Power in much of Australia operates as an energy market. Privatisation promised to introduce competition to drive down prices, and to allocate resources more efficiently.
Clarke and Dawe delightfully explained it in 2017:
The end result has been higher prices, and well-publicised blackouts in parts of the country during times of peak demand, while power stations remain idle.
The Greens are proposing a government-owned energy retailer. Seems to make nothing but sense; if the private sector can operate more efficiently and therefore deliver lower prices, they have nothing to fear by government competition.