Teresa Madaleno

Have you ever noticed the cactus in the middle of the Mexican flag? It’s called the prickly pear. Once considered sacred by ancient Aztecs, Mexicans eat it, drink it, use it in hygiene products like hair shampoo and in medicines. Now scientists think they can produce renewable energy with the green plant.

Described as a jumble of spiny discs with bright red fruit protruding from it, the prickly pear is harvested on a huge scale in Mexico. The inside of a prickly pear is softer and used in tacos, soups, salads, and jams; however, the hard, thick outer layer has always been waste. That could soon change due to an ambitious local start-up company called Suema. The company developed a biogas generator to turn the prickly pear waste into energy.

Each day workers converge on an area in Mexico that produces hundreds of thousands of tonnes of the cactus. They clean up the waste that is left behind from the previous day so it can be processed and turned into power. The current goal is to produce 175-kilowatt hours, which is enough electricity to keep close to 10,000 low-energy light bulbs working. The Mexican government is hoping the biogas generator will be the first of many.

According to national news reports, the generator is a giant cylinder surrounded by a series of pipes that churns together organic waste with a mix of bacteria and heats it to 55 degrees Celsius to produce the biogas. Any leftovers are used as compost. Mexico City scientific development chief, Bernardino Rosas recently told reporters in France that, “Our vision is to reproduce this type of project” throughout the city.

In 2015 Mexico received a lot of attention after it became the first country to announce its emissions reductions targets for the UN climate accord. At the time, officials in the country vowed to halve emissions by 2050.