The Environmental Protection Agency’s effort to limit carbon emissions from coal plants is facing a new congressional challenge this week. In choosing how to respond, the agency should be willing to adjust its short-term tactics in service of its long-term goal -- even if it seems nonsensical.

In this case, that may mean being less strict about controlling pollution from new coal plants. It is an argument that, admittedly, requires some explanation.

At issue is whether capturing and storing carbon -- which new coal plants would have to do in order to comply with a rule proposed by the EPA -- is a process that has been “adequately demonstrated,” as required by the Clean Air Act. The EPA says it has been, pointing to three U.S. plants in the works that use the technology. Critics disagree.

Some of that criticism can be readily dismissed; the agency was bound to face some attacks, regardless of how it structured its rule. Senator Joe Manchin of West Virginia, for example, has proposed legislation that would prevent the EPA from adopting such standards unless they have been used in at least six places. Why six? Is seven too many? Five not enough? Manchin’s not saying.

Last week, the House Energy and Commerce Committee identified what may be a more serious challenge to the EPA proposal: A 2005 law prevents the agency from using plants subsidized by the Department of Energy’s Clean Coal Power Initiative to show that a given technology is “adequately demonstrated.” Republicans on the committee say the three plants cited by the EPA received funding from that program.

This argument could pose a problem for the EPA’s plans to limit emissions from all coal plants, not just the new ones that would be covered by the rule. A court decision to vacate the regulation for new plants would force the agency to delay a related rule, still being written, on existing coal plants.

That second rule is more important for fighting climate change: Nobody is building new coal plants today anyway, because natural gas is so cheap. The nation’s almost 600 existing coal plants are the more pressing concern. Moreover, the approach the EPA is considering for those existing plants is more flexible and promising.

So the decision the EPA faces is whether to rewrite its proposed rule on new coal plants to make it less vulnerable to a legal challenge or to stick with its proposal.

If it were to set a looser emissions limit, equal to the lower emissions already being achieved by the most advanced coal-fired plants, it would quiet arguments that the relevant technology hasn’t been “adequately demonstrated.” But it would come at the price of higher emissions down the road, if the price gap between natural gas and coal narrows and companies start building coal plants again. Reworking the proposed rule also risks some delay in regulations for both new and existing plants.

It’s unclear whether the risk posed by the 2005 law merits a revision of the EPA’s proposed rule. Predictably, there are different opinions about the chances of a legal challenge. That’s a determination the agency will need to make, and carefully.

Whatever it decides, the EPA’s attention is best focused on the overall goal of the greatest possible reduction in emissions from all coal plants -- both new and existing.

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