Sun Metals were instrumental in fighting the 30 minute...

Sun Metals were instrumental in fighting the 30 minute settlement rule which allowed power companies to game the AEM by deliberately withholding generation to push up the auction price. Power generators bid to supply power for 5 minute periods, however the price for a successful bid applies for a full 30 minute period. So power generators can withhold power to force an increase in the auction price ("playing chicken") to give them a windfall of that price for the next 30 minutes.

This practice is a significant contributor to high power prices. The state-owned power generators in QLD also participated in this practice, until ordered not to by the Labour govt earlier this year (http://reneweconomy.com.au/how-queensland-govt-generators-loaded-200m-extra-on-consumer-bills-52605/)

The good news is that the AEMC has decided that the practice will be stopped. The bad news is that this won't happen until 2021 (after which there will certainly be a decrease in average power prices!).

http://www.aemc.gov.au/Rule-Changes/Five-Minute-Settlement