Global Warming Potential as a Challenge for Small-scale Biogas Plants in Vietnam

Bc. Marek Jelínek

Master's thesis

Abstract:

Biogas production in small-scale plants is considered as appropriate, cost-effective method of energy supply to rural households, providing many benefits including reduction of greenhouse gas emissions, organic waste management and production of fertiliser. By four-stage reaction of anaerobic digestion, the organic material is transformed into methane-rich biogas, which is used mainly for daily cooking activities in developing countries. Replacing traditionally used fuelwood and LPG by biogas promises reduction of households’ global warming potential. Problems resulting from inappropriate operation of biogas plants can result in mayor setbacks, including process inhibition and biogas loss. The amount of methane released to the atmosphere due to leakages or intentional release threats to neutralize the benefits of biogas use on the environment. The objective of this thesis was to quantify the impact of partial replacement of traditional fuels for cooking by biogas.The data collection was performed in province Thua Thien Hue in Vietnam from April to May 2017, including interviews of biogas plant owners (n = 23), masons (n = 5) and biogas facilitators (n = 5), following the previously assembled dataset of Biogas Research Team (n = 123). The quantification used Global warming potential (GWP), accounted for reported 40% methane loss, and possible scenarios of 0% methane loss and use of biogas exclusively. After implementation of biogas, traditional fuels’ use of households was reduced; fuelwood by 57.3 % and LPG by 56.3 %. Currently, households use 56.68 % of daily cooking energy from biogas. GWP was reduced by 1.05 % in comparison to the state before biogas plant (BGP) implementation. Quantification of two potential scenarios resulted in GWP reduction by 42.74 % in case of zero methane loss scenario and 74.22 % in case of using biogas exclusively. Break-even point of methane emissions was found at 41 %, close to the current reported values, indicating that the problem of methane leak is crucial and should be addressed.

Keywords

small-scale biogas technology, global warming potential, greenhouse gases, biogas

Language used: English

Date on which the thesis was submitted / produced: 2. 5. 2019

Thesis defence

• Supervisor: Ing. Hynek Roubík, Ph.D.

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Master programme / field:
Tropical Agriculture / Sustainable Rural Development in the Tropics and Subtropics