Leony Aurora, The Jakarta Post, Jakarta
Day turned to night in thousands of offices and traffic lights went out causing long jams in many cities when a massive blackout swept Java on Thursday after the Java-Bali power grid failed.
By 9 p.m. on Thursday, state power company PT Perusahaan Listrik Negara (PLN) had managed to restore 80 percent of supplies in Jakarta and Banten, the areas most disturbed by the power cut.
""We'll continue efforts to start up the power plants and feed electricity,"" Java-Bali grid general manager Muljo Adji said on Thursday.
Supplies to West Java, Central Java, and East Java have been fully restored.
A failure in 500 kilovolt (kv) transmission line between Cilegon and Saguling in West Java cut electricity supplies at 10.23 a.m. Thursday morning, PLN president director Eddie Widiono said.
""The fault caused several power plants units to disengage from the network,"" Eddie said. Two units of the Paiton plant in East Java and six units of the Suralaya plant in West Java with a combined capacity of 4,000 megawatts (MW) shut down.
Power in Jakarta and Banten went out completely while parts of West Java, Central Java, and East Java also experienced blackouts, causing a temporary halt in traffic and electric trains. Most large offices, including the Jakarta Stock Exchange, survived on back-up power systems.
""We haven't been able to establish the cause of the glitch in the transmission line,"" said Eddie. ""The interconnection system has been restored.""
Although the Paiton plant was now operating normally, only two 400 MW units and one 600 MW unit in the Suralaya plant had gone back on line on Thursday evening. Three other units, with a total capacity of 1,000 MW, were still out.
All of the power units use coal, which is cheaper than high-speed diesel fuel but slower to start up after being shut down.
Minister of Energy and Mineral Resources Purnomo Yusgiantoro said the planned development of an extra high-voltage transmission network in the south of Java would prevent such an incident from recurring in the future.
""If the (existing) north network fails, the electricity would still flow through the south,"" Purnomo said.
The construction of the south transmission line, planned since 1996, has been hampered by land acquisition problems. Locals in Depok in West Java and in Klaten and Bantul, Central Java, have refused to make way for the power line.
Eddie said PLN would speed up the project and expected the network to be completed by the end of this year.
The Java-Bali grid has an installed capacity of 19,615 MW. The usable capacity hovers at around 15,500 MW, as power plants have to be shut down in turns for maintenance and some of the electricity generated is used for operational purposes.
PLN has struggled to fulfill electricity demand in the country, as the cash-strapped government found it difficult to build more power plants after the monetary crisis in 1997.
Three power plants, with a combined capacity of some 2,000 MW, in Java are expected to start operations between the end of this year and the first quarter of 2006 to help boost supply.