Performance and social outcomes of biogas digesters: toward an integrated framework for sustainable rural development

1 Introduction

1.1 Background

Household-scale anaerobic digesters have been promoted as a multifunctional solution to rural energy poverty, agricultural productivity, environmental protection, and sustainable development since the 1960s (Nekhubvi and Tinarwo, 2017). Governments, international development agencies, and non-governmental organizations have frequently implemented household biogas programs using standardized, top-down approaches, often assuming that a single technological solution could address diverse socioeconomic and environmental challenges across rural communities (Adelekan B., 2012; Barnhart, 2014). Following the global energy crisis of the 1970s, biogas programmes expanded rapidly as countries sought alternatives to fossil fuels while reducing deforestation associated with fuelwood consumption (UNDP, 2024; UNFCCC, 2024). More recently, biogas has gained renewed attention within global climate and sustainable development agendas because of its potential to reduce greenhouse gas emissions, improve sanitation, enhance soil fertility through bioslurry utilization, and increase access to clean cooking energy.

Despite these recognized benefits, evidence from the literature indicates that the long-term sustainability of household biogas systems remains inconsistent across countries and regions (Nekhubvi and Tinarwo, 2022; Ali et al., 2023; Bryan and Meinzen-Dick, 2026). Existing studies have predominantly focused on individual aspects of biogas implementation, such as digester performance, methane production, or economic feasibility (Prasad, 2012; Chan and Sasaki, 2014), while paying comparatively little attention to the complex interactions among technical, institutional, financial, and social factors that ultimately determine sustained operation and community benefits (Bhandari, 2019; Ogryzek, 2023). Consequently, there remains limited theoretical and empirical understanding of how these interconnected dimensions collectively influence technology adoption, long-term functionality, maintenance practices, and broader rural development outcomes.

The consequences of this fragmented understanding are reflected in the high proportion of abandoned or non-functional household digesters reported worldwide. Although the definition of program failure varies among stakeholders (Kalina et al., 2022; Gbadeyan et al., 2024), it is commonly associated with installed digesters that are no longer operational or in regular use. Such failures have occurred across both small-scale pilot projects and large national programmes (Ho et al., 2015; Hoang and Kato, 2021). For example, China had installed approximately 41.9 million household digesters by 2015, yet only an estimated 40%–60% remained operational after installation (Izumi et al., 2016; Xie et al., 2023). Similarly, India has installed nearly five million household digesters, with reported post-installation functionality ranging between 40% and 80% (Bhat et al., 2001; Mittal et al., 2018). Comparable challenges have also been reported in several African countries, including Malawi, where many donor-funded digesters ceased operation shortly after project completion. Furthermore, many national biogas programmes lack comprehensive monitoring systems capable of accurately tracking non-functional or abandoned digesters, making the true magnitude of implementation failure difficult to quantify.

These persistent challenges suggest that biogas technology should not be viewed solely as an engineering intervention but rather as a socio-technical system whose success depends on interactions among technological performance, institutional support, financial viability, community participation, and enabling policy environments (Sime, 2020; Tucho and Kumsa, 2020). Recent sustainability research increasingly advocates integrated analytical approaches that recognize these interdependencies and their influence on long-term technology transitions (Abanades et al., 2022; D'Aquino et al., 2022). However, existing frameworks rarely provide a comprehensive structure that simultaneously captures these multiple dimensions and links technical performance to socioeconomic development outcomes.

To address this gap, the present study develops an Integrated Biogas Sustainability Framework (IBSF) that conceptualizes household biogas systems through four interrelated dimensions: technical performance, socioeconomic inclusion, institutional and policy support, and financial sustainability. Unlike previous frameworks that primarily evaluate engineering performance or economic feasibility in isolation, the IBSF integrates these dimensions into a unified socio-technical framework that explains how interactions among them influence long-term adoption, operational reliability, and community resilience. The framework synthesizes evidence from international experiences and contextualizes these lessons for rural communities in South Africa, where institutional capacity, financing mechanisms, and community participation remain significant determinants of successful implementation.

The principal contribution of this study lies in advancing biogas research beyond conventional assessments of technical efficiency and subsidy dependence. First, it demonstrates how technical performance and socioeconomic outcomes are mutually reinforcing rather than independent determinants of sustainability. Second, it reframes household biogas as a productive rural investment capable of generating multiple economic, agricultural, environmental, and social benefits rather than merely a subsidized household energy technology. Third, by drawing comparative lessons from international experiences, the study identifies how coordinated policy support, innovative financing mechanisms, local market development, and participatory implementation approaches can substantially improve adoption and long-term functionality. In doing so, the study provides both a theoretical framework for analysing biogas sustainability and practical guidance for policymakers, development practitioners, and researchers seeking to scale household biogas systems in South Africa and other developing countries.

Ultimately, this research contributes to the broader literature on renewable energy transitions by demonstrating that the implementation of sustainable biogas requires integrated solutions that simultaneously improve clean energy access, strengthen agricultural productivity, stimulate rural entrepreneurship, enhance institutional capacity, and support the achievement of multiple Sustainable Development Goals. Through a comprehensive synthesis of global evidence and comparative analysis, the study identifies critical barriers and enabling conditions that can inform the design of more resilient and socially inclusive biogas programmes.

2 Literature review

2.1 Biogas systems across scales

Biogas technology is widely recognized as one of the most promising renewable energy solutions for developing countries, particularly in the Global South, where rapid population growth, increasing energy demand, and limited access to modern energy services continue to constrain sustainable development (Wang et al., 2020; Kowalski and Koppetsch, 2021; Gan et al., 2023). Technology offers multiple environmental, economic, and social benefits by converting locally available organic waste into clean energy and nutrient-rich biofertilizer through anaerobic digestion (Kougias and Angelidaki, 2018). Its scalability enables deployment across household, community, and commercial levels, while advances in digester design, feedstock optimization, and process control have significantly improved operational efficiency, methane recovery, and system safety.

The increasing generation of organic waste presents a significant opportunity for expanding biogas production. Rapid urbanization and population growth have resulted in substantial quantities of biodegradable waste, estimated at approximately 0.56 kg per person per day, with more than half consisting of organic materials and approximately one-quarter being recyclable. Rather than representing an environmental burden, these waste streams constitute valuable feedstocks that can support renewable energy generation, waste valorization, greenhouse gas mitigation, and circular economy (CE) initiatives. Consequently, biogas systems are increasingly viewed as strategic interventions that can stimulate green economic growth, create employment opportunities, improve agricultural productivity through bioslurry utilization, and advance multiple Sustainable Development Goals (SDGs).

Despite these recognized advantages, the widespread adoption and long-term sustainability of biogas systems remain constrained by numerous technical, financial, institutional, and policy-related barriers. Previous studies consistently identify inadequate financing mechanisms, weak regulatory frameworks, limited technical expertise, poor infrastructure, ineffective waste management systems, and insufficient post-installation support as major obstacles to successful implementation (Bundhoo, 2018; Ebhota and Tabakov, 2024). While countries such as China, India, and Germany have demonstrated that well-coordinated national programmes can generate substantial environmental, economic, and social benefits, many developing countries continue to experience fragmented implementation characterized by low adoption rates, poor system performance, and high abandonment levels.

A major limitation of the existing literature is its tendency to examine biogas systems from isolated disciplinary perspectives. Engineering studies primarily evaluate digester efficiency, methane production, or process optimization, whereas social science research frequently focuses on individual outcomes such as health improvements, women’s empowerment, or reductions in fuelwood consumption (Ellen MacArthur Foundation, 2024; Adelekan I. O., 2012). Comparatively few studies investigate how technical performance interacts with socioeconomic conditions, institutional arrangements, financing mechanisms, community participation, and policy support to influence long-term system functionality and sustainability (Garkoti and Thengane, 2024; Sher et al., 2024). This fragmented perspective limits understanding of the complex socio-technical processes that determine whether biogas projects remain operational beyond their initial implementation phase.

Biogas production occurs through anaerobic digestion, a biological process in which naturally occurring microorganisms decompose organic matter under oxygen-free conditions to produce biogas and nutrient-rich digestate. The resulting biogas typically contains 50%–70% methane (CH₄), 30%–50% carbon dioxide (CO₂), and small quantities of hydrogen sulfide, water vapor, and other trace gases (Bond and Templeton, 2011; Abanades et al., 2022). The flexibility to process a wide range of feedstocks including livestock manure, crop residues, food waste, municipal organic waste, and human excreta makes biogas technology highly adaptable across diverse environmental, agricultural, and socioeconomic contexts. This versatility further strengthens its role in promoting circular economy principles by simultaneously addressing renewable energy production, waste management, nutrient recycling, and climate change mitigation.

However, successful technology deployment depends considerably more than engineering performance. Numerous implementation failures demonstrate that technological potential alone cannot guarantee sustainable outcomes without adequate institutional support, financial sustainability, user capacity, and long-term maintenance systems. A notable example is the United Nations Development Programme (UNDP) household biogas initiative implemented in Malawi between 2016 and 2018, during which 72 household digesters were installed across several rural communities, including six in Nsanje District, with the objective of replacing fuelwood and improving household energy security (Schröder and Barrie, 2024; González et al., 2020). Although the programme initially generated considerable optimism, an independent evaluation conducted in 2021 reported that none of the digesters remained functional throughout their intended operational lifespan.

Subsequent field observations undertaken in 2022 revealed abandoned infrastructure, including deteriorated digester bags repurposed as roofing material, rusted cooking stoves, damaged gas pipelines, and non-operational digesters. These findings illustrate how inadequate post-installation support, limited technical training, poor maintenance services, and weak institutional ownership can undermine otherwise promising renewable energy interventions. Similar implementation challenges have been documented across several countries in sub-Saharan Africa, where high abandonment rates and limited utilization of valuable co-products such as bioslurry continue to reduce the long-term socioeconomic and environmental benefits of household biogas programmes.

The experiences of China, India, and South Africa further demonstrate that installation numbers alone are poor indicators of programme success. As summarized in Table 1, China has installed more than 40 million household digesters, yet only an estimated 40%–60% remain operational, while India’s approximately five million digesters exhibit functionality rates ranging from 40% to 80% (Bhat et al., 2001; Xie et al., 2023). These differences largely reflect variations in user training, technical support systems, financing mechanisms, policy continuity, and programme management. South Africa presents an even more challenging situation. Despite considerable potential for agricultural waste utilization, fewer than 500 household-scale digesters have been installed, with operational rates generally below 50%. Key constraints include insufficient livestock manure availability, affordability challenges, inadequate technical support, limited after-sales maintenance services, and weak institutional coordination (Msibi and Kornelius, 2017; Rasimphi et al., 2024). Collectively, these international experiences demonstrate that sustainable biogas implementation depends not only on technological performance but also on the integration of effective financing, maintenance systems, institutional support, and community participation.

TABLE 1. Comparative performance of household biogas systems across regions.

These persistent implementation challenges highlight the need for more comprehensive analytical approaches that move beyond isolated assessments of technical efficiency or socioeconomic outcomes. Instead, there is a growing need for integrated frameworks capable of capturing the interactions among technical performance, financial sustainability, institutional capacity, policy support, and community engagement. Addressing this gap provides the foundation for the Integrated Biogas Sustainability Framework (IBSF) developed in this study, which seeks to explain how these interdependent dimensions collectively influence the long-term performance and social outcomes of household biogas systems.

Despite widespread installation of micro-, medium-, and large-scale digesters globally, micro-scale systems dominate, with nearly 50 million units serving around 126 million people (Selamawit and Agizew, 2022; Tolessa, 2024). Large-scale national programs, such as the 26.5 million household digesters in China and four million in India, demonstrate biogas’s potential to improve energy access, waste management, and rural development (Rasimphi et al., 2024). Nonetheless, persistent high abandonment rates indicate that technical design as shown in Table 2, financial accessibility, operational support, and institutional integration remain critical determinants of sustainable outcomes.

TABLE 2. Synthesis of evidence on biogas digester performance, impacts, and regional dimensions.

In summary, while biogas technology offers a versatile renewable energy solution, its success depends on a combination of technical reliability, community engagement, financial feasibility, and institutional support. Focusing exclusively on technical efficiency or isolated social benefits overlooks the systemic factors that influence adoption and sustainability, highlighting the need for integrated approaches to maximize impact.

2.2 Operational status and performance post-installation

Despite the technical promise of biogas digesters, evidence shows that operational challenges frequently undermine their long-term effectiveness in rural areas. Globally, high failure rates are common: up to 50% of digesters in China and Nepal become non-functional shortly after installation (Wang, 2014; Nindhia et al., 2021). In Bangladesh, small-scale cattle digesters achieve only 57% of projected energy output, while poultry-based systems reach just 28%, with 91% of plants underfed (Rahman et al., 2019; Nindhia et al., 2021). These figures indicate that the mere provision of infrastructure does not guarantee sustained use or intended benefits. Key factors contributing to underperformance include poor feedstock management, inconsistent maintenance, structural deficiencies, high installation costs, and limited technical knowledge among users (Omer, 2014; Nekhubvi, 2022; Sibanda and Uzabakiriho, 2024). Even well-established programs in Asia report utilization rates around 50%, highlighting that system design and installation must be complemented by ongoing operational support (Rasimphi et al., 2024; Barahmand and Samarakoon, 2023). Targeted interventions, such as Vietnam’s Key Farmer program, demonstrate that structured training and consistent maintenance can substantially improve performance, achieving operational rates of 92.3% alongside measurable CO₂ reductions.

However, significant gaps remain in understanding the household-level, socio-cultural, and environmental factors that influence sustained digester use. Comparative analyses of maintenance models, design efficiency, and socio-economic drivers of adoption are limited, particularly in African contexts. Similarly, environmental outcomes such as greenhouse gas mitigation and nutrient recycling through bioslurry are inconsistently documented, limiting evidence-based policy and program design (Ho et al., 2017; Hoang and Kato, 2022). Addressing these challenges requires an integrated approach that combines technical support, capacity building, community engagement, and sustainable financing models. Longitudinal field studies and structured support programs can enhance operational reliability, maximize socio-economic benefits, and strengthen environmental outcomes. Without attention to these systemic factors, laboratory or pilot-level successes rarely translate into practical, sustainable adoption of biogas technology in rural communities.

2.3 Social and environment impact of small-scale biogas digesters

Small-scale biogas digesters present substantial potential to advance sustainable development by simultaneously addressing energy, agricultural, and livelihood challenges in rural and marginalized communities (Surendra et al., 2014; Mihai, 2017). As a clean, renewable alternative to traditional biomass fuels, these systems diversify household energy sources, reduce reliance on firewood, charcoal, and kerosene, and lower household energy expenditures (Omer, 2014; Chan et al., 2015; Gan et al., 2025; Garkoti and Thengane, 2025). This energy diversification strengthens household energy security and resilience, particularly in remote areas with limited access to centralized electricity or where fuel costs fluctuate seasonally.

The benefits of small-scale biogas adoption intersect multiple Sustainable Development Goals (SDGs), including SDG 1 (No Poverty), SDG 3 (Good Health and Wellbeing), SDG 5 (Gender Equality), and SDG 7 (Affordable and Clean Energy). By linking energy access, environmental protection, agricultural productivity, and social equity, biogas digesters operate as holistic tools for inclusive and resilient rural development. However, despite these advantages, critical knowledge gaps persist. Longitudinal evidence quantifying sustained economic, social, and environmental impacts is limited (Sinharoy and Kannan, 2025). Disaggregated analyses on gendered time savings, income generation, and health improvements are sparse, leaving unclear how benefits are distributed across households and communities (Nekhubvi, 2024; Rietveld et al., 2025; Roubík et al., 2018). Furthermore, the interactions between technical performance, user behavior, and social outcomes are underexplored, reducing understanding of how adoption patterns influence the realization of social and environmental benefits (Meinzen-Dick et al., 2019). Empirical links between biogas adoption and measurable SDG outcomes remain insufficiently documented, limiting evidence-based policymaking (Wu et al., 2022). Social benefits extend beyond economic gains. Biogas adoption reduces indoor air pollution, mitigating respiratory disease risks, and improves sanitation when human or animal waste is utilized as feedstock (Smith et al., 2014; Ntaganda et al., 2024). It also promotes gender equity by reducing the workload of women and children, who traditionally collect fuelwood, thereby freeing time for education, income-generating activities, and community engagement (Kamp and Forn, 2016). These effects demonstrate that small-scale biogas digesters can contribute to broader social development outcomes, yet their potential is contingent on sustained use, technical reliability, and integration with community-level capacity-building and support mechanisms (Toponar et al., 2024; Wang et al., 2021; Xie et al., 2023; Zuloeta Bonilla and Bhandari, 2022). In sum, while small-scale biogas systems offer clear social and environmental benefits, their transformative impact depends on comprehensive, context-sensitive approaches that link technical performance, user behavior, and institutional support. Addressing the highlighted research gaps is essential to maximize the contribution of biogas technology to sustainable development.

Household biogas systems provide measurable social benefits, particularly in health and gender equity, illustrating the intersection of technological performance and societal outcomes. By replacing traditional biomass fuels, biogas significantly reduces indoor air pollution, a leading contributor to respiratory and cardiovascular illnesses (Bonjour et al., 2013; Ntaganda et al., 2024). Globally, approximately 2.8 billion people still rely on solid fuels for cooking, emphasizing the scale of the health challenge (Bonjour et al., 2013). Evidence from Nepal, India, and Vietnam demonstrates that properly installed and maintained digesters correlate with declines in respiratory diseases, confirming that biogas adoption can deliver tangible health improvements when operational support is adequate.

Beyond health, biogas adoption advances social equity by reducing the labor burden on women and children, who traditionally collect fuelwood (Ntaganda et al., 2024). Freed time allows women to pursue income-generating activities and children to focus on education (Kamp and Forn, 2016; Wainaina et al., 2020). Biogas stoves are also safer and more efficient than open-fire alternatives, reducing risks of burns and household accidents. These outcomes link energy provision directly to broader social development goals, supporting SDG 3 (Good Health and Wellbeing) and SDG 5 (Gender Equality).

Environmental benefits further reinforce these social gains. By converting organic waste into renewable energy, household digesters reduce greenhouse gas emissions, limit fossil fuel reliance, and improve local environmental quality (Surendra et al., 2014; Sovacool et al., 2019). In Vietnam, households with biogas systems reduced annual emissions from 20.53 tons CO₂-equivalent to 4.52 tons, highlighting both environmental and operational effectiveness (Roubík et al., 2020). Methane capture prevents the release of a potent greenhouse gas, while biogas use for cooking and heating reduces carbon dioxide emissions and indoor pollutants.

Biogas adoption also contributes to forest conservation by lowering fuelwood demand, preserving biodiversity, and preventing soil erosion (Ntaganda et al., 2024). The bio-slurry byproduct enhances soil fertility, improves water retention, and reduces dependence on chemical fertilizers, demonstrating a direct link between operational performance and agricultural and economic benefits (Rajendran et al., 2012; Tolessa, 2024). These outcomes integrate energy production, waste management, and sustainable agriculture, forming a circular economy model that simultaneously strengthens livelihoods and addresses climate change. This supports SDG 7 (Affordable and Clean Energy), SDG 12 (Responsible Consumption and Production), and SDG 13 (Climate Action).

At a broader policy level, household biogas systems contribute to national and global climate commitments, including the Paris Agreement, by reducing emissions from agriculture, waste management, and energy sectors. Nevertheless, translating these potential benefits into sustained impact requires attention to operational reliability, user capacity, community engagement, and post-installation support. Without these elements, the health, social, and environmental advantages remain unevenly realized, underscoring the need for integrated approaches that link technical performance to socio-environmental outcomes. Taken together, the literature shows that biogas digesters consistently deliver benefits where systems are reliable, users are supported, and institutional arrangements remain active beyond installation. Conversely, high abandonment rates, underfeeding, and declining use are closely linked to weak post-installation support, limited user ownership, and misaligned financing models. These patterns suggest that biogas outcomes cannot be explained through technical performance alone. Instead, they point to the need for an integrated analytical lens that captures how technical, social, institutional, and financial factors interact over time. This insight provides the basis for the Integrated Biogas Sustainability Framework introduced in the following section.

3 Review protocol and analytical approach

This study employed a structured narrative review and thematic synthesis to critically examine the technical performance, socioeconomic outcomes, financing mechanisms, institutional support, and sustainability of biogas technology in rural development. Unlike traditional narrative reviews that primarily summarize existing literature, this review adopted a systematic search and screening process followed by an interpretive synthesis grounded in systems thinking. The objective was not only to consolidate existing evidence but also to identify the interrelationships among technical, social, financial, and institutional factors that informed the development of the Integrated Biogas Sustainability Framework (IBSF).

A comprehensive literature search was conducted using four major electronic databases: Scopus, Web of Science, ScienceDirect, and Google Scholar. Additional publications were identified through manual searches of reference lists and reports published by international organizations, including the International Energy Agency (IEA), the United Nations Development Programme (UNDP), the Food and Agriculture Organization (FAO), and the World Bank. The search focused on studies published between 2000 and 2025, capturing the rapid evolution of biogas technologies and their applications in rural development.

The literature search employed combinations of keywords and Boolean operators, including: “biogas technology” AND sustainability, “anaerobic digestion” AND rural development, “biogas adoption”, “biogas performance”, “renewable energy” AND rural livelihoods, “biogas financing”, “circular economy” AND biogas, and “bio-slurry” AND agriculture. These search terms were refined iteratively to ensure comprehensive coverage of both technical and socioeconomic dimensions of biogas systems.

Studies were included if they:

• were published in peer-reviewed journals, conference proceedings, or reputable institutional reports;
• focused on household, community-scale, or commercial biogas systems;
• evaluated one or more dimensions of biogas performance, including technical, environmental, economic, social, institutional, or policy aspects;
• provided empirical evidence, case studies, review findings, or programme evaluations relevant to developing or emerging economies.
• Studies were excluded if they:
• focused exclusively on laboratory-scale anaerobic digestion without broader implementation implications;
• lacked sufficient methodological information or scientific rigor;
• were duplicates or non-English publications;
• addressed unrelated renewable energy technologies without explicit discussion of biogas systems.

The literature selection followed a four-stage screening procedure consisting of identification, screening, eligibility assessment, and final inclusion. Initially, titles and abstracts were reviewed to remove irrelevant publications. The remaining articles underwent full-text evaluation against the predefined inclusion and exclusion criteria. Only studies providing robust evidence relevant to the objectives of this review were retained for detailed analysis. Although this review followed a structured search strategy, its purpose was interpretive synthesis rather than quantitative meta-analysis.

Following study selection, the included literature was analysed using thematic content analysis. During the first stage, recurring concepts relating to technical performance, operational reliability, feedstock management, financing mechanisms, policy support, institutional arrangements, user participation, gender inclusion, environmental sustainability, and rural livelihoods were identified and coded. In the second stage, evidence was compared across geographical regions to identify common success factors, implementation barriers, and context-specific differences. Particular attention was given to contrasting experiences from Asia, Europe, and sub-Saharan Africa to understand how contextual conditions influence long-term biogas sustainability.

The final stage involved an integrative synthesis using Systems Thinking as the analytical lens. Rather than examining technical, financial, social, and institutional factors independently, the review explored the interactions, reinforcing feedback loops, and dependencies among these dimensions. This systems-based interpretation enabled the identification of leverage points influencing successful biogas implementation and directly informed the development of the Integrated Biogas Sustainability Framework (IBSF). The framework was therefore derived through iterative synthesis of empirical evidence rather than conceptual abstraction alone, ensuring that it reflects both theoretical understanding and practical implementation experience.

To enhance the credibility of the review, evidence was triangulated across multiple study types, including empirical investigations, systematic reviews, policy analyses, and international programme evaluations. Greater emphasis was placed on recent publications (2020–2025) to ensure that the framework reflects current advances in biogas technology, financing innovations, operational optimisation, and sustainable rural development. This rigorous analytical approach provides a comprehensive evidence base for understanding the multidimensional factors that determine the long-term performance and sustainability of biogas systems in rural communities.

4 Rural development and energy access

Biogas technology has increasingly been recognized as a strategic intervention for addressing the interconnected challenges of energy poverty, environmental degradation, and rural underdevelopment in low- and middle-income countries. In many rural communities, particularly across sub-Saharan Africa and South Asia, limited access to reliable modern energy services compels households to rely on traditional biomass fuels such as firewood, charcoal, and agricultural residues for cooking and heating (IEA, 2023; Surendra et al., 2014; Sovacool et al., 2019). This dependence contributes to deforestation, indoor air pollution, and adverse health outcomes while imposing considerable labour burdens, especially on women and children responsible for fuelwood collection. By converting locally available organic waste into renewable energy, household-scale biogas digesters provide an integrated solution that simultaneously addresses energy access, waste management, and environmental sustainability.

Beyond energy provision, biogas technology contributes to broader rural development through its multiple socioeconomic benefits. The construction, installation, operation, and maintenance of biodigesters create local employment opportunities and stimulate small-scale enterprises associated with bioslurry production and marketing (Rajendran et al., 2012; Wainaina et al., 2020). Bioslurry, a nutrient-rich by-product of anaerobic digestion, enhances soil fertility, improves crop productivity, and reduces dependence on synthetic fertilizers, thereby strengthening food security while lowering agricultural production costs. These synergies demonstrate that biogas systems should be viewed not merely as renewable energy technologies but as integrated components of circular agricultural systems that simultaneously recover energy, recycle nutrients, and improve rural livelihoods.

Evidence from diverse geographical settings consistently demonstrates the multidimensional benefits of biogas adoption. Studies conducted in the Andes have shown that small-scale digesters can satisfy household cooking and lighting requirements while substantially reducing reliance on kerosene and firewood, improving indoor air quality, and decreasing respiratory illnesses (Jaeger and Blanchard, 2022). Similar outcomes have been reported across sub-Saharan Africa and South Asia, where biogas adoption has reduced fuelwood consumption, improved household sanitation, and generated significant time savings for women and children, enabling greater participation in education, income-generating activities, and community development (Armah, 2017; Rajendran et al., 2012; Wainaina et al., 2020). These findings suggest that the benefits of biogas extend well beyond energy production, contributing to gender equity, social inclusion, improved public health, and enhanced household resilience.

Despite these documented benefits, the long-term sustainability and scalability of rural biogas programmes remain inconsistent. Numerous studies report that technical failures, inadequate maintenance, limited access to finance, weak institutional support, and insufficient post-installation services continue to constrain sustained utilization and reduce user confidence (Sovacool et al., 2019; Surendra et al., 2014). The performance of biogas systems, therefore, depends not only on engineering design but also on the interaction between technical reliability, financial accessibility, institutional capacity, community participation, and supportive policy environments. Programmes that address only technological deployment without strengthening these complementary dimensions frequently experience low adoption rates, system abandonment, and limited developmental impacts.

These observations highlight an important gap in the existing literature. While previous studies have examined the technical, environmental, economic, and social dimensions of biogas technology independently, relatively few have investigated how these dimensions interact to influence long-term sustainability. Longitudinal evidence on household energy security, livelihood improvement, gender empowerment, and agricultural productivity remains limited, particularly within African contexts. Similarly, comparative analyses examining the effectiveness of financing models, institutional arrangements, and community-based implementation strategies are scarce. Addressing these gaps requires a systems-oriented perspective that recognises biogas technology as a socio-technical system in which technical performance, financial mechanisms, institutional support, and social acceptance operate as mutually reinforcing components. This integrated understanding provides the conceptual foundation for the Integrated Biogas Sustainability Framework (IBSF) proposed in this study.

5 The financial dimension of the IBSF

Although subsidies, carbon finance, and microcredit are widely cited as solutions to affordability constraints, their effectiveness varies significantly by context. Subsidy-driven programmes in China and India have succeeded where they were combined with quality control, post-installation support, and gradual cost-sharing, reinforcing both affordability and user ownership (Tinarwo et al., 2026). In contrast, subsidy-only models in parts of sub-Saharan Africa have often contributed to weak ownership and high abandonment once external support ended.

Carbon financing has proven effective in contexts with strong monitoring systems and aggregation mechanisms, such as Vietnam’s domestic biogas programme, but has been less successful in rural African settings where transaction costs and verification requirements remain prohibitive. Similarly, microcredit schemes perform better when repayment schedules align with agricultural income cycles and when loans are bundled with technical training. Where these conditions are absent, credit can increase household risk rather than support adoption. These patterns suggest that no single financing model is universally effective. Instead, financing success depends on alignment with local livelihoods, institutional capacity, and system performance. Within the IBSF, financial mechanisms are therefore treated not as standalone inputs, but as interacting components that reinforce or undermine technical reliability and social inclusion depending on context.

6 Critical synthesis of global biogas technology

6.1 Operational performance and adoption patterns of biogas digesters: global, national, and local perspectives

The global literature on biogas digesters underscores both their potential and the persistent challenges that shape their impact on energy access, waste management, and rural development. While biogas technology has proven effective in diverse contexts, its adoption and performance are uneven, reflecting structural, technical, and socio-economic constraints that limit long-term sustainability.

6.1.1 Global performance

Globally, biogas digesters represent a significant renewable energy solution, with over 50 million units installed by 2020, primarily in Asia (Kumar et al., 2025). China alone hosts more than 40 million household digesters, supported by government programmes providing subsidies, technical assistance, and structured maintenance networks (Chen et al., 2020). These systems demonstrate reliable performance, highlighting the importance of consistent feedstock availability and institutional support. In Europe, countries such as Germany and Denmark have transitioned to industrial-scale biogas plants, contributing up to 10% of Germany’s renewable energy mix (Meyer et al., 2018). Advanced technologies, including feedstock pre-treatment, automated monitoring, and combined heat and power generation, enable year-round efficiency, even in colder climates, demonstrating that technology design and operational support are critical determinants of success.

By contrast, performance in low-income regions, particularly sub-Saharan Africa and South Asia, remains inconsistent. Between 30% and 40% of digesters in these regions fail within three to 5 years due to irregular feedstock supply, limited technical skills, and poor access to spare parts (Mwirigi et al., 2014; Ntaganda et al., 2024). Environmental constraints, such as lower microbial activity in colder climates or seasonal shortages of organic feedstock, further undermine reliability (Surendra et al., 2014; Roubík et al., 2018). These patterns illustrate that without technical, financial, and institutional support, the promise of biogas for rural energy access is rarely fully realized.

6.1.2 South Africa

South Africa has significant biogas potential owing to its agricultural and municipal waste resources and persistent energy shortfalls (Lindgren et al., 2021; Rasimphi et al., 2024). However, national adoption remains limited, with fewer than 500 small-scale digesters installed alongside a few commercial and industrial-scale plants (DMRE, 2022). Performance differs markedly by scale. Large industrial facilities, such as the Bronkhorstspruit plant processing over 1,200 tonnes of organic waste daily, operate reliably due to dedicated feedstock streams, professional management, and financial stability (GreenCape, 2022). Small household systems, however, underperform frequently. Many rural households lack sufficient livestock or face seasonal feedstock shortages, while competing uses for crop residues, such as animal feed, further limit gas production. Surveys indicate that over 60% of rural digesters are underperforming or abandoned, primarily due to inadequate maintenance, lack of spare parts, and weak user ownership (Agama Biogas, 2018). The absence of targeted subsidies and technical support, which underpin successful programmes in Asia and Europe, further constrains long-term success.

6.1.3 Local performance in limpopo

At the community level, experiences in Limpopo highlight both tangible benefits and persistent operational gaps. Household digesters have reduced firewood reliance, improved indoor air quality, and freed time for women previously responsible for fuelwood collection. In Vhembe District, pilot programmes reported up to 40% reductions in firewood use and improved household sanitation, while some users benefited from backup energy during load shedding. Despite these gains, operational reliability remains inconsistent. Households owning fewer than three cattle often experience unstable gas production, leading to frequent interruptions and a reversion to firewood or paraffin (Ali et al., 2023). A 2023 study found that nearly half of digesters installed between 2015 and 2020 were non-functional due to limited maintenance, inadequate technical support, and lack of spare parts (Rasimphi et al., 2024). Socioeconomic factors further constrain sustainability. Affordability of repairs, low technical skills, and competing feedstock uses limit long-term operational success. Youth training initiatives, which employed 20–25 young people in installation and maintenance activities (El-Maradny et al., 2025), demonstrate that local capacity-building can improve technical support and community engagement. However, without structured after-sales services and systematic monitoring, these gains are rarely sustained, underscoring the importance of integrating operational support with broader social and institutional frameworks.

Overall, global, national, and local evidence emphasizes that biogas digesters deliver meaningful energy, environmental, and social benefits, but their impact is strongly mediated by operational reliability, technical capacity, institutional support, and socio-economic conditions. High abandonment and underperformance rates in low-income contexts illustrate that technological potential alone is insufficient; sustainable adoption requires a holistic approach that combines feedstock planning, capacity-building, financing mechanisms, and monitoring systems to ensure that the benefits of biogas reach intended users and contribute meaningfully to rural development.

6.2 Financial mechanisms and innovative financing models for rural renewable energy

Financial accessibility remains one of the most significant determinants of successful biogas adoption and long-term sustainability. Although numerous financing mechanisms have been implemented to reduce the high upfront costs associated with biodigester installation, evidence suggests that their effectiveness depends less on the financing instrument itself than on the institutional, technical, and socioeconomic conditions within which it operates. Consequently, financing should be viewed as an enabling component of biogas systems rather than a standalone solution to adoption barriers.

Subsidy programmes have played an important role in expanding biogas deployment, particularly in countries such as China and India, where they have been integrated with comprehensive implementation strategies that include quality assurance, technical training, post-installation maintenance, and progressive cost-sharing mechanisms. These complementary interventions have enhanced both affordability and user ownership, resulting in higher adoption and system functionality. In contrast, subsidy-driven programmes implemented in several sub-Saharan African countries have often produced less favourable outcomes because financial assistance was not accompanied by adequate technical support, institutional coordination, or user capacity-building. As a result, many households became dependent on external assistance, contributing to poor maintenance practices, declining user ownership, and high rates of system abandonment once project funding ended.

Carbon finance has also emerged as an important mechanism for supporting biogas deployment by monetising greenhouse gas emission reductions. However, its effectiveness has varied considerably across regions. Successful programmes, such as Vietnam’s domestic biogas initiative, have benefited from well-established monitoring systems, institutional coordination, and efficient aggregation mechanisms that reduce transaction costs and facilitate carbon credit verification. By comparison, many rural African programmes have struggled to access carbon markets because of fragmented projects, limited technical capacity, and the relatively high costs associated with monitoring, reporting, and verification. These challenges reduce the financial attractiveness of carbon finance despite the significant climate mitigation potential of small-scale biogas systems.

Similarly, microfinance has demonstrated considerable potential for improving household access to biodigesters, particularly where loan products are specifically designed to reflect the seasonal and often unpredictable nature of agricultural incomes. Flexible repayment schedules, low-interest financing, and integration with technical training and extension services have consistently improved repayment performance and technology adoption. Conversely, conventional credit schemes that fail to accommodate rural livelihood characteristics may increase household financial vulnerability, discouraging investment in renewable energy technologies rather than facilitating it. These findings highlight the importance of designing financing mechanisms that respond to local socioeconomic realities rather than applying uniform financial models across diverse rural contexts.

Collectively, the literature demonstrates that no single financing mechanism can universally ensure successful biogas adoption. Instead, financing outcomes emerge from the interaction between financial accessibility, institutional capacity, technical reliability, and community participation. Effective financing therefore requires coordinated implementation that combines affordable capital with technical assistance, policy support, quality assurance, and long-term maintenance services. This systems perspective underpins the Integrated Biogas Sustainability Framework (IBSF), in which financial mechanisms are conceptualised as dynamic components that both influence and are influenced by technical performance, institutional effectiveness, and social inclusion. By recognizing these interdependencies, the framework moves beyond conventional financing models to provide a more comprehensive understanding of how financial systems contribute to the long-term sustainability of rural biogas programs.

6.3 Performance, social, environmental, and financial outcomes of biogas digesters

The adoption of biogas digesters in rural communities delivers multiple, interconnected outcomes, but the scale and sustainability of these benefits depend on technical performance, social engagement, and financial accessibility. While biogas systems are often promoted for single benefits such as clean cooking or waste management, evidence from the literature shows that their impacts are multi-dimensional. Social, economic, and environmental outcomes are closely interlinked and largely contingent on sustained system performance. Table 3 summarises these outcomes using examples from different regions, demonstrating how functional biogas systems contribute simultaneously to health improvements, livelihood enhancement, and environmental protection. Presenting these outcomes together reinforces the argument that biogas should be evaluated as an integrated rural development intervention rather than a standalone energy technology.

TABLE 3. Social, economic, and environmental outcomes of biogas adoption.

Sources: Kamp and Forn (2016); Surendra et al. (2014); Roubík et al. (2020); Ntaganda et al. (2024).

6.3.1 Technical performance

Technical performance is the cornerstone of sustainable biogas implementation because it directly determines whether the anticipated environmental, social, and economic benefits can be realised. Although numerous studies report that well-designed digesters provide reliable biogas production for household cooking and other domestic applications, evidence consistently demonstrates that technical performance varies considerably across geographical regions and implementation contexts. This variation is influenced not only by engineering design but also by feedstock availability, climatic conditions, maintenance practices, user knowledge, and institutional support.

Studies from China, Nepal, and India generally report higher functionality rates due to established quality standards, certified installation procedures, and well-developed maintenance networks. In contrast, many biogas programmes in sub-Saharan Africa continue to experience high rates of system underperformance and abandonment. These differences suggest that technical reliability depends less on the technology itself than on the institutional and operational systems supporting its implementation. Where routine maintenance, user training, and technical advisory services are absent, even technically sound digesters frequently fail to deliver expected energy outputs.

Feedstock management represents another critical determinant of operational performance. Households with insufficient livestock, seasonal variations in manure availability, or competing uses for crop residues often struggle to maintain continuous gas production. Similarly, digesters that are oversized relative to available feedstock or poorly matched to household energy demand frequently operate below their design capacity. These findings indicate that successful implementation requires context-specific system sizing and careful assessment of local resource availability rather than standardized technology deployment.

The literature further demonstrates that technical training substantially improves long-term functionality. Communities that receive practical instruction on feeding schedules, slurry management, troubleshooting, and routine maintenance consistently report higher system reliability than those relying solely on initial installation. Community-based maintenance networks and locally trained technicians have also proven more effective than centralized maintenance models because they reduce response times, lower maintenance costs, and strengthen local ownership.

From a systems-thinking perspective, technical performance should not be viewed as an isolated engineering outcome but as a reinforcing driver of overall sustainability. Reliable operation increases user satisfaction and confidence, encouraging continued utilisation, positive community perceptions, and greater willingness to invest in maintenance. Conversely, repeated technical failures generate negative feedback loops that reduce user trust, discourage adoption, and ultimately undermine programme sustainability. These interactions reinforce the central premise of the Integrated Biogas Sustainability Framework (IBSF), namely, that technical reliability both influences and is influenced by financial accessibility, institutional support, and community participation.

6.3.2 Environmental performance and resource utilization

The environmental benefits of biogas technology extend beyond renewable energy generation and encompass broader improvements in waste management, resource recovery, greenhouse gas mitigation, and sustainable agriculture. However, these benefits are highly dependent on sustained system functionality rather than simply the installation of biodigesters. Consequently, environmental performance should be evaluated as an outcome of successful long-term operation rather than an inherent characteristic of the technology.

Evidence consistently demonstrates that functional biogas systems reduce dependence on traditional biomass fuels, thereby lowering deforestation rates, decreasing greenhouse gas emissions, and improving indoor air quality. These environmental improvements are particularly significant in rural communities where firewood remains the dominant household energy source. Nevertheless, the magnitude of these benefits varies considerably among regions because fuel substitution depends on reliable gas production and consistent household utilisation. Where digesters produce insufficient gas or experience prolonged operational interruptions, households frequently revert to traditional fuels, substantially reducing the environmental gains initially achieved.

Resource recovery through bioslurry utilisation represents another important environmental advantage. Numerous studies report that bioslurry improves soil fertility, enhances crop productivity, and reduces reliance on synthetic fertilisers while supporting circular agricultural systems. However, these benefits are often underutilised because many programmes focus primarily on energy production and provide limited guidance on bioslurry management and agricultural application. As a result, valuable nutrients are frequently discarded, reducing both environmental and economic returns. This finding highlights the importance of integrating agricultural extension services into biogas programmes to maximise resource recovery and strengthen circular economy outcomes.

The literature also demonstrates that environmental performance is closely linked to operational management. Poorly maintained digesters may generate odours, slurry leakage, methane emissions, or waste accumulation, undermining the environmental objectives of biogas programmes. These challenges illustrate that environmental sustainability depends on effective maintenance, user awareness, and institutional monitoring rather than technological installation alone.

Within the Integrated Biogas Sustainability Framework (IBSF), environmental performance emerges from the interaction between technical reliability, user capacity, institutional support, and financial sustainability. Reliable systems maximise renewable energy generation and resource recovery, while supportive policies and extension services encourage appropriate waste management and bioslurry utilisation. This systems perspective demonstrates that environmental outcomes are not independent benefits but the product of coordinated technical, social, and institutional processes that collectively determine the long-term sustainability of rural biogas systems.

6.3.3 Social and health outcomes

Where systems function reliably, biogas adoption improves household wellbeing. Reduced firewood dependence lowers labor demands for women and children, freeing time for education, income generation, and community engagement (Sovacool et al., 2019; Kamp and Forn, 2016). Households report improved sanitation, better hygiene, and enhanced comfort. Biogas is often described as a “clean and dignified” energy source that strengthens social status and fosters community cohesion, with some households sharing gas with neighbors during shortages (Tolessa, 2024). Local employment opportunities arise through installation, maintenance, and bioslurry processing, contributing to youth empowerment and livelihood diversification. Gender-sensitive approaches further enhance women’s participation in training and management roles, reinforcing social inclusion as a key driver of sustainable adoption.

6.3.4 Financial outcomes and livelihood enhancement

Financially, biogas systems reduce household expenditure on firewood, charcoal, and paraffin, with reported savings of R150–R400 per month depending on household size and previous energy use (Amigun et al., 2012; Sovacool et al., 2019). These savings are often reinvested in education, food, or small income-generating activities, directly enhancing household resilience. The productive use of bioslurry for crops or livestock feed creates additional economic value, lowering input costs, increasing yields, and, in some cases, enabling commercialization through sales of organic fertilizer (Surendra et al., 2014; Tolessa, 2024). Access to biogas technology is constrained by upfront costs, emphasizing the need for innovative financial mechanisms. Models such as Pay-As-You-Go (PAYG), microfinance, results-based financing, and cooperative ownership reduce adoption barriers (REN21, 2024; SouthSouthNorth, 2025). PAYG allows households to pay in installments, microfinance aligns loan structures with local income flows, results-based financing incentivizes maintenance and performance, and cooperative ownership enables pooled resources and shared economic returns. Integrating these financial mechanisms with technical support and social inclusion ensures households not only adopt biogas technology but also sustain its use, translating operational and environmental gains into long-term social and economic benefits.

Collectively, these findings demonstrate that the impact of biogas digesters extends well beyond energy provision. Technical reliability enables environmental and social benefits, while financial accessibility ensures adoption and sustained use. The interdependence of these dimensions highlights that biogas programs must adopt a holistic approach combining technical design, capacity-building, social inclusion, and innovative financing to maximize their transformative potential in rural livelihoods, climate mitigation, and sustainable development.

6.3.5 User satisfaction and utilisation patterns

User satisfaction was directly linked to system reliability, ease of use, and access to support services. Satisfied users reported consistent use of biogas for cooking, heating water, and lighting, while dissatisfied users reverted to traditional fuels. The study found that well-functioning systems generated positive feedback loops users shared their experiences with neighbours, encouraging new installations and promoting collective maintenance practices. Conversely, systems that failed due to poor construction or neglect created negative perceptions about biogas technology. This cycle of satisfaction and feedback forms a central element of the Systems Thinking approach applied in this study. It demonstrates that sustained utilisation depends not only on technology but also on continuous learning, community trust, and the quality of information provided to users.

6.3.6 Implications for framework implementation

The observed performance and social outcomes validate the integrative nature of the proposed Framework for Successful Implementation of Biogas Technology. High-performing systems were consistently associated with projects that demonstrated strong stakeholder engagement, gender inclusion, and active feedback mechanisms. These factors fostered ownership, adaptability, and local problem-solving qualities essential for long-term sustainability. The findings also highlight the critical link between service quality, user satisfaction, and adoption rates, as captured in the study’s quality model. When users perceive biogas systems as reliable, affordable, and beneficial, utilisation increases, reinforcing the system through positive feedback. Conversely, technical failures or weak support structures erode confidence and reduce adoption. Thus, improving biogas performance requires a systemic approach that connects technical maintenance, community empowerment, and institutional coordination. The framework’s systems-based design provides a practical pathway for achieving these outcomes by aligning technical reliability with social and economic resilience in rural communities.

7 The integrated biogas sustainability framework (IBSF)

The sustainability of biogas technology in rural areas depends on more than technical design or feedstock availability. Studies across Africa, Asia, and Europe reveal that projects often fail not because of poor technology, but due to weak institutional support, limited user participation, and unsustainable financing mechanisms (Shaibur et al., 2021; Singh and Kalamdhad 2022). To bridge these analytical gaps, the Integrated Biogas Sustainability Framework (IBSF) was developed to capture the systemic interdependence among technical, social, financial, and institutional elements influencing the long-term success of biogas systems. The framework positions biogas as a socio-technical system one shaped by human behavior, policy environments, and resource dynamics rather than as a purely engineering solution. The IBSF builds conceptually on systems thinking and sustainability theory, integrating insights from global case studies to propose a unified structure for assessing performance and social outcomes. It provides a diagnostic and planning tool that identifies leverage points for sustainable implementation and equitable benefit distribution.

The Integrated Biogas Sustainability Framework (IBSF) as shown in Figure 1 provides a holistic model for understanding how multiple dimensions interact to influence both the technical performance and social outcomes of biogas digesters in rural development contexts. Unlike traditional evaluation methods that focus solely on system functionality or energy output, the IBSF integrates technical, social, institutional, and financial aspects to assess sustainability comprehensively. It acknowledges that biogas systems function as socio-technical ecosystems, where success depends equally on community participation, governance structures, and resource accessibility.

7.1 Core dimensions of the framework

7.1.1 Technical performance

This dimension focuses on the reliability, efficiency, and adaptability of digester systems. It includes parameters such as feedstock availability, gas yield, design suitability, maintenance quality, and environmental conditions. Consistent operational performance ensures that digesters deliver expected energy outputs and co-benefits such as waste reduction and bioslurry utilization. Within IBSF, technical performance acts as the foundation upon which other sustainability elements depend.

7.1.2 Socioeconomic inclusion

Biogas adoption succeeds when it aligns with local livelihoods, gender roles, and community priorities. Socioeconomic inclusion examines household participation, time and cost savings, livelihood improvements, and gender equity. When communities particularly women and youth are actively engaged in construction, maintenance, and decision-making, social ownership and long-term use increase. The IBSF highlights this as a reinforcing dimension, where social empowerment and energy access strengthen each other.

7.1.3 Institutional and policy support

Institutional stability determines the continuity of biogas programs. This dimension addresses governance structures, training systems, technical support services, and regulatory frameworks. Evidence shows that post-installation follow-up, quality standards, and coordination between government, private, and community actors are essential for maintaining functionality. Within the IBSF, institutional capacity serves as the enabling environment that sustains both technical reliability and social impact.

7.1.4 Financial mechanisms

Sustainable biogas deployment relies on accessible and inclusive financing. This component covers subsidies, credit schemes, cooperative ownership, cost-sharing, and market linkages for bioslurry. The framework emphasizes that financing models should be locally appropriate balancing affordability with user ownership to reduce dependence on external funding. Financial inclusivity thus acts as a stabilizing dimension, ensuring continuous operation and equitable access across income levels.

This study introduces a conceptual and practical innovation in the assessment of biogas technology by developing the Integrated Biogas Sustainability Framework (IBSF). Unlike conventional approaches that evaluate technical performance in isolation, the IBSF integrates four interdependent dimensions technical reliability, socio-economic inclusion, institutional and policy support, and financial mechanisms into a single analytical model. This holistic perspective reframes biogas digesters as socio-technical systems embedded within rural livelihood structures, rather than stand-alone energy devices.

The novelty of this work lies in its ability to bridge disciplinary gaps between engineering and social development research, offering a structured framework that captures the dynamic interactions among technical, social, and institutional factors influencing sustainability. By conceptualizing feedback loops and systemic interdependencies, the IBSF advances theoretical understanding of renewable energy adoption and provides a diagnostic tool for policymakers and practitioners to design inclusive, adaptive, and resilient biogas programs.

From a scientific standpoint, the framework contributes to:

• Conceptual advancement: Introducing a systems-thinking model specific to biogas technology.
• Empirical relevance: Grounding the framework in global evidence and context-specific insights from rural South Africa.
• Policy and planning utility: Enabling targeted interventions that align technical design with community engagement, financing strategies, and institutional coordination.
• Future research foundation: Establishing measurable indicators for operationalizing sustainability dimensions across diverse contexts.

By linking technical performance metrics with social, institutional, financial, and environmental dimensions, as summarized in Table 4, this study provides a novel roadmap for transforming biogas initiatives into catalysts for sustainable rural development. The proposed indicators offer practical guidance for researchers, practitioners, and policymakers to operationalize the Integrated Biogas Sustainability Framework (IBSF), evaluate implementation outcomes, and identify leverage points for improving the long-term sustainability of biogas systems across diverse rural contexts.

TABLE 4. Proposed indicators for evaluating the IBSF dimensions.

8 Analytical integration

The IBSF views these four dimensions as mutually reinforcing and interdependent (Figure 1). For example, strong institutional support improves technical performance through regular monitoring, while inclusive financing enhances social participation and ownership. Similarly, active community engagement promotes maintenance culture and improves the economic viability of projects through local entrepreneurship. Conversely, weaknesses in any one dimension such as poor financing or lack of training can destabilize the system and lead to digester abandonment. This integrated perspective allows for cross-level analysis linking household-level behavior with policy and market structures. It also accommodates feedback loops: improved biogas performance increases user satisfaction, which reinforces adoption and policy support, generating a virtuous cycle of sustainability.

9 Significance of the framework

The IBSF advances scientific and practical understanding in several key ways:

9.1 Bridging knowledge gaps

It moves beyond the fragmented literature that treats technical and social factors separately, offering a holistic framework that captures their interactions. This integration addresses a major theoretical gap in biogas research—namely, how multidimensional factors collectively influence sustainability.

9.2 Conceptual innovation

The framework introduces a structured socio-technical model specific to biogas systems, distinguishing it from general renewable energy frameworks. It contributes conceptually by mapping causal relationships among system components and identifying leverage points for sustainable performance.

9.3 Policy and planning relevance

Policymakers can use the IBSF to design comprehensive biogas strategies that align technical design with training programs, microfinance schemes, and institutional coordination. It provides a diagnostic tool for identifying weaknesses in existing programs and prioritizing interventions.

9.4 Guidance for future research

The framework establishes a theoretical foundation for empirical testing. Researchers can operationalize its dimensions through measurable indicators such as gas yield (technical), user satisfaction (social), policy coherence (institutional), and affordability (financial) to assess sustainability outcomes across contexts.

9.5 Contextual adaptability

The IBSF is adaptable to diverse settings, from household digesters in rural Limpopo to community-scale systems in Asia or Europe. Its emphasis on feedback loops and contextual drivers ensures it remains flexible and applicable across varying socio-economic environments.

9.6 Implications

By viewing biogas as a dynamic socio-technical system, the Integrated Biogas Sustainability Framework enables a more realistic and actionable understanding of why projects thrive or fail. It demonstrates that sustainable rural energy transitions cannot be achieved through technology alone, but through coordinated interventions that align technical robustness, social participation, institutional coherence, and financial inclusion. The IBSF thus serves as both a theoretical advancement and a practical roadmap for transforming biogas initiatives into catalysts for long-term rural development.

10 Conclusion

This review examined the performance and social outcomes of biogas digesters and developed the Integrated Biogas Sustainability Framework (IBSF) to provide a systems-based approach for improving the long-term sustainability of rural biogas programmes. The principal conclusions are as follows:

• Biogas technology has significant potential to improve rural livelihoods by simultaneously enhancing clean energy access, waste management, agricultural productivity, environmental sustainability, and socioeconomic wellbeing.
• Technical performance alone does not determine long-term success. Sustainable biogas implementation depends on the interaction among technical reliability, institutional support, financial accessibility, and active community participation.
• The literature demonstrates that many biogas programmes fail not because of technological limitations, but due to inadequate maintenance, weak post-installation support, limited financing, poor stakeholder engagement, and insufficient institutional coordination.
• The Integrated Biogas Sustainability Framework (IBSF) represents the primary contribution of this study by integrating technical, social, institutional, and financial dimensions into a single systems-thinking framework that captures the dynamic interactions influencing long-term biogas sustainability.
• The IBSF advances existing knowledge by moving beyond conventional technology-centred assessments and providing a holistic framework that supports evidence-based planning, implementation, monitoring, and evaluation of rural biogas programmes.
• From a practical perspective, the framework offers policymakers, development agencies, practitioners, and researchers a structured decision-support tool for identifying implementation barriers, prioritising interventions, and improving programme performance across diverse rural contexts.
• Future research should empirically validate the IBSF across different geographical and socioeconomic settings using measurable sustainability indicators, longitudinal studies, and systems modelling approaches to further refine and operationalise the framework.

Overall, the findings demonstrate that achieving sustainable rural energy transitions requires integrated socio-technical approaches rather than technology deployment alone. By recognising the interdependence of technical, financial, institutional, and social factors, the proposed IBSF provides a comprehensive roadmap for enhancing the long-term performance, resilience, and developmental impact of biogas systems in rural communities.

11 Recommendations for enhancing biogas adoption and sustainability

To address the identified gaps in operational performance, social impact, and rural development outcomes, the following recommendations are proposed:

• Promote locally adapted designs

Biogas systems should be customized to suit regional climatic conditions, available feedstock, and local cultural practices. Low-cost design innovations such as insulated digesters for colder regions, modular units for smallholder households, or simplified systems using locally sourced materials can enhance resilience, usability, and adoption. Tailoring designs to local contexts ensures digesters are functional, socially acceptable, and technically sustainable.

• Strengthen training and maintenance networks

Sustained capacity-building programs are essential to reduce the high failure rates documented globally. Establishing local service providers, community technicians, and peer-to-peer support networks can empower users to manage routine maintenance, troubleshooting, and minor repairs. Long-term technical support is critical for maintaining digester functionality, improving energy yields, and safeguarding the socioeconomic benefits of biogas adoption.

• Develop inclusive financing models

Financial barriers remain a major constraint to adoption, particularly for low-income households. Expanding subsidies, microfinance, pay-as-you-go schemes, and cooperative ownership models can lower upfront costs while fostering a sense of ownership and responsibility. Revolving credit schemes and community-based financing mechanisms can further enhance affordability and create pathways for broader uptake.

• Leverage co-benefits of bio-slurry

Bio-slurry, the nutrient-rich byproduct of anaerobic digestion, represents a key co-benefit of biogas technology. Greater emphasis should be placed on integrating bio-slurry into local agricultural value chains. Training farmers in proper application, linking surplus to local markets, and promoting value-added uses can enhance soil fertility, boost crop yields, and generate additional income streams, reinforcing biogas systems’ economic sustainability.

• Align biogas with policy and development agendas

Biogas programs should be embedded within broader strategies addressing climate change mitigation, energy access, rural employment, and sustainable agriculture. Effective coordination across government ministries, research institutions, development agencies, and private sector actors ensures that biogas is not treated as a standalone intervention but as a component of integrated development planning.

• Enhance knowledge transfer and south–south collaboration

Lessons from countries with successful biogas programs should be adapted to local contexts rather than replicated. Cross-regional learning platforms, research partnerships, and technical exchange programs can accelerate innovation, share best practices, and reduce the risk of repeating failed models. Tailored knowledge transfer ensures that programs reflect local socioeconomic, environmental, and technical realities.

By implementing these recommendations, biogas technology can move beyond pilot-scale projects and fragmented initiatives to become a reliable, scalable, and multifaceted tool for sustainable development. When coupled with supportive policies, robust training networks, and inclusive financing, biogas can transform energy access, agricultural productivity, and livelihoods in rural, energy-poor communities.

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Footnotes

Edited by: Solomon Giwa, Olabisi Onabanjo University, Nigeria

Reviewed by: Vivekanand Vivekanand, Malaviya National Institute of Technology, Jaipur, India

Satoto Endar Nayono, Yogyakarta State University, Indonesia