ENERGY - Urban underground holds sustainable energy

Vast energy sources are slumbering below big cities. Sustainable energies for heating in winter and cooling in summer may be extracted from heated groundwater aquifers. Researchers developed an analytical heat flux model and found that increasing heat in the underground is mainly caused by an increase in surface temperatures and heat release from buildings ...

http://www.sciencedaily.com/releases/2013/10/131028090414.ht