In the race to transition to renewable energy in Australia, one state is way ahead of the pack. While Australia as a whole has a renewable energy target of 20% by 2020, South Australia is now close to getting 30% of it's power from renewable electricity in 2013. You can read more about this achievement here in the Climate Spectator.
Mostly SA has done this using wind power, 10 years ago wind barely rated a mention in it's electricity generation, but now it is well over 20%. Solar PV is starting to have an impact as well, generating about 3.5% of the state's power. SA households are very keen on solar PV, but as you can see large scale wind is producing a lot more power than distributed small scale solar (at least currently). Where the solar does help though is in reducing peak demand.
The big loser in SA, as the Climate Spectator articles shows, has been coal fired generation. Since the running costs of renewable energy plants are close to zero, they can out-compete the least efficient/ most expensive generators, and in SA that has seen a number of old coal plants shut down or wound back.
The other important lesson from SA is that the power grids with a large percentage of renewable electricity can be reliable. Plenty of people have said over the years that the intermittent nature of (some) renewables would limit them to a small percentage of electricity production before we'd be in rolling blackouts etc, SA is showing this isn't true.