Decarbonisation scenarios of the U.S. electricity system and their costs

Abstract Decarbonising electricity is crucial for climate change mitigation, while understanding its economic implications has been a challenge. Previous analyses primarily rely on levelised cost or single-year optimization, which fail to account for the complex spatiotemporal dynamics of capacity expansion and dispatch decisions. Here, we present a regionally resolved national model that considers such dynamics and quantifies the cost of decarbonising the U.S. electricity system under a set of possible scenarios. The result shows that, compared to a business-as-usual scenario, reducing 80% CO2 emission by 2050 relative to 2005 level would incur, depending on the scenarios, $220~$490 billion additional costs (present value in 2020 US$, equivalent to ¢0.15~¢0.34 kWh-1) to the electric sector during 2020–2050, with regional costs ranging -¢0.08~¢0.51 kWh-1. When compared with the mitigated CO2, these additional costs equal to $10 and $37 per tCO2 reduced, which are well below the social cost of carbon in the literature.