3.1.3.B.3. Geothermal Energy

Geothermal energy is found within rock formations. Inside the earth the temperature rises with depth. The temperature in the earth’s crust is around 4000 °C.

Geothermal energy refers to the heat that is stored within the earth. As you go deeper into the earth, the temperature naturally increases. It can reach extremely high temperatures, around 4000 degrees Celsius in the earth's crust. This heat can be used for various purposes, such as heating buildings or generating electricity.

Think of geothermal energy like a campfire on a cold night. Just as the fire keeps you warm by radiating heat, the heat from the earth can be harnessed to warm homes or produce energy. In countries like Iceland, people use geothermal energy to heat their homes, making it feel like they have a fireplace running all the time.

Geysers (a natural spring that emits hot water) and hot springs are examples of geothermal energy where the steam and hot water come to the surface, in areas where the steam is tapped by drilling.

Geysers and hot springs are natural manifestations of geothermal energy. A geyser is a type of hot spring that erupts with steam and hot water when the pressure built-up becomes too much. In many places, such as Yellowstone National Park in the U.S., these natural features show that there is significant heat beneath the surface. By drilling into these areas, companies can capture the steam to either directly heat buildings or use it to drive turbines and generate electricity.

Imagine a pressure cooker on a stove. As the water inside heats up, steam builds and eventually needs to escape. If you were to capture that steam, you could use it for cooking or other tasks. Similarly, in geothermal areas, we can capture the steam from the earth's heat to use it for energy.

The obtained steam is then used to generate power. Air pollution results in case of geothermal energy where the gases like H2S, NH3, CO present in the steam coming out of the geothermal sources.

Once the steam is obtained from geothermal sources, it can be used to turn turbines, which generate electricity. However, harnessing geothermal energy is not without its challenges. When steam is extracted, it can also contain harmful gases like hydrogen sulfide (H2S) and ammonia (NH3). These gases can contribute to air pollution if not properly managed, highlighting the need for careful environmental considerations when using this energy source.

This is similar to cooking with a gas stove. While you can use the flame to cook food efficiently, if there are leaks, it can release harmful gases into your kitchen. Similarly, while harnessing geothermal energy can be beneficial, we must be mindful of the gases that come with it and find ways to mitigate them.

The overall efficiency for power production is low (15%) as compared to fossil fuels (40%).

The efficiency of converting geothermal energy into electricity is relatively low when compared to fossil fuels. Geothermal systems typically have an efficiency rate of only about 15%, meaning that only a fraction of the energy extracted is converted into usable power. In contrast, fossil fuel systems can achieve efficiencies of around 40%. This difference is important for energy planning and understanding the potential of geothermal as an energy source.

Think about using a sponge to soak up water. If your sponge can only absorb 15% of the water it touches, that’s not very effective compared to another sponge that absorbs 40%. Similarly, while geothermal energy has some potential, its lower efficiency compared to fossil fuels makes it less competitive as an energy source without additional innovations.

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