PLN to Modify Coal-Fired Plants for Low-Calorie Coal to Prevent Blackouts

PT PLN (Persero) has announced a strategic move to modify or retrofit a number of its coal-fired power plants (PLTU). The measure is being taken so that the plants can consume low-calorie coal, in a bid to prevent recurring rolling blackouts.

PLN President Director Darmawan Prasodjo explained that the policy was driven by the condition of the electricity system, particularly in Java. According to him, technological modification of the PLTUs is an urgent necessity to adapt to the availability of national energy resources.

‘Referring to the system in Java, we still have to retrofit our PLTUs,’ Darmawan said during a Hearing Meeting (RDP) with Commission XII of the Indonesian House of Representatives in Jakarta on Thursday (2/7/2026).

Darmawan cited the successful retrofit carried out at the Suralaya PLTU Units 6 and 7. Previously, these two units required coal with a calorie specification of 4,600–4,800 kcal per kg. However, after modification, they are now able to operate optimally using low-calorie coal in the range of 4,100–4,300 kcal per kg.

The success at Suralaya now serves as the basis for PLN to expand the programme to other plants. ‘Following the success of the retrofit at Suralaya 6 and 7, we are currently conducting feasibility studies for projects across all PLN power plants,’ he added.

This modification measure is seen as a long-term solution to the national coal supply mismatch. Currently, Indonesia’s coal production is dominated by low-calorie types, while the availability of medium to high-rank coal is increasingly depleting.

It was this limitation in medium-rank coal supply that triggered rolling blackouts in mid-June 2026. Through retrofitting, PLN hopes to reduce its dependence on medium-rank coal.

To secure electricity supply in the short term, Darmawan confirmed that the company has secured additional supplies of coal with a calorie value above 4,500 kcal per kg. With additional stock coming in from July until the end of the year, he guaranteed that the stability of the electricity supply in Java will be maintained.

‘With this, we ensure there will be no more blackouts in Java,’ Darmawan concluded.