NSW-based Tomago Aluminium says it has secured the company's power supply until 2028, after signing the state's largest ever energy agreement with Macquarie Generation.
The 11-year base load supply contract will replace Tomago's existing power supply contract with Macquarie when it expires in 2017.
Tomago says the deal opens the door for further talks with Bahrain-based Midal Cables International, which is looking to build a $30 million aluminium conductor and rod factory on land adjacent to Tomago Aluminium's operations in the Hunter Valley.
Midal was in talks with Tomago about a long-term hot metal supply opportunity that would create 290 jobs, but discussions were suspended in September due to the uncertainty surrounding the smelter's long-term power supply arrangements.
"This is an excellent outcome for the long-term future of Tomago Aluminium and the 5,300 jobs we sustain directly and indirectly," Tomago chief executive Brian Cooper said in a statement.
"It's significant in terms of the Hunter Region, New South Wales and national investment and employment."
Tomago, which is part owned by Rio Tinto Alcan, plans to work with Macquarie to reduce carbon emissions from Macquarie's coal-fired assets.
"Tomago Aluminium and Macquarie Generations evolution and development have been intertwined for the life of the smelter, and the long relationship we have in place will be important as we face the challenges of climate change together," Mr Cooper said.