The AEMC was forecasting about a 25% increases in wholesale electricity prices, largely forced by the Hazlewood retirement causing gas generation to more often become the marginal priced producer and set the market price.
Renewables have two contrary impacts, they reduce the market price while generating, but worsen the utilisation factor of base load generation, so tend to push forward retirements.
Seems to me, unless I am missing something, your real problem is that gas prices have doubled. That's not renewables fault.
And prices have risen without a carbon tax. They were lower with it.
But that's also all about gas prices.
http://www.aemc.gov.au/getattachmen...4d4/2016-Electricity-Price-Trends-Report.aspx
http://www.news.com.au/technology/e...e/news-story/042712e35c08bf798ed993d13ee573ea
I'd be wondering about paying Hazelwood a negotiated arrangement to stay on, if that was practicable, for a few more years, and/or designing a better standby reserve market to give gas generators (and hydro) better payment incentives to be available as increased standby reserves, and then push as much more renewables onto the system as that better reserves market would allow, to help keep prices down.
You've got the same problem New Zealand has with dairy and lamb prices. It's all set by international market prices. That's now the case with your gas prices also.
