Comments were due this week on EPA’s ACE rule – a welcome return to reason on the heels of its predecessor rule: the Obama administration’s “signature” anti-coal rule, the costly power plan (CPP). Replacing the CPP with ACE brings the EPA back into the realm of the legal, appropriately respecting the balance between state and federal authority established by the Constitution and the Clean Air Act (CAA) – a balance that the CPP completely trampled while attempting to restructure our entire electric grid.

And while NGOs and ACE critics will undoubtedly use the opportunity to bemoan the loss of their beloved and destructive CPP, there are several key points that should be understood.

Regulating individual sources is legal; mandating a restructuring of the entire grid is not. Section 111 of the CAA limits systems of emission reduction to those that can be implemented at the source. This is not a new thought. It’s consistent with more than 40 years of pre-CPP EPA precedent, which allows EPA to regulate individual sources, not the entire electric grid. The ACE proposal identifies heat rate improvements (HRI) as the best system of emission reduction (BSER) for coal-fired power plants because HRI technologies are the only demonstrated means of reducing emissions that can be applied in a cost-effective manner at individual plants.

States have rights too. The CAA created a system of shared authority by EPA and the states. The ACE rule respects that each state is different and will require a unique approach to emissions reduction.

Coal plants should be encouraged to make upgrades.  The ACE rule recognizes the importance of New Source Review (NSR) reform by removing barriers to efficiency improvements at coal plants. The complexities of current NSR law have disincentivized upgrades that would improve safety, increase energy efficiency and reduce emissions of regulated air pollutants.

Balancing costs with benefits. The ACE rule is expected to cut emissions by more than a third below 2005 levels by 2030 – nearly as much as CPP – while also reducing the compliance burden by up to $400 million annually when compared to CPP. The CPP was designed to force coal plants out of business.

In the inevitable hysteria that will surround the ACE vs. CPP argument, let it not be lost: the law matters. ACE would accomplish much for emissions control in this country, while removing important roadblocks to efficiency upgrades at existing facilities, and it would do it with a respect for the Clean Air Act and the Constitution.