In a recent article published in the journal Nature Energy, researchers aimed to fill a research gap by integrating empirically derived SRE intensities into a European energy system optimization model, exploring the broader implications of this behavioral effect on renewable energy integration, system flexibility, and overall system costs.
Image Credit: ultramansk/Shutterstock.com
Rooftop Solar Growth and the Emergence of the Rebound Effect
The deployment of rooftop photovoltaic (PV) systems is accelerating across Europe, driven by the need to reduce carbon emissions and transition to renewable energy sources.
As households adopt solar panels, a behavioral phenomenon called the solar rebound effect (SRE) has been observed, where electricity consumption increases following PV installation due to the perception of solar-generated electricity as cost-free. While the positive contributions of solar generation to the energy mix are well understood, the SRE introduces a complication by potentially offsetting some of the expected energy savings.
Previous studies have documented the SRE at the household level but have yet to incorporate it explicitly into system-wide energy planning or abatement scenarios.
The World Energy Outlook and other major energy models often consider rebound effects in sectors like transport, but many energy system models do not explicitly account for the increased electricity demand stemming from rooftop solar adoption. Empirical research estimates the magnitude of the SRE to range from approximately 7.7 % to 33 % additional electricity consumption after PV installation, with an average of around 17 %. Given Europe's ambitious renewable energy goals and the rapid expansion of distributed solar capacity, ignoring the SRE risks underestimating future electricity demand and associated infrastructure needs.
Integrating Behavioral Effects into Energy System Modeling
To analyze the systemic impacts of the SRE, the authors extend the open-source Stochastic European Energy Market Model (E2M2s), optimizing generation, storage, and transmission capacity for a sector-coupled European energy system up to 2050.
The study incorporates three distinct temporal profiles for the rebound effect: simultaneous (additional demand aligned with solar generation), sweeping (demand evenly distributed over time), and dynamic (a hybrid reflecting daytime and off-peak consumption). These profiles are informed by empirical consumption patterns, including studies that show consumption increases both during and outside periods of peak solar output.
The modelling framework explicitly separates the investment decision phase, in which households install PV systems based on current consumption, from the usage phase, where the rebound effect arises behaviorally and is not anticipated during investment. This recursive approach reflects the time lag between installation and rebound manifestation and allows for a more realistic portrayal of demand shifts caused by behavioral responses, although the rebound itself is imposed exogenously and subject to simplifying assumptions about household behavior.
The model optimizes across 34 interconnected European regions, considering renewable generation, storage technologies, and grid constraints. Cost impacts are assessed, including investments, operations, capacity expansion, and flexibility requirements, ensuring a comprehensive evaluation of how the rebound modifies system needs and expenses.
Want to save for later? Click here.
Impact of Rebound Timing on System Efficiency and Grid Dynamics
The results demonstrate that the magnitude and timing of the solar rebound significantly influence operational dynamics and investment requirements. Additional demand tied closely to solar generation (simultaneous profile) may reduce renewable curtailment and grid constraints by better matching supply and demand, yielding some system efficiency benefits.
Conversely, when increased consumption is spread evenly or occurs during low solar availability (sweeping profile), the system faces greater reliance on gas-fired plants and expensive backup capacity, especially in Central Europe, where flexibility and grid constraints are more acute.
This misalignment raises wholesale electricity prices in some regions and scenarios by up to €1.6/MWh, impacting all consumers regardless of PV adoption. The study suggests that households generating the rebound may not bear the full system costs, creating potentially regressive cost distribution effects. Higher-income households are more likely to own rooftop PV and thus exhibit rebound behavior, while the increased system costs are distributed across all consumers, which may disproportionately impact lower-income groups, although these distributional effects are not explicitly quantified in the study. This cross-subsidization could contribute to increased energy inequality within the EU.
The overall system costs increase with stronger rebound effects, reaching up to 4.2 % higher total costs by 2050 in high rebound scenarios. The findings underscore the importance of explicitly including the SRE in long-term planning models, as omitting it could underestimate infrastructure investments and distort cost-benefit analyses for grid expansions and renewable integration.
Despite the challenges, increased rooftop solar with rebound effects may be associated with household welfare through expanded energy use and access to low-cost self-generated electricity, though this outcome is not directly quantified and reflects inferred consumption benefits, with system-wide trade-offs. The interplay between behavioral demand response and system operations shows that this phenomenon cannot be analyzed in isolation but needs integrated consideration within energy transition strategies.
Implications for Policy, Planning, and Future Energy Transitions
This study provides an important advancement in representing behavioral effects within energy system modeling by incorporating the solar rebound effect into a comprehensive sector-coupled European electricity model. The findings reveal that behavioral-induced demand expansions challenge efforts to reduce emissions and require greater renewable capacity, storage, and flexibility to maintain system reliability and affordability.
As Europe expands rooftop solar and progresses toward climate neutrality, the solar rebound effect represents a significant systemic challenge that the findings suggest may require combined technical, behavioral, and policy interventions to maximize the benefits of renewable deployment while managing unintended demand increases.
Journal Reference
Delic, M., Bucksteeg, M. (2026). Implications of the solar rebound effect for the European energy transition. Nature Energy. DOI: 10.1038/s41560-026-02031-8, https://www.nature.com/articles/s41560-026-02031-8