Acumen, a global impact investment firm that backs businesses serving low-income communities, has invested $5 million in Sun King’s Zambian subsidiary to expand the off-grid solar company’s operations in the country and help it raise additional local-currency financing.
The equity investment, made through Acumen’s Hardest-to-Reach (H2R) Catalyze initiative, which backs off-grid solar companies operating in underserved African markets, is intended to help Sun King attract financing from local lenders, allowing the company to scale beyond Acumen’s investment.
The investment comes as Zambia tries to close a large electricity-access gap while reducing its dependence on hydropower, which accounts for 80% of its electricity generation, according to the World Bank. Nearly half of the country’s population still lacks access to electricity, according to the World Bank, while rural electricity access stands at 33%.
Sun King is expanding its pay-as-you-go solar business in Zambia, providing households and businesses with an alternative to the national grid. Acumen said the investment will help Sun King provide energy access to nearly 5.6 million people over the next five years, including up to 4.5 million people in Zambia who could gain access to electricity for the first time.
“Since launching in Zambia, we have confirmed there is tremendous unmet demand for reliable, affordable solar energy in communities the grid hasn’t reached,” Krishna Swaroop, Chief Financial Officer at Sun King, said in a statement. “Acumen’s investment gives us the capital and the confidence to continue our nationwide rollout.”
Founded in 2007 by T. Patrick Walsh and Anish Thakkar, Sun King designs and distributes solar kits and appliances, including lights, fans, and televisions, to off-grid households and small businesses. The company began operating in Zambia in 2021 as Greenlight Planet Zambia, and says it has since delivered one million solar kits in the country. Sun King also operates in markets including Nigeria and Kenya.
Its pay-as-you-go model allows customers to spread payments for its systems over 12 to 24 months through mobile money. Sun King has also used local financing to scale the model in other African markets. In July 2025, Sun King secured $156 million in Kenya from commercial banks and development finance institutions, backed by future customer repayments. Three months later, it opened its first large-scale manufacturing plant in Nairobi, Kenya’s capital.
In Zambia, the company is using the model to reach households and businesses that remain outside the national grid. That expansion fits Acumen’s Hardest-to-Reach Catalyze initiative, a $250 million programme focused on expanding clean-energy access across 17 underserved African markets.
“Sun King’s proven track record across other markets, combined with the clear demand for affordable, clean energy in Zambia, gave us confidence that its model could scale quickly in this newer market,” said Sandra Halilovic, Head of H2R Catalyze at Acumen. “Our investment was designed to help accelerate that scale and close the energy access gap faster, while also crowding in local currency debt from local financial institutions.”
Through H2R, Acumen has also backed off-grid energy companies in Malawi, Somalia, Benin, and Uganda, using financing structures including loans and receivables financing. In Zambia, the initiative previously invested $1.25 million in solar distributor RDG Collective through an impact-indexed loan to finance solar home system inventory and solar generators, an investment expected to provide energy access to 66,000 people and power 180 small businesses.
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