Biogas
Overview
Biogas from farm digesters is a valuable resource that provides energy savings and added profits. Using the methane produced in a manure digester to fuel an on-site power plant is now practical and profitable for a growing number of livestock producers, dairies, and finishing farms. This renewable source of economical “green” energy is friendly to the environment, considerate of neighbors, and popular with utility customers. Faced with increasing federal and state regulation of manure, livestock farmers have become aware that a properly designed and operated waste management system which includes a biogas-to-energy power plant can not only control odor, but can also reduce overall operating costs.
In regions where costs are high for electricity, heating fuels, or animal waste disposal, the production of electricity from biogas can provide substantial economic value to farmers. Energy savings plus profits are especially great where excess electric generation can be sold for profit to the utility. The total savings and payback can be impressive. For some farms, a modern, efficient, and easy to maintain biogas-to-energy system can help provide both environmental protection regulation compliance for an acceptable manure management system and the added revenue needed to offset the costs of compliance.
Figure 1. Agricultural Biogas Schematic
A modern biogas-to-energy system fits seamlessly into livestock production and dairy operations. The economical electricity generated by a biogas-to-energy system offsets all the utility power consumed by farm operations and other on-site facilities, and the thermal energy recovered from the microturbine engine can be used to maintain optimum digester temperature, to provide domestic hot water, and to heat barn space and floors.
In a typical biogas-to-energy system, manure is put into the digester where it is heated to accelerate anaerobic digestion. The biogas produced by decomposition (composed of about 55 to 70 percent methane) is captured and used as fuel to operate a generator. The energy produced is used to offset the cost of utility power and fuels for farm operations. Excess power can be sold for added profits.
More Information on Anaerobic Digestion »
Detailed AD Design Principles »
Industrial Implementation of AD »
Small scale biogas installations have also proved quite successful in both rural and developing areas. The most visible example of this may be in India: biogas reactors are referred to as ‘gobar gas’, refering to the Hindi word for ‘dung’. Several NGOs are currently working around the world to expand the use of such small scale solutions for sustainable energy.
Example Operation in Rural India »
Biogas Programs through the Netherlands Development Organization (SNV) »
