Sydney to ship in drinking water?

Giant water tankers shipping water to parched Sydney from verdant Tasmania? And you thought desalination was a wacky idea... This raises quite a few interesting economic and environmental issues, but for now I'll just say 'Wow, really?!'

Five years ago Solar Sailor won an Australian Design Award for its electric catamaran, often seen plying Sydney Harbour. With rigid sails covered in solar cells, the boat catches the wind when it blows, or generates power from the sun when it shines. If the conditions are right, it can use both.

Now the company, chaired by the former prime minister Bob Hawke, proposes initially using conventional supertankers to ferry Tasmanian water to mainland ports. Later it would use even bigger hybrid electric supertankers, powered by solar and wind energy...

North-west Tasmania had abundant water, he said, in hydro-electric dams just 15 kilometres from the coast and only a short sea trip from mainland cities: "The water is used once for hydro electricity. It is not used for irrigation or feeding a town."

Within 18 months a 50 billion-litre-a-year supply could be operating, using two conventional supertankers each ferrying 330 million litres to Sydney, the Central Coast, Melbourne or Queensland "just like delivering oil". Within five years specially built electric tankers, each carrying 500 million litres, could be plying the routes. The ships would be powered by rigid solar sails, coal-fired electric motors, or both.

The company proposes exporting up to 200 billion litres of Tasmanian water a year for 20 years, enough to supply almost a third of Sydney's needs.

The ships would moor on the horizon off Sydney and the water would be pumped through undersea pipes to Kurnell, then into Sydney's water supply. It would cost about $1 a kilolitre, including a 30 cent-a-kilolitre royalty to Tasmania for water otherwise "going to waste".