Full-scale cattle manure anaerobic digestion plant measured performance and model based environmental and techno-economic viability assessment

Full-scale manure biogas plants are often promoted as renewable energy projects, yet their commercial value may depend as much on waste stabilization, methane control, water reuse, and nutrient recovery as on electricity sales. This study tests whether cattle manure digestion can deliver measurable environmental and resource-efficiency benefits, while remaining financially non-viable under electricity-only revenue. The assessment is based on one year of measurement-derived operational data from a full-scale facility integrating anaerobic digestion, biogas cleaning, combined heat and power generation, process-water reuse, and digestate recovery. Plant records indicate net annual export of 7253 MWh of renewable electricity and a model-based reduction in methane-related climate impact equivalent to about 38,800 tons of carbon dioxide per year relative to unmanaged manure storage. Closed-loop process-water recirculation reduced freshwater demand by 55%, corresponding to an annual saving of approximately 80,300 m 3 . Stabilized digestate contained substantial quantities of nitrogen, phosphorus, and potassium, indicating potential agronomic value under suitable management conditions. A discounted-cash-flow analysis calibrated to the measured electricity performance nevertheless yielded a negative net present value of 4.37 million USD over a 15-year project lifetime under an electricity-only revenue model. This study demonstrates gate-to-gate environmental and operational performance for a full-scale cattle-manure AD-CHP system, including methane mitigation, water reuse, and nutrient recovery, but it does not establish full life-cycle sustainability because several upstream and downstream processes were outside the system boundary.