Wagner Coal Units Must be Shuttered

Author: Natalie Wu, Johns Hopkins University student, March 12, 2017

This report provides a summary and analysis of the adverse impacts of air pollution from coal-fired power plants.  This report focuses on the Herbert A. Wagner Generating Station in Curtis Bay, MD. The Wagner plant has of four units: a natural gas fueled Unit 1, coal-fired Units 2 and 3, and an oil-fueled Unit 4. Although Unit 3 has better emissions control than Unit 2, which is scheduled for retirement in 2020, this report shows why Unit 3 should also be closed.

This report will show that coal is one of the dirtiest energy sources because—in addition to its carbon intensity—it’s a source of a range of air pollutants from oxides of nitrogen (NO_x), sulfur dioxide (SO₂), to particulate matter of varying diameters (PM_x). These pollutants are can cause various acute or chronic health issues, respiratory or cardiovascular. Oftentimes, the populations most adversely affected are those of color and low socioeconomic status. This means that the issue of air pollution is one of environmental justice. Furthermore, the negative health impacts translate into economic costs, which can accumulate over time if no further steps to improve air quality are taken. Although air pollution control, and hence air quality, has improved in Maryland over the past decades, there is still room for improvement, especially in regards to the Wagner plant. This report will highlight so by first giving an overview of the Wagner plant itself, then summarizing a few of the negative impacts of coal-derived air pollutants on the human body, and finally discussing the social costs of dirty air.

Wagner Plant

            As stated earlier, the Wagner plant consists of 4 units. Unit 1 is fueled by natural gas. Unit 2 and 3 are coal-fired. Unit 4 is oil-fueled.[1] The generating station is located next to the Patapsco river and has a generating capacity of 495 MW.[2] Unit 2 is scheduled for retirement in 2020, but Unit 3 is not. Unit 3’s air emissions control technology includes over fire air (OFA), low NO_x burners, and selective catalytic reduction (SCR).[3] These measures taken, while admirable, as shown in this paper, are not enough. In February 2016, Sierra Club and the Environmental Protection Agency (EPA) determined that communities within about 22 miles of the plant had levels of sulfur dioxide pollution that exceeded the standard established in 2010.[4] Given the potential health consequences that will be outlined in the following section, it’s recommended that Unit 3 be retired in order to further improve the air quality of the area and protect the health of the citizens.

Health Impacts of Air Pollutants from Coal-Fired Plants

            This section will serve as a brief overview of the air pollutants associated with coal-fired plants and the various health concerns they pose. Pollutants covered in this section will include the following: NO_x, O_3, SO₂, and PM_x.

            NO_x is a generic term used to refer to various nitrogen oxides. Of particular concern is nitrogen dioxide (NO₂), an odorous, reddish-brown gas that is common in ground-level smog. In the atmosphere at ground level, the reaction proceeds as: “NO₂ + VOC + ultraviolet light —> O₃ + other products.”[5] (VOC stands for volatile organic compounds, such as evaporated gasoline; O₃ is ozone.) This smog is particularly concerning given that 20% of Baltimore City children under 18 have asthma—more than double the national average.[6] Although this pollutant only exceeded the maximum tolerance for “Good” Air Quality Index (AQI) in 2015 nine times, its synergistic effects with ozone levels are more severe.[7]

            Ozone, a component of photochemical smog, is a secondary pollutant that, while beneficial in the stratosphere, is dangerous at ground level. Ozone is an oxidizing molecule that normally is neutralized by the lung’s alveolar surface, but in overwhelming concentrations, it can cause oxidative damage or oxidative stress. Uncontrolled oxidative stress can trigger a positive feedback cycle in which an inflammatory response is initiated, and the inflammation can lead to an increase in local responses such as an acute exacerbation of asthma or hike in blood pressure. More concerning, if chronic, these responses can lead to the development of conditions such as lung cancer.[8] These health implications are important to consider, for in 2015, ozone was the most problematic air pollutant in the Baltimore-Colombia-Towson area. In 2015, ozone levels reached “moderate” on AQI on 72 days, “Unhealthy for Sensitive Populations” on 14 days, and “Unhealthy” on one day.[9]

            Sulfur oxides (SO_x) contribute to the formation of secondary particulate matter, which poses health consequences that will be discussed shortly. The most important form of this criteria pollutant is sulfur dioxide.[10] Sulfur dioxide, a powerful irritant in and of itself, also reacts with atmospheric gases such as water vapor to form sulfuric acid, a major component of acid rain.[11] Thankfully, it was the least problematic air pollutant in 2015 in the Baltimore-Colombia-Townson area, and it remained “Good” on the AQI every day of the year.[12]

            Lastly, particulate matter are solid or liquid airborne particles of varying diameters, but the EPA classifies particulates as PM₁₀ (between 2.5 and 10 um in diameter) or PM_2.5 (less than 2.5 um in diameter). The smaller the particle size, the greater potential it has to penetrate deeper into the body via inhalation. These health consequences are important to consider, for they can lead to a variety of cardiovascular issues. In 2010, the American Heart Association reviewed evidence that linked particulate exposure to an imbalance between the sympathetic and parasympathetic portions of the autonomic nervous system.[13] This imbalance is thought to lead to vasoconstriction, an increase in blood pressure, an increased tendency for platelets to stick together and form clots and disturb cardiac rhythm. These effects are important to consider, especially since PM_2.5 levels were “moderate” 139 days in 2015, and a few times, the levels came close to breaching the “Unhealthy for Sensitive Populations” threshold in the Baltimore-Columbia-Towson area.[14]

Environmental Justice and Economic Impact

            The potential risks air pollutants pose are not evenly distributed among the public, for the populations most likely to suffer the health consequences are those most vulnerable. For example, African Americans are likelier to be hospitalized due to asthmatic attacks than whites. In addition to minorities, youth tend to be more susceptible to the detrimental effects of air pollutants because they breathe more air per unit body weight than adults, breathe through the mouth more, and spend more time outdoors.

            Air pollution translates into both an environmental justice issue but an economic one as well. External costs, damages born by those not directly involved in an economic transaction, often include health complications. Acute events such as myocardial infarcts or asthma attacks can lead to days off work and a reduction in labor productivity. Chronic conditions can translate into healthcare costs. In its study Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use, the National Research Council estimated that health damages linked to 406 coal-fired electrical utilities were $62 billion per year (in 2007 dollars). This statistic is especially concerning as not only are coal-fired power plants more common in the middle Atlantic states than other regions of the U.S. but also because 86% of Maryland’s population live in areas that fail to meet EPA’s health-protective standards.

Other Considerations

            Another impact, while not direct, is impeding a change to clean renewable energy and contribution to anthropogenic climate change. Maryland has set an ambitious goal of cutting carbon emissions by 40% by the year 2030.[15] This is a step in the right direction as climate change creates other health risks, such as increases in heat strokes[16], and poses a threat to coastal populations, such as those of Maryland. In order to meet this goal, it’s imperative that Maryland’s energy system change—first by weaning off of coal and other fossil fuels. Unit 3 burns Eastern bituminous coal, [17] and bituminous coal produces 205.7lb CO₂ per Btu.[18] Next to anthracite coal, bituminous coal is the most carbon intensive, so it’s contribution to climate change is significant. Although “clean coal” can refer to carbon sequestration, it is often prohibitively expensive and likely is ineffective at reducing carbon emissions.[19] Therefore, it is better to instead wean off dependency on fossil fuels and move to clean and renewable forms of energy. Although the latter part of that plan is beyond the scope of this paper, the first step is. By closing Unit 3 of the Wagner plant, Maryland can cut carbon emissions and play a role in the collective effort to combat climate change.

Conclusion

            Coal is a fuel of the past. The air pollutants this dirty fossil fuel emits are linked to various health complications from acute respiratory and cardiovascular issues (e.g. asthma and stroke, respectively) to chronic diseases (e.g. lung cancer). The populations that suffer the most from air pollution and bear the brunt of these health impacts are often those already vulnerable in society (e.g. racial minorities, those of low socioeconomic standing, and children), which means the issue of air pollution is one of environmental justice. Additionally, these health consequences are classic examples of externalities, which are economic consequences associated with industrial activity that are not reflected in the costs of the services produced. These externalities should be taken seriously by legislators and citizens alike. Finally, the future of Maryland’s energy must be taken into consideration as combustion of coal is a major contributor to CO₂ and climate change. Although steps can be taken to minimize emissions of air pollutants like NO_x or even CO₂ can be taken via the implementation of technology like scrubbers or carbon sequestration, this report advocates instead for the elimination of these emissions. It’s with these points in mind thathhis report calls for the shutdown of the Herbert A. Wagner Generating Station’s coal-fired Unit 3. The retirement of this unit is a step in the right direction towards transforming Maryland’s energy system and eliminating the social and economic consequences associated with coal.