Abstract:
The increased use of renewable energy is critical to reducing emissions of greenhouse
gases in order to limit climatic change. Hydropower is currently the major renewable
source contributing toelectricitysupply. However, the successful expansion of
hydropower is dependent on the availability ofthe resource. Global warming and changes
in precipitation patternswill alter the timing and magnitude ofriverflows. This will
affect the ability of hydropower stationsto harness the resource, and may reduce
production. This study mainly deals with the vulnerability of Tana-Beles hydropower
station due to climate change impact. In which its performance is evaluated based on the
reliability, resilience and vulnerability indices(RRV-criteria) on thelake reservoir
controlled by Chara-Chara weir. Projection ofthe future climate variables is done by
using General Circulation Model (GCM) withECHAM driving data source which is
considered as the most advanced tool for estimating the future climatic condition.
Regional Down Scaling Method (RegCM3) is applied in order to downscale the climate
variables at catchment level (Downscaled climate data source, IWMI). The projected
future climate variable shows an increasing trend for both maximum andminimum
temperature however, for the case precipitation itdoesn’t manifest a systematic increase
or decreasing trend in the next century. The evaporation fromthe open water surface of
reservoir reveals an average annual increase by 5.9 % and 14.6% in 2030sand 2090s
respectively under the ECHAM5 A1B emission scenario. The averaged mean annual
Lake precipitation is increased by 2.6% and 5.3% while the average annual maximum
temperature is rise by 1.2
0
C and 2.2
0
c, average annual minimum temperature is rise
by1.6
0
c and 4.48
0
c in 2030s and 2090s respectively. A hydrological model, HBV was
utilized to simulate thewater balance. The performance of the model was assessed
through calibration and validation process and averagely resulted NS value of 0.7 for
gauged catchments. The simulated average annual inflow to the lake shows that a
decrease in volume by 2.1% and 14.3% in the scenario years of 2030s and 2090s. Under
ECHAM5, A1B scenario out puts the average dimensionless vulnerability index
evaluated to be 16.9% in the future time periods which is indicates the Tana-Beles
hydropower station is less vulnerable to climate change impact.
