The 969 MW Neelum Jhelum Hydropower Plant was shut down yesterday for a physical inspection of its head race tunnel to locate the problem that led to a decrease in pressure a month ago. Once the problem is traced, a comprehensive plan will be devised in coordination with the Project Consultants and international experts to undertake remedial works to rectify the issue.
According to the details, a sudden change in the head race tunnel pressure was observed on April 2, 2024. As per the advice of the Project Consultants for the safety of the head race tunnel, the project management kept operating the plant at a restricted generation of 530 MW since April 6 to monitor fluctuation in the head race tunnel pressure.
Neelum Jhelum Hydropower Plant continued generating about 530 MW of electricity till April 29 without any issue. However, at 2257 hours on April 29, further change in the head race tunnel pressure was observed. Subsequently, the generation was gradually reduced but the pressure could not sustain within the safe limits as per the advice of the Project Consultants. Keeping in view the safety of the head race tunnel and the powerhouse, the plant was shut down at 0600 hours on May 1 for a physical inspection of the head race tunnel to identify the problem of reduced pressure. Consequent to the detailed discussion with the Consultants for dewatering of the 48 Km-long tunnel, the intake gates at the dam site were lowered for flushing of the de-sanders. The dewatering started from the powerhouse side on the same day. The dewatering will be executed at intervals for the safety of the tunnel.
It is important to note that the Neelum Jhelum Hydropower Project has been constructed in a weak geological and seismic-prone area. It has a 51.5 Km-long tunnel system. Its head race tunnel is 48 Km long, while the tail race tunnel is 3.5 Km Long. About 90% of the project is underground. Earlier, the plant was shut down in 2022 for the repair of the tail race tunnel downstream of the powerhouse. After completion of the repair and rehabilitation work, the plant resumed electricity generation in August 2023.