- How much is 'substantial cancellation' and 'virtual elimination'?
- Where are the figures that could quantify this claim?
- How can this be when there is such a disparity in the cable size and capacity?
- How much is a 'minimal' amount of an induced electric field?
Table 2 of Basslink's response to the JAP recommendations suggests that "At 600 MW transfer, maximum predicted combined MF at 1 m above north-south aligned HVDC cable is 67.6 µT compared to background geomagnetic intensity of 61.0 µT."
Preliminary advice would appear to indicate that this is still a substantial magnetic field and that it could still have adverse effects even with the new proposal to 'bundle' the cables together. This needs to be fully quantified by Basslink and then be independently assessed to ensure the veracity of the figures. There is a lack of accurate local information here that represents scientific uncertainty. As it is the plan to only bury the proposed cable in shallow waters, this magnetic field is unlikely to be reduced by a layer of sediment in some deeper areas. These areas would be where it fails to self-bury or becomes uncovered by water and sediment movement.
There can be little doubt that due to the substantial difference in the size and capacity of the proposed metallic return cable (in comparison to the power cable), the shape of the combined magnetic fields may not be uniform and therefore may not cancel each other out.
Comment:
As far as the paucity of available information is concerned, TFIC must stand by its claims in the original submission for the Draft IIAS that this proposed technology poses a potential threat to the marine environment. Significantly more detailed information is required.
This new proposal may adversely impact on migratory species and as such may affect the valuable Southern Shark Fishery. There is significant scientific uncertainty involved in this instance and TFIC submits that the Precautionary Principle should be invoked in this instance. It is understood that there is better technology available to eradicate the problem.
Transmission Losses
The proposed metallic return will present more resistance to the return current than the seawater/earth return would have, or indeed more than the resistance that a bipolar system would present if it were used. Figures to try and quantify this extra resistance were tossed around at the hearings and previous meetings with Basslink and their representatives. They varied from 5% to 10%.
Table 2 of Basslink's response to the JAP recommendations adroitly avoids all mention of this extra resistance, alluding to it with an indication that there will be 'similar' amounts of heat generated to what would be produced with an seawater/earth return system. What exactly is 'similar'?
In their response (3.2) the claim is made that 'the greater resistance of the metallic return will increase the transmission losses…' This is followed by the suggestion that 'this small change is not significant…'.
The questions beg to be asked: "How much is 'small'?" "Not significant to whom?" Energy producers? Consumers? Stakeholders? The marine environment?
The commentary suddenly moves on to conclude that the impacts of the proposed metallic return cable will be '… therefore confined to the physical effects of installation'. When the previous claims of unacceptably high levels of resistance (encountered when using a metallic return cable) are considered, these new statements (with absolutely no values available to quantify them) are not conducive to elevating the proponent's credibility. The attention is drawn to the Draft IIAS 4-32 (Table 4.15) where the proponents themselves estimated that the losses from a metallic return cable would be in the vicinity of 5.5%.
When questioned about the loss comparison at a meeting with TFIC, the proponents indicated that the losses would be likely to be higher than that and would add to the economic difficulty of making the system pay if there were a need to invest in a metallic return. At the time of the meeting Mr McLelland clearly stated that the installation of a metallic return would jeopardise the economic viability of the project and that Basslink would not become a reality.
He very strongly made the point then (and subsequently on TV) that the economics were the drivers for this proposal, not environmental factors and that a metallic return cable was simply not viable. The added capital cost (purchase and installation) and capitalised cost of operation ($12 to $20 mill) were enough to ensure that the proposal was unable to produce a profit for the proponent. How can this have changed in a few months?
Environmental Costs:
Not only must this higher resistance and extra capital cost change the economics of the whole proposal, but also it would indicate that it creates a higher environmental cost to Tasmania. More electricity would be needed at the Tasmanian end to supply the required electricity demanded at the other end of the cable.
To do this the generators must run harder or for longer which will have the concomitant effect of more flushing and scouring of the rivers and estuaries. This is already perceived by TFIC as an unacceptable threat to the marine environment and to our members whose very livelihoods depend on that same environment. This must elevate the risk of problems to our marine farmer members in Macquarie Harbour and those members who catch fish that depend on affected estuarine regions for food and nursery areas.
Conclusion:
TFIC considers that there is a need for accurate quantification of these issues, perhaps using comparable cable experiences from any other HVDC cables in the world that use this metallic return 'bundled together' system. Surely these figures must be readily available and able to be used for this proposal with some degree of accuracy. Of course any figures quoted should be independently assessed for accuracy.
An assessment of the configuration of the Nor-Ned HVDC link could perhaps be considered.
Marine Surveys:
6.4.2.4; 6.4.4.4; 6.4.5.4 and 6.4.11.4 of the Draft Panel Report (JAP comments) all lament the lack of adequate marine studies local to the area at the time of the hearings. The observation was made suggesting that the reliance on desktop studies applying oversea experiences to local conditions were not as useful as they could have been.
Despite these comments and the related lack of marine baseline studies, it is surprising to read that the panel readily accepts the evidence supplied by Basslink in a number of areas such as the impacts of electric and magnetic fields. This is even more surprising considering the fact that the independent assessment by Brown and Root of both the Draft IIAS and the electrode electrolytic production calculations proved that there were some serious concerns about Basslink's ability to accurately address some of these crucial issues. Does this indicate a high level of risk-taking on the part of a panel that should be risk-averse?
6.4.2.3 of the Draft Panel Report discusses a detailed marine survey of the proposed route that was conducted by BPL's contractors Siemens and Pirelli, with the intention being for this report to be released at a 'later date' for the purpose of designing a monitoring program. The marine survey was to have been available from January 2002, but to date there has been no mention of it to TFIC. One would expect an interested stakeholder such as TFIC to be included in this assessment if public input were being genuinely encouraged.
Any monitoring based on a baseline study is a positive initiative providing it is paid for by the proponent and is commissioned and operated by an independent body such as a university or the Tasmanian Aquaculture and Fisheries Institute. The institution would have to have expertise in fish stock population dynamics and assessment.
Monitoring is not management:
However, it must be stated that monitoring is not management. It can only be a management tool. A decline in a fish stock for instance could be monitored very closely as it spirals into extinction. Responsible management would have to be a part of the monitoring process to ensure the viability and sustainability of commercial fish stocks and other biodiversity that could be affected by the monopole installation. Effective plans must be in place prior to installation to manage any decline observed during monitoring, especially for commercially exploited fish stocks such as the Southern Shark Fishery, which is the most likely fishery to be affected.
Along with any monitoring there must be responsibilities recognised by the proponent, with provisions in place to ensure that any damage to this important fishery (should it occur) is either remedied or the participants compensated for their loss. All of this procedure should be open and transparent.
Burden of Proof Issues:
The problem of 'Burden of Proof' (as presented by TFIC at the hearings previously) should be discussed with a plan to be formulated and put in place to address burden of proof issues. This must cater for the sustainable management of fish stocks that may potentially be affected by Basslink (through on-going assessment) or set in place an approved process to compensate any person who suffers a substantiated loss attributable to the proposed Basslink installation should it go ahead in any configuration.
Conclusion:
TFIC has little choice but to view the process to this point with serious misgivings due to the convoluted and obscure way that the entire proposal process has been handled thus far. It is important to ensure that any potential effect to marine environment biodiversity and/or commercially fished species from the monopole cable with metallic return is identified and managed responsibly.
TFIC agrees with the JAP recommendation (6.4.5.4) and must insist that thorough 'ground-truthed' baseline studies of shark migration and other fish stock assessments be completed local to the area prior to the Basslink construction commencing. These baseline studies should be independently commissioned and peer reviewed in an open and transparent way (if necessary) with the proponent to pay all costs for the initial surveys and all ongoing monitoring. TFIC would be pleased to appoint a representative to this process to help ensure that both the marine environment and the interests of its members are being considered and fairly dealt with.
A plan must be formulated (and agreed to) by the industry prior to construction of Basslink to address any potential adverse affects that may occur to the Bass Strait fishery once the cable is in operation.
Nor-Ned Cable:
It was with some interest that it was noted in the Basslink response to the JAP Draft Report that they made two comments regarding their expert witness Mr Jan Erik Skog from Statnett SF (Norway). The JAP Draft Report quite correctly quoted Mr Skog as saying that in his opinion any money put toward a metallic return cable would be better spent putting in a bipolar system. Basslink appears to be trying to explain away his comments by suggesting that they were taken out of context. This is not correct and even some cursory research can come with some facts that back up his claims.
Mr Skog is involved with the Nor-Ned cable that is being built between Norway and the Netherlands. The Scandpower webpage lists him as the Project Manager of this installation. This Nor-Ned cable will span nearly 600 kilometres with a higher capacity than that proposed for Basslink. It is a bipolar cable using no sea electrodes and utilises a flat 'twinned' oil filled cable to transmit the power. Mr Skog was alluding to this type of technology that may be appropriate for a Basslink application.
The technique of 'Bundling':
The response by Basslink to the JAP recommendations proposes to use a hitherto unmentioned technique that uses polypropylene rope to hold the two power cables and the fibre optic telecommunications cable together in a 'bundle'. While TFIC welcomes the Basslink initiative to incorporate a metallic return cable into the proposal, the new proposal raises a raft of questions that are not addressed either in the Draft IIAS or in the Basslink response to the JAP Draft Report.
Some of the more obvious questions/comments are listed below in no particular order of importance:
- Where are there other examples of where this newly proposed technique has been used?
- Or is it a new untried technique?
- If that is the case, why is Bass Strait to be the guinea pig for an untried technique that has not had a fully Integrated Impact Assessment Statement completed?
- Is it physically possible to bundle three cables together and tie them together on one lay vessel and then lay the bundle in one trench?
- Or is it all bundled and roped by the cable builder?
- Will this affect the shore crossing?
- Is it likely that the rope will disintegrate over time and create pollution and/or a hazard to marine animals or vessels?
- Are there any studies that can prove that rope will maintain its integrity over the life of a cable?
- Is it likely that any heat from the cable will cause deterioration of the rope?
- Will there be any damage to the rope over time from abrasion on seabed rocks?
- If so, can the rope become a hazard to marine creatures and vessels?
- If it is decided to leave the cable in place after decommissioning will the rope create pollution and problems for marine creatures or vessels?
- Little information is available for this technique, indeed the Managing Director of another large energy transport company had never even heard of it.
Are there any reports/surveys/studies extant that will shed some light on the technique?
- Comment from Basslink representatives indicated at the hearing that the idea of laying of a return cable at the same time as the power cable meant that there would be insufficient physical space on the boat to accommodate the cables. To do it, the boat would have to return to the cable builder in the Northern Hemisphere several times to reload at significant cost. This simple fact alone would make the technique of putting two cables together economically nonviable. If a return cable were required, it would have to be laid separately.
The Draft IIAS (4-30; Table 4.15) indicates that a metallic return cable system will add 12 to 13% to the cost of the proposal. This is around $65 million (at 13%). Costs mentioned at the hearings were in the vicinity of $100 million.
Four months later they claim to be able to lay not two but three cables bundled together at an additional cost of only $20 million.
As the usual trend is for prices to go up over time (not to be slashed by 80%), how is this possible?
- Is this new technology, or were we all misled by Basslink during the hearings?
- If we were misled, then where else have the facts been distorted?
- Where is the quantified justification for their claims?
TFIC Conclusions and Recommendations: