Colorado Rev. Stat. § 40-2-123(1)(b) allows the Colorado Public Utility Commission to consider the social costs of greenhouse gas emissions. The statute says that “[t]he commission may give consideration to the likelihood of new environmental regulation and the risk of higher future costs associated with the emission of greenhouse gases such as carbon dioxide when it considers utility proposals to acquire resources.” In 2017, the Colorado Public Utility Commission (PUC) ordered Xcel to use the social cost of carbon Energy Resource Plan (ERP) that would guide utility investments through 2024.