What has the strongest connectedness with clean energy? Technology, substitutes, or raw materials

This paper examines the connectedness of clean energy with technology, substitutes (crude oil and natural gas), and raw materials (silver, platinum, copper, corn, and soybean). This is conducted from a systemic perspective, using the quantile time–frequency connectedness approach. The results reveal that clean energy and technology stocks demonstrate the strongest pairwise connectedness across all quantile levels in the short, medium, and long terms. Meanwhile, fossil energy commodities (as substitutes) and metal and agricultural commodities (as raw materials) exhibit relatively intensive connectedness, with clean energy stocks only at the lower and upper quantiles in the short term. Furthermore, connectedness among the markets under examination is significantly enhanced during periods of financial turmoil, as was the case during the European debt crisis and the COVID-19 pandemic. Finally, the minimum connectedness portfolio analysis indicates that natural gas futures offer the highest hedge effectiveness, and technology stocks offer the lowest hedge effectiveness across frequencies and quantiles. This finding suggests that optimal portfolios will have a larger proportion of natural gas futures. These findings have significant implications for both investors and policymakers.