The Australian Government introduced mandatory renewable energy targets (MRETs) basically to force conventional power generators into renewable energy. This was done by charging them a penalty per megawatt-hour if they did not have a increasing fraction, year-by-year, of renewable power. These days you don’t have to be a power company - you can be a mini-power company generating solar power with photovoltaic panels on your roof. In fact, the name given by the government to home solar panel installations is an SGU - a small generation unit.
To qualify as an SGU, your home installation typically shouldn't have an output of more than 100kW (kilowatts), or total annual output of any more than 250MWh (megawatt hours). Anything with a higher capacity is officially classed as a power station.
When you install a solar photovoltaic setup for your home, rebates are provided in the form of STCs (small-scale technology certificates), which are redeemable for cash. A single STC is equivalent to 1MWh of renewable energy, although multipliers may apply too, which multiply the amount of STCs that an installation is eligible for. These multipliers will depend on where you live, and are scheduled to eventually be phased out.
The STCs are normally bought from you by the equipment installer, who then applies this directly as a discount on the installation. STCs can only be traded by registered traders, and their value changes rapidly so in most cases it's unnecessarily complicated to try and deal with them yourself.
Feed-in tariffs allow you to sell the power you generate on the roof back to your electricity supplier. Check these out and shop around. Tariffs can be as high as 60 cents per kilowatt-hour. A word of caution's in order here - the more you get for you feed-in, the more you pay for power you import from the grid, so depending on your situation, you may even lose out if you don’t generate enough.