Briquette and biogas in Nepal

Briquette

Briquettes are compressed blocks of biomass residue (sawdust, rice husk, charcoal dust, leaves, forest litter, banmara or Lantana and Eupatorium weeds, paper) used as fuel. In Nepal they are made with press machines, often with a binder, to replace firewood, coal and kerosene.

Types

1. Raw / non-carbonised briquettes: pressed directly from dried residue.
2. Carbonised briquettes (charcoal briquettes): biomass is first carbonised, then pressed with a binder.
3. By method of production: screw press, piston (ram) press, hand-operated or roller press (low pressure); and by shape: cylindrical, hexagonal, with a hole (honeycomb).

Uses

• Household cooking and heating (cold areas), restaurants and hotels.
• Industries: brick kilns, boilers, tea and cardamom drying, and cottage industries.

Advantages

• Cheap local fuel from waste; reduces firewood and forest cutting.
• Higher density and uniform shape, easy to transport and store.
• Burns slowly with less smoke and ash than raw biomass; higher heating value (15–20 MJ/kg).
• Creates rural jobs and helps manage waste.

Biogas

Biogas is a mixture of methane (55–65%) and CO₂ produced by anaerobic digestion of dung and organic waste. Nepal has one of the most successful domestic biogas programmes in the developing world: more than 400,000 plants (most are fixed-dome GGC 2047 design) were installed with support from the Biogas Support Programme and AEPC, covering mostly Tarai and mid-hills. Uses: cooking, lighting, small engines; slurry as organic manure. Benefits: cleaner kitchen, saves women's time, lower firewood use, carbon credits (CDM). Large institutional and municipal biogas plants are also promoted, and the potential is estimated at nearly 1.9 million household plants. Limits: needs water and cattle dung and works poorly at high altitude (cold temperature).