Water, a little bleach and a plastic bottle are all Filipino entrepreneur Illac Diaz needs to light up the world. He's out to make lighting free and safe, one slum at a time.

Until now, nearly three million people in the Philippines have gone without electricity, according to philstar.com. Those with access often use unsafe or illegal technology, creating disastrous effects. For example, 2,520 electricity-related fires were reported in 2009. In the Philippines, through the My Shelter Foundation, Diaz is implementing Solar Bottle Bulbs to diminish these problems. A used plastic bottle filled with water and a touch of bleach is placed in a hole of a tin roof. For up to five years, 50 watts of light fill up the once-gloomy windowless shack any time the sun is out, Diaz told Reuters in the video above.

Although WattWatt.com reports that the idea originally started with mechanic Alfredo Moser of Brazil, who used the creation locally, Diaz attempts to spread it worldwide. With an MIT student design, Diaz has brought the appropriate technology farther, with his two-hour seminar about the simple product. The invention is something that is so simple, cheap and sustainable that anyone can create it and maintain it themselves. As Diaz says, the three rules of appropriate technology are that people can find it, they can replicate it, and most importantly, they can make a business of it. Not only does the Solar Bottle Bulb bring free, sustainable lighting to places that haven't had it before, they also create a new market for people to install the bulb at small costs.

The only downfall of the Solar Bottle Bulb is that the idea only works during the day. But that hasn't stopped nearly 300 households, small businesses and schools in San Pedro, Philippines, from installing the Solar Bottle Bulbs.