South Australia's renewable energy infrastructure and capacity has grown due the completion of many wind projects and a gross feed in tariff: "Electricity (Feed-In Scheme-Solar Systems) Amendment Bill 2008" , which lasts until June 2028.
Normal tariff for electricity: $0.22 / kWh
Feed-in tariff: $0.44 / kWh.http://www.climatechange.sa.gov.au/PDFs/Feed-in_Discussion_Paper_submissions_closed.pdf

Result

Thousands of South Australian homes will have solar systems installed. Some businesses will turn their roofs into mini-renewable power stations. South Australia's renewable energy industry is growing and the State Premier Mike Rann

Mike Rann

Michael David Rann MHA, CNZM , Australian politician, served as the 44th Premier of South Australia. He led the South Australian branch of the Australian Labor Party to minority government at the 2002 election, before attaining a landslide win at the 2006 election...

's initiatives are promoting it. He wants the government to be carbon neutral

Carbon neutral

Carbon neutrality, or having a net zero carbon footprint, refers to achieving net zero carbon emissions by balancing a measured amount of carbon released with an equivalent amount sequestered or offset, or buying enough carbon credits to make up the difference...

 by the year 2020.

It is not clear whether there is a provision for the feed-in tariff to increase with natural increases to the price of electricity

Electricity

Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...

, at a multiple of two. This was the original intent, but may have got negotiated out. The 44 cent tariff

Tariff

A tariff may be either tax on imports or exports , or a list or schedule of prices for such things as rail service, bus routes, and electrical usage ....

 is only paid for any electricity

Electricity

Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...

exported, so only when the system output exceeds domestic demand.http://www.solarhome.com.au/?p=106

Rebates

The South Australian government does not offer any additional rebates or incentives to domestic customers. It is a solar schools program.

Estimated payback

Payback will be best for systems of largest eligible size, where the domestic demand is smallest, or mainly occurs at night and low power consumption during the day and houses without air-conditioning.http://worldisgreen.com/2008/02/19/economic-incentives-for-solar-systems-in-