Islington Council in London has a borough-wide decentralisation energy programme and Bunhill 2 Energy Centre forms a pillar in their ambition to become Carbon-neutral by 2030. Low-grade waste heat from the London Underground system is converted via a heat-exchanger coil and a 1 megawatt, two-stage ammonia heat pump into hot water for their district heating network. Major engineering challenges were overcome to deliver cheaper and greener heat to schools, two leisure centres and more than 1500 homes with a target of 20,000 megawatt of heat. Reduced fuel poverty increases the health and wellbeing of the community. Air quality pollution impact is low. The comfort of public transport users will also be improved with fresh cooled air returned to the Underground.  Bunhill 2 Energy Centre is an energy infrastructure that wittily draws together threads of the urban systems.