In July last year, Origin executed a conditional agreement to purchase Fletcher Challenge South West Cogeneration Limited, which held a 50% interest in the South West Cogeneration Joint Venture, for $68.5 million.

The JV owns and operates a 120 MW natural gas-fired cogeneration facility, which supplies steam and power to the Worsley Alumina Refinery near Bunbury and electricity to the Western Power Corporation.

Origin said the acquisition would add to the company's portfolio of efficient natural gas-fired power generation and cogeneration projects as well as complement its existing energy base in WA.

The acquisition would also allow Origin to more readily participate in emerging energy growth opportunities in WA, the company added.