Data centres are booming in Australia - but at what cost?

The sheer size and noise of data centres are what people tend to notice first. Some say they sound like a jet plane about to take off, others complain of a high-pitched whine.

When Lucy* puts her child to bed, she hears a constant humming. "I'll hear it and think, 'What is that? What is going on?'," she says.

And then she'll remember that the noise is a data centre just 350m (0.2 miles) from her front door in the desirable suburb of Lane Cove, in Sydney's lower north-shore. Another four are in the pipeline at the local industrial park.

Australia has quickly become a global destination for data centres, with investors attracted to the country's abundance of clean energy, natural gas reserves, and land to power and house their technologies.

Earlier this year, OpenAI's CEO Sam Altman said Australia could become a data centre capital of the world, if it wanted to.

Australia is already headed in the direction of big tech's wishes. There are 162 data centres across the country, with plans for 90 more, and an estimated more than A$155bn (£80bn) of investment money lined up.

If approved, one of the world's biggest data centres will be built in western Sydney. At one gigawatt, it is expected to be Australia's largest single energy user.

And in Marsden Park, also in western Sydney, the biggest data centre in the Southern Hemisphere is already under construction only 100m away from a local community.