In a ward South Africa's governing African National Congress (ANC) won handily in local elections three years ago, party campaign worker Poppy Vilakazi has been getting a decidedly frosty reception lately.

"Mostly they are angry," she told Reuters, speaking in Komati, a village in the shadow of a shuttered power plant in Mpumalanga province, an ANC stronghold in the country's coal belt.

"They feel the ANC let them down by allowing this power station to close."

South Africa's creaky power sector and the economic fallout from state utility Eskom's struggle to keep the lights on are top issues in a May 29 election that polls predict could see the ANC lose its 30-year parliamentary majority.

But as President Cyril Ramaphosa seeks to balance the need to boost energy output against dwindling funding for coal - which generates 80% of the country's power - and global demands that South Africa decarbonise, the issue is dividing his party.

Nowhere is that more evident than in Komati, where the conversion of a 60-year-old, 1,000-megawatt coal power plant has triggered a local and national backlash.

Eskom is installing 370 megawatts of solar, wind and battery storage at Komati. It is meant to be a blueprint for future coal station closures and create new jobs and training programmes in the renewable energy sector.

But local residents like Dumisani Mpungose - laid off from his maintenance job at the plant - say so far, they've seen nothing but unemployment, poverty and rising crime.

"Komati was a place of happiness, of life," said Mpungose, 37, whose wife returned to her parents' home after he lost his job, taking their daughter with her. "It's been two years I haven't seen them now. Two years that I haven't been working."

Ramaphosa's ministers have piled on the criticism.

Mineral Resources and Energy Minister Gwede Mantashe labelled Komati's closure a disaster. 

Electricity Minister Kgosientsho Ramokgopa called it a mistake and has successfully lobbied cabinet to delay future closures.

"If you can't make your pilot work, it's going to send a very bad message. It means you've failed," said Chris Yelland, an energy expert who believes South Africa must pivot to renewables but worries Komati risks undermining that shift.

The ANC's main rivals - and potential coalition partners if it loses its majority - are proposing their own solutions.

The left-wing Economic Freedom Fighters want to stop decommissioning coal plants and add new nuclear capacity, while the centre-right Democratic Alliance wants to liberalise the sector and break Eskom's monopoly.