Techno - economic analysis of biogas plants

Abstract

Renewable energy sources are playing a vital role in the developed as well as the developing countries to meet partially the need of global energy, Long term sustainable development requires a gradual shift towards renewable sources of energy that are more evenly distributed and environmentally less destructive than fossil fuel sources, In this respect, biogas plant could be one of the renewable sources of energy that offers Bangladesh with the prospect of increasing its energy supplies in a self-reliant way along with attended economic, social and security benefit Biogas plants of different sizes have been installed in different parts of Bangladesh, There are three different types of biogas plant - (i) Fixed dome biogas plant (ii) Floating cover biogas plant and (iii) Bag design biogas plant Floating cover biogas plant has higher initial capital cost and shorter working life, Bag design biogas plant incurs higher capital cost and low gas delivery pressure than fixed dome biogas plant Considering relative advantages and disadvantages of the different types of the biogas plants, the fixed dome plant is mainly used in the country, The technology of biogas plant is very simple, Gas is generated from the plant by anaerobic digestion of cow-dung/animal dung in the absence of air. The biogas is currently used for cooking, lighting and as fertilizer on the land, The plants are not very costly, the major share of costs are incurred at the initial stage, The operating and maintenance costs are quite low, The present work attempts to study some technological parameters of commonly used fixed dome biogas plant and identifYa tecno-economic viable size of biogas plant Cost figures relating to plant fabrication have been collected from various sources and other cost items were estimated on the basis of available information, It has been found that fixed dome biogas plant is very suitable in the context of Bangladesh, It has also been observed that economic viability ofbiogas plant increases with the size ofbiogas plant Sensitivity analyses were performed to identifY the limiting conditions under which biogas plant would be functioning economically, Through this study, technological suitability in the context of prevailing situation, economic viability, and future scope of biogas plants have been Page -VIII evaluated. The findings of this study could give some directions and guidelines for future planning and implementation of biogas plants in Bangladesh.