The savings would come despite the significant up-front investment needed to build wind turbines off the coast, a study found, due to lower costs for transmission equipment, fuel, and compensation for landowners.
Star of the South Wind Farm released the findings on Wednesday from an analysis produced by consulting firm Jacobs.
The research comes months after the federal government slashed the price of offshore wind licence and application fees for two years, and after three major projects were paused or abandoned for Victoria and NSW.
Offshore wind projects have yet to be launched in Australia, although the nation has six dedicated zones for the renewable energy developments off the coast of NSW, Victoria, Western Australia and Tasmania.
The Offshore Wind Benefits study analysed two scenarios: one in which a seven gigawatt offshore wind project operated in Bass Strait, in Victoria's Gippsland zone, by 2040, and one in which the technology played no part in the National Electricity Market.
It found the capital and operating costs would be $6.4 billion higher with offshore wind in the mix, but those costs would be more than offset by savings from other elements of the project.
The biggest reductions, estimated at $6.1 billion, would come from building and operating transmission infrastructure, the report found, though the project would also save $2.5 billion on fuel costs and $600 million on landowner compensation and social licence fees.
"Although offshore wind is not the cheapest option from a standalone capital cost perspective, offshore wind reduced overall system costs," the report noted.
The project could deliver a $151 annual saving for a typical Victorian household by 2040, the analysis found, or an $84 saving for homes on the east coast.
The findings underlined the hidden benefits of offshore wind technology, Star of the South chief executive Charles Rattray said, which could help to replace coal-fired power plans and complement solar by generating energy at night.
"This study shows offshore wind produces big benefits for the entire grid," he said.
"Offshore wind helps give our national electricity market independence from volatile global gas and oil prices."
Reducing the number of transmission lines and towers needed to deliver renewable energy would be important for land use as well as the cost, Farmers for Climate Action chief executive Verity Morgan-Schmidt said.
"Transmission on farmland has become the toughest part of the clean energy shift," she said.
"While many farmers are eager for the diversified and drought-resistant income that hosting solar and wind projects provides, transmission presents unique challenges."
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