PJM, ERCOT, MISO and SPP File Joint Comments on Proposed EPA Emissions Rule


PJM, the Electric Reliability Council of Texas, Midcontinent Independent System Operator and Southwest Power Pool on Tuesday filed joint comments in response to the U.S. Environmental Protection Agency’s proposed rule on the implementation of nitrogen oxides emission limits on electric generating units. 

The U.S. Environmental Protection Agency (EPA) has proposed establishing nitrogen oxides emission budgets requiring fossil fuel-fired power plants in 25 states to participate in an allowance-based ozone season trading program beginning in 2023. The agency is also proposing to establish nitrogen oxides emission limitations applicable to certain other industrial stationary sources in 23 states with an earliest possible compliance date of 2026.

The comments (PDF) filed by PJM, ERCOT, MISO and SPP (collectively referred to in the filing as the Joint ISO/RTOs) focus on the reliability-related implementation challenges of the EPA’s proposed rule and highlight the need for including a reliability-based “safety valve” provision in any future final rule.

PJM separately submitted its own comments (PDF) to the EPA. In addition to providing further detail on the outlined reliability safety valve, PJM proposed:

  • The addition of a dedicated bank of reliability allowances to address seasonal reliability concerns
  • The elimination or substantial modification of dynamic budgeting because, if allowed to remain, it will unnecessarily reduce the ability of capacity resources to operate
  • Recognition of the potential cost impacts associated with purchasing allowances that will likely be passed through to end-use customers

All parties submitted suggested modifications to the EPA’s proposed rule to avoid the potential for distinct reliability challenges resulting from the rule’s implementation.

For its part, PJM examines the potential reliability impacts of state and federal policies to help those entities implement policies without sacrificing grid reliability.