Impacts of changes in flow in glacier fed river in Nepal on hydropower production.

Abstract:

Variability of water flow in rivers due to change in temperature, precipitation and melting of glacier translates to change in water availability for agriculture, biodiversity conservation, and hydropower production impacting 1.5 billion people living downstream in India and Nepal. Previous studies ranked hydropower sector as the highest priority sector considering the urgency and severity of impacts in countries such as Nepal where hydropower shares 96 percentage of electricity production. In India, 45 per cent of hydroelectricity is generated from glacier fed rivers and hydropower shares 17 per cent of power generation. This study developed a framework to estimate the change in river flow attributed to global climate change and quantify its impact on hydropower generation in South Asian Mountains. The framework is applied on one of the major rivers Koshi River in Nepal with existing and proposed hydropower plants. The integrated assessment approach involved estimation of the change in flow in the river in the first part. Model was developed to estimate the change in flow that uses time series data on precipitation, temperature, remote sensing imagery on snow accumulation and ablation, and slope and surface hydrology. In the second part, another model was developed to investigate the impact of change in flow on hydropower production in various types of hydropower production plants. Data on flow, characteristics of hydropower plants and hydropower produced monthly from power plants in and outside of the river basin were used to model the flow and power generation from various categories of power plants. We will further discuss the results of the integrated assessments of potential changes in hydropower generation in various categories of hydropower plants based on Koshi River under various expected changes in flow and the implications for hydropower generation from other river systems in Nepal and India.