Punatsangchhu-I HEP is a 1200 MW run-of-the river project located on the left bank of Punatsangchu river in Wangdue Phodrang Dzongkhag( District) in Western Bhutan. Its estimated capacity is 5700 million units of electricity in an average year. Construction of Punatsangchhu-I HEP was commenced in November 2008 at a project cost of Rs 3514.8 crore. In July 2015, the Union Cabinet approved the Revised Cost Estimate of Rs. 9375.58 crore for the project .Physical progress of the project, as of August 2016, is 79.3%. So far, GoI has released Rs. 7069.8 crores to the Project Authority.
The project was scheduled to be completed by November 2015.However, due to the sliding of the right bank at dam site which happened in July 2013, the commissioning of the project is getting delayed. Stabilisation measures have been undertaken by the PHPA management and as per the current projection of the project authorities the project is expected to be completed in March 2020.Complex geology at the dam site has been a major challenge in implementing the project.