Biogas and biofuels are renewable and carbon neutral sources of energy. The crops that have ultimately been targeted for biogas production such as corn however, have been shown to displace sources of food and feed for cattle while having some of the same negative effects of commercial crop production such as runoff pollution and soil erosion. Nopal, a type of cactus commonly found in over 52 percent of the Mexican territory, even in the dry desert, has been found to not only provide a cleaner burning alternative to natural gas; but also grown with less than half the required amount of water necessary for a corn field.
The process of making biogas from the nopal plant does not involve complex machinery as it simply involves shredding the leaves and placing them in a bio digester where they start decomposing and generate biogas. The biogas produced contains up to 65 percent methane that is fed into an internal combustion engine generator that produces electric energy.
Yield could be up to 800 tons per acre and produce about 43,300 m3 of biogas or the equivalent, in energy terms, to 25,000 liters of diesel per acre. This nopal yield is significant compared to the yield of corn, which produces the equivalent to 1,600 liters of diesel per acre. It also surpasses other possible renewable options such as the flowering plant, Jatropha, which produces the equivalent to 3,000 liters of diesel per acre.
The nopal helps retain soil in places where the ground has eroded and can grow in some of the driest conditions such as those found in the deserts of the western U.S. The entire list of products generated from the use of the nopal as biomass are: biogas, electricity, water, nitrogen, humus, earthworm flour (animal feed) and carbon credits by participating in the process of carbon dioxide absorption, making them one of the best possible solutions for greener future renewable energy sources.
By Efrain Esparza, ESG Writer