More than 1.2 billion people worldwide live without electricity. Low-tech solutions using everyday objects such as soccer balls and bags help reduce this number.

Now there’s another option.

Massachusetts Institute of Technology graduate Illac Diaz created a solar light bulb from a plastic liter bottle. He fills the bottle with water and a little chlorine and embeds it in the roof of a house. The bottle refracts sunlight, providing as much light as a 55-watt light bulb. He hopes to give light to 1 million homes by 2015.

Illac, who is from the Philippines, founded the nongovernmental organization A Liter of Light to brighten homes in metropolitan Manila. He started his research through the Humphrey Fellowship, a program that brings young and midcareer professionals to the U.S. for a year of nondegree graduate-level study and professional collaboration with American counterparts.