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Energy Planet Care

58: Prickly pear ‘petroleum’

Problem:

Crops such as corn, sugar cane, soybean and palm oil, which make up 97% of biofuels worldwide, are often grown in large monocultures. This takes up land that could otherwise be used to produce food, destroys habitats and leads to less balanced ecosystems. It also leads to intense pressure on water resources, and has been linked to drought.

Solution:

Use nopal cactus (prickly pear) as the biomass


Wayland Morales, head of Elqui Global Energy in Santiago, Chile argues that ‘an acre of cactus produces 43,200 m3 of biogas or the equivalent in energy terms to 25,000 liters of diesel.

In the year 2000, Elqui Global built the first biogas plant using nopal cactus (prickly pear) as the biomass. Nine years later, in the Naucalpan de Juárez Area of Mexico, Rogelio Sosa Lopez who had already succeeded in the corn-made tortilla industry, teamed up with Miguel Angel Ake who had been experimenting with Nopal cactus as biofuel to found Nopalimex.

Nopal crops produce between 330 and 440 tons (300 and 400 tonnes) of biomass per hectare in less fertile lands, and up to 880 – 1,100 tons (800-1,000 tonnes) in richer soils. Nopal also requires minimum water consumption and its waste, if properly processed, can be turned into biofuel.

First, the cacti are cut and processed to extract flour, which is used to make tortilla chips. The remaining inedible scraps of the plant are mixed with cow dung in a bio-processor, a fermentation tank that heats the wasted cactus pulp. Then the fuel is distilled from the remaining liquid and collected via tubes and into a tank.

While Nopal biofuel produces enough fuel for the buildings that process all parts of the nopal plant in a sustainable way, a commitment has been signed with the local government of Zitácuaro, in the state of Michoacan, to provide official vehicles, from police cars to ambulances, with cactus-based fuel with world’s first cactus-based biogas refueling station selling at 2 pesos (US$ 0.61) per liter since March 2018.

With the amount of Nopal growing in Mexico, this biofuel could eventually replace the traditional use of gas and fuel of non-renewable sources.

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