Turning waste plastic bottles into solar bulbs

Providing interior lighting for the poor, one litre at a time. 


by Lidija Grozdanić  

Photo courtesy of A Liter of Light.

Slums exist at the outskirts of almost every big city in the developing world. They are usually constructed from discarded material- plastic sheeting, corrugated metal, etc. Although poorly built and often unhygienic, these housing conglomerates offer an abundance of examples of human ingenuity. 


In order to fulfill their basic needs for water, light and power, people resort to improvisation, finding incredible ways to get by. One of the most inventive and recent adaptations has to do with cheap and efficient ways to create interior lighting, using only a plastic bottle, water and some bleach. 

The idea is simple: discarded soft drink bottles are filled with water and some bleach and sealed. The bleach is used to keep the inside of the bottle from molding. Pieces of shingle or any other roofing material are glued to the bottle and the whole thing is then placed on the roofs of houses, allowing the sunlight to be refracted and overflow the interiors during the day. 

Photo courtesy of A Liter of Light.

“A Liter of Light” is the most recent venture of the My Shelter Foundation, established by Illac Diaz. It was developed to help people living in Manila’s slums. So far, more than 15,000 solar light bottles have been installed in slums around the Philippine capital. The plan is to install another 100,000 in the Philippines’ second-largest city, Cebu. What began as a small-scale effort evolved into a global initiative, bringing light into the homes of millions of impoverished people throughout the world. Starting from Southeast Asia, the project reached as far as Colombia and Mexico. 

Diaz states that, unlike Al Gore’s expensive strategy of importing clean energy technologies to developing countries, projects like Solar Bottle Bulbs are both cheap and eco friendly. According to studies, each solar light bottle saves 17 kilograms of carbon dioxide a year. Multiplied by a million bottles, the project would save more carbon than one big windmill. Solar Bottles emit the same amount of light as a 55 watt electric globe, and are expected to last for up to five years. The project also addresses the issue of security- besides presenting a wide array of social and health problems, slums are also high-risk areas in terms of improper installations. As the Philippine Bureau of Fire Protection (BFP) has reported, a large number of fires are caused by faulty electrical connections in these informal settlements. Solar Bottle Bulbs eliminate this problem, in addition to significantly reducing electricity bills. 

Photo courtesy of A Liter of Light.

Although the idea of using plastic bottles for sustainable lighting has existed for over a decade, the My Shelter Foundation can be credited for popularizing the project and reaching so many people. It has also earned Diaz recognition from the United Nations. He was invited to present the project at the United Nations Forum on Climate Change in Durban, South Africa, last December. He was joined by Demitrio Bukas, who talked about the success of the same project in the town of San Pedro, Philippines. Together they showed the world leaders how "solar light bottles" are helping to tackle global warming issues.