Australia's dirtiest power plant - responsible for more than 3% of the country's emissions - will shut a decade earlier than planned.
The coal-fired Loy Yang A power station in Victoria will close in 2035, its owner AGL Energy said.
Australia - one of the world's biggest emitters per capita - has long been considered a climate policy laggard.
AGL is the nation's biggest electricity generator and polluter and has come under pressure to limit fossil fuels.
Loy Yang A emitted 16.6 million tonnes of greenhouse gas in 2019-20, according to most recent data. Australia in total emitted 513.4 million tonnes during the same period.
The closure is "a major step forward in Australia's decarbonisation journey", AGL chief executive Damien Nicks said in a statement to Australia's stock exchange.
The plant currently supplies a huge chunk of Victoria's energy.
It was initially scheduled to close by 2048, but that was brought forward by three years in February. The new 2035 deadline comes amid leadership changes at AGL.
Earlier this year, Australian billionaire Mike Cannon-Brookes became the company's largest shareholder in a bid to force it to become greener.
The energy giant owns several of Australia's biggest power stations, and contributes about 8% of the country's reported carbon emissions.
Since his election in May, Prime Minister Anthony Albanese has committed to a 43% reduction in 2005 emissions by 2030, up from his predecessor's pledge of 26-28%.
But scientists have criticised the government for continuing to support fossil fuel industries.
The Climate Council says AGL's decision is proof coal is no longer commercially viable in Australia.
"Coal is unable to compete on cost with renewable energy, it is also inflexible, ageing, unreliable and inefficient," spokesman Greg Bourne said.
Australia's biggest coal-fired power station will also shut earlier than planned, it was announced earlier this year.
And on Wednesday, the Queensland state government unveiled a plan to shift the state away from coal power by 2035.