Geothermal energy is heat that comes from inside the earth. The word is the combination of the Greek words “geo” (earth) and “thermos” (heat).

• Thermal energy is energy contained in rocks that can be transformed into electrical energy by a geothermal plant.
• Geothermal fluid is the means by which this process of energy transformation is accomplished: it is extracted through the production of wells and is returned to the reservoir via re-injection wells.

For a geothermal resource to be industrially usable, it is necessary that a large amount of thermal energy be stored in permeable rocks and close to the surface (1-3 km).

• Magmatic Intrusion: this acts as the heat source that gives rise to the geothermal system.
• Geothermal reservoir: Body of permeable rock, where hot steam or water is trapped under high pressure beneath a narrow and impermeable layer (seal layer characterized by clays – Caprock or Claycap), thereby forming a geothermal aquifer. The reservoir is heated by the heat emanating from the magmatic intrusion.
• Fluid & Permeability: Meteoric water that infiltrates the crust through fractures and faults and is able to reach deep areas. Along the way, the temperature of the fluid increases when approaching a heat source, triggering advection processes, transferring heat from deep areas to higher levels.
• Recharge Areas: Surface sections where meteoric water catchment takes place, feeding the reservoir in depth.

• Renewable and free of fossil fuels.
• Low level of CO2 emissions, which prevent Global Warming.
• Capacity to reliably and stably provide energy in the long term.
• It produces energy at a relatively low and competitive cost compared to other sources of generation, such as coal and gas.
• Geothermal energy allows the diversifying of electricity supply sources and reduces the risk of potential price increases due to fuel costs.

Due to geothermal plants not burning fossil fuels, they produce low levels of CO2 emissions. Geothermal production is currently estimated to prevent the emission of 22 million tons of CO2 per year, compared to coal-based electricity production. A case study of a coal plant including purifiers and other emission control technologies, emits 24 times more carbon dioxide (CO2), 10,837 times more sulfur dioxide (H2S) and 3,865 times more nitrogen oxides (NO3) per megawatt/hour than a geothermal steam plant.

There are currently 24 countries that produce geothermal energy, reaching a total installed power of 12,600 MW * approx.

Note *: 10,800 MW of Flash Plants and 1,800 MW of Binary Plants

Chile’s geothermal potential would increase from 2,440 to 3,500 MW if other less explored projects are developed in the next 20 years.

The energy needs of Chile and any other country must be envisaged using a horizon of several years and, in this context, geothermal energy is a viable option:

• Clean energy in its operation and environmentally friendly.
• Permanent energy source. Capacity factor greater than 90%. There is no intermittency.
• It uses less land than any other energy source.
• Uses no water in the generation process.
• Generation of sources of employment.
• Innovation and sophisticated technology.
• Energy source with more than a century of development.
• Local energy source.