Leading energy utility AGL says it is getting harder and harder to keep the ageing Liddell coal fired generator on line because it is so old that it is throwing up issues which are unique in the world.

AGL has been put under pressure by the federal Coalition government and conservative commentators to keep the increasingly unreliable Liddell unit on line, even though it has warned that the cost of maintenance of doing so would push up its levellised cost of electricity to more than $110/MWh – double that of renewable energy alternatives.

The federal and NSW governments announced last year that they had formed a “taskforce” to look at the Liddell issue, but AGL CEO Brett Redman said on Wednesday that apart from answering questions and providing information, the company had received on feedback.

AGL last year volunteered to keep some of the Liddell units operating for one more summer beyond its planned 2022 closure, and it will now completely close in 2023.

“We extended the life of plant into early part of 2023,” Redman told reporters at the announcement of its latest battery storage investment, in Queensland, alongside a proposed 1,000MW solar plant.

“(Liddell) is a very old plant. It’s more than 50 years old. And the interesting thing is that we are routinely finding issues with this plant that nowhere else in the world they have found because it is such asn old plant, just doesn’t have anything to compare it to.

“Extending the life of the plant would require significant new investment. We continue to put forward that 2022/23 schedule, because we think it’s the right schedule from an economic point of view and from a safety point of view.”

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