The best known is the Snowy Mountain Hydroelectric scheme that has been operating for decades. It has since been joined by further large hydro schemes in Tasmania and smaller ones in other states such that there are now over 100 hydroelectric plants in operation.
By far the strongest growing source of power there are about 10 wind farms that generate over 100 megawatts of electricity, with many more of all sizes under construction. Current estimates are that total wind power is now over 7,700 GWh per year.
Sunwiz maintain a list of all solar installations over 40kW which is available here. This shows there are many commercial solar installations both completed and underway and they keep getting larger with multiple 1 Megawatt power plants in existence in 2013, including Uterne deployed by community groups near Alice Springs with the assistance of the Northern Territory Power and Water Authority (PAWA). The largest is the Greenough River power station near Geraldton in Western Australia that was commissioned in 2012 and generates 10 megawatts of electricity.
PowerWater (The Northern Territory grid operator) has also been heavily involved in trial projects to deploy a tidal power turbine in the Clarence Strait between Bathurst and Melville islands north of Darwin. The company driving the commercialization of this system, Tenax, have recently signed agreements with PowerWater and Charles Darwin University to develop a 2MW Pilot Plant and a Research and Tropical Tidal Testing Centre. This places Australia at the forefront of tidal power development globally and is also the only system designing and testing in the tropics. This creates vast opportunities to extend this technology through Asia after developing the intellectual property and experience in Australia.
There are two utility scale wave generation projects occurring in Australia, the first is in Victoria and the second in Western Australia. The Victorian project is being run by Victorian Wave Partners, an organisation funded by Ocean Power Technologies, Inc and ARENA (the Australian Renewable Energy Agency). The project announced in January of 2014 that Lockheed Martin had been engaged to manage the build of the equipment used in phase one to generate 2.5MW of electricity. The final plant, when complete, is expected to generate around 19MW steadily with a peak production of 62.5MW.
The Western Australian project, Bombora Wavepower, is deploying a completely different wave powered solution in which each individual generation unit is expected to provide 1.5MW of electricity. This is roughly the same as a current wind generator; meaning around seven units would be enough to power an average city suburb.
Another company, Geodynamics, completed a successful pilot of a 1 MW geothermal power plant in the Cooper Basin, South Australia in 2013. It ran for 160 days and proved that the area is viable for continuous production of geothermal power in Australia with the opportunity for significant expansion in size. The Cooper Basin area is integral to the AEMO plan for 100% renewable energy and could be connected to the national grid via a HVDC cable link.