The Southeast Asian nation is a major exporter of coal and the rules could hit miners currently enjoying coal prices at their highest level in five years.
With elections looming in 2019, the government plans to keep electricity tariffs unchanged this year and next, and the cap on thermal coal for power is intended to shield state-owned utility Perusahaan Listrik Negara (PLN) from price fluctuations.
“The (maximum) price of coal … for power stations is US$70 (RM274), fixed,” energy ministry spokesman Agung Pribadi told reporters on Friday at a news conference on the step and other new rules.
That price is based on coal with a calorific value of 6,322 kilocalories, the same specification as in the Indonesian Coal Benchmark Price (HBA).
The rule will be applied retroactively to January 1, 2018, and will be reviewed in December 2019.
Where the HBA drops below US$70 (RM274) per tonne, the domestic thermal coal price for power stations will revert to HBA, Pribadi said.
The monthly HBA was set last week at US$101.86 (RM398.56) per ton for the month of March, its highest since May 2012.
The new rule allows coal miners supplying PLN to apply for an increase to their approved production quota for the year of up to 10%.
“Energy and Mineral Resources Minister Ignasius Jonan emphasizes this setting of coal prices for power stations is so that electricity rates can be maintained to protect people’s purchasing power and competitive industries,” Pribadi said.
The rules are expected to generate savings of 18 trillion rupiah (RM4.9 billion) for PLN if the HBA stays above US$100 this year, PLN Strategic Procurement Director Supangkat Iwan Santoso told reporters.
Under the new rules, PLN, which uses coal with a calorific value of between 4,200 and 4,500 kcal, will pay around US$37 per ton for coal while the HBA remains above US$70 (RM274), Santoso said.
At the current HBA price, PLN pays around US$55 (RM215) per ton, he added. PLN expects its coal demand to climb 18% this year to 90 million tonnes.
The government has been working on plans to regulate domestic coal prices since late 2017, under pressure from PLN, and the discussions have knocked back some coal miners’ share prices.
Over the past three months, the Indonesian mining share index has gained more than 22%, outperforming all other asset classes, and is up around 33% over the past year. But, in the past five days, the sector has fallen over 6% – more than any other.
“We are still studying the impact (of the new rules). We want market prices,” said Indonesia Coal Mining Association Executive Director Hendra Sinadia.
According to Suherman, corporate secretary for state-owned coal miner PT Bukit Asam, “the impact of the new price is not really significant on our target revenue and bottom line”.
A spokeswoman for Adaro Energy, Indonesia’s second-largest coal miner by output, declined to comment.
Adaro shares were down just over 3% at 2.15pm local time.
The government has said national coal output could reach 485 million tonnes in 2018, up from a realised output of 461 million tonnes in 2017. About 118 million tonnes of this is to be for domestic coal consumption, with the rest exported.