The US Environmental Protection Agency (EPA) responded to concerns raised by the US Supreme Court in June by defending the efficacy of the "good neighbor" plan in reducing NOx emissions regardless of the number of participating states.
The high court's concerns were over the issue of severability — that is, how effective the good neighbor plan would be in lowering ozone season NOx emissions if only some of the original 23 states participated. In other words, it is the question of whether the emissions limits placed on states as part of the Cross-State Air Pollution Rule (CSAPR) cap-and-trade program under the plan would have changed based on the number of participating states.
In a notice published in the Federal Register on Tuesday, EPA rejected the idea that the effectiveness of the good neighbor plan — and as a result, the NOx emissions limits imposed on each state — would wane if the number of participating states changed.
Instead, the agency said that its plan is "by design severable by state" because the NOx emissions limits are imposed on individual sources rather than the states themselves. Each participating state's emissions obligations depend on the number of obligated power plants, their emissions and the types of emissions reduction measures they already have in place. As a result, pausing the imposition of tighter NOx limits under the good neighbor plan in certain states does not affect the NOx limits imposed in other participating states, EPA said.
In a similar vein, EPA addressed concerns that the larger version of the CSAPR Group 3 seasonal NOx allowance trading program established under the good neighbor plan would become more illiquid if it covered fewer states than planned, which could lead to a smaller supply of allowances and higher prices. Calling those concerns "unjustified", the agency said that states can withdraw their sources from a trading program by submitting their own ozone reduction plans. EPA also cited previous instances from past cross-state ozone programs where the number of participating states has changed, noting that there has been no evidence of allowance shortages.
EPA also responded to concerns that it used an inconsistent methodology to determine emissions obligations for each source — including the emissions reduction strategies that could be used and their associated costs. The agency said it used a methodology that was "nearly identical to prior good neighbor rules" and considered NOx reduction technologies that have been in place "for decades throughout the US."
The severability issue was raised by the Supreme Court in June, when it paused implementation of the good neighbor plan nationwide. The court majority said that EPA did not provide a sufficient explanation in response to public comments from states that highlighted those concerns — especially because, until the court issued its stay, only 10 states were participating in the good neighbor plan because of lower court stays.
But in September, the US Court of Appeals for the DC Circuit allowed EPA to respond to the issue of severability, while it paused related litigation.
EPA finalized the "good neighbor" plan last year to help downwind states meet the 2015 federal ozone standards. It imposed more rigorous CSAPR ozone season NOx emissions limits on more than 20 states and called for new NOx limits for industrial sources. Illiquidity has been persistent in the CSAPR market, depressing activity and keeping prices steady for almost a year because of uncertainty surrounding the numerous legal challenges against the plan. The ozone season runs from May-September each year.
With plan halted for the time being, EPA has returned to less-stringent seasonal NOx budgets and reshuffled the remaining participating states into the Group 2 and new "expanded" Group 2 markets, leaving the Group 3 market empty.
