Solar energy is planned to undergo large-scale deployment along with Thailand’s transformation to a carbon neutral society in 2050. In the course of energy transformation planning, the issue of energy infrastructure adaptation to climate change has often been left out. This study aims to identify climate-related risks and countermeasures taken in solar power plants in Thailand using thematic analysis with self-administered observations and structured interviews in order to propose points of consideration during long-term energy planning to ensure climate adaptation capacity. The analysis pointed out that floods and storms were perceived as major climate events affecting solar power plants in Thailand, followed by lightning and fires. Several countermeasures were taken, including hard countermeasures that require extensive investment. Following policy recommendations were derived from the climate-proofing investment scenario study. Policy support in terms of enabling regulations or financial incentives is needed for implementation of climate-proofing countermeasures. Public and private sectors need to secure sufficient budget for fast recovery after severe climate incidents. Measures must be taken to facilitate selection of climate-resilient sites by improving conditions of power purchase agreement or assisting winning bidders in enhancing climate adaptability of their sites. These issues should be considered during Thailand’s long-term energy planning.

One key aspect of the Global Goal on Adaptation is to examine transformational adaptation at different scales and sectors. While there are several adaptation assessment frameworks in the energy sector, there is still room for further development to properly capture and quantify the adaptability of energy infrastructure against climate change. Therefore, this study aims to define a definition for the adaptability of resilient energy infrastructure and develop the adaptive resilience curve to quantify it. The study hypothesized and confirmed definition boundaries for the resilience, adaptation, and adaptability of resilient energy infrastructure and an adaptive resilience curve. Definitions of resilience and adaptation are often interchangeably used, yet differences were found. Common keywords extracted from definitions of resilience and adaptation were utilized to define the adaptability of resilient energy infrastructure. The adaptive resilience curve was formulated, borrowing attributes from concepts contributing to adaptability, including global catastrophic risk, beyond design basis accident, and foresight. The definition for the adaptability of resilient energy infrastructure sets a common ground for the understanding of the concept, on which the adaptive resilience curve is developed to facilitate its visualization and quantification. The adaptive resilience curve can capture temporal change in the adaptability of resilient energy infrastructure under multiple scenarios using multiple figures-of-merit.