Geothermics

Geothermics is the science and engineering discipline concerned with the Earth's internal heat and its practical use. It encompasses the study of heat flow, rock properties, reservoir behavior, and the development of technologies to exploit geothermal resources for electricity, direct heating, and industrial applications.

Geothermal resources arise from natural heat in rocks and fluids beneath the surface. They include hydrothermal systems with hot water or steam, hot dry rock formations, geopressured reservoirs, and enhanced geothermal systems that create artificial reservoirs by improving permeability.

Electricity is produced mainly by conventional hydrothermal plants in which wells bring hot fluid to the surface to drive turbines, or by binary-cycle plants that use lower-temperature fluids to vaporize a secondary working fluid.

Direct-use applications include district heating, space heating, greenhouses, aquaculture, and industrial processes, often at lower temperatures than electricity generation. Geothermal heat pumps extract heat from the ground at modest depths to provide space conditioning.

Environmental considerations include water use, land footprint, and potential induced seismicity, particularly with hydraulic stimulation. Reinjection of produced fluids and careful reservoir management help mitigate risks and improve sustainability.

Geothermal energy offers baseload power and a relatively small land footprint, but resource location, upfront capital costs, and reservoir decline pose challenges. Ongoing research aims to expand enhanced geothermal systems, improve drilling and efficiencies, and integrate geothermal with other renewables.