Duke Energy is wise to revisit mercury emissions

Duke Energy wisely has agreed to re-evaluate whether its planned new coal-fired Cliffside generating plant is capable of achieving maximum controls on mercury emissions. The state air quality division suggested the reassessment recently after a federal court ruled the EPA was wrong to exempt coal-fired plants from the federal Clean Air Act's requirements on certain pollutants.

Its unclear, however, whether Duke is committing sufficient time and resources to make sure that maximum achievable controls are in place. Duke said it would conclude its evaluation by the end of June, though state officials have said an adequate review can take six months to a year.

Still, Duke is persuaded that its design for the new Cliffside units in Cleveland and Rutherford counties, set for 2012 operation, will remove 90 percent of mercury emissions. ``I don't know of any technology that will get a higher removal rate than what we expect from this plant,'' Cliffside project manager Harry Lancaster told the Observer's Bruce Henderson.

We hope he's right. Coal-fired power plants have been associated with a variety of hazardous air pollutants, including mercury deposits linked to developmental difficulties in infants. A coalition of environmental groups has fought Duke's plans to build the plant despite Duke's arguments that it will be far cleaner than four old coal units it will replace.

The Southern Environmental Law Center believes Duke has failed to abide by the Clean Air Act and has argued that Duke is breaking the law by continuing to build the new plant while it re-evaluates its emission controls.

The center, which represents six other environmental groups, has told the company it may file a lawsuit in federal court to force compliance.

The issue is complicated because the state already had issued Duke a permit to proceed before the federal court ruling this year.

It is not clear whether projects permitted before that decision must start over. But failing to require new plants to provide maximum protection from harmful substances such as mercury emissions would make a mockery of federal environmental laws and could threaten the health of millions of residents of this area. State regulators should closely examine Duke's re-evaluation and, if necessary, work with the utility to change its plans to make sure the job is done right..