Implication of Climate Change on Hydropower Water Footprint in Kenyir Lake: Climate Change on Hydropower Water Footprint

Abstract

The Hydropower Water Footprint (HWFP) is a key metric for assessing historical water use and predicting future trends. This assessment becomes increasingly important as greenhouse gas (GHG) concentrations rise, leading to more heat retention, which ultimately impacts the availability of water in reservoirs for hydropower generation. This study contributes to the long-term development of the HWFP, specifically considering the impact of long-term evaporation in Kenyir Lake, Terengganu. To project the HWFP, it is essential to consider climate variables (such as rainfall, temperature, evaporation, and relative humidity) and electricity supply (ES), as the HWFP equation is linked to evaporation rates from reservoirs and the electricity produced by hydropower plants. For this purpose, the Statistical Downscaling Model (SDSM) version 4.1 was used to analyze climate variation and forecast future evaporation rates from 2025 to 2100. The Representative Concentration Pathways (RCP2.6, RCP4.5, and RCP8.5) from the IPCC Fifth Assessment Report (AR5) provided future climate scenarios for three different radiation levels. Additionally, an ES equation was developed using multiple linear regression. The HWFP was then calculated based on the projected ES data, along with rainfall and evaporation rates. Both the Gross Hydropower Water Footprint (GHWF) and Net Hydropower Water Footprint (NHWF) methods were employed to determine the long-term HWFP pattern. The results indicate significant increases in projected electricity supply during February, July, and October from 2025 to 2100. At the same time, the future HWFP is expected to show negative values, implying a situation where more water is entering the reservoir than being lost to evaporation. The GHWF between 1997 and 2020 ranged from 2.5 m³/GJ to 5 m³/GJ, and in the future, it is projected to rise, especially in months like February, September, October, and November. These findings are crucial for improving hydropower plant performance and development.