If you think we’ve uncovered all the different methods of generating alternative energy, a 15-year-old science whiz is about to prove you wrong. In his entry for The Google Science Fair 2014, Angelo Casimiro of the Philippines explains how he tapped into one energy gold mine no has has used before: walking. Casimiro created the Electricity Harvesting Footwear Insole, a slip-in shoe insole that creates enough electricity to charge the batteries in your smartphone. Having long been interested and passionate about the topic of renewable energy, Casimiro says he wanted to challenge himself to create something truly innovative— and then he had a eureka moment.

“It wasn’t easy to think of an energy alternative that’s not related to wind, solar, hydro, or biogas,” Casimiro explains in his Google Science Fair entry video.

“But there was this time where an idea just hit me.”

Casimiro reported that after jogging for eight hours, he was able to charge a 400 mAH Li-ion in full from the electricity he generated. There is room for improvement, but Casimiro says the product is “ready for production and highly usable for smart clothing/shoes, although charging USB devices won’t suffice just yet.”

Among the uses he foresees for his perfected electricity-generating shoe insole, Casimiro hopes a product like his can provide electricity in remote areas where there is none available.

“I live in the Philippines, and just by looking around at my surroundings, I can see that a lot of people are suffering from poverty,” Casimiro says.

“A simple source of light is a big deal for people who don’t have access to electricity.”

Regional finalists and local award winners for the Google Science Fair 2014 will be announced on June 26.