Energy Integrated dairy Farm System in Puerto Rico

Technical Report · Wed Oct 01 04:00:00 EDT 1986

OSTI ID:6885900

Sasscer, D S; Morgan, T O

Principles of energy-integrated farming were applied to the Rio Canas Dairy Farm, a privately-owned dairy farm and one of the largest dairy farms in Puerto Rico with a milking herd of 400 cows. Animal wastes were fed to two anaerobic digesters where methane gas was produced by bacterial degradation of organic material. The methane gas fueled an engine-generator to produce electricity for farm use and for sale to the public utility. The Wastes were partially stabilized by bacterial action with the digesters and the digester effluent passed to a liquid-solid separator. Solid fraction was composted and either used as bedding material for the cows or marketed as soil conditioner. The liquid fraction flowed to a storage pond and was used in the Greenfeed subsystem to fertilize forage crops for the cows. Estimated energy savings of the system were 1705 MBtu for the first two subsystems and 7,718 MBtu's for all three subsystems. Simple payback for the first two subsystems was very long (20 years) because facilities for effective manure recovery did not exist on the farm at the outset of the project, operational costs for manure collection were charged against the project, and system components were oversized. Including the Greenfeed subsystem, simple payback for the project was 8.2 years. Assuming that manure collection facilities and practices already existed and assuming proper sizing of all components, simple payback for the Anaerobic Digestion and Electrical Production subsystem and the Farm Waste Management subsystem was 5.8 years. Using data from this project, an estimate of the return on investment was projected for different herd sizes. Results suggested that for dairy farms with less than 500 cows, anaerobic digester systems are only marginally profitable.

• Research Organization: Center for Energy and Environment Research, Mayaguez (Puerto Rico)
• DOE Contract Number: FC07-80CS40376
• OSTI ID: 6885900
• Report Number(s): DOE/CS/40376-T1; ON: DE87005834
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
090122 -- Hydrocarbon Fuels-- Preparation from Wastes or Biomass-- (1976-1989)
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320305* -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Industrial Waste Management
AGRICULTURAL WASTES
AGRICULTURE
ALKANES
ANAEROBIC DIGESTION
ANIMALS
BIOCONVERSION
CATTLE
COWS
DAIRY INDUSTRY
DIGESTION
DOMESTIC ANIMALS
ECONOMIC ANALYSIS
ECONOMICS
ENERGY ANALYSIS
ENERGY CONSERVATION
FARMS
FEDERAL REGION II
FOOD INDUSTRY
GREATER ANTILLES
HYDROCARBONS
INDUSTRY
ISLANDS
MAMMALS
MANAGEMENT
MANURES
METHANE
NORTH AMERICA
ORGANIC COMPOUNDS
ORGANIC WASTES
PAYBACK PERIOD
POWER GENERATION
PROCESSING
PUERTO RICO
RUMINANTS
USA
VERTEBRATES
WASTE MANAGEMENT
WASTE PROCESSING
WASTE PRODUCT UTILIZATION
WASTES
WEST INDIES