This summer, the US Environmental Protection Agency released its proposed rule under the Clean Air Act to reduce CO2 emissions from existing electric generating resources. When the rules become final, the EPA will mandate that state agencies implement policies to meet CO2 reduction targets. As states begin to understand how the new requirements fit within existing renewable portfolio standard (RPS) programs (already implemented across 29 states, Puerto Rico and the District of Columbia) and existing carbon cap-and-trade programs implemented in the Northeast and California, states need to consider what tools they have available to track power sector emissions, reductions and compliance. This research paper published by APX, Inc. outlines the current tracking system features available today in all 50 states and how they can support specific state policies.


  • Section 111(d) implementation will require tracking of power attributes
  • The current registry infrastructure can support tracking attributes from all power sources.
  • Matching physical power paths and emission attributes may be required.
  • Renewable Portfolio Standards and the voluntary green energy market can exist side-by-side with Section 111(d) implementation.
  • Protocols and project workflows to support tracking of Energy Efficiency Credits is already implemented and utilized by some tracking systems.


To download the paper click APX Research: Section 111(d)..