In Jambi, central part of the island, alone there are three power plants operating below capacity, said Khairullingga, the Network Assistant Manager of the Jambi branch of PLN.
Khairullingga, said in the past several months cities in Jambi have taken their turn of being without electricity.
After the interconnection system of networks, PLN has to rotate blackouts when anyone of the power plants was in trouble, he said here on Saturday.
"There are several regions such as Lampung, Bengkulu, Palembang and Jambi having to experience the inconvenience every day set in rotation by the state power utility PLN," he added.
The power plants that could not operate at full capacity include the 2nd unit of PLTU Teluk Sirih, the 3rd unit of PLTMG Balai Pungut, the 7th units of PLTMG Pungut, the 1sr, 2nd and 3rd units of PLTG Teluk Lembu, PLTMG CNG Sei Gelam, the 1st and 2nd units of PLTG Payo Silincah, the 3rd unit of PLTG Kota Panjang, the 3rd unit of PLTA Maninjau, PLTA Koto Panjang, PLTA Singkarak and PLTS Maninjau.
Khairullingga , however, gave no reasons for the power plants to operate below capacity in Sumatra.
Power generating plant in Sumatra are dominated by coal fired power plants, diesel power plant and hydro electric plants.