Geothermal Energy

- Overview

Geothermal energy is heat energy that comes from the earth. The word geothermal comes from the Greek words geo (earth) and therme (heat). Geothermal energy is a renewable energy source because the earth continuously produces heat. 

Geothermal energy is used for bathing, heating buildings, and generating electricity. Wells are drilled into underground reservoirs to tap steam and hot water. The steam or hot liquid drives turbines that generate electricity. The steam or hot liquid is then reinjected back into the reservoir.

Geothermal energy is more environmentally friendly than conventional fuel sources. However, it's location specific and gases are released into the atmosphere during digging.

The Geysers Geothermal Complex in California is the world's largest geothermal installation. It supplies energy to five surrounding counties in Northern California.

Please refer to the following for more information:

• Wikipedia: Geothermal Energy

- How To Obtain and Use Geothermal Energy

Geothermal energy, heat from the earth, can be obtained from a variety of sources: hot water or steam reservoirs deep in the earth obtained through drilling; geothermal reservoirs are located near the earth's surface, and shallow ground near the earth's Relatively constant temperature of 50°-60°F. The diversity of geothermal resources allows them to be utilized on both large and small scales. 

Utilities can use the hot water and steam from the reservoir to drive generators and generate electricity for their customers. Other applications use geothermally generated heat directly for various purposes in buildings, roads, agriculture and factories. Still others use heat directly from the ground to heat and cool homes and other buildings.

- The Main Advantages of Geothermal Energy

Geothermal energy is a reliable energy source with a small footprint compared to other renewable energy sources; it can be harnessed on both a large and small scale, the industry is expanding, and its infrastructure is durable. The downside is that geothermal power plants can only be built in certain locations, they are often expensive to build initially and can cause surface instability and earthquakes.

Here are five important benefits of geothermal energy:

• Reliable power supply
• Small footprint
• Available for large and small installations
• The scale of the geothermal energy industry continues to expand
• Geothermal infrastructure has long life

[Geothermal Energy - NASA]

- The Main Limitations of Geothermal Energy

While geothermal energy is a clean and renewable resource, it can be expensive and challenging to develop. 

Barriers to deploying geothermal resources are mainly a result of geothermal energy's unique characteristics as a subsurface resource. Exploring, discovering, developing, and managing geothermal resources is inherently complex and can have greater risks and upfront costs than other renewable energy technologies.

Some of the main limitations include:

• High upfront costs: Drilling deep wells to access geothermal reservoirs is expensive, making geothermal power plants four to six times more expensive to build than combined-cycle gas plants. The average installed cost per kilowatt of geothermal energy worldwide was $3,478 in 2022.
• Location dependence: Geothermal power plants can only be built in specific locations where the necessary geological factors exist.
• Seismic activity: Drilling and injecting fluids into the earth can trigger small earthquakes.
• Environmental concerns: Geothermal plants can produce undesirable gaseous emissions and require large amounts of water for cooling.
• Transmission losses: Geothermal plants are often located far from load centers, which can result in transmission losses.
• Long development times: Conventional geothermal power plants can take 5–10 years to develop.

[More to come ...]