The Energy Grid Alliance has released a report this week comparing preliminary findings from AusNet Services and an independent report completed by Amplitude Consultants regarding the proposed 190-kilometre high voltage transmission line between Sydenham and Bulgana.
On November 26, AusNet released its findings as required by the Environmental Effect Statement (EES) process.
The findings stated undergrounding the power lines would cost 16 times more than the overhead lines, and although still subject to peer review, recommended overhead construction.
This recommendation has prompted the review of AusNet’s underground construction summary which, in a statement, the Energy Grid Alliance said was created “to provide a high-level comparative review of the undergrounding concepts and relative design information”.
The report was also completed to understand how AusNet has estimated the underground costs to be 16 times greater than overhead transmission.“As a side-by-side comparison, AusNet’s Underground construction summary is what it claims to be…a broad overview of HVAC (high-voltage alternating current), HVDC (high-voltage direct current), underground construction, potential routes and key differences in environmental impacts” the statement read.
“However the absence of design and cost detail for both the underground HVAC and HVDC options referenced make it difficult to verify and substantiate the conclusion.
“When compared to the [Amplitude] report it becomes evident there is conflicting information that needs to be clarified by an independent HVDC expert.”
The key findings of the report were summarised into seven points, including that AusNet’s summary indicates these are ‘preliminary findings’ that have not been peer reviewed.
The recommendations of the report state that these preliminary findings “require further scrutiny” and that “misconceptions may have inadvertently led to overhead HVAC construction being recommended as the preferred solution”.
Finally, the report recommended further investigations be conducted by a suitable independent expert before the final plans are determined.
In response, an AusNet spokesperson said there is still further work to do as part of the EES.
“…we know undergrounding is an important issue and wanted to share a summary of preliminary investigation findings with landholders and the community.
“Further technical information – including cost and design, will be provided as part of the EES which will be exhibited for public comment.
“Several independent consultants contributed to the investigation, including experts in route selection, electricity transmission and cost estimation.
“Costs for an overhead transmission solution were an element of the project’s RIT-T (Regulatory Investment Test for Transmission) process, as well as a feature of the comprehensive competition process that led to AusNet Services being selected to deliver the Project.
“As the transmission network service provider in Victoria, AusNet Services has very good operational and financial expertise in overhead transmission. This strong foundation in overhead transmission enables our independent experts and specialists in undergrounding to provide excellent advice on comparison options and costs.”
