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The Forum > Article Comments > Desalination: a last resort > Comments

Desalination: a last resort : Comments

By Lyn Allison, published 18/9/2007

Desalination will guarantee water, but at what cost? Melburnians are offered a project that will guarantee their profligate use.

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Yep, there is plenty of room for Victorians to scrimp on water instead of going straight for desalination.
Just don't water those roses, among other things.

So why not scrimp and save? Save 30 per cent. on consumption - that will delay desalination until half a generation later: the time when the population has increased by 30 per cent.

Then, scrimp and save another 30 per cent in order to placate the god of economic growth - you know, that diety the Victorian Government lights candles to; and appeases by stimulating population increase.
The Little Desert is just a bit to the west - help along its progress eastwards - keep boosting the population along.
Posted by colinsett, Tuesday, 18 September 2007 9:39:27 AM
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This article is typical of those that seek to oppose desalination:

"a large percentage of what we collect in our near-empty dams is subsequently lost via a leaking and inefficient reticulation system."

OK, but what is "a large percentage"? Would fixing it contribute in a significant way to solving the problem?

"but it could be so much better spent, whether on rebates for rainwater tanks"

Is that spending it better? Where are the figures that show that rainwater tanks are a cost effective way of supplying water? When people install tanks, do they reduce their reticulated water consumption, or do they just avoid restrictions on watering their garden?

"The proposed plant at Wonthaggi is expected to add 2 per cent to Victoria’s greenhouse gas emissions every year. And yet the amount of water processed will only produce the equivalent of that required to power two of the regions four coal-fired power stations."

So what? We need the power those power stations produce, and we need the water.

"Water, or lack of it, and global warming are inextricably linked. Yet desalination is a silo attempt to tackle the water crisis and by so doing the Victorian State Government is only exacerbating the problem."

If the desalinator is not built, will the resulting slight reduction in global warming make the problem go away? No, of course not.

There is a viable alternative - potable water recycling - but until the population is willing to accept that, desalination is the way to go.

Sylvia.
Posted by Sylvia Else, Tuesday, 18 September 2007 9:43:11 AM
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Water in Melbourne currently costs $0.81 a kilolitre (KL). Rainwater tanks will supply each of Melbourne’s one million separate houses with 70 KL of water a year at a cost of $1.45/KL. Mains water will cost more than $1.60/KL after the price doubles within five years to pay for the desalination plant and pipeline infrastructure. Rainwater collected from roofs is rejected by the Victorian State Government, on cost grounds. Greg Cameron
Posted by GC, Tuesday, 18 September 2007 9:54:57 AM
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Yes I have to agree a very airy fairy article lacking any numbers or science, just a lot of what ifs.

"the long Victorian drought is now generally understood to be permanent"
Obviously not....the timeseries graphs at the bom shows that it is more likely cyclical in nature with a very dry 1900-1940 period (drier than now) followed by a very wet 1940-2000 period. Climate is never permanent.

"As more usable water is generated by desalination more greenhouse gases are generated which warm the climate which in turn produces lower rainfall and a greater need for desalination. It is a vicious cycle that is ultimately unsustainable."
Oh my this is an extremely tenuous link...isn't a warmer world supposed to be wetter? With larger extreme rainfall events (pefect for filling up large dams)??

"Like Saudi Arabia, in time we could have all the water we need for spa baths and other water guzzling appliances but be surrounded by desert."
Again a feeble attempt to equate desalination with decreased rainfall and now even desertifcation. Don't let any proof get in the way of a great story.

"80 per cent of which is used to flush toilets"
Come up with a better alternative? One that doesn't stink.

"The fact that a four-meter diameter pipe will suck up five truck loads of marine organisms a day suggests the sea bed will soon be become an underwater desert."
Says who? The whole sea? How big a desert are we talking about? Come on...

"rebates for rainwater tanks"
Anyone done an energy comparison between desalination and making all of those plastic (oil) rainwater tanks? Or better yet concrete and steel ones?

"They should also think about the urgency of climate change and see the link between water shortages and global warming."
Climate change isn't that urgent as temperatures in the Southern Hemisphere are the same as they were in 1978 when satellites first started measuring temps. Also a warmer world is a wetter world, colder is drier....where is the link?
Posted by alzo, Tuesday, 18 September 2007 10:15:58 AM
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Surely it would be better to convert all the waste plastic into rainwater tanks than into garbage bags. It has to be converted into something, so it might as well be useful.

Those of us who live out in the country away from a reticulated supply seem to manage all right with what we collect from our roofs. We even manage to water our vegetable patch, so it can't be that hard. At today's prices, the total cost of installing about 50,000 litres of tanks with pumps and piping is around $5000. No one provided us with any subsidy.

David
Posted by VK3AUU, Tuesday, 18 September 2007 11:50:02 AM
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Greg,

I cannot get the cost of rainwater tank water down to that level unless I assume that the pump will last 25 years, which is hardly realistic. I get a cost per kilolitre of more like $2 based on pumps lasting 12 years and tanks lasting 25.

Another issue is that the water company's cost of delivering water is largely determined by the maximum rate of delivery, which is in turn determined by the consumption rate when the rainwater tanks are dry (as they will be from time to time). Since the company has to recover its cost of delivery, if reticulated water is displaced by rainwater, it just pushes up the price of reticulated water. Effectively, the rainwater displaces water at its bulk price, not at its price in the tap.

Sylvia.
Posted by Sylvia Else, Tuesday, 18 September 2007 6:55:31 PM
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