Greenhouse Gas Emission Reductions from Domestic Anaerobic Digesters Linked with Sustainable Sanitation in Rural China Open Access

Abstract

Anaerobic digesters provide clean, renewable energy (biogas) by converting organic waste to methane, and are a key part of Chinarural energy plan. Here, experimental and modeling results are used to quantify the net greenhouse gas (GHG) reduction from substituting a household anaerobic digester for traditional energy sources in Sichuan, China. Tunable diode laser absorption spectroscopy and radial plume mapping were used to estimate the mass flux of fugitive methane emissions from active digesters. Using household energy budgets, the net improvement in GHG emissions associated with biogas installation was estimated using global warming commitment (GWC) as a consolidated measure of the warming effects of GHG emissions from cooking. In all scenarios biogas households had lower GWC than non-biogas households, by as much as 54%. Even biogas households with methane leakage exhibited lower GWC than non-biogas households, by as much as 48%. Based only on the averted GHG emissions over 10 years, the monetary value of a biogas installation was conservatively estimated at US$28.30 ($16.07 ton^-1 CO2-eq.), which is available to partly offset construction costs. The interaction of biogas installation programs with policies supporting improved stoves, renewable harvesting of biomass, and energy interventions with substantial health co-benefits, are discussed.

Table of Contents

Table of Contents Introduction 1 Methods 2 Study area 2 Household survey 3 Leak identification and quantification 3 Household energy budget 5 Greenhouse gas emissions and global warming commitment 5 Uncertainty and sensitivity analysis 7 Results 8 Household survey 8 Leak measurements and flux estimation 8 Global warming commitment 9 Discussion 9 Conclusion 12 References 13 Tables and Figures 16 Figure 1. Experimental setup for plume mapping 16 Figure 2. Reconstructed methane concentration profile at a leaking biogas location 16 Table 1. GWC models for households with and without biogas systems 17 Table 2. GWC as g-CO2 per 2 MJ for all modeled households 18 Appendix A 19 Table A1. Global warming potentials (GWP) for selected greenhouse gases 19 Table A2. Stove/fuel pairings 19 Table A3. Reported daily energy usage from solid fuels for cooking 19 Table A4. GWC/2 MJ to pot for non-renewable model, with propagated uncertainty 20 A1. Scenario-Based Sensitivity Analysis 20 Table A5. Scenario-based sensitivity analyses of leaking BG models 21 6

About this Master's Thesis

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School	Rollins School of Public Health
Department	Environmental Health
Degree	MSPH
Submission	Master's Thesis
Language	English
Research Field	Health Sciences, Public Health Engineering, Environmental Environmental Sciences
Keyword	GHG Methane Greenhouse Gases GHG benefit rural household Sichuan methane leak biogas Anaerobic digester
Committee Chair / Thesis Advisor	Remais, Justin V, Emory University
Committee Members	Tolbert, Paige, Emory University
Partnering Agencies	International governmental organization (e.g., Agency for International Development, etc.) US (Federal) agency other than CDC CDC

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