Future cost-competitive electricity systems and their impact on US CO2 emissions

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Carbon dioxide emissions from electricity generation are a major cause of anthropogenic climate change. The deployment of wind and solar power reduces these emissions, but is subject to the variability of the weather. In the present study, we calculate the cost-optimized configuration of variable electrical power generators using weather data with high spatial (13-km) and temporal (60-min) resolution over the contiguous US. Our results show that when using future anticipated costs for wind and solar, carbon dioxide emissions from the US electricity sector can be reduced by up to 80% relative to 1990 levels, without an increase in the levelized cost of electricity. The reductions are possible with current technologies and without electrical storage. Wind and solar power increase their share of electricity production as the system grows to encompass large-scale weather patterns. This reduction in carbon emissions is achieved by moving away from a regionally divided electricity sector to a national system enabled by high-voltage direct-current transmission.

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The authors would like to thank M. Marquis and A. Reiser for their comments on the paper. The Office of Oceanic and Atmospheric Research at the National Oceanic and Atmospheric Administration provided funding for the project.

Author information

Author notes

    • Alexander E. MacDonald
    •  & Christopher T. M. Clack

    Joint first authors.


  1. Earth System Research Laboratory, NOAA, 325 Broadway, Boulder, Colorado 80305, USA

    • Alexander E. MacDonald
    • , Christopher T. M. Clack
    • , Anneliese Alexander
    • , Adam Dunbar
    • , James Wilczak
    •  & Yuanfu Xie
  2. Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80305, USA

    • Christopher T. M. Clack
    •  & Anneliese Alexander


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A.E.M. developed the original concept. C.T.M.C. wrote the majority of the paper along with help from all the other authors. C.T.M.C. produced all the figures and associated data. C.T.M.C. devised, ran and computed the results for all of the experiments, created and developed the mathematical optimization along with the associated software, and wrote the Supplementary Information. C.T.M.C. also finalized the spatial, load and transmission data sets for the optimization routine. A.A. created the initial spatial availability and electrical load data sets, and compiled the original weather data sets. A.D. computed the costs for each technology. J.W. verified the weather data and assisted extensively with editing the paper. Y.X. helped with the initial optimization approach and verified the mathematical approach. All authors contributed to data review and consistency checks.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Alexander E. MacDonald or Christopher T. M. Clack.

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