Renewable Natural Gas from Swine Waste: Responsible Solution or Greenwashing? (2023)
Undergraduate: Matthew Price
Faculty Advisor: Marc Alperin
Department: Environment, Ecology, and Energy Program
Understanding methane (CH₄) is highly important as we strive to curb our impact on the overall climate. Through measures of reducing our greenhouse gas (GHG) emission, we are able to create a more responsible future. Although it is hard to determine if an action is truly responsible if there is a lack of understanding of the topic. Especially in the agriculture industry, humans have contributed large, if we are trying to convert swine waste into renewable natural gas (RNG) as a means of heating homes and businesses. It is vital that we understand how large this resource is. Using a modified Arrhenius equation, proposed by Sommer et. al and Peterson et. al, I am able to simulate CH₄ production that responds to changes in cycling, temperature, volatile solids (VS) and population size. Additionally, the model is able to track two portions of the volatile solids, the degradable and the nondegradable (VSd and VSnd), each day portions of these values are consumed in the production of CH₄, and what is not consumed is then left for the next day. This study focuses on Duplin County in North Carolina, because of its large agricultural industry, and the fact that it houses over 300 Feeder-Finish farms, which have been the main focus of waste-to-energy programs thus far in the States. And between those 300 farms, there are approximately 1.4 million hogs, and each hog produces roughly 38 kg of waste every day. If all of the Feeder-Finish farms in Duplin participated in CH₄ capture, the county would produce 50.7 million m³ annually which would be worth 9.2 million dollars.
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