碩士 / 國立成功大學 / 環境工程學系 / 102 / Technology innovations are common in nowadays. They are intended to improve the old technology. However, innovations that targeting on one particular improvement, may not result positively in overall. Therefore, introduction of prospective life cycle assessments to systematically examine the economic and environmental impact of products/services life cycle can support the decision-making. The challenge for predicting future change is the uncertainty evaluation. This study proposes two alternative LCA applications, which are the development of indifferences curve and decision-tree analysis, to treat the uncertainty. The methods highlight the incorporation of expert judgment and stakeholder involvement in the uncertainty evaluation processes. A case study of ecological method in shrimp farming is chosen to demonstrate the proposed LCA approaches.
In the innovation of case study, input of heterotrophic bacteria with revised feeding strategy improves aqua-cultural pond ecology; thereby expected to reduce virus outbreaks, main cause of unstable shrimp production. Currently, no standard application guideline for this practice exists. Thus, uncertainties in its economic and environmental effectiveness hold back implementation of this innovative farming practice. This study present decision tools developed to support experts (i.e., farmers) in tailoring the application strategy to respective ponds. Based on expert judgments on expected effectiveness, our figures clarify decision criteria in cost and life cycle environmental impact (GHG emission in this study) in an integrated manner.
First, a cradle-to-gate, stand-alone LCA is performed to benchmark the contribution of the new ecological practice in terms of cost and GHG emission for shrimp production, based on inventory data of farm-scale experiment and literatures. To allow farmers to explore alternatives in bacteria input and feeding strategies, 1) a indifferences curve, or tipping-point-curve, which shows the required productivity enhancement to outweigh additional economic and environmental cost on the basis of benchmark practice and 2) a decision-tree analysis, or figure for two-way sensitivity with three potential outcomes are developed.
The assessment result shows that fresh shrimp at farm gate cost 161 TWD kg-1 and is associated with 3.977 kg-CO2eq. kg-1 in benchmark application. The indifferences curve (see Figure 5-7) shows for example, increase in bacteria frequency to a 20 day-interval expecting a 1% increase in production is worthy in terms of GHG emission reduction but does not pay off in terms of cost. The decision tree analysis (see Figure 5-12) for feed altering strategies presents the cost effective domain and low GHG domain in overlapped layers. It shows either the interest of cost and GHG benefits is consistent or trade-off is required for each intended strategy.
Any decision must be made under some degree of uncertainty. These approaches delegate the role of uncertainty judgment to the experts, while taking responsibilities on removing the complexity due to expansion of scope across the product lifecycles. They are particularly useful in agri-/aqua- cultural studies, because acquiring sufficient volume of data for highly variable environments consumes years of time. Farmers’ experiences and implicit knowledge are assumed to be the best available alternative to scientifically valid data in most of the cases.
| Identifer | oai:union.ndltd.org:TW/102NCKU5515018 |
| Date | January 2014 |
| Creators | Heng YiTeah, 張恒毅 |
| Contributors | Yasuhiro Fukushima, 福島康裕 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 92 |
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