During Brazil’s 2001 energy crisis, Alfredo Moser cut a hole in his roof and slid a plastic bottle through it. Filled with water and bleach, the bottle refracted sunlight into his dark home. What began as a DIY fix would spread to over a million homes in areas without electricity.
A Spark from the Amazon
Moser said the idea came from a 1970s conversation while working in Brasília. His boss told him that a plastic bottle filled with water could act as a lens, focusing sunlight enough to start a fire—an idea that stayed with Moser for decades before becoming practical.
Experiments on a Rooftop
Back home in Minas Gerais, Moser tested bottles filled with water and bleach. The solution diffused sunlight into rooms with no power. He refined the technique using resin and improved materials. The bottles lit rooms during the day without using any electricity.
Spreading Light Globally
His invention was adopted by the MyShelter Foundation and spread through the Liter of Light project. By 2014, Moser’s idea had been installed in more than one million homes. In some places, people even used the lamps to grow crops under makeshift greenhouses.
During Brazil’s 2001 energy crisis, Alfredo Moser cut a hole in his roof and slid a plastic bottle through it.
Filled with water and bleach, the bottle refracted sunlight into his dark home.
What began as a DIY fix would spread to homes without electricity…🧵👇 pic.twitter.com/NZXavwywyg
— Detective Tiger's Stories (@TigerDetective) May 7, 2025