Coal-fired plants close, then prices fall Before Northern closed, South Australia had Australia’s highest price. Five years after the closure of Northern in 2016, and four years after the closure of Hazelwood in 2017, South Australia and Victorian have wholesale prices one-third lower than those in NSW and two-fifths lower than those in Queensland. Something happened after the closure (largely as a result of the closure) that forced prices down. South Australia became a renewables powerhouse. The Australian National University’s Hugh Saddler points out that renewable-sourced power – wind and grid-scale solar and rooftop solar – now accounts for 75% of South Australia’s needs, and at times for all its needs.