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Emissions reductions of rooftop solar are overstated by approaches that inadequately capture substitution effects

Nature Climate Change volume 15, pages 1173–1175 (2025)Cite this article

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The Original Article was published on 07 March 2025

arising from Z. Zhang et al. Nature Climate Change https://doi.org/10.1038/s41558-025-02276-3 (2025)

Many decarbonization options have power-sector implications, including rooftop solar, electric vehicles and heat pumps. However, common approaches to estimate emissions impacts of these interventions can omit key channels that materially alter stated environmental benefits, including structural impacts, scale and policy context. Here we show that widely used guidance may systematically overstate emissions reductions from rooftop solar by downplaying substitution from non-rooftop solar generation. We show that including these effects can lower the mitigation benefits of rooftop solar by 41–98% relative to analysis by Zhang et al.1 for a US case study.

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Fig. 1: Comparison of installed RPV capacity from Z25 with 2024 US data for hourly load and RPV capacity.
Fig. 2: US CO2 intensity from Z25 compared with REGEN model outputs.

Data availability

The data supporting this study are available from the corresponding author upon reasonable request.

Code availability

This analysis was conducted using the open-source version of the REGEN energy systems model, which is available at https://github.com/epri-dev/US-REGEN. Code is available via Zenodo at https://doi.org/10.5281/zenodo.17027722 (ref. 18).

References

  1. Zhang, Z. et al. Worldwide rooftop photovoltaic electricity generation may mitigate global warming. Nat. Clim. Change 15, 393–402 (2025).

    Article  Google Scholar 

  2. Creutzig, F. et al. The underestimated potential of solar energy to mitigate climate change. Nat. Energy 2, 17140 (2017).

    Article  Google Scholar 

  3. Borenstein, S. Private net benefits of residential solar PV: the role of electricity tariffs, tax incentives, and rebates. J. Assoc. Environ. Resour. Econ. 4, S85–S122 (2017).

    Google Scholar 

  4. Vaishnav, P., Horner, N. & Azevedo, I. Was it worthwhile? Where have the benefits of rooftop solar photovoltaic generation exceeded the cost? Environ. Res. Lett. 12, 094015 (2017).

    Article  Google Scholar 

  5. Cole, W., Lewis, H., Sigrin, B. & Margolis, R. Interactions of rooftop PV deployment with the capacity expansion of the bulk power system. Appl. Energy 168, 473–481 (2016).

    Article  Google Scholar 

  6. Gagnon, P. & O’Shaughnessy, E. Consequential Analysis of the Greenhouse Gas Emissions Impacts of Actions That Influence the Electric Grid: The Theory and Practice of Using Marginal Emissions Rates (NREL, 2024).

  7. Holland, S., Kotchen, M., Mansur, E. & Yates, A. Why marginal CO2 emissions are not decreasing for US electricity: estimates and implications for climate policy. Proc. Natl Acad. Sci. USA 119, e2116632119 (2022).

    Article  CAS  Google Scholar 

  8. The Greenhouse Gas Protocol: Guidelines for Quantifying GHG Reductions from Grid-Connected Electricity Projects (World Resources Institute, 2007); https://ghgprotocol.org/sites/default/files/standards_supporting/Guidelines%20for%20Grid-Connected%20Electricity%20Projects.pdf

  9. Hirth, L. The market value of variable renewables: the effect of solar and wind power variability on their relative price. Energy Econ. 38, 218–236 (2013).

    Article  Google Scholar 

  10. Bhandarkar, R., Luo, Q., Dimanchev, E. & Jenkins, J. Are EVs cleaner than we think? Evaluating consequential greenhouse gas emissions from EV charging. Environ. Res. Lett. 20, 104041 (2025).

    Article  CAS  Google Scholar 

  11. Bistline, J. & Young, D. Emissions impacts of future battery storage deployment on regional power systems. Appl. Energy 264, 114678 (2020).

    Article  Google Scholar 

  12. Gagnon, P. & Cole, W. Planning for the evolution of the electric grid with a long-run marginal emission rate. iScience 25, 103915 (2022).

    Article  Google Scholar 

  13. Gagnon, P., Bistline, J., Alexander, M. & Cole, W. Short-run marginal emissions rates omit important impacts of electric-sector interventions. Proc. Natl Acad. Sci. USA 119, E2211624119 (2022).

    Article  CAS  Google Scholar 

  14. Bistline, J. The importance of temporal resolution in modeling deep decarbonization of the electric power sector. Environ. Res. Lett. 16, 084005 (2021).

    Article  Google Scholar 

  15. Browning, M. et al. Net-zero CO2 by 2050 scenarios for the United States in the Energy Modeling Forum 37 study. Energy Clim. Change 4, 100104 (2023).

    Article  CAS  Google Scholar 

  16. Hourly Electric Grid Monitor (U.S. Energy Information Administration, accessed 11 April 2025); https://www.eia.gov/electricity/gridmonitor/

  17. Electric Power Monthly: Table 6.1.B. Estimated Net Summer Solar Photovoltaic Capacity from Small-Scale Facilities by Sector (U.S. Energy Information Administration, accessed 11 April 2025); https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_6_01_b

  18. Bistline, J. & Watten, A. Code for Bistline and Watten “Emissions reductions of rooftop solar are overstated by approaches that inadequately capture substitution effects”. Zenodo https://doi.org/10.5281/zenodo.17027722 (2025).

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Acknowledgements

The views expressed in this article do not necessarily reflect those of EPRI or its members.

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Authors and Affiliations

  1. EPRI, Palo Alto, CA, USA

    John E. T. Bistline & Asa Watten

Authors
  1. John E. T. Bistline
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  2. Asa Watten
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Contributions

J.E.T.B. and A.W. wrote and edited the article. J.E.T.B. conducted the analysis and created the visualizations.

Corresponding author

Correspondence to John E. T. Bistline.

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Competing interests

The authors declare no competing interests.

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Peer review information

Nature Climate Change thanks Pei Huang and Siddharth Joshi for their contribution to the peer review of this work.

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Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Regional generation changes by technology in 2050 for scenarios with and without RPV.

Model outputs are based on REGEN scenarios with current policies, as described in Supplementary Note 118. Basemap created with TIGER/Line Shapefiles from the US Census Bureau.

Extended Data Fig. 2 Heatmap of hourly long-run CO2 emissions intensities and RPV capacity factors.

Long-run marginal emissions rates come from the National Renewable Energy Laboratory (NREL) Cambium dataset. RPV capacity diurnal capacity factors come from the REGEN model and are shown across 16 model regions (Supplementary Fig. 1).

Extended Data Fig. 3 Diurnal capacity factors of rooftop and utility-scale solar by US region.

Average annual capacity factors across diurnal hours come from EPRI’s REGEN model. Regional definitions are shown in Supplementary Note 1.

Supplementary information

Supplementary Information

Supplementary Figs. 1–3 and discussion.

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Bistline, J.E.T., Watten, A. Emissions reductions of rooftop solar are overstated by approaches that inadequately capture substitution effects. Nat. Clim. Chang. 15, 1173–1175 (2025). https://doi.org/10.1038/s41558-025-02459-y

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