Geothermal energy is the heat coming from beneath the Earth’s surface near tectonically active regions. Geothermal power is used for generating electricity, heat, and cooling. Geothermal energy is a renewable and stable resource, which does not depend on exterior factors. Geothermal systems allow to produce energy with little gas emissions, they are rather efficient and durable. The main challenge of building a geothermal plant is a great dependence on the resource's location.
Geothermal energy is heat originating beneath Earth’s crust and going down to magma. As there is heat inside the Earth, the temperature is getting higher moving down below the subsurface. This heat is called geothermal energy. In order to generate power from geothermal energy, a reservoir needs to be dug to reach steam and hot water. The main applications of geothermal energy are heating, cooling, and electricity generation. Geothermal energy exists in volcanoes and geysers and it is also stored in rocks of the Earth’s crust. High-temperature resources (300°F to 700°F) are required to generate electricity from geothermal energy and they are normally situated near tectonically active regions, in the countries like Iceland, New Zealand, El Salvador, Philippines, the United States, Indonesia, Turkey, Mexico, and Kenya.
Geothermal energy is normally captured through:
geothermal power plants generating steam for electricity,
geothermal heat pumps using heat close to the Earth’s crust for heating water or buildings.
Types of geothermal power plants:
Dry steam plants are the oldest of geothermal power plants. Dry steam moves from the production reservoir to turn generator turbines. Such plants require very high temperatures and little fluids.
Flash steam plants represent the most widespread type of plant using high-pressure hot water over 180°C to turn it into steam driving generator turbines. After cooling down the remaining steam is condensed into water and flows back into the ground.
Binary cycle plants use water with a lower temperature than the other two types, which makes it possible to place them for geothermal power generation in more regions. Such plants transfer the heat from geothermal hot water to a liquid with a low boiling level, such as pentane or butane converting it to steam and driving a generator turbine.
The advantages of using geothermal energy
Renewable source of energy. Geothermal energy is naturally replenished without creating a deficit from using it.
Stable. Unlike sun or wind, geothermal energy does not depend on weather conditions or other external factors making it possible to be confident about a certain amount of energy to be obtained.
Environmentally friendly. The carbon footprint of utilizing geothermal energy is minimal in comparison to conventional fossil fuels such as oil, coal, and natural gas.
Efficient systems. From 25% to 50% less electricity is utilized for geothermal pumps in comparison to traditional heating and cooling systems. With geothermal energy, it is possible to achieve saving up to 80% over conventional systems.
Longevity. Geothermal heat pump equipment functions for approximately 20 years and underground infrastructure lasts about 50 years.
Rapid technology development. Numerous innovations in geothermal energy promise further improvements and mitigation of the current disadvantages.
Challenges associated with geothermal systems
Despite the important advantages of geothermal power, there are some drawbacks, which need to be considered and paid attention to. Some of the gases are released into the atmosphere during digging, still, they are much lower than the gases related to fossil fuel. Geothermal plants might cause the risks of earthquakes, which can be minimized by strict standards. Many of the areas are not able to use geothermal resources as the plants have to be built where the hydrothermal sources are accessible.