A new solar-wind complementarity index: An application to the climate of Morocco

Energy complementarity is a promising approach in the realm of renewable energy systems, enabling the integration of multiple energy sources to achieve a stable and sustainable power supply. This paper presents a comprehensive solar-wind complementarity study encompassing all regions of Morocco. A novel method for assessing complementarity is introduced, utilizing a fluctuation approach that classifies the power output of each source based on the median and the standard deviation. The classifications of both solar and wind sources are then combined to establish a basis for complementary classification, categorizing each day as complementary, non-complementary, low-complementary, or concurrent for both sources. An innovative complementarity index is proposed, ranging from 0 to 1, with values closer to 1 indicating high complementarity. This index is applicable to any location and is used to generate maps illustrating solar-wind complementarity. Additionally, dominance metric is derived from this approach that indicates which source is most likely to complement the other source. The results reveal that temporal complementarity is high in the internal Northern regions reaching indices above 0.7, followed by the Northern coastal regions with indices that range between 0.6 and 0.7. The lowest complementarity occurs in the South with indices below 0.6. Additionally, the complementarity plots that displays the monthly indices reveled, for most regions, that complementarity maintains certain level except in the summer where it peaks or drops. The solar dominance is higher in the South reaching above 60 %, even though the wind potential is important in those regions. For spatial complementarity, two locations were considered and the method is applied for four scenarios: solar-wind, wind-solar, solar-solar and wind-wind. Results favor all the combinations except for the solar-solar scenario. The suggested index yields similar results to Kendall's tau correlation. The negative correlation index indicates high complementarity when positive and a low complementarity when close to −1. For this approach, it is not limited to the degree complementarity but can describe other states of complementarity and its frequency of occurrence compared to other states. This provides additional insights compared to the commonly used correlation methods. The proposed method contributes to a more profound understanding of complementarity between two energy sources.