Khimti I
The Khimti I hydropower plant supplies almost 15 percent of Nepal`s total electricity output.
The plant
Khimti I is a run-of-river hydropower plant with a capacity of 60 MW and an annual production of 350 GWh. It is located in Dolakha District east of Kathmandu, and utilises a drop from 1,270 to 586 metres above sea level in the Khimti River, a tributary of the Tama Koshi River.
Khimti’s low diversion dam leads water through de-sanding chambers into a headrace tunnel which ends in a surge chamber. From there, a steel-lined concrete penstock shaft leads to the underground powerhouse. A free flow tailrace tunnel brings the water into the Tamakoshi River. The power is transferred through bus-bars in the access tunnel to outdoor transformers where the voltage is stepped up to 132kV for supply to the national grid and to 33kV for local supply.
Operation
Khimti I began commercial operation in July 2000. The plant is operated according to a fixed monthly energy contract during the wet season from mid-May to mid-November. In the dry season any energy produced above the contract level is purchased by the state utility accord pay agreement in the Power Purchase Agreement.
Sustainable development
Khimti I was built and is operated, with minimal environmental impact. The plant complies with the stringent health, safety and environmental standards set by the Asian Development Bank and the World Bank. The project provided considerable employment opportunities and extensive knowledge transfer for the local population during the construction phase. The plant continues to do so during operation. Current community development programmes include rural electrification, irrigation and drinking water projects, support of local schools and Non-Formal Education classes and operation of a clinic catering for more than 12,000 patients annually.
Kirne expansion
In November 2008 a survey licence to expand Khimti 1 by adding 50 MW of generation capacity in a new plant was granted. Called the Kirne hydropower project, the investment is expected to nearly double the wet season energy production with a minimum of negative environmental impacts. The project is at an early feasibility stage.