ACCIONA is a leading company in the areas of infrastructure, renewable energy and water services. In November 2008, the company set up the Microenergy Foundation (FUNDAME) with the aim of promoting social development in remote rural areas through increased access to basic services including energy, water and infrastructure. For its part, FUNDAME established a non-profit association in Peru known as ACCIONAMicroenergía Perú (AMP) with the ultimate goal of promoting development in rural, off-grid areas through expansion of electricity services. AMP introduced a so-called “service rate management model” designed to ensure the project’s economic sustainability by charging users affordable monthly payments. Under the framework of its Luz en Casa (“Light at Home”) program, AMP aims to expand access to basic electricity services powered by solar home systems to 3’500 rural families by 2013 in Peru’s Cajamarca region.This WBCSD case study provides context for ACCIONA’s Microenergy Foundation and discusses the pay-per-use social enterprise model utilized to facilitate a self-sustaining project in Peru.