Unveiling the connotation and significance of wind-solar complementarity from a novel perspective

The integration of variable renewable energy sources like wind and solar power into power systems presents significant challenges due to their inherent volatility and uncertainty. Traditional evaluation methods for wind-solar complementarity primarily focus on correlation or performance improvement of hybrid generation, but overlook the coupling relationships between variable renewable energy and load. To fill this gap, this paper proposes an innovative framework that assesses wind-solar complementarity by emphasizing its impact on net load characteristics, offering a more practical perspective for grid operations. Key contributions include the introduction of novel complementarity indices to quantify improvements in net load stability, fluctuation amplitude, and scheduling risk; the development of high-accuracy white-box mapping models (with coefficient of determination about 0.99) linking renewable energy capacity to net load features; and systematic analysis revealing the advantages of wind-solar complementary on net load characteristics compared to single renewable energy. Validated using data from Belgium's power system, the proposed method demonstrates superior performance.