CAPE TOWN (Reuters) -South Africa is in talks with groups helping to fund its switch to a greener economy about delaying the closure of some coal plants as it battles to boost power supplies, and is optimistic of an agreement, the head of its state electricity utility said.

Africa's most industrialised country became the poster child for the global energy transition when developed economies including Britain, the European Union and the United States together pledged $8.5 billion at U.N. climate talks in 2021 to help South Africa cut emissions and move away from coal.

But keeping the lights in a struggling economy while shutting down some old coal-fired plants supplying most of South Africa's electricity needs has proven a tough task, forcing Eskom to delay commitments to shutter at least three power stations before 2030.

"There are some concerns with regards to how our strategy will impact some of the commitments that government has made and also how it will affect some of the funding that was earmarked for these initiatives," Dan Marokane, the new chief executive of Eskom told an energy conference in Cape Town.

"We have spoken to them (partners), we've engaged with them and explained our rationale and the need for tactical cost adjustment and they've all understood this," he said ahead of scheduled talks with funders in June and July.

Eskom has managed to suspend rolling power outages - which have plagued the country for years - for almost two months ahead of an election on May 29 that could see the ruling African National Congress lose its majority for the first time since it came to power in 1994.

Improving the low energy availability factor - the amount of power available at any given time - at old coal-fired power stations is a key aspect of the utility's turnaround strategy.

Eskom had told Reuters last week that the country's power supply crisis made it "nearly impossible" from a technical and political economy perspective to decommission its Camden, Grootvlei and Hendrina (CGH) coal stations over the next few years as originally intended.

"Eskom intends to delay the shut down of the CGH plants until March 2030, and to manage its carbon reduction targets through fleet-wide initiatives," Eskom said.

On Tuesday, Eskom's head of generation Bheki Nxumalo said four out of 10 units at the Hendrina plant had already been shut and the utility did not plan to bring these units back online.

"There is no plan to bring those other three or four units back because as we continue to improve the availability then the pressure becomes less," Nxumalo said.

(Additional reporting by Joe Bavier; Writing by Tannur Anders;Editing by Alexander Winning and Mark Potter)

By Wendell Roelf