Effectiveness of state climate and energy policies in reducing power-sector CO2 emissions


States have historically been the primary drivers of climate change policy in the US, particularly with regard to emissions from power plants. States have implemented policies designed either to directly curb greenhouse gas (GHG) emissions from power plants, or to encourage energy efficiency and renewable energy growth. With the federal government withdrawing from the global climate agreement, understanding which state-level policies have successfully mitigated power-plant emissions is urgent. Past research has assessed policy effectiveness using data for periods before the adoption of many policies. We assess 17 policies using the latest data on state-level power-sector CO2 emissions. We find that policies with mandatory compliance are reducing power-plant emissions, while voluntary policies are not. Electric decoupling, mandatory GHG registry/reporting and public benefit funds are associated with the largest reduction in emissions. Mandatory GHG registry/reporting and public benefit funds are also associated with a large reduction in emissions intensity.

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Fig. 1: Carbon dioxide emissions (in million metric tonnes (MMT) per year) from the power sector in each state in 2014, ranked from lowest to highest.
Fig. 2: Coefficient estimate in million tonnes of CO2 emissions (MMTCO2) per year for each of the state-level policies tested individually.


  1. 1.

    Friedrich, J. and T. Damassa. The History of Carbon Dioxide Emissions (World Resources Institute, last modified 21 May 2014, accessed 5 April 2017); http://www.wri.org/blog/2014/05/history-carbon-dioxide-emissions

  2. 2.

    Sources of Greenhouse Gas Emissions (U.S. Environmental Protection Agency, 2015, accessed 8 September 2017); https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions

  3. 3.

    Rabe, B. G. Statehouse and Greenhouse: The Emerging Politics of American Climate Change Policy (Brookings Institution Press, Washington, DC, 2004).

  4. 4.

    Goulder, L. & Stavins, R. Challenges from state-federal interactions in US climate change policy. Am. Econ. Rev. 101, 253–257 (2011); http://www.jstor.org/stable/29783749 retrieved from.

  5. 5.

    Grant, D., Bergstrand, K. & Running, K. Effectiveness of US state policies in reducing CO2 emissions from power plants. Nat. Clim. Change 4, 977–982 (2014).

    CAS  Article  Google Scholar 

  6. 6.

    Climate Change 101: State Action. Climate Change101: Understanding and Responding to Global Climate Change (Center for Climate and Energy Solutions, 2011).

  7. 7.

    Wheeler, S. State and municipal climate action plans: The first generation. J. Am. Plann. Assoc. 74, 481–496 (2008).

    Article  Google Scholar 

  8. 8.

    Yin, H. & Powers, N. Do state renewable portfolio standards promote in-state renewable generation? Energy Policy 38, 1140–1149 (2010).

    Article  Google Scholar 

  9. 9.

    Carley, S. State renewable energy electricity policies: An empirical evaluation of effectiveness. Energy Policy 37, 3071–3081 (2009).

    Article  Google Scholar 

  10. 10.

    Michaels, R. J. National renewable portfolio standard: Smart policy or misguided gesture? Energy Law J. 29, 79–119 (2008).

    Google Scholar 

  11. 11.

    Delmas, M. A. & Montes-Sancho, M. J. U.S. state policies for renewable energy: context and effectiveness. Energy Policy 39, 2273–2288 (2011).

    Article  Google Scholar 

  12. 12.

    Menz, F. C. & Vachon, S. The effectiveness of different policy regimes for promoting wind power: experiences from the states. Energy Policy 34, 1786–1796 (2006).

    Article  Google Scholar 

  13. 13.

    Shrimali, G. & Kniefel, J. Are government policies effective in promoting deployment of renewable electricity resources? Energy Policy 39, 4726–4741 (2011).

    Article  Google Scholar 

  14. 14.

    Drummond, W. J. Statehouse versus greenhouse. J. Am. Plann. Assoc. 76, 413–433 (2010).

    Article  Google Scholar 

  15. 15.

    Climate Policy Maps (C2ES, 2016, last modified September 2016; accessed 5 April 2017; https://www.c2es.org/us-states-regions/policy-maps/emissions-targets

  16. 16.

    Prasad, M. & Munch, S. State-level renewable electricity policies and reductions in carbon emissions. Energy Policy 45, 237–242 (2012).

    Article  Google Scholar 

  17. 17.

    Lyon, J. W. M. Environmental public voluntary programs reconsidered. Policy Stud. J. 35, 723–750 (2007).

  18. 18.

    Matisoff, D. Sources of specification errors in the assessment of voluntary environmental programs: understanding program impacts. Policy Sci. 48, 109–126 (2014).

    Article  Google Scholar 

  19. 19.

    Pigou, A. C. The Economics of Welfare. (Macmillan and Co., London, 1920).

    Google Scholar 

  20. 20.

    Montgomery, W. D. Markets in licenses and efficient pollution control programs. J. Econ. Theory 5, 395–418 (1972).

    Article  Google Scholar 

  21. 21.

    Stavins, R. N. What can we learn from the grand policy experiment? Lessons from SO2 allowance trading. J. Econ. Perspect. 12, 69–88 (1998).

    Article  Google Scholar 

  22. 22.

    Goulder, L. H. & Parry, I. W. H. Instrument choice in environmental policy. Rev. Environ. Econ. Policy 2, 152–174 (2008).

    Article  Google Scholar 

  23. 23.

    Multi-State Climate Initiatives (C2ES, 2017, accessed 5 April 2017; https://www.c2es.org/us-states-regions/regional-climate-initiatives

  24. 24.

    State CO 2 Emissions from Fossil Fuel Combustion, 1990-2014 (U.S. EPA, 2016, accessed 5 April 2017; https://www.epa.gov/sites/production/files/2017-07/documents/co2ffc_2014.pdf

  25. 25.

    Morey, M. J. & Kirsch, L. D. Retail Choice in Electricity: What have we Learned in 20 Years? (EMRF, 2016); https://sites.hks.harvard.edu/hepg/Papers/2016/Retail%20Choice%20in%20Electricity%20for%20EMRF%20Final.pdf

  26. 26.

    State Carbon Dioxide Emissions (U.S. Energy Information Administration, 2016, accessed 5 April 2017; https://www.eia.gov/environment/emissions/state/

    CAS  Article  Google Scholar 

  27. 27.

    Kaya, Y. Impact of Carbon Dioxide Emission Control on GNP Growth: Interpretation of Proposed Scenarios (IPCC, 1990).

  28. 28.

    Nakicenovic, N. & Swart, R. (eds.) in Special Report on Emissions Scenarios Ch. 3 (IPCC, 2000).

  29. 29.

    Public Benefit Funds (C2ES, 2014, last modified 2014, accessed 5 April 2017; https://www.c2es.org/us-states-regions/policy-maps/public-benefit-funds

  30. 30

    Kim, S. E., Yang, J. & Urpelainen, J. Does power sector deregulation promote or discourage renewable energy policy? Evidence from the states, 1991–2012. Rev. Policy Res. 33, 22–50 (2016).

    CAS  Article  Google Scholar 

  31. 31

    Net Generation by State by Type of Energy Producer by Energy Source. (U.S. EIA, 2016, accessed 8 August 2017; https://www.eia.gov/electricity/data/state/

  32. 32

    Kaya, K. Y. Environment, Energy, and Economy: Strategies for Sustainability (United Nations University Press, New York, 1997).

  33. 33

    Rosa, E. A. & Dietz, T. Human drivers of national greenhouse-gas emissions. Nat. Clim. Change 2, 581–586 (2012).

  34. 34

    Lyon, T. P. & Yin, H. Why do states adopt renewable portfolio standards? An empirical investigation. Energy J. 3, 133–157 (2010).

    Google Scholar 

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Correspondence to Eri Saikawa.

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Martin, G., Saikawa, E. Effectiveness of state climate and energy policies in reducing power-sector CO2 emissions. Nature Clim Change 7, 912–919 (2017). https://doi.org/10.1038/s41558-017-0001-0

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