• biogas plants;
  • cost functions;
  • fixed dome;
  • floating drum


An attempt towards the development of a generalized framework for analysis and evaluation of the various factors affecting the cost of the three types of biogas plants in India has been made. Four different approaches have been suggested for estimating the capital cost of biogas plants. The first cost function is based on the economies of scale in the capital cost, whereas the second cost function makes use of the fact that the ratio of the cost of a given size of plant to the cost of a reference plant remains almost constant in time. The third cost function takes into account the effect of retention time and other important factors on the capital cost, while the fourth cost function is based on the costs of constituents. An attempt to develop functional relationship for the operation and maintenance cost has also been made.