This book presents an overview of geothermal heating systems using ground source heat pumps in different countries. It evaluates the emissions and energy costs generated by the operation of low enthalpy geothermal systems, with heat pumps fed by different energy sources, and assesses, from an international point of view, those policies whose aim is a sustainable, low-carbon economy. The use of low-impact energy sources is gradually growing with the aim of reducing greenhouse gases emission and air pollution. The alternatives offered by geothermal systems are one of the key solutions for a future renewable development, enabling the electrification of heating systems and the use of biofuels. The book will be of interest to energy professionals and researchers.