Simpa Networks and Kenyan solar energy company M-KOPA are bringing pay-as-you-go models to solar photovoltaics while also capitalizing on innovations in mobile banking. In Simpa’s system, customers make payments—via mobile phone if they have access to mobile banking—for a particular amount of energy, and the company unlocks the customers’ equipment until they use what they’ve paid for. When a customer has paid in full for the equipment, it unlocks permanently. Needham believes that this financing approach will allow investment in larger systems by those who would otherwise have been able only to afford a small light.

While many of these ideas are still unproven at the large scale, UNDP’s Gitonga says the sun will play a growing role in providing energy to the developing world. “Solar energy will remain a big piece of energy expansion, especially in decentralized remote areas,” he says. “There are 1.3 billion people without electricity as we speak. This figure has remained like this for the last 50 years. If we don’t do anything, it will remain like this until 2030.”