PLN Modifies Power Plants to Ensure Electricity Reliability Amid Coal Supply Changes

PT PLN (Persero), Indonesia's state-owned electricity company, is undertaking modifications to several steam power plants (PLTU) to utilize lower-calorie coal. This initiative aims to mitigate the risk of electricity outages, which have been a concern in recent months due to dwindling supplies of higher-calorie coal.

According to PLN's President Director Darmawan Prasodjo, the company has already completed retrofitting at the Suralaya power plant units 6 and 7, enabling them to operate on coal with a calorific value of 4,100 to 4,300 kcal/kg, down from the previous requirement of 4,600 to 4,800 kcal/kg. This adaptation is crucial as the availability of higher-calorie coal, which is typically above 4,500 kcal/kg, continues to decline.

“We are making adjustments to our power plants to prevent a recurrence of electricity outages,” Darmawan stated during a hearing with the Commission XII of the Indonesian Parliament. The modifications will be applied to both PLN-owned and private power generation facilities, reflecting a broader strategy to enhance the reliability of Indonesia's electricity supply.

“We are making adjustments to our power plants to prevent a recurrence of electricity outages.”Darmawan Prasodjo, President Director of PT PLN (Persero)

In addition to retrofitting existing plants, PLN is optimizing operations during off-peak hours, specifically from midnight to 6 AM. This strategy includes storing excess energy generated during these hours in a Battery Energy Storage System (BESS) with a capacity of approximately 4 GWh, equivalent to 500 MW. This approach aims to bolster the reliability of the electricity system without the need for constructing new power plants.

PLN has also secured additional coal supplies, with plans to receive 1.8 million tons in July 2026 and an expected 3 million tons per month from August to December 2026. This additional supply is intended to enhance the capacity of power generation in Java by approximately 5 GW, which is critical for maintaining stability in the region's electricity grid.

“This additional supply is intended to enhance the capacity of power generation in Java by approximately 5 GW.”Darmawan Prasodjo, President Director of PT PLN (Persero)

Despite these immediate measures, PLN acknowledges the need for long-term strategies as the production of high-calorie coal is projected to continue decreasing. The company is exploring further retrofitting options across its power plants and encouraging independent power producers (IPPs) to adopt similar modifications.

PLN is also accelerating the development of renewable energy sources, in line with government directives for a 100 GW renewable energy target, particularly focusing on solar power. Darmawan emphasized the importance of utilizing available land and reservoirs to strengthen the electricity system while reducing reliance on fossil fuels.

While PLN has reported that electricity supply in Java has stabilized since June 21, 2026, the company is committed to maintaining this reliability through ongoing system enhancements and community engagement. The challenges in Sumatra, particularly regarding transmission networks, are also being addressed as PLN seeks to improve the overall electricity distribution across the archipelago.