Biogas System Planning for Rural Households Based on Energy Demand (The Case of Holeta District)
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Date
2017
Authors
Journal Title
Journal ISSN
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Publisher
Addis Ababa University
Abstract
This research is conducted to study the energy consumption trend and to make easy of
planning the biogas system design which can helps to meet the energy demand of the
rural households found in Holeta district. The energy demand of the households is
assessed based on the questionnaire paper. The information of the assessed households is
collected randomly from different family sizes that live in “Geda Jogo” and “Ada odo”
Villages. Households are using electricity mostly for lighting purpose. Fire wood,
Charcoal and dung cake are the main sources of energy to meet the cooking Energy
demand. The average amount of annual fertilizer consumption by the peasant households
is 220 kg.
Spreadsheet modeling tool is prepared and it is used to estimate Households biogas
demand, gas production potential of the households and Digester volume including the
expected Loading rate. It is also used to forecast the basics of Economical aspects which
should be known before the plant is designed. To crosscheck the proper functionality of
the spreadsheet modeling tool Manual calculations has been performed for the average
and peak values observed in the surveyed households and compared with the values
found from the spreadsheet model. For the average values, the Biogas demand, the gas
generating potential of the Households and digester volume observed in the spreadsheet
calculation tool are 6.001m
3
/day, 6.8 m
3
/ day and 20.3949 m
3
respectively. The values
gained using manual calculations are 6.114m
3
/day, 6.8m
3
/day and 20.4 m
i
3
.
For the peak values calculation in spreadsheet modeling tool, the Biogas demand, the gas
generating potential of the Households and the digester volume needed are 9.19m
3
/day,
8.8 m
3
/ day and 26.3934 m
3
respectively. Where as in the manual calculation the values
are 9.16 m
3
/day, and the digester volume is . Priority rank on the
households energy demand has been performed, so that it will help on the biogas system
design. The economical aspect of the biogas system is also included and how the
households could be benefited using this technology. The estimated cost to construct the
plant for the average values are ETB 29,840 with a payback period of 3 years. The cost
spent to buy chemical fertilizer could be saved. Finally the benefit cost ratio is calculated
to be 1.44 which is greater than 1.
Description
Keywords
Biogas, rural households, Holeta district, energy demand