Techno-economic assessment indicated a barrage was suitable for the hydropower project

Phurpa Lhamo | Wangdue

The government had conveyed to the Indian government that a barrage would replace the dam at the Punatsangchhu Hydroelectric Project I (PI), according to Tengye Lyonpo Loknath Sharma.

He said so yesterday at the meet the press held online.

Lyonpo Loknath Sharma said that the techno-economic assessment indicated the barrage option was suitable.

He, however, said that to avoid issues similar to the dam, the ministry had planned to invite specialists from outside Bhutan to conduct further geological investigations. Specialists could not visit due to travel restrictions due to the pandemic.

According to the minister, they planned to complete the barrage option design and drawing by end of June, but it might take until July and August.

The barrage construction over a dam comes after the dam site suffered multiple landslides.

The project started in 2008 and witnessed its first slide in July 2013. Another slide followed in 2016 and a recent one in 2019.

Following the largest landslide at the right bank of the dam, the project consultant Centre Water Commission (CWC) submitted a holistic report, stating the dam could be constructed with stabilisation measures.

National Hydroelectric Power Corporation (NHPC) who reviewed the report shared differing views on the design and the report.

It was reported that the factor of safety wasn’t enough and wasn’t up to the international standards. NHPC had instead recommended constructing a barrage 825ms upstream, which would decrease the power generation capacity.

In an interview earlier with Kuensel, Lyonpo Loknath Sharma shared that for Bhutan, the dam needed to last more than 70 years. “We have communicated to the government of India and the government of India is considering and looking into facts and figures.”

Budget and deadline

As of date, Nu 80 billion (B) of around Nu 93.7B budget has been spent.

Initially, the 1200MW PI project was allotted Nu 35B.

Lyonpo Loknath Sharma said that be it barrage or the dam construction, an additional budget would be required.

He said that it was estimated that dam construction would require approximately more than Nu 20B, whereas barrage construction could be achieved at a slightly lower cost. “However, experts are working on designs and drawing of barrage so the exact amount can not be spelt.”

With constant landslide challenges and the decision to replace the dam with a barrage, construction work is expected to complete between 2024 and 2025.

Lyonpo Loknath Sharma said that work would be delayed due to the pandemic. “When it comes to constructing barrage or dam, the timeline was almost the same.”

He said experts were estimating that barrage construction would take lesser time than that of the dam. “The details are being worked out as part of preparing barrage detailed project report (DPR). We can schedule the timeline of the project only after that.”

At site, about 87 percent of project work has completed.

Edited by Tashi Dema