SYDNEY Australian billionaire Mike Cannon-Brookes on Thursday stood by the economics of a plan to ship energy from a giant solar farm in the country's north to Singapore via undersea cable as he took possession of the A$20 billion ($12.73 billion) project.

Cannon-Brookes, the co-founder of tech firm Atlassian turned environmental activist, said he continued to believe outside investors would be drawn to the Sun Cable project, adding it already had demand for more energy than it could produce.

"We have spent a lot of time with customers and are pretty clear on the unit economics," Cannon-Brookes told reporters after his business Grok Ventures' purchase of the project for an undisclosed sum was completed on Thursday.

"We believe that there's enough margin ... to make it an investable project," he added.

Sun Cable under Cannon-Brookes' control will be split into two business units, focusing on Australia and Singapore, which may broaden its appeal to investors, Cannon-Brookes said.

Sun Cable was owned by the private firms of Cannon-Brookes and Fortescue Metals billionaire founder Andrew Forrest. But it was put into voluntary administration, Australia's closest equivalent to Chapter 11 bankruptcy, in January after the two parties failed to agree on future funding.

Forrest had said he was unconvinced of the commercial viability of sending power via undersea cable.

Cannon-Brookes said the company would apply for a licence with Singapore's Energy Market Authority this month with hopes of meeting that country's objective of importing at least 4 gigawatts (GW) from low-carbon sources by 2035.

The company was also in talks with the Indonesian government about building the cable in its waters, he added.

The proposed Australia-Asia PowerLink would send power from a 20 GW solar farm with the world's biggest battery in Australia through a 4,200 km (2,610 miles) undersea cable to Singapore.

($1 = 1.5706 Australian dollars)

(Reporting by Byron Kaye; Editing by Jamie Freed)