Cities are critical to the global energy transition. The most visible energy transitions today occur in major cities. With their comparatively large revenue bases, big cities have the regulatory frameworks and infrastructure to scale up renewables and meet emission reduction targets. Small and medium-sized cities (with less than one million inhabitants) often lack access to sufficient financing and policy support to move effectively in this direction. Despite being less visible than megacities they are home to some 2.4 billion people – or 59% of the world’s urban population – and are growing faster than any other urban category. The Renewable Energy Policies for Cities: Experiences in China, Uganda and Costa Rica series of reports aims to provide much-needed knowledge regarding the deployment of renewable energy in medium-sized cities, focusing on the challenges faced and successes achieved to date.