In a quest for renewable energy, French scientists have found a potentially limitless energy source by extracting electricity from Mother Nature’s original power source: plants.

Until now, scientists have not been able to duplicate the ability of plants to produce oxygen and “fuels” in photosynthesis. But in an article published in the journal Analytical Chemistry, the researchers describe the process of harnessing the energy produced in photosynthesis — the conversion of carbon dioxide and water into sugar and oxygen when a plant is exposed to sunlight — into usable energy, Science Daily reports.

The chlorophyll in plants helps them convert carbon dioxide and water into sugar and oxygen during photosynthesis, a complex series of chemical reactions that humans have not been able to replicate. But researchers at the Centre de Recherche Paul Pascal developed a biofuel cell that is made up of two enzyme-modified electrodes, which are sensitive to oxygen and glucose.

Inserted into a cactus, the electrodes generated 9 microwatts per square centimeter, a process the researchers were able to observe. The output was relative to light intensity, meaning the brighter the light on the cactus, the more power the electrodes produced.

For researchers, the initial goal was to develop biofuel cells for medical purposes, such as providing power for implanted medical devices or powering sensors that monitor glucose levels in diabetic patients.

“We found that these electrodes, implanted into a living plant, responded in real time to visible light as an external stimulus triggering photosynthesis,” researchers wrote in their findings. “We demonstrate that with our electrodes we could harvest glucose and O2 produced during photosynthesis to produce energy, transforming sunlight into electricity in a simple, green, renewable, and sustainable way.”