Question

Write about the reservoirs of geothermal energy in detail and how geothermal energy affects land stability. Explain about it in your own words.

Answer 1

Geothermal energy is considered renewable energy. When compared to the energy content available in the earth only fractional energy is captured. Hence it is considered as renewable energy.\

The kinds of geothermal power stations are

1. Dry steam power stations

2. Flash steam power stations

3. Binary steam power stations

A geothermal reservoir occurs naturally when the magma beneath the earth's surface approaches the groundwater. The heat will be transferred to the groundwater and the groundwater tries to escape from the ground to the atmosphere as water vapor or water at a high temperature(Thermal spring).

A geothermal reservoir is a huge collection of rocks under the ground and at a great depth which facilitates the exchange of energy in a profitable manner.

The reservoirs are classified as:

1. High-temperature reservoirs

The temperature is more than or equal to 1500C or more. Water evaporates at 1000C at the atmospheric pressure. (It may not evaporate at great depths as the pressure acting on it is more). Hence these reservoirs are profitable in converting water into steam and making electricity.

They are located near the areas where active volcanos are found easily.

Hot Dry Rock (HDR) are fractured to facilitate the circulation of water in the thermal reservoir with the help of Enhanced Thermal system (ETS).

2. Middle Heat reservoirs:

The temperature of these reservoirs is in the range of  1000C-1500C. There are chances of high gradients in the temperature.

They are used in heating systems and Industrial process

3. Low-Temperature reservoirs

The temperature of these reservoirs ranges from 300C - 1000C. The thermal gradient is appreciable in these regions the energy is extracted by drawing the hot water(This water shall become cold) and again injecting the cold water into it. Used in industrial process

4. Very Low-Temperature reservoirs

The temperature range is less than 300C. They can be located anywhere. Their usage is limited to the airconditioning of houses and in agriculture etc

A heat exchanger is buried in the ground which facilitates a stable fluid which transfers the heat to the surface/houses.

Springs can also be considered as a thermal reservoir. THey escape quickly to the ground surface from the beneath layers.

Disadvantages

1. They shall cause global warming due to the release of gases like co2, SO2, and silica emissions.

2. Land stability is another major issue,

As the water, fluids, and oil are extracted from the earth the land will subside to occupy the voids created. Hence it is practiced to inject back the extracted fluid into the deep layers.

3. They are highly location-specific.

4. High cost of electricity

5. Reservoirs are prone to be depleted when the rate of withdrawal of water is not equal to the rate of injection of water into the reservoir.

I hope you have understood.

All THe Best.!

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