Impact of Climate Change on Hydropower Generation: A Case Study of Devighat Hydropower Station

Abstract

The proper study of climatic parameters is the most important, yet somewhat neglected aspect during the design, construction, and operation of most of the hydropower plants in Nepal. This research aims to screen climate change's impact on hydrology and hydro energy production at Devighat Hydropower Station a cascade of the Trishuli Hydropower Plant in Nepal. The study implements a simulation model developed on the Arc SWAT application using the spatial-meteorological data inputs of the basin. SUFI-2 algorithm is used for calibration and validation purposes. The temperature and precipitation time series data from 1997 to 2019 are used to create the baseline scenario. In order to evaluate future hydropower production, the future climatic dataset (2023-2100) was created using a group of five CMIP6 models from the most recent generations under two Shared Socio-Economic Pathways (SSP245 and SSP585). Model calibration was performed from 2000-2010 for eleven years and validation from 2011-2019 for ten years. The Trishuli Basin has clearly seen the effects of climate change, with observable changes in climatic variables. Clear predictions point to a significant increase in the basin's temperature and precipitation. It is projected that the basin's average annual flow would significantly increase. The yearly flow is expected to go down by 1.4% in the near future under the SSP245 Scenario, but to go up by 4% and 7.4% in the mid-and far future, respectively. Similar to the SSP585 Scenario, the yearly flow is anticipated to climb by 14.5% and 26.5% in the mid- and long-term, respectively, before rising by 1.1% in the near future. In the near future, midfuture, and far future, respectively, yearly generation is predicted to rise by 4.3%, 3.6%, and 4.9% under the SSP245 Scenario. The yearly generation is expected to rise by 4.1%, 4.6%, and 4.7%, respectively, in the near future, mid-future, and far future, according to the SSP585 Scenario. The hydropower plant is intended to reach a capacity of 114 GWh at all times in the future.