Various charts of Australian retail electricity prices and indices
First from 2010 by  UBS shows prices falling in real terms when power was generated by State Electricity Commission

2nd Chart produced in 2014 during the carbon tax which was repealed mid-2014

3rd Chart also starts 1955 but produced in 2017 and shows the quota of renewable power installed 

The 4th chart  was generated for AEMO in May 2017  by Jacobs and also models the future

The 5th chart is from St Vincent de Paul  from the second half of 2017 and shows power bills in dollars

Renewable  Energy category at the blog lists many articles on electricity prices. If anybody finds other charts worth adding please let me know at the blog.