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Exploring a systems approach for the economic assessment of small-scale anaerobic biodigesters for rural areas. Michael Smith University of KwaZulu-Natal. Energy Postgraduate Conference 2013. Anaerobic Digester (AD). Anaerobic digestion
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Exploring a systems approach for the economic assessment of small-scale anaerobic biodigesters for rural areas Michael Smith University of KwaZulu-Natal Energy Postgraduate Conference 2013
Anaerobic Digester (AD) • Anaerobic digestion • Decomposition of organic matter under the absence of oxygen • Producing a gas (Biogas), and an effluent (bioslurry/digestate) • Anaerobic Digester/Biodigester • Tank/Construction of varying size in which organic matter is fed and allowed to decompose via AD (International Workshop on Domestic Biogas, 2009)
AD for Rural Areas • Off-grid energy provider? • Using the AGAMA BiogasPro6 • Households required to feed digester • 20l water per day • 20kg cow manure per day • Provides approx.. 2 hours burn time per day • Plus: fertiliser for crop production
Economic assessment • Typical findings • There is potential, although significant capital costs tend to outweigh the financial benefit • Financial results from Smith (2011) – WRC Project K5/1955 • Financial cost R 38 532.23 • Financial benefit R37 880.37 (over 15 year assessment; discounted at 6%) • NPV -R651.85 • IRR -0.25% • BCR 0.98 Economic results!!
A systems approach • Considering the whole system as it applies to a rural household… • In a standard cost-benefit assessment: • Avoided Fuel Costs • Electricity • Paraffin • Firewood • LPG BIOGAS Fertiliser Avoided chemical fertiliser purchases
BIOGAS A systems approach • Environmental Benefits • Reduced deforestation • Erosion • GHG mitigation • Reduced GHG emission • Clean & efficient cooking • Reduced emission from cattle manure • Time saving • Meal preparation • Instant cooking • Cleaning • Health benefits • Reduced Indoor Air Pollution (IAP) • Reduced respiratory disease • Better productivity • Reduced cost of illness • Reduced loss of life
Digestate augmented with Rain Water (RW) Harvesting A systems approach • Fodder crops • Cattle fed reduced pressure on grazing lands • Reduced erosion • Healthier cattle • Time saving • Reduced water collection RW used in HH • Food crops • Improved yield • Improved quality • Food security Digestate (+water) used for crop cultivation Grey water used to feed digester
Valuing non-market impacts • A challenging, but necessary process • Urban setting: • Contingent valuation • Hedonic pricing • Travel cost method (TCM) • Rural setting: • Limited methodology • Shadow pricing Namaste SA
The challenge moving forward • Developing a rural programme that integrates and develops a biodigester SYSTEM • To assure the realization of ALL economic benefits • Rain water harvesting • Improved / changed cattle keeping practice • Improved water management practice • Improved farming methods • A system leading to food security, energy security, and natural resource management
Thank you Michael Smith University of KwaZulu-Natal e. mikesmith@live.co.za m. +27 82 822 4688 f. +27 86 528 2116