On December 18, 2017, EPA Administrator Scott Pruitt signed an advanced notice of proposed rulemaking (“ANPRM”) to solicit input regarding the emissions guidelines limiting greenhouse gas (“GHG”) emissions from existing electric utility generating units (“EGUs”) that the U.S. Environmental Protection Agency (“USEPA”) is considering proposing.

The Clean Power Plan regulations adopted by the Obama administration would have limited GHG emissions by substituting generation from lower-emitting existing natural gas combined cycle units and zero-emitting renewable energy generating capacity. However, EPA proposed on October 16, 2017 to repeal those rules on the grounds that they exceed EPA’s authority under Section 111(d) of the Clean Air Act by proposing emissions reductions beyond those that can be applied at and to an individual source, such as measures based on a physical or operational change to a building, structure, facility, or installation at that source.

The ANPRM solicits information on the following issues:

• The respective roles of state and federal government in establishing GHG emission guidelines, including the suitability of EPA regulations establishing procedures and requirements for state plans and the role of EPA in developing guidelines by providing sample state plan text and determining the Best System of Emission Reduction (“BSER”);
• Systems of GHG emission reduction that can be applied at an to an individual source;
• How to define BSER and develop GHG emission guidelines, including efficiency improvement technologies and other systems of emission reduction; whether emission guidelines should include presumptively approvable limits; use of carbon capture and storage as a compliance option; criteria for determining affected sources; and potential subcategories.
• How a GHG emission limit will interact with existing statutory and regulatory programs such as the New Source Review program and the New Source Performance Standards; and
• Any other comments that may assist USEPA in setting emission guidelines to limit GHG emissions from existing EGUs.

The issues addressed by the ANPRM show that EPA’s focus is on maximizing flexibility for existing units. Specifically, it notes that presumptively approvable limitations (even at a subcategorized level) may not be appropriate for GHG emissions from EGUs; suggests allowing States to set unit-by-unit emission standards “considering the unique circumstances of the State and the EGU”; and mentions additional flexibilities for compliance that States could employ including emissions averaging within a single facility, among units within a State, or even beyond the State. While this recognition that a one-size fits all approach may be difficult to implement across the industry will certainly benefit existing units, it also seems likely to create uncertainty and increase the burden on States to implement the emission guidelines.

Comments in response to the ANPRM must be submitted within 60 days of the date the notice is published in the Federal Register.