Those figures come from a report commission by the Minerals Council that was released over 2 years ago. I think the solar figure includes feed-in tariffs, which aren't really relevant to federal policy, and the high end of which are being phased out. The wind figure seems to match with the price of a LGC for the RET. The price for these has continued to fall as more capacity comes online, and given supply will exceed demand, you can expect these to rapidly head towards $0 in the few years.
The regulator says:
Both the RET and Carbon Price have proved to be effective at reducing emissions, and lamb roasts haven't risen to $100 as predicted. If we put market mechanisms in place, we can reduce our emissions soon with little financial pain. So good reason to be optimistic.