An independent costing report on underground cabling for the HumeLink project has shown significant discrepancies in Transgrids costings and ignited calls for an urgent re-assessment of the proposed works.
Following a $2 billion cost blowout and the new report which found undergrounding would be cheaper in the long run, the HumeLink Alliance and HumeLink Action Groups have said if Transgrid was truly committed to working with the community, it must reapply the regulatory investment test for transmission (RIT-T).
According to the independent report, the original regulatory investment test applied to HumeLink was based on outdated costings with regulators and government now having a skewed understanding of the viability of undergrounding.
The action groups also called on Transgrid to conduct a proper cost-benefit analysis of the undergrounding solution using the new report that debunks claims that undergrounding is three to 10 times more expensive than overhead transmission lines.
HumeLink Alliance vice president, Andrea Strong, said the outdated information, misinformation and speculation had driven decisions on HumeLink.
"In light of new evidence, including the latest independent costing report, Transgrid must now start showing genuine consideration for the community, our environment and electricity consumers by thoroughly and transparently analysing the cost benefits and externalities of both options for HumeLink," she said.
"Within the next 21 days, Transgrid must formally notify the Australian Energy Regulator of their intention to reapply the RIT-T using the new $4.9 billion overhead construction cost and publicly release a like-for-like comparison of undergrounding to justify their final solution.
"Engineers are telling us that there have been major advances in underground cabling technology, it is entirely feasible and the world is looking on in disbelief as Australia builds more overhead transmission lines."
Chair of the HumeLink Action Group, Bill Kingwill, said the current support of overhead by regulators and governments was "based on old analysis, arbitrary decision-making by Transgrid on what they will thoroughly assess, plus a grab bag of unfounded claims about undergrounding".
The action groups have also demanded Transgrid halt any further investments in equipment procurement, contract signings, or land acquisitions while the feasibility of undergrounding was subject to a select committee inquiry.
Chair of that inquiry, NSW Greens MP Cate Faehrmann, said the select committee inquiry should not stop the progress of renewable energy projects.
"We're kidding ourselves to think that would be possible anyway," she said.
"I'm aware of the independent report and the reason behind establishing the new inquiry was because I think that the government-dominated original inquiry paid lip service to evidence from experts in underground transmission.
"We received quite a bit of evidence of the benefits of underground transmission, even if it does cost more to begin with. I want the committee to really scrutinise the costings and that didn't happen with the first inquiry.
"But even if it does cost a bit more for undergrounding, the externalities aren't costed into the overheads versus underground.
"I'm not saying that underground transmission lines should replace overhead transmission everywhere. But what seems to be an ideological opposition by the government and the regulators and Transgrid needs to be challenged."
Ms Faehrmann said she wanted to provide a thorough analysis when the select committee reports at the end of March.
"What we intend to do with our report is produce, maybe for the first time, a really solid analysis and critique by a parliamentary body," she said.
"The first committee, the state development committee, failed in its duty because it didn't adequately compare both of them. It just accepted Transgrid's and the Australian Energy Regulators evidence without examining the evidence from people who are experts in underground transmission."
A Transgrid spokesperson said a NSW Parliamentary inquiry has already concluded that undergrounding HumeLink is not a feasible option.
"It would cost consumers multiple times the above ground option," they said.
"HumeLink is urgently required to avoid rolling blackouts and jeopardising the supply of electricity to millions of Australians on the eastern seaboard.
"As such, Transgrid remains committed to HumeLink's completion by 2026.
"Further, the delays associated with undergrounding will result in a loss of up to $1 billion in lower cost renewables for consumers."
Transgrid based this figure on a delay period of up to five years at a cost of circa $3.5 million for every week it is delayed.
The spokesperson said that the independent report is flawed and not fit for purpose.
"Specifically, the report fails to address the transmission capacity estimates, accurate costing of undergrounding and represents a failure to recognise key safety risks," the spokesperson said.
"If the analysis prepared by Amplitude is aligned with the technical realities and requirements of HumeLink, the suggested disparity of underground costs would be greatly minimised, if not disappear altogether."
Transgrid said it conducted extensive investigations and has worked closely with landowners and local communities over the past two years to examine the feasibility of undergrounding HumeLink.
"We will continue to work with landowners, the community, regulatory authorities and governments to find solutions to balance local impacts, consumer costs, time constraints and critical supply reliability," the spokesperson said.
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