Report: Air pollution controls at Duke Energy’s Allen coal plant ineffective

CHARLOTTE, N.C.— Air pollution reduction systems at Duke Energy’s Allen Steam Station near Belmont are not working efficiently, and the rate at which nitrogen oxides are emitted by the plant has increased in recent years, according to a report commissioned by the Sierra Club. 

Sierra Club retained Dr. Ranajit Sahu, an engineer with decades of experience with air pollution control technology and coal plant operations, to evaluate the performance of nitrogen oxides (NOx) emission reduction systems at the Allen coal burning plant. Sahu looked at data Duke Energy reported to the U.S. Environmental Protection Agency, specifically at hourly NOx emission data, as well as plant operational data.

In the Technical Report on the Recent NOx Emission Control Performance at Allen Steam Station, Sahu observes that, between 2016 and 2018, four of the five units at the Allen plant emitted NOx at rates higher than during the years following installation of pollution control systems (2009–10). In addition to NOx, air emissions at Allen include volatile organic compounds, sulfur dioxide, particulate matter and carbon dioxide.

The report concludes that the likely reason for such deterioration in the performance of the pollution control systems is Duke’s operation of the Allen coal units as peaking or intermediate resources, with varying operating loads.

Duke installed the pollution control systems, at ratepayers’ expense, at a time when it was operating the Allen plant as a baseload resource. Thus, the systems were likely designed to work best at consistent and high capacity factors. Because the company is no longer operating Allen as a baseload plant— and has no plans of doing so ever again—the existing pollution controls are not actually controlling pollution effectively. 

Allen is located close to Mecklenburg County, the only county in North Carolina that got a failing grade for air quality from the American Lung Association this year, based on the most recent verified data from 2015, 2016 and 2017. 

Breathing ozone reduces lung function and continues to damage the lungs even after symptoms have disappeared. People with impaired immune systems, and those living with asthma, emphysema, and chronic bronchitis are particularly vulnerable to this pollutant. 

Meanwhile, to reduce NOx emissions to rates achieved in past years at Allen, Duke would need to retrofit the boilers with additional pollution control equipment—at a cost of about $5 million for each of the five units—or close the plant.

Dave Rogers, Southeast deputy regional campaign director for the Sierra Club’s Beyond Coal campaign, issued the following statement:

“Allen’s five coal boilers started operating 62 years ago, when Eisenhower was in office, and more than a decade before astronauts first walked on the moon. And now we know the pollution control systems at this old, outdated facility aren’t even working. 

“Every single day that Allen stays online is another day that it’s polluting the community’s air, water and land, and contributing to the climate crisis. If Duke’s leaders are serious about their new climate goals, they can start with the lowest hanging fruit of getting rid of their outdated, polluting coal fleet—and Allen is a prime example. 

“They should also stop their rush to build unnecessary, dangerous fracked gas infrastructure, and instead make bold investments in energy efficiency, battery storage and clean, safe, renewable solar and wind. 

“In the meantime, not even one more ratepayer cent should be spent on propping up Allen. It’s way past time for Duke to close this plant and start helping the Belmont community transition to an equitable economy, powered by clean energy.”