Posted on | April 26, 2010 | 1 Comment
Institute of Environment and Sustainable Development (IESD), Vietnam
CSTM Technology and Sustainable Development, University of Twente, Netherlands
Biogas plants have been present in Vietnam for decades although since about 2000, there has been an increase in interest from NGOs and donors for this technology. As in other countries, several different models of biodigesters have been introduced, from the simple plastic tube to the fixed dome systems.
Generally speaking, family-sized continual feed biodigester models can be grouped into 4 broad categories:
- Plastic tube flow-through types
- Floating-dome types (nearly totally abandoned due to technical problems plaguing the systems)
- Fixed-dome “hydraulic pressure” systems (Dinabandu, Chinese, Vietnamese KT1, KT2, etc…)
- Hybrid systems (Sri Lanka floating drum, VACVINA’s HTASC)
These models each have their specific advantages and disadvantages, which may differ for different user groups and for different conditions and settings. Other differences may be in requirements for sales and awareness, construction or maintenance. For example, VACVINA’s Hybrid technology with Automatic Scum Control (HTASC) has a lower price and maintenance requirements than the fixed dome model, but also a lower gas pressure for cooking. The simple plastic tube biodigester offers lower quality energy services, but because of the low costs it can function as an entry-level model. It is possible that the different models do not necessarily compete on the same market, but each have their own market segment, which could have the added value especially of making the technology available to different income groups.
However, in the current market for biogas digesters, not only in Vietnam, the widespread use of subsidies that only promote one specific type of system influence the market. Such support could make expenditures that are meant for the promotion of sustainable development not only less sustainable but even counterproductive where inappropriate models are promoted for a given market segment.
The promotion of certain models is typically based on specification analysis. Such assessments compare models on the basis of their specifications only and/or on field data obtained immediately after construction. These assessments are based on construction design, efficiency and specifications, as this information is easily available and assessable for engineers and project managers and hence can be desk based. However, for a sustainable development of the biogas digester market, the reality of the users should be the main criteria for appropriateness of a certain technology. For biogas digesters, the users experience a different reality to that provided in manuals and designs. Not the theoretical operational characteristics or a cost-benefit analysis are decisive in purchase decisions or user satisfaction, but the perceived advantages and a willingness to pay, and the extent to which the systems functions to meet the users’ requirements and expectations. Therefore, for understanding suitability of technologies for certain market segments, the concrete requirements of different user groups (specifying particularly between males and females and their perceptions of benefits, as well as technical information on functioning of the digesters in real life situations is necessary.
The main objective of this practical independent study is to assess the suitability and market niche of 4 different biogas digester models currently on the Vietnamese market. The results will be useful to identify the best conditions and target group of each model, as well as to improve project implementation for the dissemination of biogas digesters. The assessment will be based on systems installed at least 3 years ago, both functioning and non-functioning.
The evaluation will be based on criteria firstly from the perspective of the (former) users of the biogas digesters, secondly from the perspective of suppliers and organisations involved in the dissemination of biogas digesters, and thirdly from the perspective of development policy with objectives for poverty reduction and climate change mitigation.
The criteria to be evaluated will therefore include:
- technical functioning of the system: biogas production, operation and maintenance requirements by design and in practice, operating condition of digesters
- characteristics of users (gender, income groups, size of farm and household, skills and levels of education, location –climate and distance to institutions for dissemination and maintenance)
- characteristics of dissemination design: selection of target groups, characteristics of sales and awareness activities including price setting, maintenance infrastructure and institutional and climatic setting.
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