Alinta expects to close the two coal-fired power stations at Port Augusta next March, once the final coal stockpiled at Leigh Creek is used up.
The Playford and Northern power stations and the associated coal handling plant will be demolished from mid-2016.
The entire program will take until 2018 to complete, with the removal of asbestos likely to be the most challenging aspect.
Apart from demolishing the majority of the buildings and the 200m tall Northern chimney, the dam that stores the fly ash also needs to be remediated.
The company plans to fill and revegetate the dam area, although Alinta will also look into other industrial uses for the site.
The Sydney-based, American-owned gas and electricity retailer announced in June that its Augusta generative capacity was being shut down.
The company has already set aside an $80 million package for redundancies and transitional support services for workers and the Leigh Creek community.
South Australia is increasingly reliant on wind power and power generated from Victoria, however the loss of the 275,000 volt interconnector in early November caused a blackout for about 110,000 homes and businesses across the state.
SA is looking at expanding its ties with the Queensland network as well.
Alinta entered SA in 2012 and had intended to keep its Augusta generation capacity running until 2018, but brought forward the closure by two years.
Playford and Northern burns brown coal from Leigh Creek, some 280km away.
Playford B has four 60 megawatt turbines capable of generating 240MW, but was commissioned in the early 1960s and in recent years it has been used mostly for peaking power in the summer.
A mid-life refit and refurbishment was completed in 2005.
Northern has two 260MW turbines that generate a total of 520MW of electricity.
The plant was commissioned in 1985 as a baseload generator, but now runs for just six months of the year.
Alinta had hoped to develop a new coal resource to keep the Northern plant operating until 2030, but those plans did not pan out.
An explosion in June appears to have helped Alinta decide to shut the mine and facilities.
Almost 450 people have been employed at the company’s Flinders operations and the associated Leigh Creek coal mine.
