The production environments are often demanding, and nickel alloys and nickel stainless steels are needed to make geothermal energy viable from an engineering point of view. Building a geothermal power station is an expensive undertaking but once up and running, the operating costs are relatively low.
Paths to geothermal energy
Geothermal energy is obtained by capturing the heat from the earth’s thermal core.
Geothermal fluid is a naturally occurring mineralised mixture of pressurised water and steam heated underground to between 200–325 ºC. The steam and hot water are drawn up from a geothermal field by production wells from depths of up to three
kilometres. High-pressure hot water from the geothermal field is separated at a geothermal plant into steam and water, and the dry steam is used to spin the turbines of generators to produce electric power.
There is also a potential to generate geothermal energy from underground hot dry rocks, where there is heat but no liquids to be tapped.