Over Half of Nepal’s Household Biogas Plants Abandoned, Study Reveals Systemic Collapse

Major New Study Exposes Mass Abandonment of Biogas Plants

In Tanahu district, one of many areas where Nepal has promoted household biogas for decades, the technology now shows clear signs of decline. As researchers moved through the mid-hill settlements, they found many units in disrepair where digesters split by cracks, mixers jammed in place, and pipelines corroded after years without maintenance.

A new study at the Renewable and Sustainable Energy Laboratory (RSEL), Kathmandu University has uncovered a deepening crisis in Nepal’s household biogas sector, finding that more than half of such systems may have been abandoned since the time of their installation. The research, published in Scientific Reports, a journal of the Nature Portfolio highlights that technical failures, shifting rural livelihoods, and flawed policy frameworks have undermined the national biogas promotion program.

This issue is compromising Nepal’s ability to meet its 2045 net-zero target and a broader set of Sustainable Development Goals (SDGs). Based on field observations from across 10 districts and interviews with 2,559 households, the study reveals a sector plagued by easily preventable technical problems calling for urgent policy and institutional intervention.

The national scale numbers are sobering. Across the ten districts included in the assessment, 54 percent of all biogas plants surveyed were non-functional, amounting to roughly 1,380 abandoned systems. With each plant costing around NPR 80,000, this represents more than NPR 110 million in wasted infrastructure in the sample alone. Since Nepal has installed nearly 450,000 household biogas systems, almost all of them subsidised, similar failure rates elsewhere would signal a loss of national wealth running into tens of billions of rupees. What was intended to be a durable, subsidy-supported clean-energy asset is instead becoming one of Nepal’s largest pools of stranded public investment.

Prof. Sunil Prasad Lohani, the lead author, emphasized the urgency of the findings: “This study reveals major challenges in Nepal’s biogas sector and underscores the need for transparent subsidies, expert involvement, and strong local service networks. Without urgent interventions and systemic reforms, Nepal’s biogas sector will collapse, and its role as a sustainable cooking solution is likely to diminish.”

The study found that the biogas plants surveyed were non-functiona,due to technical problems such as cracked digesters, rusted pipes, and broken mixers. Even operational digesters produced only 0.4 m³/day average gas output, less than half the designed capacity. “Households that once relied on biogas as a sustainable solution now express deep dissatisfaction,” said Poushan Shrestha, co-author of the study. Persistent low gas production and the lack of repair services have eroded people’s trust and confidence in this technology.

Technical failures were the primary driver of widespread abandonment. Many of the defunct systems could be revived with simple repairs. Yet, the absence of local technicians and spare parts has left households stranded, forcing them to revert to firewood and liquefied petroleum gas (LPG).

Share of the In-use and abandoned household biogas plants in the surveyed districts

Prof. Marc Jeuland, co-author of the study from Duke University, noted, “Nepal’s experience with biogas is alarming, but is unfortunately not unique across the world, where the technology has struggled to prove sustainable. Well-built systems are very high in cost, and the quest for affordability has sometimes led to compromises on quality, and the problems that ensue ultimately prove difficult to overcome.

Nepal’s shifting rural demographics are straining household biogas systems. Youth migration and fewer livestock have disrupted the traditional model—14% of households lack sufficient manure, leading to plant abandonment. With smaller, aging families and declining household size, maintaining biogas systems is increasingly difficult, while larger households sustain them more effectively.

Heavy reliance on upfront installation subsidies, without adequate post-installation support, has also prioritized quantity over quality. Despite generating several millions from carbon credit under the Clean Development Mechanism (CDM), reinvestment in maintenance and monitoring has been negligible. The resulting collapse of biogas systems has led households to spend an estimated $5.2 million annually on LPG and to emit 0.66 million tonnes of CO₂ from renewed firewood use.