People have utilized geothermal energy to generate power for
more than 100 years since geothermal steam at the vapordominated
field in Larderello, Italy, was first used to produce
electricity in 1904. Conventional geothermal resources provide
a wide range of uses for power production and direct applications.
A large scientific and industrial community has been involved in
developing enhanced geothermal systems (EGS) for unconventional
systems in the last 20 years [1,2]. Field testing of EGS systems,
designed to extract and utilize the earth stored thermal energy at
depths ranging from 2 to 6 km, has been successfully demonstrated
in the United States, Europe and Japan. Such progress is leading to
the goal of operating a commercial-sized EGS reservoir. The U.S.
Department of Energy has broadly defined Enhanced (or engineered)
Geothermal Systems as engineered reservoirs that have
been created to extracted economical amounts of heat from low
permeability and/or porosity geothermal resources [3].