Greenhouse Gas Mitigation of Rural Household Biogas Systems in China: A Life Cycle Assessment
Rural household biogas (RHB) systems are at a crossroads in China, yet there has been a lack of holistic evaluation of their energy and climate (greenhouse gas mitigation) efficiency under typical operating conditions. We combined data from monitoring projects and questionnaire surveys across hundre...
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MDPI AG
2017-02-01
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| Series: | Energies |
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| Online Access: | http://www.mdpi.com/1996-1073/10/2/239 |
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| author | Jun Hou Weifeng Zhang Pei Wang Zhengxia Dou Liwei Gao David Styles |
| author_facet | Jun Hou Weifeng Zhang Pei Wang Zhengxia Dou Liwei Gao David Styles |
| author_sort | Jun Hou |
| collection | DOAJ |
| description | Rural household biogas (RHB) systems are at a crossroads in China, yet there has been a lack of holistic evaluation of their energy and climate (greenhouse gas mitigation) efficiency under typical operating conditions. We combined data from monitoring projects and questionnaire surveys across hundreds of households from two typical Chinese villages within a consequential life cycle assessment (LCA) framework to assess net GHG (greenhouse gas) mitigation by RHB systems operated in different contexts. We modelled biogas production, measured biogas losses and used survey data from biogas and non-biogas households to derive empirical RHB system substitution rates for energy and fertilizers. Our results indicate that poorly designed and operated RHB systems in northern regions of China may in fact increase farm household GHG emissions by an average of 2668 kg CO2-eq· year−1, compared with a net mitigation effect of 6336 kg CO2-eq per household and year in southern regions. Manure treatment (104 and 8513 kg CO2-eq mitigation) and biogas leakage (-533 and -2489 kg CO2-eq emission) are the two most important factors affecting net GHG mitigation by RHB systems in northern and southern China, respectively. In contrast, construction (−173 and −305 kg CO2-eq emission), energy substitution (−522 emission and 653 kg·CO2-eq mitigation) and nutrient substitution (−1544 and −37 kg CO2-eq emission) made small contributions across the studied systems. In fact, survey data indicated that biogas households had higher energy and fertilizer use, implying no net substitution effect. Low biogas yields in the cold northern climate and poor maintenance services were cited as major reasons for RHB abandonment by farmers. We conclude that the design and management of RHB systems needs to be revised and better adapted to local climate (e.g., digester insulation) and household energy demand (biogas storage and micro power generators to avoid discharge of unburned biogas). More precise nutrient management planning could ensure that digestate nutrients are more effectively utilized to substitute synthetic fertilizers. |
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| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-13T01:19:56Z |
| publishDate | 2017-02-01 |
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| record_format | Article |
| series | Energies |
| spelling | doaj.art-65b261a4776140f69a2d7329ed8ee0f62022-12-22T03:08:48ZengMDPI AGEnergies1996-10732017-02-0110223910.3390/en10020239en10020239Greenhouse Gas Mitigation of Rural Household Biogas Systems in China: A Life Cycle AssessmentJun Hou0Weifeng Zhang1Pei Wang2Zhengxia Dou3Liwei Gao4David Styles5Center for Resources, Environment and Food Security, China Agricultural University, Beijing 100193, ChinaCenter for Resources, Environment and Food Security, China Agricultural University, Beijing 100193, ChinaCenter for Resources, Environment and Food Security, China Agricultural University, Beijing 100193, ChinaCenter for Animal Health and Productivity, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA 19348, USAAgricultural Information Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, ChinaSchool of Environment, Natural Resources and Geography, Bangor University, Wales LL57 2UW, UKRural household biogas (RHB) systems are at a crossroads in China, yet there has been a lack of holistic evaluation of their energy and climate (greenhouse gas mitigation) efficiency under typical operating conditions. We combined data from monitoring projects and questionnaire surveys across hundreds of households from two typical Chinese villages within a consequential life cycle assessment (LCA) framework to assess net GHG (greenhouse gas) mitigation by RHB systems operated in different contexts. We modelled biogas production, measured biogas losses and used survey data from biogas and non-biogas households to derive empirical RHB system substitution rates for energy and fertilizers. Our results indicate that poorly designed and operated RHB systems in northern regions of China may in fact increase farm household GHG emissions by an average of 2668 kg CO2-eq· year−1, compared with a net mitigation effect of 6336 kg CO2-eq per household and year in southern regions. Manure treatment (104 and 8513 kg CO2-eq mitigation) and biogas leakage (-533 and -2489 kg CO2-eq emission) are the two most important factors affecting net GHG mitigation by RHB systems in northern and southern China, respectively. In contrast, construction (−173 and −305 kg CO2-eq emission), energy substitution (−522 emission and 653 kg·CO2-eq mitigation) and nutrient substitution (−1544 and −37 kg CO2-eq emission) made small contributions across the studied systems. In fact, survey data indicated that biogas households had higher energy and fertilizer use, implying no net substitution effect. Low biogas yields in the cold northern climate and poor maintenance services were cited as major reasons for RHB abandonment by farmers. We conclude that the design and management of RHB systems needs to be revised and better adapted to local climate (e.g., digester insulation) and household energy demand (biogas storage and micro power generators to avoid discharge of unburned biogas). More precise nutrient management planning could ensure that digestate nutrients are more effectively utilized to substitute synthetic fertilizers.http://www.mdpi.com/1996-1073/10/2/239biogasmanure storageenergy substitutionsubsidysmall-scalesubsistence farming |
| spellingShingle | Jun Hou Weifeng Zhang Pei Wang Zhengxia Dou Liwei Gao David Styles Greenhouse Gas Mitigation of Rural Household Biogas Systems in China: A Life Cycle Assessment Energies biogas manure storage energy substitution subsidy small-scale subsistence farming |
| title | Greenhouse Gas Mitigation of Rural Household Biogas Systems in China: A Life Cycle Assessment |
| title_full | Greenhouse Gas Mitigation of Rural Household Biogas Systems in China: A Life Cycle Assessment |
| title_fullStr | Greenhouse Gas Mitigation of Rural Household Biogas Systems in China: A Life Cycle Assessment |
| title_full_unstemmed | Greenhouse Gas Mitigation of Rural Household Biogas Systems in China: A Life Cycle Assessment |
| title_short | Greenhouse Gas Mitigation of Rural Household Biogas Systems in China: A Life Cycle Assessment |
| title_sort | greenhouse gas mitigation of rural household biogas systems in china a life cycle assessment |
| topic | biogas manure storage energy substitution subsidy small-scale subsistence farming |
| url | http://www.mdpi.com/1996-1073/10/2/239 |
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