After the resounding success of the Chukha Hydropower Plant and its socio-economic bearings on the people of Bhutan and India, the proposal for another hydropower plant in the Wangchu river basin was conceived and resulted in a pre-feasibility report prepared in 1983. Following the discussions held between His Majesty the Fourth King of Bhutan and the then Union Minister of Energy, GoI, in January 1990, a high-level expert term was deputed by GoI to reconnoitre the various Project areas in February 1990. The expert team indicated the prima-facie feasibility to two projects namely, the Tala Project and the Wangchu Reservoir Scheme and recommended that detailed studies be taken up. Thereafter, the two Governments entered into a Memorandum of Understanding on November 25, 1990, for carrying out detailed investigations and studies. The work was assigned by the MEA, GoI to M/s. Water and Power Consultancy Services (WAPCOS), an Undertaking of the Ministry of Water Resources,Government of India, vide an Agreement of February 18, 1991. In July 1991, WAPCOS initiated Site Surveys, Field Investigations and Studies relating to hydrology, meteorology, topography, geology, seismology, geophysical and geo-technical properties, quarries for construction materials and environmental aspects.
The Tala Project is located in Chhukha, Western Bhutan, just downstream of the Chhukha Project. Field investigation work related to the Tala Project was completed in March 1993. After finalizing of desk studies, a draft Detailed Project Report (DPR) was prepared by WAPCOS, on schedule, by August 1993. Various comments and suggestions on the draft DPR were received during a presentation of the draft DPR. A final DPR, incorporating these comments/suggestions, was prepared in October, 1993.
The Agreement for the implementation of the Tala Hydroelectric Project was signed by the two Governments on March 5, 1996, following which an autonomous body named the Tala Hydroelectric Project Authority (THPA) was constituted for the construction, operation, and maintenance of the Project.
WAPCOS was appointed as the engineering design Consultants to the Project Authority. The expertise of premier organizations of the GoI viz the Central Electricity Authority, Central Water Commission, Central Water & Power Research Station, Central Soil & Materials Research Station, Geological Survey of India and Survey of India were also made available to the Project through WAPCOS. The National Institute of Rock Mechanics (NIRM) still continues to provide consultancy in instrumentation in various appurtenants of the Project.
The implementation of the Project, including creation of basic infrastructural facilities started in October 1997. The main works of the Project started in early 1999. Despite many adverse geological problems encountered in many components of the Project and the extensive damages caused by the unprecedented rains of 2000, the first unit of the Project was commissioned on July 31, 2006, and the last unit was added on the bar on March 30, 2007. The Project components stretch for approximately 100 km from the Dam at Wangkha to TRT Outfall at Tabji.