Indonesia: Prolonged drought drains dams, halts electricity supplies

Ganug Nugroho Adi and Syofiardi Bachyul Jb, The Jakarta Post 3 Nov 15;

A prolonged dry season that began earlier this year has triggered an electricity crisis in several regions across Java and Sumatra, as some hydroelectric power plants (PLTA) have had to stop operating due to the lack of water supply available to move the turbines.

In Wonogiri, Central Java, the absence of rain over the past several months has severely decreased the water volume of Gajah Mungkur Dam, preventing the nearby PLTA from operating properly.

According to data from Perum Jasa Tirta I’s Bengawan Solo region, the dam’s operator, the water surface at Gajah Mungkur is currently resting at 127 meters above the sea level, far below the normal dry season height of 129.12 m above sea level.

“We only have 7.5 cubic meters [m3] per second [of water debit] at the moment. This is only sufficient for maintenance purposes,” the company’s water resource and service division head, Winarno Susiladi, said on Monday.

According to Winarno, Gajah Mungkur PLTA needs a water debit of 118 m3 to move each of its two
turbines. Thus, the PLTA needs at least 236 m3 of water debit to run full throttle.

Winarno also explained that four of the dam gates had been closed since October, because that water had mainly been channeled to a local tap water company.

During normal days the PLTA produces 12.4 megawatts (MW) of electricity to meet the power demand in the southern Wonogiri area.

To fulfill the power demand amid limited water supply, the Gajah Mungkur PLTA has connected to the electricity network in the neighboring Surakarta municipality.

The Meteorology, Climatology and Geophysics Agency (BMKG) has warned that the dry season this year would last longer than that of previous years due to the weather phenomenon known as El Niño.

The BMKG predicts that the El Niño effect will extend the dry season, which normally takes place between April and September, until November, and affect at least 18 out of the country’s 34 provinces.

In West Sumatra, local residents have also been complaining due to recurrent rolling blackouts over the last two months, also predominantly triggered by limited water volume in some of the province’s major lakes and dams. Last month, several PLTAs in the province reportedly experienced losses in power capacity of up to 200 MW due to the same reason.

In Solok regency, a regent candidate debate on Saturday was stopped for 45 minutes due to a sudden blackout, switching off the loud speakers and leaving the venue in darkness.

“We understand [state-owned power company] PLN’s difficulties and that is why we sent a letter asking them not to apply a blackout in the region during the debate program. But, the blackout was applied,” chairman of Solok General Elections Commission (KPUD), Elwiza, told The Jakarta Post on Sunday.

Spokesperson of PLN’s West Sumatra region, Ridwan, said that the rolling blackout policy had to be implemented for several reasons, inclusive of the water crisis, machine damage in some power plants, and also ongoing maintenance.