Indonesia’s Electricity Systems – Sumatera Interconnected System

The Sumatera interconnected system is the second largest electricity network in Indonesia, second only to the Jawa-Madura-Bali (JAMALI) grid, and covers the entire Sumatera mainland.

At a Glance

Operational systems: Sumatera Bagian Utara (SUMBAGUT)
Sumatera Bagian Selatan & Tengah (SUMBAGSELTENG)
Operating voltages: 275kV, 150kV, 70kV, 20kV, 0.4kV
Number of customers: 17,030,853 (2016)
Peak load (2017): SUMBAGUT: 2,388 MW
Installed capacity (2017): SUMBAGUT: 3,270 MW
Firm capacity (2017): SUMBAGUT: 2,399 MW
Maximum reserve margin at peak load (2017): SUMBAGUT: 0.46%
Base Generation Cost (2016): Aceh: 1,383 Rp/kWh
Sumatera Utara: 1,235 Rp/kWh
Sumatera Barat: 1,074 Rp/kWh
Riau: 1,349 Rp/kWh
Sumatera Selatan, Jambi & Bengkulu: 1,046 Rp/kWh
Lampung: 1,034 Rp/kWh

Energy Sales

Customer Type 2016 Energy Sales
GWh % Total
Residential 18,752 58.41%
Industry 5,170 16.10%
Commercial 5,296 16.50%
Social 1,152 3.59%
Government 632 1.97%
Streetlighting 1,100 1.25%
Total 32,102 100.00%

Power Plant Fuel Mix

Fuel mix based on energy delivered as at Dec 2016:

Operational Characteristics

While physically one contiguous network, the Sumatera Interconnected system is actually normally operated as two separate islands due to inter-area oscillatory stability issues. The system dispatcher is PLN P3BS based in Pekanbaru, Riau.

A 275kV transmission backbone is currently being developed along the main north-south corridor of the island. At present, the main backbone is still operated at 150kV, although several 275kV sections in Sumatera Selatan, Jambi and Begkulu (S2JB) were energised at the end of 2016.

This article is part of a series examining all of the major electricity networks in Indonesia. For more information and links to all of the articles, please refer to the overview page.

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