A major milestone has been achieved at POWERCHINA’s Tarbela 5th Extension Hydropower Project, as the joint hydrostatic test of the steel penstock bifurcations was successfully completed, the company announced, according to Gwadar Pro.

The tested structure includes one pressure relief pipe and three branch pipes. According to the company’s statement, the largest component features a sphere diameter of 14.6 meters, a maximum plate thickness of 130 millimeters, and a water-filled weight exceeding 12,000 tonnes—making it the largest and most complex structure of its kind in the world today.

The 64-hour test was carried out smoothly, with all results meeting expected standards. “This marks a strong validation of the structure’s integrity, welding quality, and overall design, laying a solid foundation for the safe and stable operation of the generating units,” the statement said.

The Tarbela 5th Extension Project is part of ongoing efforts to expand Pakistan’s hydropower capacity. Once completed, it will add three 470-megawatt units, increasing the total installed capacity of the Tarbela hydropower plant to 6,298 MW.

As Pakistan’s largest hydropower facility, the expansion is expected to further strengthen the country’s energy supply and support long-term power generation needs, according to the company.

Credit: Independent News Pakistan (INP) — Pak-China