The total project cost is about $406 million, AGL Energy Limited said in a release Wednesday.
Projects include a 102-megawatt solar plant at Nyngan and a 53-megawatt solar plant at Broken Hill, with the federal government providing $150 million toward the total cost and the New South Wales government pledging $58 million, AGL said.
Both projects would begin construction in 2014 with completion expected by 2015, it said.
"Solar PV (photovoltaic) in Australia has come a long way from being a small-scale industry in a relatively short time frame," AGL Managing Director Michael Fraser said in a statement on Wednesday.
When completed the two projects are expected to provide power to 50,000 New South Wales homes, he said.
"The Nyngan and Broken Hill solar plants will be the nation's largest solar projects with the Nyngan plant also being the largest in the Southern Hemisphere," Fraser said.