Bio-methane: Giant King Grass as Feedstock for Producing Green Renewable Methane

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Bio-methane is produced from Giant King Grass using proven and widely used anaerobic digestion and by second-generation gasification technology. Bio-methane is the "green" energy equivalent of methane, the principal component of natural gas which is widely used for heating, cooking, electricity generation and as a vehicle fuel. Biogas is produced when organic matter decomposes without oxygen (anaerobic digestion). Composed mainly of methane (55%) and carbon dioxide, biogas can also be upgraded to pure methane and inserted into the existing natural gas pipelines for efficient transmission. The byproduct of anaerobic digestion is organic fertilizer that can be put back on the Giant King Grass fields.

Giant King Grass has been independently tested for biogas yield, and the results are excellent. Anaerobic digesters favor fresh leafy green biomass. For this application, Giant King Grass should be harvested every 30-60 days when it is 3-5 feet tall with an annual yield of 167 tons per acre (375 metric tons per hectare). Drying is not necessary. The laboratory test results show that 1 ton of Giant King Grass produces biogas that contains 5489 standard cubic feet of methane (171 m3/metric ton). The biogas production per ton is 50% higher than elephant grass, and the yield per acre is also much higher. Both factors contribute to the cost advantage of Giant King Grass for biogas production.

Power generation and heating are the most common applications for biogas worldwide. Burning biogas in water and steam boilers is an established method of generating heat to serve the needs of industrial installations, or to feed into district heating systems. The green biogas is also used to generate electricity in combustion engines or turbines that turn generators or fuel cells. The most efficient way to utilize biogas is by using combined heat and power, employing a gas engine to generate electricity and capture the heat generated in the process to be used in heating, steam or drying systems.

With the high yield of Giant King Grass, a biogas plant generating 1 MW of electricity and 1 MW of heat can be fueled by a 170 acre (70 ha) plantation.