Coast water plant boost

Geelong Advertiser
Monday 29/1/2007 Page: 7

Geelong's water woes are set to be solved forever with a desalination plant an the ocean coast.

State Water Minister John Thwaites said earlier this month that a $1 billion desalination plant was inevitable to boost Melbourne's shortage of water:, But Mr Thwaites virtually ruled out building such a plant in Port Phillip or Western Port bays, leaving open an ocean site either to the east or west of The Heads. Any site to the west of The Heads would see desalinated water pumped to Melbourne via Geelong.

Barwon Water said last week it supported a state government feasibility study into a desalination plant, and was doing its own work on what it described as a long term source of water for Geelong.

Geelong's surface water supplies have fallen to about 20 per cent full, and Barwon Water is increasingly relying on groundwater to augment supplies. But groundwater is also limited, - with Barwon Water's licence only allowing it to take 80,000 million litres over a 10-year period.

Barwon Water chief executive Dennis Brockenshire said the use of desalination would depend on its economic and environmental sustainability. The one drawback of a desalination plant, apart from the fact that it costs twice as much as surface storages to produce a litre of water, is the power needed, and the resultant effects on greenhouse emissions.

The West Australian Government recently commissioned a $378 million desalination plant at Kwinana which will supply Perth with 17 per cent of its water needs. To produce 45 billion litres of water the Kwinana plants requires 24 million watts of electricity - the amount needed to power 30,000 households.

The West Australian plant draws on the state's power grid for its energy requirement, but the state's water authority has argued that a new windfarm 200 kilometres away puts enough power into the grid to power the desalination plant.

There is one wind turbine on the Bellarine Peninsula near Barwon Water's Black Rock treatment plant. The Kwinana desalination plant would require 35 wind turbines to power it.

Mr Brockenshire said desalination was a technically proven and increasingly attractive strategy worldwide to extend urban water supply. Most desalination plants installed in Australia use reverse-osmosis, where energy drives water mechanically through a membrane filter.

Mr Brockenshire said the suitability of desalination will be evaluated on a sound business case, including capital and ongoing operational costs, environmental and social impacts, and comparison to other new water supply options.

"In order to be cost effective desalination plants need to be in close proximity to existing water distribution infrastructure," he said. "Perth's Kwinana desalination plant became operational in November, 2006, and is now Perth's largest, single source of water, supplying 17 per cent of the city's needs."