• As in a conventional power plant, this thermal energy can then be converted into electricity via steam or gas-powered turbines, or it can also be used for other industrial processes such as water desalination, cooling or, in the near future, the production of hydrogen.

• Subsurface steam or hot water usually contains gases such as carbon dioxide (CO2), hydrogen sulphide (H2S), ammonia (NH3), methane (CH4), and trace amounts of other gases, as well as dissolved chemicals, such as sodium chloride (NaCl), boron (B), arsenic (As) and mercury (Hg), whose concentrations usually increase with temperature and which are sources of pollution if discharged.

• This thermal energy can then be used to produce electricity via a steam turbine or heat engine that drives a generator.