Urbanisation offers substantial opportunities to reduce poverty, in part because it is more cost-effective to meet many basic needs in cities than in rural areas. This paper demonstrates that providing electricity to the 200 million urban residents who currently lack access would require only US$1.37 billion per year to 2045. Generating this electricity from low-carbon options (consistent with avoiding a 2°C temperature rise) would cost only one per cent more. This demonstrates that relatively small amounts of resources need to be mobilised to deliver basic services and infrastructure to the urban poor – an essential precursor to inclusive and sustained economic growth.