Sun King, the world’s largest off-grid solar company, has grown from a small college project into a global clean energy powerhouse, providing solar lighting and energy solutions to more than 25 million homes across Africa and Asia.

Founded in 2007 by Patrick Walsh and Anish Thakkar, two University of Illinois alumni, Sun King was born from a shared goal: to replace smoky kerosene lamps with cleaner, safer, and more affordable solar alternatives for communities without access to electricity.

Patrick Walsh, an engineer and member of Engineers Without Borders, was working on biofuel microgrids in rural India when the idea for solar-powered lighting first took shape. His classmate, Anish Thakkar, who was then running a nonprofit supporting families affected by cancer, joined the mission after recognising the social impact of accessible energy.

Their early prototypes evolved into solar lanterns designed for affordability and reliability in off-grid homes. However, the co-founders soon realised that providing solar products alone wouldn’t solve the problem; affordability and accessibility were key.

That realisation led to Sun King’s innovative pay-as-you-go (PAYG) model, which allows customers to pay small, manageable amounts daily or weekly for solar systems. Using mobile money or cash payments, customers can keep their systems running and eventually own them outright. This financing model has become central to Sun King’s success, making solar energy available to millions of low-income families.

With early seed funding from Dr. Prabha Sinha — co-founder of ZS Associates and an early believer in the company’s mission — Sun King established its first operations in Mumbai before expanding to Africa. Today, the company’s network of local agents, known as Sun King Saathis, delivers products directly to rural households.

The company has since raised over $700 million in funding and provides more than $1.3 billion in solar loans to households and small businesses. Its solar systems have collectively installed over 195 MW of solar capacity across 11 African countries, adding more than 300,000 new users each month.

Sun King’s impact goes beyond electrification. The company’s affordable, scalable approach has helped reduce carbon emissions, improve education outcomes by extending study hours for children, and create thousands of local jobs in solar distribution and maintenance.

“What started as a simple idea to replace kerosene lamps has evolved into a complete financial and service ecosystem,” said co-founder Anish Thakkar.

Today, Sun King stands at the forefront of the global clean energy transition, bridging the gap between technology and access for millions of people.