Probing the asymmetric impact of clean energy technologies on environmental quality: testing load capacity curve hypothesis in Spain

Climate disturbances and environmental degradation are major issues of concern in the current era, and imposes socioeconomic strain on nations worldwide as mankind continues to develop at an unprecedented rate. Within this context, this study seeks to investigate the relationship pattern between load capacity factor, clean energy technology, and economic growth of Spain for the 1974–2018 period, considering the country's specific environmental degradation challenges. The study performed non-linear tests to assess the association between these variables, including skewness, kurtosis measures, and BDS tests. Additionally, non-linear autoregressive distributed lagged (NARDL) method and asymmetry tests were conducted to analyze the relationship further. The results demonstrate that introducing Spain's clean energy technologies improves environmental quality through positive shocks. However, this positive impact is diminished when negative shocks occur in relation to clean energy technologies. Furthermore, the study confirms the LCC hypothesis, which suggests that income initially has a negative impact on environmental quality but eventually leads to its once a specific threshold is crossed. This turning point occurs at an income level of 20,832US$. At this point, Spain has attained income levels that enhance the load capacity factor, contributing to improved environmental conditions. Based on these results, it is recommended to prioritize research and development for clean energy technologies in Spain, as they are crucial in promoting sustainable development and addressing the country's specific environmental degradation challenges.