The Bunhill phase 2 project involved the construction of a new Energy Centre to take waste heat from London Underground’s ventilation shaft and provide additional heat to the existing Bunhill heat network. The original network consisted of Bunhill Phase 1, a Combined Heat and Power (CHP) plant which used gas to generate electricity on site and to provide heating and hot water to local residents. Bunhill Phase 2 project uses a combination of waste heat from the London Underground and heat and power from two small CHP engines and a large heat pump. Moreover, Bunhill Phase 2 provides cheaper heat to nearby schools, leisure centres and residents, reducing carbon emissions by an additional 500 tonnes per year. During warmer months, the fan installed in the London Underground ventilation shaft will be reversed, injecting cooling to the underground network. This is the first scheme in the world to take waste heat from an underground train network and use it to provide lower cost, greener heat.