Skip to main content Skip to secondary navigation
Main content start

Solar light at scale

A pair of Stanford students set out 16 years ago to provide solar lanterns as a cleaner, safer alternative to kerosene lamps. One of them, Nedjip Tozun, spoke at a recent Sustainability Accelerator event about bringing their idea from a class project to a reality in millions of homes in underresourced regions.

Almost 20 years ago, when Nedjip Tozun, BS ’02, MBA ’07, was a student at Stanford Graduate School of Business, he learned that many people around the world still lit their homes at night with lanterns fueled by kerosene – dangerous, polluting, inefficient kerosene.

“We can launch satellites in space and do all kinds of crazy stuff. Yet so many people are living without access to very basic technology,” Tozun said during a recent lecture in an ongoing series sponsored by the Sustainability Accelerator, part of the Stanford Doerr School of Sustainability. The series invites entrepreneurs, policymakers, investors, and others working in sustainability to share their stories about transitioning innovative ideas into scalable solutions.

Tozun had studied Earth systems and computer science as an undergraduate at Stanford before enrolling in business school, and he knew the limits of electricity’s reach from visits to family overseas. But he was still surprised to learn that billions of people lacked reliable access to electricity. Around that time, conversations with a classmate in Stanford’s Entrepreneurial Design for Extreme Affordability course inspired him to try to improve access to a safer, more sustainable alternative to kerosene. “We wanted to do something about it,” Tozun said.

The classmate, Sam Goldman, had witnessed firsthand the high consequences of kerosene while serving in the Peace Corps in the West African country of Benin. A 12-year-old neighbor was burned head to foot after kerosene spilled from a lamp, Goldman told Tozun.

Soon, the pair set out to start a company that would sell solar-powered lanterns to replace kerosene lamps. A pilot program began in Myanmar. Tozun and his wife relocated to China, and Goldman to India, to get their fledgling company off the ground.

During the recent lecture event at Stanford, which was moderated by Sustainability Accelerator director of policy Michael Mastrandrea, Tozun recalled obstacles the co-founders had to overcome to replace kerosene lamps on a global scale. They had not anticipated the lack of distribution channels in the largely rural areas they were targeting, or the technological skepticism they encountered among potential customers.

“Here we have Walmart, but in rural Africa and rural India distribution is very disorganized, very informal,” Tozun said of his dawning realization of the challenges ahead. “There’s a lot of mom-and-pop retail shops. You have to figure out how to not only design for the end customer, but design for who’s going to be selling your product in a way that’s affordable and commercial.”

Tozun recalled the challenges of bringing one of the company’s first products to India. Unexpectedly, the lantern would attract and fill with bugs, obscuring the light.

Friends in the software industry had technical bugs to deal with in the apps they were building, Tozun recalled. “But ours were actual bugs and there’s no over-the-air update for that,” he said. “We had to take those learnings and put them back in our design process and continually improve based on what we learned.”

In response to these unanticipated hurdles and others, Tozun and Goldman expanded their business idea from their original plan to build a conventional product company. In trying to provide a solution that would be practical in rural areas with unreliable energy systems across dozens of countries, they quickly found themselves having to build not just a product company, but also a last-mile distribution network, and a bank – all in one. Over the past 16 years, the company, known as d.light, has successfully delivered lanterns and other solar-powered energy systems to millions of people.

The payoff for all this effort was greater than Tozun expected, and not merely financial. He said that when you can coax someone to trade in their kerosene lamp for solar, surprising things can happen. “Kids get better test scores because they can study at night. Health improves in the household. There are more productive hours in the day. The transformation is awesome when you see it and the need is so vast,” Tozun said.

Mastrandrea is also a senior research scholar at the Stanford Woods Institute for the Environment.

Explore More