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To be accurate, Eyre Peninsula does not lack water, it lacks fresh water. It is shaped like an equilateral triangle with the sea on two of its sides. Apart from the good quality groundwater that is being mined, there is also quite a bit of saline groundwater, although the rate of its recharge is very slow.
So far as I know, waste water is not cleaned-up and recycled anywhere on Eyre Peninsula. There is certainly scope of this in at least the cities.
For more on wind-generated electricity in South Australia see Wind Power.
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If the rate of production of fresh water exceeds demand then it can easily and cheaply be stored. Electricity cannot economically be stored.
If the wind generator is connected to the grid then the power will be available for desalination when there is low electricity demand on the grid, and when electricity demand is high (and wholesale electricity prices are high) desalination can be stopped and the electricity from the wind turbine(s) can be sold into the grid.
In regard to using wind power to desalinate sea water, the economics of running the desalinator only when wind power was available would have to be compared to running it full time. It could be that the capital cost of building the desalinator might only be justified if it ran full time.
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A pipeline has recently (mid 2006) been built from Whyalla to Kimba. There are two problems or limitations with this.
The true cost of water on Eyre Peninsula would be much higher than $0.90/kL, probably more like $2/kL. Since on Eyre Peninsula the cost of water to SA Water is higher than the price at which they sell it, it is to their advantage to sell as little water as possible. Therefore it is also to their advantage to discourage anyone from setting up a desalination plant that produces water at, say, $1.50/kL; every kilolitre would represent a loss to them.
I do not say this as a criticism of SA Water, I am just pointing out that under the current government pricing policy, however well meaning that may be, there is a built-in disincentive to SA Water to desalinate Eyre Peninsula's water supply. (The same might well apply to recycling Port Lincoln's waste water.)
Desalination can compete with $2/kL, it is much more doubtful that it can compete with water sold at a heavily subsidised $0.90/kL. So whether a desalination scheme, this one or any other, is viable on Eyre Peninsula will depend on how the Government decides to charge for the water.
Renewable electricity currently costs around $30/MWh more
than fossil fuel generated electricity. The latter is cheap because the
operators of the power stations do not have to pay for the damage that they
are doing to the world's atmosphere; the burning of fossil fuels is the major
cause of climate change, it is unsustainable and must eventually be phased out.
The Federal Government's Mandatory Renewable Energy policy currently
helps to fund some wind farms (see
Mandatory Renewable Energy Target).
Would any similar subsidy be available for wind-powered
desalination? This could be a critical point.
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The cost of water from the new
Kwinana (near Perth in WA)
desalination plant is estimated to be $1.17/kL.
How many turbines would you need?The electrical requirement for desalination is discussed in Desalination data from internet. A fair average figure is 6kWh/kL (or 6MWh/ML). Under Water supply and consumption on Eyre Peninsula I mention that around 2005 annual water consumption was about 9GL. This equals one ML per hour, so 6MW of electricity would be sufficient to desalinate an equal amount of water to Eyre Peninsula's present requirement. Wind power availability is typically 35%, so 18MW of installed wind energy should be sufficient; this could be supplied by nine 2MW turbines. |
If wind-generated electricity is to be used to desalinate seawater
then there are four main factors to consider:
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In these notes I am not including Whyalla, where the water supply
comes from the Murray River.
Annual water consumption on the Eyre Peninsula has averaged about 9.3GL per year. Most consumption is for farming and, in particular, for stock watering. Stock watering requirements vary greatly: stock drink more water in hot weather and need less water when eating green feed. Stock are moved from place to place depending on seasonal conditions. Of the 9.3GL/yr, about 7.5 is groundwater from the Uley Basin in the far south of the Peninsula. While the main Eyre Peninsula water supply system is often referred to as the 'Todd Scheme', the name is misleading. The average contribution of the Todd Reservoir is only 4%; in 2000/2001 the Todd contributed 1%, and in 2001/2002 nothing. The above information was kindly supplied by Dave Cliff of SA Water. |
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Several proposals for wind-farms to generate electricity to be fed
into the national grid are current. These face problems such as
not being close to
high capacity
power transmission lines and being remote from highly populated areas.
If they were integrated into a water
desalination system I suspect that their economics would be greatly
improved.
Installed cost of wind generators is somewhere about $1500/kW. As of February 2007 there are two operating wind farms on Eyre Peninsula: Cathedral Rocks and Mount Millar. |
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Where else in the world is wind desalination in use?Rather than me rewriting the many names here, I suggest you refer to Water Technology. |
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A comparison is given in: CommonwealthKnowledge.net.
The best method appears to depend on plant capacity. If less than
10ML/day (3.6GL/yr) is required reverse osmosis is generally used,
if more than 25ML/day (9.1GL/yr) then multistage flash is almost
always used. (These figures may be skewed by the fact that the
largest desalination plants are in the oil-rich Middle East where
fuel is cheap.)
From Seawater Desalination: A Source for Supply of Drinking Water;
Western Australian Water Symposium, Perth, WA, 7-9 October 2002
The boiling point of water is lower at lower pressures. In the flash distillation process heated water flows into a chamber where the pressure is sufficiently low for some of the water to change to steam. This steam is taken away, condensed, and much of the heat recovered via a heat exchanger. The remaining water, now cooler, passes into the next chamber where the pressure is still lower; more water changes to steam and the process is continued. With each stage more steam is taken off, and both pressure and temperature are reduced.
Of course the salt stays in the liquid water, the water condensed
from steam is quite fresh.
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In a pdf document available on the Internet giving an overview of the
proposed Perth desalination unit by the WA Water Corporation...
The desalination plant was expected to produce 45GL of fresh water from
sea water each year and its power consumption was expected to be 24MW.
Also in this document,
under "Major International Desalination Examples, Point Lisas - Trinidad"
is noted "Power Consumption 3.6 to 4.0 kWh/kL"
From http://www.israel-mfa.gov.il/mfa/go.asp?MFAH0apv0. INVESTMENTS COSTS for medium to large plants are of the order of 500 to 1000 US$/m3/day TYPICAL COSTS OF DESALTED WATER
Electrical consumption figures from Californian Coastal Commission for the desalination of seawater. (I converted the US figures to metric and calculated the cost figures. Note that these costs are for electricity only, other heat is required for MSF and MED.)
Cost is based on Aust$0.07/kWh and includes only electrical consumption, does not consider capital or maintenance costs.
Note:
For MSF and MED additional thermal energy is required; I gather that Aust$60-70/MWh (Aust$0.06-0.07/kWh) is a typical wholesale price for green electricity (about Aust$30-40/MWh for fossil fuel electricity). The differential is connected to a 'Renewable Energy Certificate' which is currently about Aust$30/MWh. Information from Pacific Hydro |
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LinksGreen electricity linksFor questions regarding the renewable energy rebate etc. Office of the Renewable Energy RegulatorNational Electricity Market Management Co. Ltd. NEMCO. NEMCO average price tables were available at this site. An instructive site on the ins and outs of wind generated electricity by the Danish Wind Industry Association (link no longer functioning; you may be able to find it using a search engine).
Australian Wind Energy Association Has some interesting stats: General electricity generation linksBeyond Logic An oddly named, but very informative page on electricity generation in SA.Desalination linksClean Ocean Internet site; the full URL for one of the more interesting pages is http://www.cleanocean.org/index_general.asp?menuid=040.090.010.Sustainability and Economics in Agriculture: The Economics of Desalination and its Potential Application in Australia. SEA
Water Desalination International
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Inquired by email 21st June 2003. Unit for ~8GL/year?
Lifestream Watersystems Inc.; Inquired by email 21st June 2003. HOH Canarias S.A. advertise "Desalination of sea-water for less than 3kWh/m3 ". Apparently RO. Calculations on their spreadsheet indicate Aust$0.77/kL, capital cost of Aust$1.17M for a plant that produces 328ML/yr. (These have been the most informative people so far. Aust$1=0.57 Euros.) Freddy Ludvigsen, vandmand@post7.tele.dk
Asian and Pacific Centre for Transfer of Technology (link no longer
functioning); |
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Murray Basin water figuresThe Australian Bureau of Statistics had an informative page on irrigation extraction in Australia (link no longer functioning). This gave 10 232 GL as the total water diversion from the Murray- Darling Basin for irrigation and an additional 452 GL for domestic, industrial, stock and town use.Link to the Murray-Darling Basin Commission, MDBC. From The Australian Academy of Technological Sciences and Engineering (link no longer functioning); Of the total annually utilised (Murray Basin) flow of 13 000 GL, usage in the states is:
From Grains Research and Development Corporation. Gross margin in $ per ML:
From The Age. "The rice industry uses 7% of our water to generate 0.02% of our GDP". |
Index
On this page... Alternative to desalination Cost of wind-powered desalination Desalination data from internet How many turbines? Links Location Murray Basin water figures Seawater desalination in WA Sustainability Top True cost of water Water supply on Eyre Peninsula Where is wind desalination in use? Wind energy on Eyre Peninsula |
