PTS says it plans to have one barge operating six days a week with three sailings per day.
This would have the capacity to move over 230,000 cars off the port annually, Roberts said.
On August 10, Goff said the Auckland Council group looking at the supply chain out of the port had received PTS's submission.
"PTS currently take about 80 per cent of the used cars from Auckland wharves to their Highbrook property and obviously they could potentially do more," Goff said.
"That's an area that's in the south where most of the vehicle processing work takes place.
"It gets the trucks and the traffic off the city to Highbrook interchange, which is the most congested part of the motorway.
"That's one of the options clearly the ports would be looking at. They have an existing relationship with PTS.
"That's not to say that's the only option the ports will look at, but it's an important option."
Roberts said PTS would begin building a second five-storey solar-panelled car depot, within a year of the first being completed - estimated in August 2021.
"Once the earthworks have been completed on the first structure we'll start on the second structure and perhaps a third," Roberts said.
"On the horizon we're looking at approximately 15,000 to 17,000 vehicles stored under cover on site at Highbrook."
In competition with the PTS Group proposal, Marsden Maritime Holdings has urged Auckland Council to consider using land at Marsden Point in Northland to unload imported cars.
Marsden Maritime Holdings has suggested a business model that would see cars discharged from container ships directly to purpose-built vehicle storage facilities outside Northport in Whangarei harbour.
Marsden Maritime Holdings Chairman Murray Jagger said there was a potential area of 180ha at Northport for car storage - more than twice the area of the 77ha available at Ports of Auckland.