EXPLAINER: Island blackout a dark reminder of how energy dependent Bali is on Java

A steam tower pokes out over a village in Jepara, Central Java. Photo: Greenpeace Indonesia

An issue with power being supplied to Bali from Java that left most of the resort island without electricity for several hours yesterday is a *powerful* reminder just how energy dependent Bali is on its neighbors.

While inconvenient, the mass outage was nowhere near the dramatic apocalyptic situation of the “entire island plunging into darkness” like sensationalist press (clearly not based in Bali like the Daily Mail) would have you believe. For the record, the outage was roughly from 12:36pm to 3:30pm, so lights were only off during peak daylight hours.

Photo: Daily Mail
Photo: Daily Mail

Anyone living in Bali knows that power outages are fairly commonplace, but state electricity firm PLN has been quick to point out that this is the first mass-level blackout in Bali since 2015 when a transmission substation in East Java was struck by lightning.

“This is the first blackout like this in 2018. Before, even in 2017, there was nothing at all,” PLN Bali Distribution Manager Eko Mulyo HW told Tribun Bali from his office in Denpasar on Wednesday afternoon.

Yesterday’s blackout originated from electrical interference at electric steam power plant (PLTU) Pacitan, East Java, according to Mulyo. The disturbance then had a domino effect, impacting the electrical system at PLTU Paiton, Situbondo, East Java.

This was problematic for Bali, since PLTU Paiton provides 25 percent of the island’s electricity via submarine cable at a capacity of about 340MW.

The other 75 percent comes from other PLTU, diesel power centers (PLTD), and gas power plants (PLTG).

Of these Bali-based plants, the PLTU Celukan Bawang plant has a capacity of 380MW, PLTDG Pesanggaran has 358.7MW, PLTG Gilimanuk has 130MW, and PLTGU Pemaron has 80MW. This comes out to a rough total of 1,288MW of available electricity for Bali.

“So, the supply from the submarine cable at PLTU Pemaron is 25 percent, from inside Bali is 75 percent. Because 25 percent suddenly disappeared, the electricity system in Bali suddenly blacked out,” Mulyo explained.

As of April 2018, the nighttime peak load in Bali reached 863.2MW, out of 1,290MW available net supply, so there was a 49 percent reserve. Meanwhile, the peak daytime load was around 600MW, according to Mulyo.


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To get why Bali was cut off so suddenly yesterday, you need to understand the difference between how steam plants need a “normalization” process to convert energy, unlike diesel and gas plants that stand alone and do not need a supply of energy for the normalization process, says Mulyo.

He compared the gas and diesel plants to an automobile starting up.

“So, PLTG and PLTD are like a car. Once they are turned on, they immediately ignite, but PLTU needs a supply of voltage for it to work normally,” he explained.

Yesterday, PLTU Celukan Bawang was waiting for power supply from Java—but the supply got cut off.

“Once you get electricity from Java, (power from) the PLTU can enter the system. The nature of (this steam) power plant is that it cannot release voltage. It must get a supply of voltage first,” he said.

But what about the supply from the Bali-based PLTD and PLTG? Why couldn’t those plants cover the energy deficit yesterday?

There are protection systems in place, says Mulyo, adding that PLTD and PLTG have tolerance limits.

The sudden system changes in the Pacitan and Paiton power plants triggered a blackout in Bali.

It took several hours to get the power back on in a “recovery process” across substation areas because this a process that can only be done gradually, he said.

Bali was not the only place to get cut off thanks to the supply issues in Pacitan and Paiton.

Most parts of East Java like Surabaya, Situbondo, Banyuwangi, and Jember also reported outages. Meanwhile, blackouts also occurred in a number of regions in Central and West Java.

“We apologize profusely for the outages that occurred. This was due to the distribution of the 500KV Pacitan-Grati system. We are continuing to do normalization efforts, even in Bali, most of it is back to normal,” PLN spokesman Made Suprateka told Tribun Bali.

Although seems to have returned to how they were in Bali before the outage, PLN is pleading with the public to temporarily reduce their electricity consumption to help prevent any further blackouts.

“Once again, we apologize and understand all customers were affected by this disturbance. We promise to everything we can and exert as much effort as possible to improve the system so that the electricity returns to normal,” Suprateka said.

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