Sunday, September 17, 2006

Recycled water for electricity production

The vast majority of electricity produced in Australia is generated by burning coal. This process uses large volumes of water, much of which is converted to steam (and subsequently lost to the atmosphere). For example, Delta Electricity in NSW report the use of around 1 Megalitre of water for each gigawatt-hour of electricity produced. Given the large volumes of water required in a single location, power production seems like an ideal use for recycled water.

In fact, Australia is a world pioneer of using recycled water for power stations. Pacific Power’s Eraring Power Station supplies around 25 % of the electricity requirements to NSW and has been using recycled water for a decade now.

Eraring Station is located in the Hunter Valley close to the Dora Creek Sewage Treatment Plant. In the mid 1990s a 15-year agreement was signed to enable Eraring to access more than five megalitres of effluent from Dora Creek STP each day. This water is transferred directly to a water reclamation plant at the station where it undergoes further treatment by microfiltration and reverse osmosis.

Access to recycled water provides a sure source for Eraring Power Station. Furthermore, it helps protect the sensitive aquatic environment of Lake Macquarie, which would otherwise be further impacted by treated effluent.

In the last couple of years, Western Australia, Queensland and now Victoria have identified similar opportunities. In these cases, the primary motivation has been to free-up potable water supplies, which are currently used for power production.

Recycled water efforts around Perth have largely focused on an industrial precinct called Kwinana, about 40 km south of Perth. At Kwinana, a centralised water recycling plant supplies 17 megalitres per day to a diverse range of industries, including power production by Western Power.

Shortly before the recent Queensland state election, Premier Beattie announced plans to build a pipeline from Luggage Point sewage treatment plant to Tarong and Swanbank power stations, which are major suppliers of electricity to Brisbane.

In just the last few weeks, Victorian Government plans have been revealed to allocate large volumes of recycled water from Melbourne for use by power plants in the Latrobe Valley, 100 kilometers west. This plan would add more than 20 per cent to Melbourne’s total water supply, significantly increasing security during extended dry periods. It would be a massive water recycling scheme and is estimated to come at a cost of $1-2 billion dollars.

In addition to potable water savings, the Victorian Government plan has plenty of potential environmental benefits to recommend it. Importantly, it would drastically reduce water discharged by ocean outfall at Gunnamatta, southeast of Melbourne. Furthermore, the reduction of freshwater use by the Latrobe Valley power stations would significantly boost flows in the Gippsland rivers (and subsequently add to drinking water supplies for Melbourne).

The primary opposition to the proposal, appears to have been expressed by Victorian National Party leader, Peter Ryan who was quoted this week as saying "The Nationals' view is that Melbourne already receives enough of Gippsland's fresh water and has to learn to live within its water means".

What do you reckon?


Damien Townend said...

Sounds fine in general, but how does the water recycling industry feel about further supporting (subsidising?) the consolidation of fossil-fuel burning power production throughout Australia??

Stuart Khan said...

G’day Damien,

I think this is a fair order to be truly sustainable, water recycling needs to be associated with sustainable industries. Nonetheless, I think we have to be realistic and identify the immediate opportunities for improved water management in Australia. If electricity supply changes significantly in the future we will simply need to meet the challenge and keep up. We will need to develop technologies and strategies that are widely applicable and adaptable.

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