The administrative building of the Umrangsu unit of Neepco. File picture

Shillong, June 19: Two units of 275MW Kopili hydroelectric plant have been temporarily shut down by the North Eastern Electric Power Corporation (Neepco) because of severe corrosion of machineries following acidification of the reservoir water.

Neepco has also shut down Agartala gas turbine plant and Assam’s gas-based power plant, Kathalguri, which require proper maintenance.

A Neepco official confirmed acidification of the reservoir water of Kopili and Umrong reservoirs on the Assam-Meghalaya border and severe corrosion in the underwater parts of the units and hydraulic structures of the 275MW Kopili hydroelectric plant.

“This has resulted in frequent forced outages as well as increase in the outage period,” the official said.

He added that the recent forced shutdown was taken for safety of the power station as there was heavy leaking of water while running the units.

“Expeditious remedial actions are taken by the plant’s engineers for earliest resumption of the units,” the official said.

The Kopili flows through Umrangsu in the Dima Hasao district of Assam bordering Jaintia Hills.

The first plant, Kopili hydroelectric power plant in Dima Hasao (erstwhile North Cachar Hills district of Assam), was commissioned in March 1984. This plant, which has two reservoirs and comprises three power stations, was commissioned in three stages totalling 275MW with an annual generation of 1,550 mega unit.

Unscientific mining in Jaintia Hills district has not only affected aquatic life but has also eroded Neepco’s machines. The acidic water from the mines has corroded the machines that are used for power generation from the Kopili river.

From the project, 12 per cent free power is distributed equally between Assam and Meghalaya, besides 17 per cent given to other northeastern states.

Because of acidic corrosion of the metallic parts, the generating units have encountered frequent failure of underwater parts, cooling water pipes and tubes, the Neepco official pointed out.

The official said the shutdown of the Agartala and Kathalguri plants were planned, required for proper maintenance and running of the generating units.

The 291MW Assam gas-based power plant commissioned during March 1995 to March 1998 is by far the biggest gas-based plant in the region. This plant was declared “Centre of Excellence” in 2002 by the Union government.

Neepco had also commissioned 84MW Agartala gas turbine power plant in February 1998. This is an open cycle plant with four gas turbines.