Decarbonizing South Asia: A spatial-temporal mapping of solar, wind, and wave energy potential using ERA5

South Asia faces fast-growing energy demand driven by population growth, urbanization, and economic development, while simultaneously facing an urgent need to reduce carbon emissions to meet climate commitments. Renewable energy has gained global importance, yet detailed studies on South Asia remain limited. The region still lacks a systematic evaluation of its solar, wind, and wave energy resources. This paper provides a comprehensive region-wide assessment of these resources using 15.5 years of high-resolution ERA5 data from January 2010 to July 2025. Key variables, such as solar irradiance (SI), wind speed, wind power density, significant wave height, and wave energy flux, were analyzed and mapped on monthly and annual scales. The results reveal substantial untapped renewable energy potential across the region, including strong wind and wave resources along exposed coastal zones and high SI over large inland areas. The analysis provides policymakers, investors, and planners with a consistent evidence base for identifying promising sites for future projects. By evaluating all major renewable energy resources in a unified framework, this study supports strategic planning, investment decisions, and a transition to reduced fossil fuel dependence.