Yallourn is closing. Now the mine needs 665 gigalitres of water to fill its void. - Herald Sun

Yallourn, Victoria's brown coal power station, is closing, and its open-cut mine will require 665 gigalitres of water to be filled. The Herald Sun reports the mine's void as a consequence of decades of coal extraction that powered the station. Filling the void is part of the decommissioning cost and environmental remediation.

Where this fits

Yallourn's closure is a necessary step in Australia's energy transition away from coal. But the scale of remediation, 665 gigalitres of water, a material environmental liability, is a data point often absent from transition costings. Renewables-only pathway analyses typically count the cost of new generation capacity and grid connection, but not the full lifecycle of retiring dispatchable plants or the water and land footprints of their replacement. This is a firm-power closure cost that sits outside the headline megawatt figures.

What it means

Yallourn's retirement removes 1.5 gigawatts of reliable baseload from the grid at the moment when Victoria is accelerating renewable build-out. That capacity will be replaced by weather-dependent solar and wind, requiring either battery storage or continued gas firming, both of which add cost and complexity to the system. The water remediation bill is real money, as is the transmission augmentation needed to wire in distributed renewables across the state. A nuclear plant, by contrast, occupies a fraction of the land footprint, requires no mining void, and produces firm power without weather dependency or the supply-chain exposure Australia now carries in solar panels, batteries and inverters sourced from China.