Mitigation measures needed for Waco-McLennan greenhouse gas hotspots

ALAN NORTHCUTT Guest Columnist

Waco has suffered from extreme weather events due to rising greenhouse gas emissions in the atmosphere, including a record drought in 2023, followed by record rainfall and flooding in 2024. To mitigate these greenhouse gases in McLennan County, we need to understand the main sources of emissions.

To achieve this goal, former Vice President Al Gore and his colleagues developed Climate Trace, an incredible tool that detects and quantifies greenhouse gas locations using satellites and other remote sensing techniques, analyzes trillions of data points with artificial intelligence, and creates an online map that is accessible to everyone.

The primary greenhouse gases analyzed are carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Because these gases have different warming strengths and survival times in the atmosphere, their warming potentials are converted to a 100-year equivalent amount of CO2, called CO2e, for comparison. McLennan County’s total greenhouse gas emissions are 5.48 million tCO2e (tonnes of carbon dioxide equivalent) in 2022, the most recent year available.

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The county’s top 10 pollution hotspots are listed in descending order and quantified in tonnes of CO2e in 2022. Methods to mitigate pollution are also provided.

1. Sandy Creek Power Plant: 3.512 million tCO2e in 2022. This coal-fired power plant in Riesel generates 900 megawatts of electricity and almost five times more greenhouse gases than the second largest emitter.

Mitigation: Rapid decommissioning is recommended, a process completed or started by 72% of coal-fired power plants in the U.S. since 2010. Decommissioning is superior to much-vaunted carbon capture technology, which has not been tested at scale, eliminates only 90% of greenhouse gases, would cost $421 million per year, and would not clean up toxic wastewater, metal pollution, or coal ash ponds. The energy from this plant could be replaced by a large wind farm with battery storage. In addition, individuals and businesses can do their part by purchasing 100% renewable electricity or installing solar, wind, or geothermal systems.

2. Road transport: 764,662 tCO2e. The more than 1,000 miles of local roads produce a mixture of CO2, CH4 and N2O as well as toxic exhaust gases.

Remedy: Local governments and businesses should expand electric vehicle charging infrastructure, while citizens and businesses can use Waco Transit, walk or bike more, and drive electric bikes and electric cars. If you drive frequently, Tesla, Rivian, and Ford electric vehicles are currently recommended, as all three brands can utilize the superior Tesla Supercharger network.

3. Lehigh Cement Plant: 764,002 tCO2e. Cement production is a surprisingly large source of CO2, accounting for 3% of global greenhouse gas emissions. This is due to the enormous energy required to reach the reaction temperature of 1,500 degrees Celsius and the CO2 released during the chemical reaction.

Mitigation: Lehigh recognizes the problem, stating, “We have defined a sustainability strategy to reduce carbon emissions with a 10-year plan.” Key methods to reduce emissions include using renewable energy to heat reaction furnaces and capturing and sequestering CO2 from the concrete reaction in the concrete product. Homeowners and builders can request low-carbon concrete under names like CarbonCure and Duke City Redi Mix.

4. Woodland: 311,759 tCO2e. Forests release CO2 through cellular metabolism and after deforestation, clearing and degradation. Globally, forests store about twice as much carbon as they emit and act as a carbon sink for about 7.6 billion tonnes of CO2 annually.

Mitigation: Protecting and preserving trees in the county and planting native, drought-resistant and fast-growing trees will help increase this carbon sink.

5. Waco Regional Landfill: 155,205 tCO2e. In 2022, the Highway 84 landfill deposited 310,000 tons of waste, with greenhouse gases being almost entirely CH4. The landfill is expected to reach full capacity in July 2025 when it closes.

Mitigation: A new landfill under construction with a clay and geomembrane lining is scheduled to open near Axtell in May 2025. Landfill gas will be regularly monitored and a landfill gas collection and control system will be installed “if necessary,” the application summary states. Given the high climate warming potential of methane and its tendency to leak, I believe a methane collection system is imperative. For residents and businesses, careful recycling and composting will reduce their contribution to the waste stream. Composting can be done using a garden bin, through the Urban REAP composting service, or using an electric home composter such as the Nutrichef, Airthereal or GEME machines.

6. Net shrub grass: 101,715 tCO2e. As far as I know, shrubs and grasses in the district also absorb CO2 in an unquantifiable amount. They probably represent a net carbon sink.

Remedy: To optimize the population of local shrubs and grasses, residents and businesses can avoid mowing (observe the mowing ban), allow weeds to thrive as much as possible, and use only electric gardening equipment.

7. Lacy Lakeview Landfill: 84,252.3 tCO2e. The Selby Lane facility is managed by Waste Management, Inc. Greenhouse gas emissions consist almost entirely of CH4.

Remedy: The landfill’s website does not describe CH4 capture. This feature should be retrofitted or included in new landfill construction where possible. The citizen recommendations regarding the Waco landfill apply here as well.

8. Cattle pasture: 29,006.7 tCO2e. The pastures in McLennan County are home to about 20,000 cattle; emissions therefore consist almost entirely of CH4.

Mitigation: The CH4 emissions from cattle come primarily from their burps and also from their manure. Recently, it was discovered that small amounts of red algae in the feed of cattle reduced the CH4 emissions in their burps by up to 80%. People can reduce their individual carbon footprint and the demand for cattle by adopting a vegan or vegetarian diet, or at least reducing their meat consumption. The foods with the highest greenhouse gas emissions are beef, followed by lamb, dairy, farmed shrimp, cheese, pork and poultry.

9. Waco Regional Wastewater Treatment Plant (WMARSS): 14,774.6 tCO2e. The plant emitted 134 tonnes of CH4 and 41 tonnes of N2O, but ranked ninth in total emissions because both gases have high global warming potential. The small CH4 molecule likely escaped from the plant’s pipes and during flaring, and N2O may have come from the plant’s fertilizer-like solids.

Mitigation: Sealing leaks is helpful to limit volatile CH4. Biological methods using anammox bacteria and oxygen management help reduce N2O emissions. Citizens and businesses can contribute by carefully avoiding water waste.

10. Grain fields: 13,170.9 tCO2e. The county covers 54,363 acres of cropland, with an estimated 3,000 tons of nitrogen fertilizer applied per hectare, resulting in the release of only 48.25 tons of N2O.

Mitigation: Solutions include using appropriate nitrogen fertilizers, their placement, timing and application rate. In addition, the use of low-nitrogen crops, cover crops and reduced tillage are helpful.

Climate Trace has identified the main sources of greenhouse gas emissions in McLennan County and empowered governments, businesses, organizations and individuals to take action to curb those emissions. And action is the best antidote to climate despair.

Alan D. Northcutt is a retired Waco physician and director of Waco Friends of the Climate, a grassroots climate action and education group. For free “The Climate Crisis Is Here” yard signs, email [email protected].