* AGL defers closures of Liddell, Torrens A plants
* Extension to help energy market cope with "critical summer"
* Outlines plans to progress other power projects (Adds analyst quotes, background)
By Devika Syamnath
Aug 2 (Reuters) - AGL Energy AGL.AX , Australia's biggest power producer, said on Friday it will keep two power plants open for slightly longer than previously flagged to help meet any shortfall in electricity supply over the critical summer period.
AGL also outlined plans to progress several projects, including hydro and gas, to cover the eventual shutdown of its ageing coal-fired Liddell plant, as the company looks to move away from coal to reduce its carbon footprint.
"There's a lot of pressure on companies such as AGL to extend the life of their coal-fired stations, notwithstanding the community's expectation of them heading more toward renewables," said James McGlew, executive director of corporate stockbroking at Argonaut.
Coal- and gas-fired power plants are essential to back up intermittent supply from wind and solar power.
AGL said it had informed the Australian Energy Market Operator (AEMO) of its new schedule "that will help the national energy market cope with the critical summer months."
Three out of four units at its Liddell power station will run for a year over schedule. The plant was originally slated to close in 2022.
The ageing gas-fired Torrens A power station near Adelaide in South Australia will be closed progressively by 2022 but remain open this summer to help offset loss of production from an ongoing outage at its Loy Yang A Power Station in Victoria.
The surprise extension and subsequent increase in production would likely add about A$100 million ($68 million) to AGL's pre-tax earnings in fiscal 2023, at current prices, said a utilities analyst, who declined to be named as they were not authorised to talk to media.
Blackouts and soaring electricity prices have been a hot political issue in Australia.
AGL was strongly urged by the government last year to sell or keep running its Liddell Power Station, as Australia has suffered blackouts in previous summers when demand for air-conditioning soared. government has also been eager to maintain competition in the sector, but AGL rejected a A$250 million ($170 million) offer for Liddell from Chinese-owned Alinta Energy. = 1.4674 Australian dollars)