Cost of construction, amortization
As a rule, it costs DM 1000 or more to install a masonry biogas plant, including all peripheral
equipment, i.e. improved stabling, gas appliances, piping, etc. A favorable payback period of less
than 5 years can be anticipated for such an investment, if the biogas is used in place of a
commercial energy source like kerosene or firewood, but not if it is used as a substitute for "free"
firewood.
Dissemination of biogas technology
Thanks to the broad scale of potential uses for biogas, in conjunction with an increasingly advanced
state of technical development' numerous developing countries are intensively promoting the
dissemination of biogas plants. The undisputed leaders are the PR China (4.5 million plants), India
(200 000 plants) and Brazil (10 000 plants). Other countries also have launched biogas
dissemination programs with some or all of the following components:
- development of appropriate appliances and plants,
- establishment of technology and advisory-service centers,
- continuous support for the users,
- training of biogas practicians,
- advertising and promotional activities,
- assistance for private craftsmen,
- provision of financing assistance.
Criteria for the utilization of biogas technology
Building a biogas plant is not the kind of project that can be taken care of "on the side" by anyone,
least of all by a future user with no experience in biogas technology. The finished plant would
probably turn out to be poorly planned, too expensive and, at best, marginally functionable - all of
which would disappoint the user and spoil the prospects for the construction of additional plants.
Consequently, the following rules of thumb should be observed:
- There are workable alternatives to biogas technology:
Regarding energy: energy-saving cookstoves, afforestation, wind/solar energy, small-scale
hydropower, etc.; better access to commercial energy supplies
Regarding fertilization: spreading or composting of fresh dung
Regarding animal husbandry: pasturing instead of stabling in combination with a biogas plant.
Any decision in favor of or against the installation of a biogas plant should be based on due
consideration of how it compares to other alternatives according to technical, economic, ecological
and socioeconomic criteria.
- Both the available supply of substrate and the energy requirements must be accurately
calculated, because the biogas plant would not be worth the effort if its energy yield did not
cover a substantial share of the energy requirements.
- The system must be properly built in order to minimize the maintenance & repair effort.
- Siting alternatives must be painstakingly compared, and only a really suitable location
should be selected for the biogas plant.
The financial means of the plant's user must not be overextended (risk of excessive indebtedness).
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