Nepal’s experience underscores the complex interplay between technology, socio-economic context and policy design in clean-energy transitions. What once seemed a straightforward path to cleaner cooking and rural development has become emblematic of broader challenges

Once touted as a cornerstone of Nepal’s clean-energy transition and rural development, household biogas systems are increasingly falling into disuse across the Himalayan country, threatening decades of investment and undermining national climate and sustainable development targets. A new large-scale scientific study, backed by field surveys in 10 districts, reveals that more than half of Nepal’s roughly 450,000 subsidised household biogas plants are now abandoned or non-functional – a stark reversal for a technology long championed for sustainable cooking and reduced reliance on fossil fuels.

Widespread Failure After Early Success

Nepal rapidly embraced household biogas over the past six decades, installing nearly 450,000 small digesters nationwide to convert livestock manure and organic waste into clean cooking gas and fertiliser. These systems were heavily subsidised and positioned as a scalable, low-carbon alternative to firewood and liquefied petroleum gas (LPG).

However, data from a comprehensive study published in Scientific Reports confirm what researchers and rural families are witnessing on the ground: 54 per cent of these biogas plants are now abandoned. Most of these systems were expected to function for up to 20 years, yet many fell into disrepair long before reaching that lifespan.

The study’s authors – researchers from Kathmandu University, Duke University and other institutions – conducted structured interviews and visual inspections of 2,559 household biogas plants across Nepal’s Terai, middle hill and Siwalik regions. They found that malfunctioning mixers, broken valves, corroded pipes and other technical issues were the primary reasons systems ceased to operate.

Technical Flaws and Lack of Support

Technical failure emerged as a core driver of abandonment, with faulty mixers and key piping components common in defunct systems. Even among plants still in use, biogas output averaged just 0.4 cubic metres per day – far below designed capacity – leading many households to question the technology’s value.

A lack of local technicians and spare parts has made household repairs difficult, and routine maintenance services are scarce. “Plant inspections reveal mechanical problems that could be fixed relatively easily,” said one co-author of the research, “yet without trained personnel or accessible components, households are left stranded.”

Researchers also pointed to policy shortcomings. Heavy emphasis on upfront installation subsidies without long-term monitoring, maintenance funding or performance incentives has prioritised rapid rollout over sustainable operation. Although the government has earned millions from carbon credits under the Clean Development Mechanism (CDM), little of that revenue has been reinvested in supporting plant longevity.

Socio-Economic Shifts Strain Biogas Use

Beyond technical issues, shifting rural demographics are weakening the traditional behavioural and economic foundations of household biogas systems. Youth migration from rural areas, smaller and ageing households, and declining livestock numbers – the primary feedstock for biogas digesters – have reduced the labour and organic input required to keep systems functioning. Approximately 14 per cent of households cited insufficient manure due to livestock decline as a key reason for giving up their biogas plants.

Households that abandoned biogas installations have mostly reverted to LPG or increased firewood use. The study estimates that this shift costs Nepalese families an additional US$5.2 million annually in LPG purchases and contributes an extra 0.66 million tonnes of carbon dioxide emissions – reversing some of the climate benefits the technology was meant to deliver.

Environmental and Health Impacts

The collapse of the biogas sector also carries social and environmental costs beyond greenhouse gas emissions. Increased reliance on firewood exacerbates deforestation pressures and exposes families, especially women and children who predominantly handle cooking and fuel collection, to household air pollution – a significant public health concern.

While biogas digestate has the potential to reduce reliance on chemical fertilisers – another environmental benefit – many households perceive it as difficult to handle, limiting agricultural use and further diminishing the technology’s appeal.

A Cautionary Tale for Clean-Energy Programmes

Experts argue that meeting Nepal’s 2045 net-zero target and Sustainable Development Goal 7 – affordable and clean energy for all – will require a fundamental rethink of biogas policy. Instead of focusing narrowly on installation numbers, the government must adopt a lifecycle approach that includes post-installation training, robust maintenance networks, and performance-based incentives for households.

Recommendations also include engaging local governments more deeply in selecting beneficiaries and monitoring system performance, and aligning biogas dissemination with household needs to ensure long-term viability. Some researchers suggest exploring larger, centralised biogas production models that may be more resilient to demographic changes.

Nepal’s experience underscores the complex interplay between technology, socio-economic context and policy design in clean-energy transitions. What once seemed a straightforward path to cleaner cooking and rural development has become emblematic of broader challenges faced by many low- and middle-income countries: sustaining adoption over time, maintaining infrastructure in dispersed rural settings, and adapting programmes to evolving livelihoods.