The takeover of Loy Yang A power station last year has helped deliver new owner AGL a six-month profit of $364.7 million.
AGL managing director Michael Fraser said the acquisition of Loy Yang A power station late last June had contributed to the company's strong earning growth.
"Loy Yang has been successfully integrated into our portfolio of generation assets; it has performed well since we acquired it in June last year," Mr Fraser said.
However Environment Victoria's Mark Wakeham said the announcement was only further evidence the Federal Government's compensation for brown coal generators was delivering windfall profits for the generators.
"Clearly the carbon price has done very little to affect the profitability of AGL's Loy Yang investments, and in fact generation has increased significantly at Loy Yang A at the expense of Hazelwood and Yallourn," Mr Wakeham said.
"Loy Yang is also significantly better off financially as a result of the overly-generous compensation payments the Gillard Government is making to the nation's dirtiest power stations."
Loy Yang A received $240 million last year in the government's first instalment of a five-year $5.5 billion carbon price compensation plan for brown coal generators.