Risk Assessment of Bhutan’s Power Grid: First Step Towards Sustainable and Resilient Power Generation

Located in fragile mountainous ecosystem, Bhutan is highly vulnerable to climate change and natural disasters. In addition, its economy is largely dependent on hydropower which is climate sensitive. This study aims to develop a framework for risk assessment of Bhutan’s power system and derive recommendations for resilience enhancement. The assessment started from a national level questionnaire survey which followed the method recommended by National Renewable Energy Laboratory. The results of Chukha district were extracted to compare with the results at national level to confirm similarities and differences in hazards and vulnerabilities. Walk-in inspection and drone survey were conducted to confirm the validity of hazard and vulnerability information. A multi-hazard map was also developed to enable prioritization of the implementation of proposed resilience measures. Natural hazards were considered more threatening for power facilities in Bhutan compared to technological and man-made hazards. Hazards with high likelihood included lightning, incessant rainfall, landslide, windstorm, and flash flood. Aging infrastructure was the common and most impactful vulnerability for all power facilities. Other vulnerabilities include undersized capacity and lack of redundancy. Threats and vulnerabilities identified in Chukha district were similar to other districts, except for the inconsistent water inflow for the hydropower plants and the higher susceptibility to lightning strikes due to its geological conditions. Apart from the resilience measures to alleviate the abovementioned risks, the power utility was recommended to keep records of climate events and their impacts on power infrastructure and to consider using multi-hazard map to prioritize the implementation of resilience measures.