Water plant to guzzle energy

• Peter Ker Water And Environment Reporter
• The Age, August 30, 2008
• http://www.theage.com.au/national/water-plant-to-guzzle-energy-20080829-45r3.html?page=-1

AUSTRALIA could be using 400 per cent more energy to supply its drinking water by 2030 if the policy trend towards seawater desalination were to continue.

The warnings in a soon-to-be released report by the Water Services Association of Australia come after seawater desalination was likened to a petrol-guzzling "six cylinder" family car by one of Australia's top water bureaucrats at a major summit in Melbourne.

The WSAA energy report is understood to model several national water-supply scenarios for 2030, with a future based around seawater desalination the most energy-intensive.

The report will warn that if desalination became the primary source of supplying around 300 litres per person per day, energy use would rise by 400 per cent above today's levels.

During the severe water restrictions of 2007, Melburnians consumed a daily average of 277 litres per person.

If a mixture of water sources — including desalination, recycling and stormwater harvest — were used to supply Australians with around 220 litres per day, rises in energy consumption for water use could be closer to 200 per cent by 2030.

WSAA executive director Ross Young confirmed the report contained those statistics but said it was wrong to use them to criticise desalination.

"Pumping water long distances is also incredibly energy intensive, you've got to look at the options available for each city and assess them on a range of parameters."

"And of course energy use is one of those," he said.

State Governments have opted for seawater desalination in Melbourne, Perth, Sydney, Adelaide and the Gold Coast, while the Federal Government has also been a financial supporter.

Speaking at a water summit in Melbourne this week Queensland Government scientistTed Gardner urged water professionals to carefully consider whether desalination was the best solution. "You have to wonder whether we are building another Ford Falcon. The most sophisticated six-cylinder car that Australia has ever made and nobody wants to buy it. The reason is they believe petrol is too expensive," he said.

"If we are going to go for the sophisticated technology in a future when energy costs are going to go a lot higher, I would have to question the wisdom of it."

Mr Young said the comparison was unfair and significant amounts of energy — up to 30 per cent of household consumption — was used to simply heat water.

Desalination uses the same technology to purify water as sewage recycling, but uses much more energy because seawater carries more dissolved salts and minerals.

Despite increasing pressure on energy supplies and prices, water sector officials believe their ability to create "green energy" out of bio-gas from sewage plants will keep help them remain profitable and environmentally neutral.

Mr Young said Melbourne's Werribee Treatment Plant was a good example, as its bio-gas production accounted for 72 per cent of its energy use.