| Basslink -
Tasmania must demand better
By Bob Lister
Chief Executive
Tasmanian Fishing Industry Council
Published in 'The Advocate': 13 December 2001
The Basslink proponents are promoting the installation of a high voltage direct current electric power cable under Bass Strait to link the Tasmanian and Victorian power grids together.
The Tasmanian Fishing Industry Council is not opposed to the concept of Basslink but along with a great many others we have very serious concerns about the proposed monopole and sea electrodes configuration and its potential impact on the marine environment in Bass Strait.
Every electrical current needs a method of completing the circuit, usually a return cable or earth wire or similar. The proposed monopole system will run a single cable across Bass Strait and it will have electrodes, an anode and a cathode, mounted on each side of Bass Strait to allow the return current to be conducted through the seawater and the seabed.
Off the Tasmanian coastline the positive anode array (on a very large 24 hectare area of sea bed at Stony Head to the north-east of George Town) will produce many tonnes of chlorine gas a year which an official Hydro Electric Commission's report admits could produce a "marine desert".
This is a technology that is currently being abandoned by European nations and in North America due to the substantial negative side effects that can impact upon both the marine and terrestrial environments.
Another expert report identifies electro magnetic fields from the monopole cable as having a significant impact on the breeding and migratory patterns of fish species such as sharks and rays which are particularly sensitive to such events.
The Southern Shark fishery centred around Bass Strait is valued at $13m per annum so any disruptions to school and gummy shark species in particular is a very serious matter.
If you then add the seriously increased rate of stray current electrolytic corrosion on steel structures across an area of land and water up to 100 kilometres from George Town and as far away as Stanley it is obvious we have got a serious potential problem in the making.
Basslink have said that changes in the voltage gradients will require them to pay for cathodic protection for many steel structures on land and the impact on marine wharves, jetties, moorings, steel fishing vessels and pipelines etc. is also likely to be of concern.
It is no wonder that Esso, Duke Energy and other infrastructure operators are very worried about the monopole cable producing massive corrosion problems on their undersea steel structures worth more than $13 billion.
TFIC is naturally very concerned about all these possible impacts on the marine environment and commercial fisheries such as abalone, rock lobster and many scalefish species including school and gummy sharks and Australian salmon.
Basslink claim it is economic factors and not environment protection critical to Tasmania that are driving their project agenda and on that basis the old technology cable would most likely suit their coffers very well.
It almost goes without saying however that this profit would come with an environmental and potential social cost to Tasmania if the project proceeds in the monopole configuration as is currently proposed.
A monopole system is clearly not responsible or world's best technology for electricity transmission, but fortunately most negative marine environmental impacts can be overcome by installing a more expensive bipolar cable where the return cable is built into the same casing as the power cable and requires no marine electrodes.
The Basslink cable will most likely be in use for more than half a century and Tasmanians must therefore demand now that maximum protection be afforded to our marine environment and our sustainable fish resources in Bass Strait.
After considerable research we at TFIC have concluded that anything less than a bipolar system would be environmentally irresponsible.
The detailed written TFIC submission to the Basslink Joint Advisory Panel addressing marine environment issues can be viewed on-line by clicking here.
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