It's taken some time, but AGL is ready to replace its 50 year old 480MW Torrens Island A station.
The new gas fired power station will be less than half the old ones capacity at 210MW.
It'll be ready by 2019 and create about 200 construction jobs.
The multi-million dollar investment nearly didn't happen after the State Government announced a $360 million gas-fired plant in March.
That prompted AGL to take another look at its own plans.
But the Government says its new station won't be a market competitor and will only exist as a back up option in times of emergency.
Just across the Port River, rival firm ENGIE plans on boosting its own power station at Pelican Point to 479MW from July 1 after doing deals with clients including Origin Energy.
Meantime five bidders have been shortlisted in the tender to build Australia's biggest battery, paid for by the $150 million Renewable Technology Fund.
Work is expected to begin on AGL's new power station in August.