Pumped Hydro Energy Storage across Australia, page-108

The thing is we're not talking about today's technology. We're talking about the pathway over the next 5-20+ years. And we should not be talking about pumped storage alone.

Whether we are better to build new high tech coal now to replace old clunkers is moot. My view is that the tech will arrive within 5 years so that you won't need either form of coal generation for much longer than that. It'll be just how quick you can build out a renewable grid with storage. So investments in new coal will likely be stranded.

You also don't need all the battery storage, that you provide your picture of Sydney to Perth for, if you hold back existing coal to provide reserves, continue solar and wind build and utilise Snowy differently, plus if you develop Snowy further and also develop any other economic and viable pumped storage and other hydro storage projects.

Plus battery solutions will become more energy dense as the tech develops.

My personal decision, under uncertainty regarding the pace of tech change, would be just to keep some of the existing coal plant around for long enough, as reserves only if need be, to cover your bases, while replacing as much of their energy with renewables as you can. You are then in a better position to judge a few years down the track. That's unless you are prepared to write off a new coal investment inside of 10-15 years or your viewpoint is that we'll need some of them for their normal 40-50 year lifetime AND that we can afford to still be burning that coal from a climate perspective that long.

Tricky choices and there will be a few differing viewpoints around. Some of them more politically than sensibly motivated.