(CNN) -- Turning grandmothers into solar engineers is one of Sanjit "Bunker" Roy's favorite jobs.
Roy is the social entrepreneur and founder of the Barefoot College and has been championing a bottom-up approach to education and empowering rural poor since 1972.
It is now a global enterprise with roots in India. Roy recruits women from around the world to install and maintain solar lighting and power in their home villages.
"If you ask any solar engineer in the world, 'Can anyone make this in a village?' they say it's technically impossible. And if I say a grandmother is making it who is illiterate, he can't believe it, it's beyond his comprehension," says Roy.
The United Nations estimates that around 1.5 billion people still live without electricity, and often the best and most immediate way to bring non-polluting electricity to remote regions is with solar energy.
Roy certainly believes so.
"The way to go about this is not a centralized grid system, which brings in power from hundreds of miles away," he says.
"It is to bring in basic light right down to the level of basic household wherein they take ownership and control over that technology."
Women are the focus for the solar power projects that the Barefoot College runs because men "were very untrainable," says Roy.
"(Men) were restless, compulsively mobile, and they all want a certificate and the moment you give them a certificate they leave the village and go to the cities looking for jobs.
"So why not invest in women, older women, mature women, gutsy women who have roots in the village and train them."
Coming from countries across the world, the women are trained for six months before returning home. Many of the women have previously never left their villages before.
"We were scared. We don't even know (our neighbor) Rwanda...how can we go to India?" says Moyoonia Olive from Democratic Republic of Congo.
"But, since everyone was interested in having electric current soon, we even convinced our husbands!"
To overcome any language barrier, classes are taught primarily with sign language and color-coded circuits. The women learn to build and maintain a variety of solar-powered lamps and chargers.
The Barefoot College "campus" in Tilonia, Rajasthan, is a testament to the power of solar --everything there is powered by the sun; food is prepared using a parabolic solar cooker, night classes are powered by solar lanterns.
Roy says that the school has trained 150 grandmothers from 28 countries, electrified around 10,000 houses with solar power and saved several thousands of liters of diesel and kerosene from polluting the atmosphere.
"We have shown that solar-electrified villages can be technically and financially self-sufficient," says Roy.
"The Barefoot College is supposed to be a sparking off process. People are adopting it and owning it, which is really the story behind the college."