Continuing with a model that prioritises installation over sustainability will only deepen abandonment, inflate environmental losses, and diminish the credibility of national clean energy commitments
Nepal's household biogas programme has long been regarded as a flagship initiative in the country's clean cooking transition. For decades, biogas was promoted as a near-ideal solution by reducing greenhouse gas emissions, improving indoor air quality, and enhancing agricultural productivity using organic slurry. Supported by substantial investments from national programmes and international development partners, nearly 500,000 household biogas plants were installed across the country. With billions of dollars mobilised over several decades and steady revenues generated from carbon credit markets, Nepal once appeared well positioned to become a regional leader in sustainable clean cooking innovation.
However, evidence reveals a sobering reality. A large-scale survey by the Renewable and Sustainable Energy Laboratory at Kathmandu University (KU), covering 2,559 biogas-owning households across 10 districts and published in Scientific Reports found that 54% of plants were non-functional. Notably, the sampling strategy was inherently biased towards identifying functional plants. Researchers consulted municipal officials to locate "biogas clusters", followed community guidance to areas with historically higher adoption, and then randomly selected households.
Since residents tend to recall working plants more readily than abandoned ones, this approach should have increased the likelihood of encountering working plants. Yet more than half were still non-functional, suggesting that Nepal's true national abandonment rate may exceed 80-90%, posing a serious threat to its net-zero clean cooking ambitions. The problem is not biogas technology itself, but neglect of durability, maintenance, and lifecycle performance. Many abandoned plants failed because of easily preventable technical problems: defective mixers, broken valves, corroded pipes, clogged gas outlets, and scum-choked digesters due to lack of routine cleaning. The absence of functional mixers reported in 83% of dis-adopted plants undermined digestion efficiency. Without accessible repair services, spare parts, or trained technicians, households often reverted to firewood or LPG.
The sustainability crisis is also linked to demographic and socio-economic changes. Outmigration of young men and declining livestock reduce labour and manure available for daily feeding of digesters, making biogas impractical regardless of initial motivation to adopt the system. Nearly one in seven households reported declining livestock numbers, while 7% explicitly attributed abandonment to migration. Widespread dis-adoption results in an estimated annual loss of 0.66 million tonnes of CO₂-equivalent mitigation valued at roughly US$ 7.6 million in forgone climate benefits. For a country struggling to mobilise climate finance, this loss is significant. Households that once cooked with biogas are now shifting back to firewood or LPG, increasing indoor air pollution, accelerating deforestation, and heightening exposure to smoke particularly for women, who bear the brunt of cooking responsibilities. These reversals undermine progress towards SDGs related to health, gender equality, clean energy access, climate action, and forest conservation.
Agricultural impacts deepen the challenge. When digestate is poorly managed or unused, its fertilizer value is lost, forcing farmers to depend on costly chemical fertilizers. This erodes household incomes, increases agricultural emissions, and diminishes the integrated energy agriculture benefits that originally justified the program's promotion.
At the heart of this crisis lies a flawed subsidy paradigm. Nepal's biogas policy emphasised capital subsidies to boost installation rates. While this expanded access, it created perverse incentives. Installers, rewarded by plant numbers rather than performance, frequently overlooked household suitability and long-term functionality. More critically, the subsidy structure failed to establish mechanisms for routine servicing, replacement of parts, or follow-up assessments. The programme celebrated installation milestones while neglecting operational longevity. Weak reinvestment of carbon revenues worsened the problem. Despite generating over $32 million from international carbon markets, little of this income has been channeled back into system maintenance, user training, quality improvements, or supply-chain strengthening, weakening trust and undermining system reliability.
Nepal now stands at a decisive juncture. Continuing with a model that prioritises installation over sustainability will only deepen abandonment, inflate environmental losses, and diminish the credibility of national clean energy commitments.
Thus, a reformed biogas strategy should prioritise lifecycle performance, not installation counts. Subsidies must be redesigned to support long-term service and quality assurance, ensuring access to trained technicians, spare parts, scheduled maintenance, and performance-based incentives for installers. Strengthened monitoring and verification systems, including independent audits, are essential for credible carbon accounting and tracking plant functionality. Policy design must also reflect demographic realities by prioritising households with stable livestock access and sufficient labour.
Equally essential is the development of rural repair ecosystems, including certified technicians, reliable spare-part supply chains, and accessible service centres can significantly improve user confidence and system longevity. Integrating biogas into broader clean cooking and agricultural strategies, ensuring that digestate use, livestock management, and energy access are mutually reinforcing.
If Nepal is to meet its net-zero cooking energy goals, sustaining existing plants must become a national priority. Biogas still holds immense potential to deliver climate, health, and livelihood benefits, but realising this potential requires a decisive shift from counting installations to ensuring durability, reliability, and long-term impact.
Lohani is professor at the School of Engineering, KU