The Environmental Protection Agency defended its rule limiting power plants’ greenhouse gas emissions against a legal challenge in federal court from Republican states and business groups, arguing the regulation does not threaten grid reliability as alleged. 

In April, the EPA finalized standards, requiring new and existing power plants that plan to operate past 2039 to reduce 90% of their carbon pollution by 2032. To help meet the EPA’s standards, power plants must install carbon capture and sequestration/storage technology. 

However, the rule faces legal challenges in the U.S. Court of Appeals for the District of Columbia Circuit by parties such as regional grid operators that say that the agency’s rule forces plants to use CCS technology that doesn’t yet exist.

Grid operators, including Midcontinent Independent System Operator, Inc., PJM Interconnection L.L.C., Southwest Power Pool, Inc., and Electric Reliability Council of Texas, Inc., filed an amicus brief in September, asserting that power plants unable to install CCS could lead to early closures and threaten the electric grid’s reliability. 

“Given the implausibility of CCS as a viable option for mitigating CO2 emissions and the resulting likelihood of premature retirements of fossil-fired generators, the Final Rule is likely to hamper Amici in their efforts to provide reliable power to the communities and consumers that they and others serve,” the grid operators stated. 

The grid operators joined the lawsuit initially brought by Republican states, led by West Virginia, shortly after the rule was finalized. The Chamber of Commerce also joined the lawsuit, in which the parties alleged the agency exceeded its statutory authority. They asked the court to suspend the rule but were denied. 

Yet the EPA on Friday called claims regarding threats to grid reliability “unfounded.” In a brief response, the EPA stated the grid operators’ arguments “assume the conclusion that the Rule imposes impossible requirements. The record demonstrates otherwise.” 

It added the “EPA thoroughly considered grid-reliability impacts and designed the Rule to avoid disrupting power-sector operation.” 

The EPA argued that it identified 90% CCS as the best tool to reduce emissions from power plants through a comprehensive review of an extensive record. 

“Petitioners’ criticisms of EPA’s technical findings misapply the statutory standards, misrepresent the record, and ignore the totality of the evidence,” the EPA wrote. 

The agency added that the EPA has the authority to promulgate these standards under the Clean Air Act to control pollution from fossil fuel-fired power plants. 

“The Rule falls within the heartland of EPA’s standard-setting authority and does not implicate the major-questions doctrine,” the EPA wrote. “As this Court previously ruled in denying Petitioners’ motion for a stay, EPA based the Rule on measures that will reduce pollution by causing the regulated source to operate more cleanly, a type of conduct that falls well within EPA’s bailiwick.”