Techno‐economic and environmental assessment of converting mixed prairie to renewable natural gas with co‐product hydroxycinnamic acid

Abstract

There is a need for research into clean alternative energy sources to meet future energy requirements. Renewable natural gas (RNG) can assist in fulfilling a growing projected demand for natural gas in a sustainable manner. This study focuses on a techno‐economic analysis (TEA) and a life cycle assessment (LCA) for the co‐digestion of manure with pretreated prairie biomass. This process offers higher biogas yields and an additional co‐product, hydroxycinnamic acid (HCA), to decrease the minimum fuel selling price (MFSP) of RNG. The plant produces between 524 000 GJ year−1 and 1 176 000 GJ year−1 of RNG in the five modeled scenarios. The MFSP of RNG for scenarios where biomass pretreatment occurs is estimated to be between $15.87 GJ−1 and $18.94 GJ−1. The MFSP for the scenario where no pretreatment occurs is estimated to be $21.21 GJ−1. The global warming potential results range from −7.30 kg CO2e GJ−1 to 21.59 kg CO2e GJ−1. Sensitivity and uncertainty analyses are also completed.