Simpa is an Indian start-up which provides access to electricity in rural and peri-urban areas thanks to a reliable, affordable and flexible prepaid (pay-as-you-go) solar energy service. Simpa currently operates in Uttar Pradesh, one of the poorest and most populous States. It is targeting a rapid expansion in northern India, where it benefits from a unique position as the first mover. India is the country the most affected by the lack of access to modern energy services, with 360 million people not connected. Simpa provides access to energy by marketing credit for solar power facilities in rural regions in India. Simpa’s clients are typically: a) rural households which do not have a connection to national power grids, b) rural households which are only provided with a limited quantity of electricity from the grid, and c) microenterprises, such as tea vendors, village stalls or small. Clients pay an initial small amount for the installation of their photovoltaic solar energy system and the service subsequently operates without a subscription for the electricity consumption. Simpa is thereby replicating the highly efficient tariff model applied to prepaid mobile phones (pay-as-you-go). The small amounts paid by the client for the service are added together and reduced from the total sale price. Once it has been fully paid, the client becomes the owner of their equipment, which supplies them with clean, reliable and free electricity.