A key link in the national electricity network will significantly increase the risk of deadly blazes in areas still recovering from the Black Summer bushfires, a new report says.
The report to be released on Wednesday calls for the federal and NSW governments to force the $3.3 billion HumeLink project underground, rather than having wires running over bushland and prime farmland.
One of the state's largest energy infrastructure projects, the 500-kilovolt transmission line is expected to increase transfer capacity between southern NSW and greater Sydney and become a critical link in the National Electricity Market.
Bill Kingwill, from the grassroots group Stop, Rethink HumeLink which commissioned the report, said an overhead HumeLink would exacerbate bushfire risk already rated "above normal" by the Australasian Fire and Emergency Service Authorities Council.
"The HumeLink towers proposal is based on flawed and short-sighted economic thinking, and ignores the findings of numerous bushfire inquiries and Transgrid's own assessment that there is a high degree of bushfire risk along parts of the route," the volunteer firefighter said.
"It is well recognised in several recent bushfire inquiries that overhead powerlines not only start deadly bushfires, but also hamper our efforts to fight them because of the clear dangers that they present to volunteer firefighters on the ground and in the air."
Andrea Sturgess, whose property near Batlow was devastated in the Dunns Road fire of January 2020, said there was no way known she and husband Paul could defend their property in a fire if HumeLink proceeds as planned.
Existing lines crossing her property thwarted fire crews on land and in the air from assisting them in 2020, she said.
"Our strong message to (everyone) is just put it underground," Mrs Sturgess said.
The $11.5 billion price tag for a subterranean HumeLink is vastly over-inflated, the group maintain.
But network operator Transgrid says going underground was "unsustainable" for cost and time reasons.
Higher costs would be passed to consumers while the extra years spent putting the project below ground would threaten the timely connection of new renewable energy and related essential new interstate connections to the national grid.
"It is essential that the infrastructure is completed by 2026 to secure the network before the ageing power stations are decommissioned," it said.
"A significant delay would put the energy security and stability of large parts of eastern Australia at risk of failure."
The report will be released in Wagga Wagga by Mr Kingwill, local MP Joe McGirr and bushfire survivors.