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.