Geothermal power plants are used in order to generate electricity by the use of geothermal energy. Read and learn more about geothermal power plants.
Hydrothermal resources—resources with both water and heat—are used in geothermal power plants. Geothermal power plants require high-temperature hydrothermal resources—300 degrees Fahrenheit (°F) to 700° F—that come from either dry steam wells or from hot water wells.
In this article, we’ll explore geothermal power plants. Please keep reading.
- Why is Geothermal Energy Considered a Renewable Resource?
- Does Geothermal Energy Cause Pollution?
- Advantages and Disadvantages of Geothermal Power Plants
What Are Geothermal Power Plants?
You would observe that the temperature rises as you go deeper if you dug a large hole straight down into the Earth. This is due to the heat that is present deep within the Earth. Geothermal energy is the name given to this heat.
In order to pump steam or hot water to the surface at a geothermal power plant, wells are dug one or two miles beneath the surface of the planet. A hot spring, geyser, or volcanically active area is where you’re most likely to find one of these power plants because these are regions where the Earth is particularly hot just below the surface.
The power plant is fueled by hot water or steam that is drawn from the earth through a network of wells. In the majority of geothermal facilities, the groundwater that has been pumped up is redirected underground. Since the rate of water use frequently exceeds the rate of water return, make-up water supplies are typically required.
Types of Geothermal Power Plants
The flash cycle is the most prevalent of the three main types of geothermal power plants. The amount and temperature of the geothermal resource determine the type of plant to be used. The less fluid that must be drawn from the ground to use a resource, the hotter it is, and the more useful it is.
Some details of each plant may be seen below:
Dry Steam Plants
Dry steam produced by the ground is used by these plants. After transferring its energy to the turbine, the steam moves from the production well to the surface and through a turbine before condensing and being injected back into the Earth.
These are the most traditional forms of geothermal power plants; the first one was constructed in Italy in 1904.
Although this type of power plant requires the least amount of fluid flow, it can only be used in locations where the underground temperature is quite high because it requires the highest temperatures.
The biggest geothermal source of electricity is a dry steam plant at the Geysers in northern California, which was first drilled in 1924. The equivalent of two sizable coal or nuclear power plants’ worth of electricity was produced by them at their peak output in the late 1980s when they produced a staggering 2 GW.
But because of the high rates of extraction, power capacity has since dropped to 1.5 GW, with an average output of less than 1 GW.
Flash Cycle Steam Plants
Due to the lack of naturally occurring high-quality steam, these types are the most prevalent. With this technique, water must be hotter than 180°C and travels through the well under its own pressure.
This is a lower temperature than what dry steam plants have. As its pressure decreases, some of the water “flashes” to steam, which is passed through the turbine section. The water that did not turn into steam is cycled back into the well and can also be used to heat things.
These systems are more expensive because their parts are more complicated, but they can still compete with traditional power sources.
Binary Cycle Plants
In the future, as geothermal energy is used in places other than the known hot spots, binary power plants are anticipated to be the most widely used type of geothermal power plant. This is so that, in comparison to the other two types of plants, binary cycle plants can use water that is cooler in temperature.
They use a secondary loop (hence the name “binary”) which contains a fluid with a low boiling point, such as pentane or butane. Because of its low boiling point, the water from the well vaporizes as it passes through a heat exchanger, which transfers heat to the fluid. It then completes the same task as steam by being passed through a turbine.
How Does the Geothermal Power Plant Work?
Steam is used in geothermal power plants to generate electricity. The hot water reservoirs that produce the steam can be found several miles or more below the surface of the earth. Below is the process of a geothermal power plant:
Wells Are Drilled
A production well is dug into a well-known geothermal reservoir. An injection well is typically also dug to return used geothermal fluids to the geothermal reservoir. For the purpose of generating electricity, hot geothermal fluids travel through pipes to a power plant.
Steam Turns the Turbine
The turbine blades on a shaft are turned by allowing hot, pressurized geothermal fluid—or a secondary working fluid—to expand quickly and produce rotational or mechanical energy.
The Turbine Drives the Electric Generator
Magnets inside a big coil are spun to produce an electrical current using the rotational energy of the rotating turbine shaft. The two main pieces of machinery used to transform geothermal energy into electrical energy are the turbine and generator.
Transmission – Power Lines Deliver Electricity
A step-up transformer located outside the power plant receives electrical current from the generator. Electrical current is transmitted over power lines to residences, buildings, and businesses as the transformer’s voltage rises.
You can learn more about other types of power plants, such as Nuclear Power Plants, Hydroelectric Power Plants, Thermal Power Plants, Solar Power Plants, Wind Power Plants, Tidal Power Plants, and Biomass Power Plants.
Where to Acquire Geothermal Energy?
Only in areas with heat below a geothermal power plant can it operate. This typically occurs in a seismically active region where steady heat sources can be found thousands of feet below the surface and below.
The west of the country, particularly near the western edges of the Rocky Mountains, is where geothermal heat is most advantageously distributed in the United States. Instead of necessarily needing to be close to volcanoes, geysers, and other hot spots, plants that use milder heat for direct heating draw their resources from closer to the surface.
In contrast to conventional geothermal power, enhanced geothermal systems can extract energy from a wider variety of rock formations, but they are still in the early stages of development. The technology was used to produce electricity in the United States in 2013. and Australia.
The U.S. National Renewable Energy Laboratory study noted the high potential for conventional hydrothermal sources; however, its research also found that hot dry rock resources can supply an equal amount of power or even more than the country’s current electrical needs. Read More: Where is the Best Place for Geothermal Energy?
How Do Geothermal Plants Differ from Other Power Plants?
The main distinction is the lack of additional heat. Deep underground geothermal reservoirs heat water that drips down from the surface and then rises as a result of a natural phenomenon known as hydrothermal convection.
Consequently, neither heating fuel nor boilers are required. Extracted water typically ranges in temperature from 220 to 600°F. Furthermore, plants have rock catchers. Not only hot fluids but also other substances could rise up the well. Rocks can seriously harm the steam turbines, rendering the plant unusable. they frequently install filtration systems.
Geothermal power plants typically have low levels of efficiency. They are never higher than 23% and occasionally lower than 10%. However, because a facility is not dependent on fuel, its operating costs are unaffected.
Additionally, byproducts that contain thermal energy, such as exhaust heat, warm water, and others, can be used to boost actual efficiency.
Is Geothermal Power Plant Good?
Thanks to long-lasting, safe, reliable plants, geothermal energy is increasingly low risk and brimming with untapped potential. It is silent, always there, leaves little of an environmental footprint, and has many uses. More jobs are created by it than by any other green energy, and it can even be used for cooling.
Is Geothermal Better Than Solar?
With geothermal, the energy you generate will not replace the electricity you use, but it can lower your heating and cooling bills over the long term. On the other hand, solar energy can significantly reduce your need for electricity or even completely replace it, saving you a ton of money each month.