Tracer Gas Method Evaluation for Assessing the Energy Potential of Biogas from Chicken Farms in the Canary Islands

Abstract

Biodigestion in farming and agriculture offers environmental and economic benefits, but investing in biodigesters carries real-world risks for enterprises. This study analyzes methane (CH4) emissions from a poultry farm biodigester in Tenerife Island, Canary Islands, Spain, conceptualized as a right-angled prism measuring 45 m wide, 25 m long, and 12 m tall, with an internal volume of approximately 13,500 m3. Using a Neon tracer gas technique, CH4 emission rates were quantified in situ during two surveys in February 2021 and October 2022, capturing seasonal variability in ambient conditions. Biogas analysis was performed using a portable micro-gas chromatograph in less than 5 min, revealing stable CH4 production rates of approximately 200 kg·d−1 (~310 m3·d−1) and 330 kg·d−1 (~500 m3·d−1) for the two experiments, respectively. The composition of biogas indicated CH4 concentrations of around 38–43%, with the remaining composition consisting of carbon dioxide (19–26%), nitrogen (36–27%), oxygen (7–4%), and trace amounts of other gases. A comparison with a theoretical model showed a good correlation. This approach enhances biodigester investment attractiveness by enabling enterprises to optimize efficiency promptly. The obtained data were used to estimate the energy potential of biogas from chicken farms in the Canary Islands.