Unlocking Earth's Power: The Rise of Enhanced Geothermal Energy

For thousands of years, humans have used naturally occurring hot springs to cook, heat their houses, and even bathe. This type of energy is referred to as geothermal.

 

For more than a century, geothermal sources have been used to generate electricity. The first geothermal power facilities went online around the beginning of the twentieth century. They use drilling technologies to extract steam and hot water from the Earth's subsoil. This heat then powers turbines, which generate energy.

 

Geothermal energy accounts for a large portion of electricity consumption in countries with tectonically active regions such as Iceland, New Zealand, Kenya, and the Philippines. They take advantage of the ability to drill directly into existing hydrothermal reserves.

 

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What do you understand about EGS? 

 

A naturally occurring geothermal system, also known as a hydrothermal system, requires three critical factors to generate electricity: heat, fluid, and permeability (the capacity of water to move freely through subsurface rock).

 

In many regions, the subterranean rock is heated, yet there is insufficient natural permeability or fluids. In such instances, an upgraded geothermal system can be employed to construct a man-made reservoir from which heat can be extracted for energy.

 

In an EGS, fluid is injected deep down under precisely controlled conditions, causing pre-existing cracks to reopen and create permeability. Increased permeability allows fluid to travel within the now-fractured heated rock, and the fluid heats up as it moves. 

 

Operators pump hot water to the surface, where it generates power for the grid. Learn more about how an EGS works or watch a video about the EGS development process and benefits.

 

EGS could help geothermal development expand outside conventional hydrothermal zones, extending geothermal energy production across the country. EGS improvements are being exhibited around the world today, in both the public and private sectors. 

 

How Geothermal Energy Works?

 

Heat from the earth can be exploited as an energy source in a variety of ways, ranging from massive and complicated power plants to small and relatively simple pumps. This heat energy, known as geothermal energy, may be found practically anywhere, including isolated deep wells in Indonesia and the dirt in our own backyards.

 

Geothermal energy is captured by extracting high-pressure water from the earth using geothermal power plants or geothermal heat pumps. After reaching the surface, the pressure drops and the water turns into steam. The steam rotates turbines that are connected to a power generator, generating energy. Finally, cooled steam condenses into water, which is pumped underground through injection wells.  

 

The process has been well explained below:

 

1. Heat from the earth's crust produces steam

 

Geothermal energy is derived from steam and high-pressure hot water in the Earth's crust. Wells reach depths of up to 2 miles beneath the Earth's surface to catch the hot water required to power geothermal facilities. Hot water is delivered to the surface under high pressure until the pressure drops above earth, transforming the water into steam.

 

2. Steam rotates the turbine.

 

When geothermal water is transformed to steam above the Earth's surface, the steam powers a turbine. The turning of the turbine generates mechanical energy, which can eventually be turned into usable electricity. A geothermal power plant's turbine is connected to a geothermal generator, which produces electricity as it turns.Because geothermal steam often contains significant quantities of corrosive substances such as chloride, sulfate, hydrogen sulfide, and carbon dioxide, turbines must be manufactured of corrosion-resistant materials.

 

3. Generator produces electricity.

 

The rotors of a turbine are linked to the rotor shaft of a generator. When steam drives the turbines, the rotor shaft rotates, and the geothermal generator converts the turbine's kinetic (or mechanical) energy into electrical energy that customers may utilize.

 

4. Water is injected back into the ground.

 

When steam from hydrothermal energy production cools, it condenses back into water. Similarly, there may be residual water that is not transformed into steam during energy creation. To increase the efficiency and sustainability of geothermal energy generation, excess water is cleaned and then injected back into the underground reservoir using deep well injection

 

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Real World Use cases of geothermal energy

 

Several geothermal technologies have been created to exploit the earth's heat for a variety of applications. Geothermal energy is most typically employed to generate heat or electricity on a variety of scales. There are major ways we use geothermal energy:

 

1. Direct Heating

 

Direct heating (or direct usage) geothermal systems use heat from the Earth's crust to heat and cool water and air. Natural hot springs were used by ancient Roman and Chinese societies for cooking, heating, bathing, and other purposes. Some places still use hot springs for bathing. Nowadays, natural hot springs are used to directly heat buildings. District heating systems, which run naturally heated water through buildings to generate warm air, can be used in commercial buildings as well as entire communities. 

 

2. Production of electricity

 

Massive heat from the subsurface is used to generate power, and this is where geothermal energy has a wide range of applications. Consider geothermal power plants; then you will understand the significance of heat within the Earth's interior. The United States is at the pinnacle of energy production due to its vast geothermal energy potential. So far, the United States has reached a milestone by using its geothermal resources to generate 16.7 billion kilowatt-hours of electricity in 2018.

 

3. Heat pumps

 

In addition to direct heating, we can use geothermal energy to indirectly heat (and cool) structures. Use very low-temperature geothermal reservoirs to heat or cool buildings. Heat pumps rely on the fact that the temperature of the ground a few feet beneath the surface remains relatively consistent throughout the year, allowing them to heat or cool air.

 

4. Steam Process for Fishing

 

Geothermal energy is heavily used in the fishing and fish processing industries. Geothermal industrial heat, as well as the Earth's natural thermal energy, are utilized to generate heat for industrial fishing and fish preservation.

 

The Future of Geothermal Energy

 

Geothermal energy has the potential to play an important role in transitioning the United States (and other parts of the world) to a cleaner, more sustainable energy system. It is one of the few renewable energy technologies capable of generating continuous, baseload power. Furthermore, unlike coal and nuclear plants, binary geothermal facilities can be used as a flexible source of energy to offset the intermittent supply of renewable resources such as wind and solar. Binary plants have the capability of ramping production up and down numerous times each day, from 100 percent of nominal power down to a minimum of 10%.

 

The cost of electricity from geothermal installations is also becoming more competitive. According to the US Energy Information Administration (EIA), the levelized cost of energy (LCOE) for new geothermal plants (coming online in 2019) will be less than 5 cents per kilowatt hour (kWh), compared to more than 6 cents for new natural gas plants and more than 9 cents for new conventional coal . There is also a promising future for the direct application of geothermal resources as a heating source for homes and businesses in any area.

 

These intriguing new geothermal innovations will be backed by unprecedented levels of federal R&D financing. The American Recovery and Reinvestment Act of 2009 provided $400 million in new funding to the DOE's Geothermal Technologies Programme. This $90 million was used to fund seven demonstration projects to verify the viability of EGS technology. Another $50 million went into 17 demonstration projects for various emerging technologies, such as co-production with oil and gas and low-temperature geothermal.