Alcoa chief executive Bill Oplinger told Wall Street the US aluminium specialist could take strong action to boost profits from alumina, most of which it refines in Western Australia.
South West WA's power grid reached a record 91 per cent peak renewable energy share in December - driven by 1,225 MW of new battery storage - while wholesale power prices fell 13 per cent and carbon emissions dropped 15 per cent as coal and gas generation declined.
The green light for Black Mountain Energy comes just months after Federal experts said its environmental risk assessment was "limited and disjointed" and reached "largely unsupported" conclusions.
Ahead of opposition leader Peter Dutton releasing costs for his nuclear policy this week, for the seventh straight year renewables were the lowest-cost new power generation technology.
