NBPA

Nepal Biogas Promotion Association (NBPA) is the umbrella organisation for biogas construction companies and biogas appliance manufacturing workshops in Nepal. With over 114 member companies, it is one of the largest private sector organisations in Nepal's biogas field. NBPA coordinates quality standards, advocates for the sector, and promotes technical innovation in biogas plant design and operation. A notable achievement includes conducting an independent project evaluation commissioned by German BMZ to assess technical improvements in implemented biogas technologies — findings from which were shared with international partners.

Field of Work
NBPA advances Nepal's biogas sector through quality assurance, technical expertise, promotion of bio-slurry as a value-added agricultural input, and innovation in digester design and operation. It advocates for clean energy solutions in both rural and urban settings, supports the conversion of organic waste into usable energy, and develops new financing and technical modalities to expand biogas adoption across the country.

Technologies Used by NBPA

Biogas Plants — Construction and Design

NBPA member companies construct the full range of biogas plant types deployed in Nepal. The dominant design is the GGC 2047 fixed-dome model (developed jointly by the government's Gobar Gas Company and BSP-Nepal), an underground hemispherical brick-and-mortar digester built entirely from local materials. The plant consists of a mixing pit (where dung and water are combined in a 1:1 ratio), the underground digester chamber (where anaerobic digestion takes place over a hydraulic retention time of 40–60 days), a gas holder dome, an overflow tank for displaced slurry, and a gas pipe leading to the kitchen.

Plant sizes range from 4 m³ to 20 m³, selected based on the household's cattle ownership. A 6 m³ plant produces approximately 1.5–2 m³ of gas per day — enough to cook three meals for a family of five, with additional gas available for lighting. Construction requires skilled masons certified by BSP-Nepal and NBPA, using a precise ratio of cement, sand, and brick to ensure gas-tightness. NBPA enforces construction quality standards and manages the certification of biogas masons nationally.

Biogas Appliances Manufacturing

Beyond plant construction, NBPA's membership includes workshops that manufacture the appliances and fittings used in biogas systems. These include biogas burner stoves (single and double-burner, designed for biogas pressure characteristics which differ from LPG), biogas lamps (mantle-type or pilot-flame designs for indoor and outdoor lighting), gas valves and regulators, and flexible gas pipes and connectors. The domestic manufacturing of these components reduces the cost of the complete biogas system and ensures availability of replacements in rural areas.

Bio-Slurry Utilisation and Organic Fertiliser Production

Bio-slurry is the nutrient-rich effluent discharged continuously from the overflow tank of a biogas digester. It contains the same macro-nutrients (nitrogen, phosphorus, potassium) as the original dung feedstock, but in a mineralised, plant-available form — making it a more effective fertiliser than raw manure. Additionally, the anaerobic process significantly reduces pathogen load compared to untreated dung, making bio-slurry safer for field application.

NBPA trains member companies and farmers in bio-slurry management, including liquid slurry storage, composting with dry materials to produce enriched solid fertiliser, and direct application through irrigation channels. Properly utilised bio-slurry can reduce a household's chemical fertiliser expenditure by 30–50%, strengthening the economic case for biogas adoption and linking clean energy with sustainable agriculture.

Decentralised and Community-Scale Biogas Systems

While household-scale biogas is NBPA's core domain, the association also promotes decentralised community and institutional biogas systems suited to schools, health posts, hotels, prisons, and slaughterhouses — where organic waste is generated in larger, more concentrated quantities. These systems use larger fixed-dome or flexible membrane digesters, often with plastic or fibreglass construction for faster installation. Community systems can power institutional kitchens entirely on biogas, eliminating LPG and firewood costs while managing organic waste hygienically.

New Digester Technologies and Innovation

NBPA actively explores and promotes emerging biogas technologies to improve performance and broaden applicability. Flexi-bag digesters (made from UV-resistant polyethylene or reinforced PVC) are portable, faster to install, and suitable for areas with difficult ground conditions where traditional brick construction is challenging. Two-stage digestion systems separate hydrolysis and methanogenesis into distinct chambers, improving gas yield and stability. Research into co-digestion (combining dung with food waste, crop residues, or water hyacinth as supplementary feedstocks) is expanding the range of households that can benefit from biogas even without large cattle herds.

🌐 nbpa.org.np | 📧 nepalbiogas@gmail.com | 📞 +977-01-4622113
📍 Santinagar, Gyankunja Marga, Ward No. 31, Kathmandu