Life Cycle Energy Assessment for Domestic Biogas Systems
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Date
2020
Journal Title
Journal ISSN
Volume Title
Publisher
Uva Wellassa University of Sri Lanka
Abstract
With the rapid economic development and urbanization, Sri Lanka is facing a huge
challenge in terms of energy security and environmental pollution due to the drastic
increase in burning fossil fuels. Therefore, it is important to explore the potential of
renewable energy sources for domestic and industrial consumption. Biogas is one of the
best solutions for these issues as it provides triple benefits namely sustainable
environmental protection, energy generation, and agricultural & farming support.
However, to further development of biogas energy technologies in Sri Lanka, it is
important to do a detailed energy analysis of this technology by considering the initial
energy requirements and energy generation at the end. The life cycle energy assessment
(LCEA) can be used for this analysis and can be used as a basis for the calculation of
energy pay-back time (EPBT). This analysis includes the energy requirements during the
collection and transportation of waste, construction, and operation of the plant,
upgrading the biogas produced and final energy generation from the biogas. In this
study, different sizes such as 8, 10, 12, 15, 22, 35, and 65 m3 of Chinese fixed dome type
biogas plants were analysed using LCEA to determine the EPBT. Embedded Energy
Values (EEVs) were evaluated from the quantity of materials used for the construction
of different sizes of biogas plants and EPBT of the plants were calculated using EEVs
and final biogas energy production. As per the analysis, the relationship of EPBT and
the volume (in m3
) of the biogas plant (X) was EPBT= 0.0006 X2
- 0.008 X + 0.590.
Accordingly, the construction of the higher capacity plant has lower EPBT and therefore
it is more energy-efficient than a smaller capacity plant. However, a detailed economic
analysis is required to carry out when selecting the optimum size of the biogas plants.
Keywords: Biogas plant, Life cycle energy assessment, Embedded energy values,
Energy pay-back time
Description
Keywords
Engineering, Bio Chemicals Engineering, Environmental Engineering, Biogas