Why We Need Seawater Desalination Plants

Posted on 15 October 2014

Opinion piece by Neil Palmer, NCEDA CEO

The Victorian Desalination Plant at Wonthaggi  (Victorian Desalination Project).

The Victorian Desalination Plant at Wonthaggi (Victorian Desalination Project).

Consider the following scenario.  In a few years Melbourne (or Sydney or Adelaide or Brisbane) is in the grip of a drought.  It’s happened before and we all know it will happen again.  Dam levels are dropping dramatically.  The water utilities respond to these conditions with the imposition of water restrictions.  These gradually increase in severity and impact on our everyday lives – particularly those of us who live in houses and love gardening.   Ultimately no garden watering or car washing is allowed and even time in the shower is limited.  Everyone is complaining “why don’t they do something?”

Well actually something has already been done.

Large seawater desalination plants have been built in all mainland Australian state capitals and can now supply water during the worst droughts, providing water security to our cities for the first time.  These plants, ranging from 15% of the city’s total demand in Sydney, 30% in Melbourne to 50% in Adelaide, Brisbane and Perth, make a massive difference.

So what does “water security” mean?   Simply put, it means there will be no need for water restrictions, even when there is a drought.   We don’t have petrol, food, clothing, internet download or electricity restrictions.  Given the great advances of clever desalination technology that now allows us to affordably separate salt from water, an advanced economy like Australia does not have to have water restrictions.

However, don’t be fooled into thinking that desalination plants are there to be turned on when the dams are nearly empty.  They are not “peak load” water plants.  They are more like base load plants and begin to operate when dams start to drop in level, ramping up to 100% when it becomes apparent that the drought is becoming serious.  What the supply of desalinated water does is slow the rate of fall in dam levels – what water restrictions used to do – by supplying water to consumers from the sea where the supply is unlimited.

There has been much ill-informed and short sighted commentary that Australia’s seawater desalination plants are “white elephants” and we don’t need them now that rain has fallen.  Well, very little rain has fallen in the West and half of Perth’s water comes from the sea via two large desalination plants.

The total cost of the desalination plants was around $12 billion.  No Government makes decisions to spend this quantum of taxpayer’s money on water infrastructure for merely short term benefits.  All the Australian desalination plants will last more than 50 years, by which time they will have more than earned their keep by providing new water to our cities to compensate for weather variability (droughts), climate change and new demand from population growth.

The cost? The most expensive plant was the Victorian Desalination Plant which now provides (for the first time) a 100% guarantee of water security for Melbourne.  The fixed costs, some $670 million per year, may be considered “insurance” against future water restrictions.  Spread over Melbourne’s population, it equates to around 40 cents per person per day, or $8 per week per household, the price of one glass of beer from the bar.

We contend that this is excellent value to maintain Melbourne’s homes, parks and gardens as one of the world’s most liveable cities.

In time, it will be abundantly clear to everyone how much we need our seawater desalination plants.

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