Water Journal : Water Journal May 2011
debate 38 MAY 2011 water feature articles In Defence of Desalination Neil Palmer, CEO, National Centre of Excellence in Desalination, Western Australia Neil Palmer has degrees in civil and public health engineering. His career spans 35 years in the Australian water industry -- 20 in Government and 15 in the private sector. Neil is the CEO of the Australian National Centre of Excellence in Desalination, a partnership of 13 Australian universities and research organisations seeking to improve desalination performance. Neil is also a Director of the International Desalination Association, a member of the Institution of Engineers Australia and a Life Member of the Australian Water Association (AWA). Email: Neil.Palmer@murdoch.edu.au Introduction Of the water on Earth, 97% is too salty to drink. Of the fresh water, two-thirds is locked up in ice and glaciers. This means only 1% of the planet's water is readily available for human use. So why not look to the 97% as a water resource? It is not easy to look out to sea from the Gold Coast or Cottesloe and conclude that either place has a water shortage. The key is desalination. The technology is well proven, affordable and has only a small environmental impact. Well-Proven Technology There are more than 15,000 desalination plants operating in the world today, delivering 65,000ML/d of fresh water from brackish or seawater resources to 300 million people in 150 countries (GWI 2010, IDA 2010). The installed capacity is growing by around 10% per year. Large scale desalination commenced in the Middle East in the 1950s using distillation technology. Since the 1980s lower energy reverse osmosis desalination has gradually become the dominant technology. The industry is mature. Having agreed an industry- standard reverse osmosis membrane size in the 1980s, competition between major membrane manufacturers has resulted in better performance and lower prices. There has been a 10-fold reduction in specific energy consumption since 1980 and this trend is likely to continue as new membrane materials, for example those derived from nanotechnology, are developed. Increasing demand for membranes also brings new entrants to the market with significant growth in supply from Asia, further improving performance and reducing price. The Australian Government has also invested $20 million over five years in the National Centre of Excellence in Desalination. One of the centre's research priorities is to improve energy efficiency of the desalination process. The world population is increasing and with limited alternative water sources, decision makers will look to desalination to fill the gap between increasing demand and limited supply. In Israel, for example, desalinated water currently supplies 20% of drinking water. By 2020, the Israeli Ministry of Health expects this to increase to 50% (WQRA 2011). In Australia, there has been a large investment in desalination technology in all mainland state capitals. This has been driven by drought and the desire to provide a secure and sustainable water supply that is not dependent on rainfall. By 2015, up to 30% of Perth's water needs, 10% of Brisbane's, 15% of Melbourne's, 10% of Sydney's and 40% of Adelaide's will be available through desalination. Affordable Cost The total cost of desalinating seawater, including finance, operations, maintenance, consumables and energy, typically varies from $0.75 to $1.25 per kL (IDA, 2010). Australian desalination plant prices reflect the more expensive cost of construction, attention to minimise environmental impact and, in the case of Perth, purchase of wind energy (at double the cost of coal energy) as an offset for all energy consumed by the plant. The total cost of desalinated water to the Water Corporation from the new Southern Seawater Desalination Plant will be $2.40 per kL (West Australian, 2011). $2.40 for a tonne of water compares favourably with bottled water, which typically sells for $2.40 per bottle, or $4,000 per tonne! By comparison, the total cost of water from a domestic rainwater tank supplying just a fraction of the average household demand would be up to $17 per kL (Marsden Jacob Associates, 2009). The total cost of water from a 3000km pipeline from the Kimberley to Perth would be almost $10 per kL (Water Corporation 2009). While the cost of pumping groundwater from the South West Yarragadee Aquifer may have been less than for desalinated water, the environmental risk of (and community opposition to) drying large and sensitive wetlands in the South West were significant factors in favour of building the Southern Seawater Desalination Plant. So goes the line from the famous poem by Samuel Coleridge, 'The Rime of the Ancient Mariner'. But times have changed and with today's technology seawater is emerging as a major potential source of potable water. With its enthusiastic champions and equally passionate opponents, desalination is an issue that incites strong points of view in industry players and the public alike. So is it a sustainable solution for Australian water security? AWA Project Manager -- Sustainability, Gregory Priest, sought the opinion of two experts. Water, Water, Everywhere, Nor Any Drop To Drink... Ninety-seven per cent of the world's water is seawater.
Water Journal April 2011
Water Journal July 2011