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Sun King

Energy · Chicago, United States · Founded 2008

Sun King, formerly known as Greenlight Planet, is a major player in the off-grid solar energy market, primarily serving communities in Africa and Asia that lack reliable access to electricity. The company was founded in 2007 by T. Patrick Walsh and Anish Thakkar, who met at the University of Illinois. Walsh had been working on biofuel microgrids in India, which sparked the initial idea to create a cleaner, more reliable alternative to kerosene lamps. Joined by Thakkar, they developed their first solar products and secured initial seed funding after a pitch to one of ZS Associates' co-founders, Dr. Prabha Sinha, who became a long-term mentor. Based in Nairobi, Kenya, Sun King has since expanded its operations to multiple countries, powering the lives of over 82 million people. The company's core business revolves around designing, manufacturing, distributing, and financing solar home energy products. Its offerings range from simple solar lanterns for lighting and phone charging to more extensive solar home systems that can power lights, radios, mobile phones, and even larger appliances like televisions and refrigerators. Sun King also provides powerful solar inverter systems that can serve as a complete energy storage solution for homes and businesses, acting as a reliable alternative to generators. This product range allows customers to leapfrog traditional electrical grids and fossil fuels entirely. Sun King's business model is centered on a direct-to-consumer, pay-as-you-go (PAYG) system, which makes its products affordable for low-income households. Customers can acquire a solar system with a small initial payment and pay off the remaining balance in small, flexible installments using mobile money. This model removes the significant barrier of high upfront costs. The company operates one of the largest direct-to-consumer distribution networks for solar products, utilizing a large team of field agents for sales, installation, and service. As of early 2026, the company announced a $150 million investment to expand its PAYG model into Ethiopia, aiming to reach over 2 million households and businesses by 2030. Since its inception, Sun King has raised significant funding over multiple rounds to fuel its expansion. A notable Series D round in 2022 raised $260 million to help the company rebrand from Greenlight Planet to Sun King, the name its products were already known by. The company has also made strategic acquisitions, such as purchasing PayGo Energy, to expand into clean cooking technologies. Sun King's integrated approach, which covers everything from product design and manufacturing to last-mile delivery and financing, has established it as a key provider of energy access in emerging markets. Keywords: off-grid solar, pay-as-you-go, solar home systems, energy access Africa, rural electrification, solar lanterns, PAYG financing, clean energy, emerging markets, sustainable energy, mobile money payments, direct-to-consumer solar, solar inverters, last-mile distribution, financial inclusion, Kenya, Nigeria, Ethiopia, Anish Thakkar, Patrick Walsh