Economics of family sized biogas plants in India

Abstract A generalized framework for economic analysis of biogas plants by capturing the effect of the biogas plant capacity in the benefits accruing from biogas utilization is presented. This has been achieved by empirically developing a generalized cost function for the floating dome gas holder (KVIC) type biogas plant in terms of its rated daily gas output. the benefits are quantified in terms of the quantity of fuelwood the biogas replaces for cooking and the quantity of kerosene substituted through the use of biogas for lighting. The effect of varying the fraction of the gas used for cooking and lighting on the benefits and, hence, the economic viability of biogas plants is also examined. The fertilizer value of the spent slurry is also taken into account in the analysis, and the effect of ignoring its benefits is also studied. Since the actual benefits from the biogas plant depend on the values of the various parameters assumed, a sensitivity of the monetary benefits on some of these parameters is examined to identify variables influential in determining the economic viability of biogas plants. These include the price of fuelwood, efficiency of fuelwood cookstoves, interest rate on capital, cost of fresh dung, the lifetime of the biogas plant and the fuelwood price escalation rate.