Really good point. Worsley uses the process to condense the...

Really good point. Worsley uses the process to condense the steam so the whole process relies on boilers to generate the heat. Something will need to operate the boilers gas or coal
Alcoa have gas turbines in which they use the by product heat specifically in the calcination of the Bayer Process. Alcoa is better equipped to utilise the green energy for the rest of the process bought of the grid which can drive input costs lower
i.e.run the plant of the grid using renewable energy and use the Gas Turbines specifically for the grid load following by making a smarter calcination process.
Considering Worsley are the second largest Alumina refinery in the world, they are taling a huge risk staying with coal.