What is a geothermal power plant and how does it work?

  • Geothermal energy is a renewable energy source that harnesses the heat from the Earth's subsoil.
  • A geothermal power plant extracts heat through pipes and converts it into electricity using steam to drive turbines.
  • There are three types of power plants: dry steam, flash steam and binary cycle, each with different technologies.

geothermal power plant

Geothermal energy is a renewable energy source that harnesses the heat from the Earth's interior to generate electricity, heat buildings and obtain hot water in an environmentally friendly way. Often less known compared to other renewable energies Like solar or wind, geothermal energy has multiple applications and offers remarkable energy efficiency.

This energy It is obtained and processed in specific facilities called geothermal power plants. But what exactly is a geothermal power plant and how does it work?

Geothermal power plant

gas emissions from a geothermal power plant

A geothermal power plant is an electricity generating plant that uses the earth's heat. These facilities, responsible for extracting heat from underground, are essential for converting thermal energy into electricity without depending on external factors, such as weather conditions, unlike other renewable sources.

Regarding environmental impact, carbon dioxide emissions from a geothermal power plant are significantly lower than those produced by fossil fuel plants. On average, they release only 45 g of CO2 per kWh generated, less than 5% of the emissions of traditional plants.

However, geothermal energy is limited in where it can be harnessed efficiently, due to the need to drill into the earth's crust in areas with high geothermal activity. The United States, the Philippines and Indonesia are among the largest producers of this energy due to their favorable geography.

Despite its potential, it is estimated that Only 6,5% of global geometric capacity is being used, according to the Geothermal Energy Association.

Geothermal energy resources

geothermal energy reservoir

Heat from the Earth's core is transmitted through the Earth's crust, which acts as an insulator. To harness that heat, it is necessary to drill into the earth, which requires infrastructure such as pipelines and geothermal wells.

En general, The amount of geothermal energy available increases with the depth of drilling and proximity to the edges of tectonic plates, where the temperature is higher.

How does a geothermal power plant work?

Operation of a geothermal power plant

The electricity generation process in a geothermal power plant is based on two fundamental stages of operation: the geothermal field and the conversion plant.

Geothermal field

The geothermal field is the area where the geothermal gradient is highest. It usually corresponds to a confined aquifer with hot water, stored under impermeable layers that retain heat. This geothermal reservoir is the source of the heat that will be used for electricity generation.

The wells in this field extract a mixture of water and steam that is piped to the plant, using the steam to turn turbines and drive the power generation system.

Generation process

The generation process begins with the extraction of steam and hot water from the geothermal reservoir and its transfer to the plant. Once there, the steam is separated from the liquid by a cyclone separatorThis steam is what makes the turbines spin at high speed (3.600 revolutions per minute), generating electricity.

The excess water is reinjected into the reservoir, a process that ensures the sustainability of the system. If this reinjection were not carried out, the resource would be depleted, and the energy could not be considered renewable.

Types of geothermal power plants

Types of geothermal power plants

There are three main types of geothermal power plants:

Dry steam plants

dry steam geothermal power plant

This type of power plant is the simplest. It works by extracting steam directly from underground at temperatures above 150 °C. This steam drives turbines that generate electricity.

Flash Steam Plants

flash steam geothermal power plant

In flash steam plants, high-pressure hot water rises from wells and, when introduced into low-pressure tanks, part of the water vaporizes, driving the turbines.

Binary Cycle Centrals

Binary cycle geothermal power plant

Binary cycle power plants are the most efficient and modern. They use liquids with a low boiling point to transfer heat from the water, thus generating steam for the movement of the turbines, allowing them to operate with fluids at temperatures as low as 57 °C.

The efficiency and low environmental impact of binary cycle power plants make them the most environmentally friendly, as they do not emit steam or other gases to the outside.

The evolution of geothermal technology has enabled better use of underground resources, improving the sustainability of the system and reducing emissions associated with energy generation. As more countries invest in this technology, geothermal energy is expected to play an even more relevant role in the transition towards clean and renewable energy sources.


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