Enhanced value of grid-connected PV with battery storage in a negative price environment

In recent years, global PV capacity – particularly in the EU – has reached record levels, supporting decarbonization goals but also intensifying market effects such as increasingly frequent negative electricity prices driven by oversupply and limited system flexibility. These conditions pose growing economic challenges for utility-scale PV assets. This study examines the impact of negative price hours on PV performance and assesses the role of battery energy storage systems (BESS) in mitigating these effects, using Germany as a case study. A temporal analysis identifies pronounced seasonal and diurnal patterns, with negative prices peaking in spring and around midday. Under high negative electricity price scenarios, PV systems experience curtailment-related energy losses of up to 10%, while BESS output increases through active participation in day-ahead and intraday markets. Contrary to common assumptions, increasing BESS capacity does not significantly reduce PV curtailment or enhance PV-specific value. Instead, while total system revenues (PV – BESS) rise monotonically with storage size, the gains are driven entirely by BESS revenues. Economically, standalone PV systems exhibit substantial value erosion, whereas hybrid PV-BESS configurations demonstrate greater resilience and higher net present value (NPV) across all scenarios. These findings underscore that the primary value of storage lies in market-based revenue generation rather than curtailment mitigation, highlighting the strategic importance of storage-ready PV designs, either integrated at deployment or retrofitted to preserve asset value in increasingly volatile electricity markets.