Do Renewable Portfolio Standards Deliver Cost-Effective Carbon Abatement?

The most prevalent climate policies in the U.S. are Renewable Portfolio Standards (RPS), which mandate a specified share of electricity come from sources such as wind and solar. Using a com-prehensive data set and a difference-in-differences style research design, we find that electricity prices are 11% higher seven years after RPS passage and carbon emissions are 11-24% lower. Point estimates suggest that the cost per ton of CO2 abatement ranges from $80-$210 in preferred speci-fications. We also find suggestive evidence that the cost of each increment of mandated renewable generation has declined over time as the costs of renewable energy sources have fallen.