Climate-resilient solar resource potential in Central Asia under future climate scenarios using a tiered site ranking framework

Climate-induced variability poses a major challenge to the long-term planning of solar energy systems, particularly in climatically sensitive and underexamined regions such as Central Asia (CA). This study introduces a scenario-informed solar-resource suitability framework integrating multi-ensemble CMIP6 projections of Surface Downwelling Shortwave Radiation under SSP2–4.5 and SSP5–8.5 scenarios. By combining exceedance probabilities, seasonal variability (coefficient of variation, CV), and emissions scenario sensitivity, we develop a five-Tier ranking system to assess climate-driven solar-resource suitability across Kazakhstan, Kyrgyzstan, Uzbekistan, Turkmenistan, and Tajikistan over historical (1992–2021), near-future (2022–2051), and far-future (2071–2100) periods. Our results reveal strong seasonal and spatial contrasts. In summer, “Excellent” exceedance rates under SSP5–8.5 increase from 40.4% to 91.3% in Kazakhstan, from 76.9% to 94.1% in Kyrgyzstan, and from 98.5% to 99.8% in Turkmenistan by the far-future. In winter, however, solar suitability deteriorates, with average rank losses under SSP5–8.5 exceeding +90 in Turkmenistan, +87 in Uzbekistan, and +69 in Kazakhstan by the near-future. Only a limited share of sites, around 15%−30%, fall into the most favorable categories for climate-resource screening (Tiers 1 and 2). In contrast, more than 60% of sites are classified as Tier 3, representing scenario-sensitive areas, particularly in winter and autumn. Under SSP5–8.5, CV decreases by around 30%−60% in several regions. For example, winter CV in Kazakhstan decreases from 0.133 to 0.091, equivalent to a reduction of around 32%, while fall CV in Kyrgyzstan decreases from 0.059 to 0.024, representing a reduction of nearly 59%. These changes indicate lower normalized inter-annual variability of modeled seasonal irradiance in some periods, although they should not be interpreted as direct evidence of reduced intra-day intermittency or lower operational storage requirements. Taken together, these findings highlight the importance of climate-informed solar-resource planning in CA. The proposed framework should be interpreted as a solar-resource suitability and resilience-screening tool that can support broader renewable-energy planning, but not as a full assessment of energy security, grid reliability, affordability, or system-level performance.