Considerable attention has recently been focused on the development of farm management practices that utilize the total resource potential of animal wastes. In addition to the fertilizer value of manure, energy in the form of bio-gas can be generated from manure wastes by an anaerobic digestion process. The purpose of this economic analysis was to evaluate the feasibility of producing energy from the anaerobic digestion of dairy-cow manure. Anaerobic digestion systems were rationally designed for several farm management practices on Vermont dairy farms. These designs were sized to accommodate dairy herds of 20, 50, 100, and 200 cows for both free- and tie-stall arrangements.

The realistic evaluation of the potential of any energy source must include a cost effectiveness analysis. This 1974 economic analysis, with selected 1977 cost updatings, included considerations of both the total annual financial investment and the unit cost of net energy production. Minimum unit costs of net energy production for 1977 prices are approximately $0.19 per kwh for the 20-cow operation, but these values decrease with increasing herd size to $0.05 per kwh for the 200-cow dairy farm. At the present time, the generation of bio-gas from the anaerobic digestion of dairy farm manures becomes economically feasible as an alternate source of energy for dairy farms in excess of 200 cows.

Meeting Name

4th Annual UMR-DNR Conference on Energy (1977: Oct. 11-13, Rolla, MO)

Document Type

Article - Conference proceedings



Document Version

Final Version

File Type





© 1977 University of Missouri--Rolla, All rights reserved.

Publication Date

13 Oct 1977