Currently, there is no doubt anymore that biogas systems all over the world are functioning under a variety of climatic conditions. They respond successfully to needs of poor rural populations, urban communities and industrial estates. However, a widespread acceptance and dissemination of biogas technology has not yet materialized in many countries.
One main reason, often mentioned, is the required high investment capital. But often the reasons for failure were the unrealistically high expectations of potential users. Biogas technology cannot solve every problem of a farm, a village or a big animal production unit. If disappointment is to be avoided, the limitations of biogas technology should be clearly spelt out.
If from the below listed guiding questions one or more cannot be answered with 'YES', the success of biogas technology is questionable or even unlikely.
- Is there a real problem that biogas technology can address?
e.g. Is there a problem with the affordability and availability of energy? Is the substrate to be bio-degraded an environmental hazard? Is the lack of high-quality fertilizer a serious problem in the farming system?
- Can a permanent supply of bio-degradable material be guaranteed at low cost?
e.g. Are animals kept in a stable, connected to the biogas plant? Would filling the biogas plant reduce the workload of the farmer? If necessary, is transport capacity for the substrate guaranteed permanently? Will the biogas plant be connected reliably to the sewage system?
- Can the financing of biogas systems realistically be solved?
e.g. Do potential users have access to credit? Can a substantial subsidy be expected from private or public sources? How realistic is the optimism of the biogas plant owner-to-be?
- For unheated biogas plants: does the climate allow bio-digestion for most of the year? Is it economically feasible?
- Under arid conditions: Is the availability of water secured and affordable?
- Is the use of human feces as substrate and fertilizer culturally acceptable?
- Is the use of human feces as a fertilizer in accordance with environmental / agricultural regulations?
- Is the use of biogas, generated from human waste, acceptable for cooking?
- Are there allies among government and institutional decision makers with a certain degree of awareness of environmental problems?
- Is in the region a sufficient number of skillful craftsmen available who can be upgraded to be 'biogas technicians'?
e.g. Is good quality masonry work known in the region? Is plumbing a trade that is practiced in the region?
- Does the number of potential biogas users in the region justify a 'biogas project' or the establishment of private 'biogas business'?
Biogas technology is not a universally accepted technology such as the transistor radio. A biogas plant has to fit into existing farming-, production- or waste disposal systems. Attempts to make the system fit to the biogas plant will result in expensive and frustrating failures. Biogas technology has many competitors. Energy can be produced by fuelwood plantations (with other positive side-effects), by solar systems, micro-hydro-power and other renewable energy technologies. Producing high quality fertilizer can be done in other, cheaper ways such as composting which are even closer to traditional techniques. What makes biogas an attractive option is the fact that this technology can provide solutions to a variety of problems simultaneously. That is, if this variety of problems exists.
GTZ: Biogas Digest Volume II: Biogas - Application and Product Development