Net-zero farming: Trigeneration with carbon capture and storage

Aiming to achieve net-zero farming, this study explores the potential of anaerobic digestion of various biowastes to produce biogas for meeting the energy demands of a dairy farm, including electricity, heating, and cooling. Two options were investigated: Option 1 focuses solely on meeting the farm's energy demand, while Option 2 focuses on a big system that utilizes all available biowastes to produce biogas, with surplus electricity sold back to grid. These options were modelled using ECLIPSE software and evaluated in terms of practicality, environmental impact, and economic viability. Option 2, employing trigeneration, achieved an overall efficiency of 80.0 %, significantly higher than Option 1's 48.4 %. However, the efficiencies of the combined heat and power (CHP) system for Option 1 and 2 were 62.2 % and 81.1 %, respectively, both higher than their corresponding trigeneration. Option 2 also produced a greater annual carbon dioxide offset of 4206 Ton CO₂-eq compared to 299 Ton CO₂-eq for Option 1 by leveraging digestive fertilizers and carbon capture and storage technology (CCS). Finally, it was found that the payback period for Option 1 was projected at 11 years while Option 2 would require 12 years, with anticipated profits of £124,900 and £891,900 for Options 1 and 2, respectively.