by Neil Palmer, CEO
Presented on World Environment Day 2012 at Sultan Qaboos University, Muscat, Oman
Australia faced a severe and prolonged drought from 1997–2009. It was considered to be a one in a thousand year event and became known as the “Millennium Drought”. During this period, increasingly severe water restrictions were imposed on consumers across Australia. Water stored in reservoirs became depleted and in some cases almost ran out.
As a direct result, Governments in Australia invested heavily in climate resilient water supply technology. This included seawater reverse osmosis desalination and waste water recycling. The total amount invested was more than $US10 billion and resulted in construction of six major seawater desalination plants and one major indirect potable water reuse system.
Capacity and Cost of Australia’s Major Urban Desalination and Reuse Plants
|Gold Coast (Tugun)||2009||142||1.20|
|Brisbane Western Corridor Water Recycling Project||2009||232||2.80|
|Perth Southern (Binningup) Stages 1 and 2||2012||300||1.40|
|Adelaide (Pt Stanvac)||2012||300||1.83|
Source: ATSE: “Sustainable Water Management – Securing Australia’s Future in a Green Economy” ARC April 2012 pp 53-55
A further private desalination plant of 140 ML/d capacity has been built for Citic Asia Pacific iron ore mine near Cape Preston in northern Western Australia and a new 280 ML/d plant has been approved for construction for BHP Billiton’s Olympic Dam expansion project near Whyalla in South Australia, bringing the total installed capacity to more than 2200 ML/d. This is significant by world standards and also redressements very rapid development.
Following this investment in water resilient infrastructure, the Australian Government funded two research centres: The National Centre of Excellence in Desalination, Australia and the Australian Water Recycling Centre of Excellence. These Centres have each been funded $A20 million over 5 years from the Australian Government’s National Water Initiative.
Desalination is sometimes termed “energy guzzling” in Australia, even though the consumption of energy for supplying a whole household with water is relatively modest (about the same as the energy used in running the household domestic refrigerator). Notwithstanding its modest power consumption, Australia’s water utilities have elected to purchase renewable wind energy to offset the entire energy budget of all the six major seawater desalination plants. It can be said that effectively these desalination plants have a negligible operating carbon footprint.
In Western Australia, the Water Corporation expressed a desire for a significant portion of the renewable energy from the Southern Seawater Desalination Plant to be derived from “other than wind power” and as a result one of Australia’s largest solar power stations is being constructed near Geraldton on the mid west coast. This will supply 10% of the total energy used in the plant. Construction of the six major urban desalination plants has resulted in massive development of wind farms in Australia as a green alternative to enlarging the capacity of coal burning power stations.
The National Centre of Excellence in Desalination (NCEDA) has been in operation since 2009 and has run four funding rounds with proposals being accepted from all of the 14 Participating Organisations. The funding is competitive and is highly sought after by the academic community. The NCEDA has a focus on commercialisation and projects that invent or develop new technology are highly regarded.
The NCEDA has a mandate from the Government to “efficiently and affordably reduce the carbon footprint of desalination facilities and technologies”. A number of projects are in progress to develop seriously the use of renewable resources to power desalination.
A remote indigenous community has a limited brackish water supply. A project is under way to develop solar powered vacuum assisted membrane distillation to take hypersaline water and produce fresh water to blend with the brackish source. Subject to successful demonstration of the process, a plentiful supply of water complying with the Australian Drinking Water Guidelines will be available to the community for the first time.
A mineral processing plant has waste heat available and an NCEDA project is developing a modified multiple effect distillation system to use this readily available supply of energy. Upon successful completion and development, this will not only supply fresh water to the process and reduce dependence on the environment, but a potential excess wastewater balance will be eliminated.
Lastly, a future project approved for funding by the Centre will investigate use of geothermally heated water brought from deep below the earth’s surface to power desalination. Geothermally heated water is available in a surprisingly large area of Australia including aquifers beneath the Perth metropolitan area.
An Australian company, F Cubed, has developed a commercial wick solar distillation system which produces fresh water from highly saline water in a single pass. Although small in scale, the concept has been demonstrated and there is much interest from developing countries.
An international company, Sundrop Farms, has developed a solar powered greenhouse in South Australia where hyper saline groundwater is desalinated for growing tomatoes, capsicums and cucumbers hydroponically. Operating for less than two years, the fruit and vegetables grown from sunshine and seawater are sold profitably in the Adelaide markets. Australia has a great deal of land available close to the sea and the concept of a reliable, climate resilient water supply powered from renewable solar energy is very appealing in a world that is increasingly short of food.
In summary, Australia has invested heavily in urban desalination and water recycling technology over the past ten years. In doing so, decisions of state Governments to power the desalination plants effectively from renewable resources has provided a big boost to the renewable energy industry as well as ensuring a secure water supply is always available, but with a very low operating carbon footprint. Research is also focussing on ways to reduce carbon footprint in a number of ways by developing renewable sources including solar, waste heat and geothermal energy to power desalination.