Climate change effects on solar energy potential: CMIP6-based projections and policy implications

This study evaluated how different SSP scenarios affect solar energy potential in Türkiye's GAP region by examining projected changes in surface downwelling shortwave radiation (RSDS), air temperature (Tas), and photovoltaic cell temperature (Tcell), along with their implications for photovoltaic (PV) and concentrated solar power (CSP) systems. Multiple CMIP6 climate models, including the multi-model ensemble (MME), were used, and bias-adjustment procedures were applied through the Delta Method, Quantile Mapping, and Empirical Quantile Mapping. Correlation and sensitivity analysis were also conducted to better understand the drivers of spatial variability. RSDS projections show pronounced spatial differences. Gaziantep and Kilis consistently exhibit the largest increases, reaching 3.47 % under SSP1-2.6 and 2.62 % under SSP2-4.5. Under SSP5-8.5, RSDS intensifies further, reaching 4.20 % in Kilis by 2100, with Gaziantep and Adıyaman also strongly affected. Tas projections similarly reveal substantial warming, supported by quantitative increases across the region. Under SSP1-2.6, Adıyaman shows the highest early-period warming at 5.17 %, while Diyarbakır exceeds 9 % in later periods. Under SSP5-8.5, Mardin records the strongest early-century warming at 2.57 %, whereas Siirt undergoes the largest mid-future (13.11 %) and late-century (24.69 %) temperature increases. These values confirm that the magnitude and timing of Tas increases vary considerably among provinces. CSP thermal power responds positively to increasing RSDS, with maximum values of 4.49 %, 3.60 %, and 5.95 % across the three scenarios. Tcell rises sharply, 7.91 %, 12.89 %, and 19.23 %, and sensitivity analysis shows that removing wind cooling elevates Tcell by 3.7–5.7 °C, highlighting the importance of wind as a thermal regulator. PV power potential with wind (PVP1) increases moderately, whereas wind-excluded PV potential (PVP2) amplifies thermal stress impacts, reaching up to 19.23 % in Gaziantep. Findings highlight the vulnerability of solar energy systems to climate change, underscoring the need for adaptive cooling strategies to maintain efficiency. This study provides critical insights for future energy planning, emphasizing the importance of climate mitigation policies for the sustainable development of solar energy.