Cumulative Impacts and Joint Operation of Small-scale Hydropower Cascades Supported by REDP

Small Hydropower (SHP) in Vietnam is defined as having less than 30 MW of installed power and is considered to have an important current and future contribution to renewable energy generation. Already more than 370 small hydropower plants are operational or under construction. A further several hundreds of plants are planned, with a total power capacity of approximately 3.5 GW. Besides the obvious advantage of carbon dioxide free electricity production, the proliferation of small hydropower plants can have detrimental impacts on the environment and on water use.

Vietnam. sedimentation in front of the intake of Van Ho SPH in the Ngoi Xan basin

Initiators

To obtain more insight in the consequences of hydropower cascades and on the possibilities to improve the cascade planning process in order to reduce such impacts, the Vietnamese Ministry of Industry and Trade and the World Bank jointly initiated the study on Cumulative Impacts and Joint Operation of Small-scale Hydropower Cascades Supported by the Renewable Energy Development s

Analyzing six river basins

A total of six SHP cascades situated in six river basins in the Northwest mountainous region of Vietnam were analyzed, together representing a total future maximum installed capacity of 256 MW from small hydropower and 200 MW from one medium size hydropower project. Four cascades were subjected to a more detailed analysis: Ngoi Xan, Nam Tha, Chien, and Sap.

Scope of study

The scope of the study was to identify (possible unforeseen) cumulative impacts of a series of SHPs and potential optimization of their joint operation in order to give operators, planners and policy makers recommendations on how to strategically plan, implement and operate such cascades to maximize production and minimize environment and social impacts.

Findings

The study found that development of SHP in Vietnam has come a long way. A well-established institutional framework in Vietnam has promulgated legal and policy procedures for hydropower development, and experience and skills are embedded in the organizations of the major ministries, institutes, and local consultants.

Based on the observations, analysis and conclusions from the study we formulated a number of recommendations that may improve the sustainability of small hydropower development in Vietnam.