The Farmer’s Friend Biodigester is an underground construction where biogas is produced from decomposing animal manure under anaerobic conditions, which is then harnessed as a fuel for domestic gas stoves and lamps. Families don’t need to purchase or cut down wood for cooking in smoke-filled rooms anymore. Thanks to reduced burning of firewood, the improved manure management system and the utilization of biogas, greenhouse gas emissions fall annually by 5 t CO2 per biodigester. The effluent (digester slurry) is used as an effective organic fertilizer improving soil quality and production while reducing farmers’ expenditures. The farmer’s friend design is based on the ‘Deenbandhu’ model which is in use for over 20 now years in India. The majority of domestic biodigesters is promoted and constructed by private Biodigester Construction Companies (BCC) which were established and coached by joint NBP-SNV-PIN initiative and support. BCCs are small enterprises providing employment and qualification to over 800, predominantly young people living in the rural areas of Cambodia. According to the latest monitoring report, around 2,000 man-years of rural employment have been created between 2006-2013.
In the rural areas of Cambodia, more than 90% of the people depend on traditional sources of fuel for cooking contributing to the fact that Cambodia is having the third highest deforestation rate in the world. Replacing fuel wood by biogas means a saving of around 8 kg of wood per household per day, which – based on the existing number of almost 21,000 biogas systems – amounts to annual savings of more than 61,000 tons of trees and reduction of greenhouse gases emissions by over 99,000 tons in 2013 alone, roughly equivalent to taking 21,000 American cars off the road annually.
In Cambodia, more than 90% of poor people live in the rural areas. However, the main drivers of growth – garment, tourism and construction sectors – are based in and around major urban centers, providing limited benefits to remote rural areas. The biodigester market is based in rural areas and provides work to more than 800 people.
Clients can choose different sizes of biodigesters depending on the quantity of animal dung. The most demanded ones are the 4 m3 which cost 550 USD and the 6 m3 which costs 620 USD. However, this price is still a barrier to motivate farmers to buy biodigester despite of the great benefits it can provide. Therefore, NBP is providing subsidies of 150 USD to farmers in order to tackle the investment barrier. Moreover, 75% of the farmers need to take a loan from a microfinance institute that partners with the NBP. Thanks to this partnership, lower interest loans (1.2% per month) are available for farmers. A biodigester reduces costs but can also results in additional income. According to the last Biogas User Survey done in 2014, the availability of bioslurry leads to higher yield (31% increase) that can be valued at 182 USD additional income per year. At the same time, the average savings on fertilizer, fuel wood and healthcare are 165 USD per year per household. Therefore, the investment is reimbursed after two years.
A 4 m3 biodigester requires approx. 20-40 kg of animal dung per day while 6 m3 requires approx. 40-60 kg. A pig provides 2-3 kg per day and a cow 5 to 8 kg. A 4 m3 gives enough gas for 3-4 hours of daily stove usage and 8-10 hours of daily lamp usage.
Biodigester also saves time thanks to less time needed for cooking (30 min), for wood collection (26 min) and for cleaning (16 min). Women save most time, approx. 56 minutes per day. This extra time is mainly used for economic activities (60%): farming, animal care and other economic opportunities. Currently, 59 biodigester construction companies are active with 200 masons, 352 sales agents and 179 local technicians providing after sale services.