Buildings in urban areas are entirely lacking in significant energy-use developments. Energy production and distribution in urban areas are hugely inefficient, losing most of their production to waste heat. Over the past 100 years, the clay surrounding London’s Underground has warmed and is no longer able to absorb the trapped waste heat, causing the Underground temperature to increase to over 30°C.
Thies, Nicholas J. "London Calling to the Underground: Waste Heat in Urban Morphology is Going Down the Tube." Sustainable Development Law & Policy 15, no. 1 (2015): 50-51.