Hedging Shape Risk in Renewable Energy Markets: Empirical Evidence on Hedging Effectiveness Using the Quality Factor (QF) Index

As variable renewable energy (VRE) penetration increases, renewable generators face revenue risk from electricity prices, generation volumes, and their time-varying co-movement, commonly referred to as shape risk. This study evaluates whether the Quality Factor (QF) index, interpreted as a standardized capture-rate or value-factor index, can support hedging of this risk. We construct daily and weekly QF indices for solar photovoltaic generation in Kyushu, Japan, and wind generation in ERCOT, Texas, and use generalized additive model (GAM)-based hedge-effectiveness models to examine stylized settlement-index-based QF futures/forward contracts. The results show that QF-inclusive hedging can provide additional risk reduction, with effects depending strongly on technology and time granularity: Kyushu PV benefits at both daily and weekly horizons, whereas ERCOT wind benefits mainly at the weekly horizon. Bootstrap confidence intervals and yearly holdout sweeps support these main hedge-effectiveness findings. We also develop a quantile generalized additive model (QGAM) approach for probabilistic QF forecasting and indicative valuation of nonlinear QF-linked derivatives. Distributional forecasts show that QGAM specifications are competitive with empirical, ARIMAX, and GAM + GARCH benchmarks, although no single specification dominates across years and windows. These findings highlight the potential role of QF-linked settlement indices in renewable energy risk management.