Methane Fuel from Grass Straw and Dairy Manure

Methane will be generated from the anaerobic fermentation of waste grass straw mixed with dairy manure. The fuel will be used for power generation using internal combustion engines. The mixing of the two wastes provides a synergistic effect whereby the combination of feedstocks generates more methane than the individual streams. Preliminary laboratory tests have shown that grass straw and dairy manure can produce about 5 cubic feet of methane per pound of volatile solids. At this rate, such wastes in Oregon can fuel over 100 megawatts (MW) of power generation. Nationally, the total is over 20,000 MW. This can all be accomplished while producing electricity at a savings of 15% to 85% over current rates. A dual uniqueness exists in this project: first, a new process for using two agricultural wastes simultaneously on a commercial scale and, second, optimal power generation tailored for such a system. The project includes process R&D into several critical variables including nutritional additives, pre-treatment, and feed ratios.