The energy rests inside the surface of the earth is called geothermal energy. The USA has the biggest geothermal power plant in 900Mw.
Out of all energy resources; Iceland gets 65% of energy from this source. At some places, it is available at a depth of 20 km to 80 km inside the earth. However, at some locations, it is available at a depth of 30-3000 meters.
The energy that exists in the form of heat inside the surface of the earth is called geothermal energy. Here, the source of energy is earth, that why we called it, geothermal energy.
How does Geothermal Energy Work?
Extraction of Geothermal Energy
• We cannot access it from anywhere, but if we want to get it from anywhere, then we have to drill more than 50 km inside the surface of the earth, and which is currently not seems to possible.
• First of all, we have to choose a place where hot spring, volcano, etc. are available, after choosing we have to drill on the surface of the earth. Then we also need a sour of water. Generally, what we do, we put water through one pipe and get hot steam through another pipe. It is like an open circuit.
How the Geothermal Energy was stored in the Earth?
• During the formation of the earth, at that time there was only dust around the sun. Also, that dust was of the planetary level. When these dust particles collapsed due to gravity. Then there was a vast amount of energy that was trapped. Because these planetary level dust particles were colliding with each other and during the collision, the generation of energy occurred.
• There was late bombardment also occurred, due to which many asteroids fall. During this process, a considerable amount of energy had been stored inside the earth.
• Moreover, we know that our space behaves like an insulator. It is also one reason that it remains inside the earth. Inside the earth, there are different types of radioactive elements also present.
These radioactive elements are present inside the core of the earth; slowly, these radioactive elements are also decaying. It is also a reason for geothermal energy stored inside the surface of the earth.
In which Layer of Earth is this Energy Exists
• There are mainly three general layers of earth. Out of them, the deepest layer contains Magma. This layer is very hot and in liquid form.
• Above this layer, solid rocks are connected by the conduction. These solid rocks are heating by the heat of Magma.
• Above the solid rock, there is a porous rock. In which there are many holes for water flow.
Also, from these rocks, we get heat, which we called geothermal energy.
Extraction of Geothermal Energy from the Earth
Firstly a hole or well is drilled inside the surface, up to the porous rock.
Moreover, another hole also drilled near to this hole. From one well we get steam or hot water, and from others, we send hot water (converted from steam) inside the earth. This steam or energy we can use for the production of electricity.
There are three types of the Geothermal Energy Power Plant which are
1. Dry steam geothermal power plant.
2. Flash steam geothermal power plant.
3. Binary cycle geothermal power plant.
1. Dry steam geothermal power plant
After getting steam from the well, this steam is filtered, and then this steam is used for the rotation of the turbine. Then this steam reaches the condenser, where it is converted into a liquid. Then this liquid is further transferred to earth by another well with the help of a pump. The generator is connected to the turbine and electricity is produced. It is a vapor-dominated system. This method works there, where the temperature inside the earth is more than 350 Fahrenheit.
2. Flash steam geothermal power plant:-
In this method, we use the flash chamber for removing impurities of steam. And steam rotates the turbine. Then, we send steam to the condenser. From there we send liquid inside the earth with the help of the pump. It is a liquid-dominated system.
3. Binary Cycle Geothermal Energy Power Plant
This method is used there, where the geothermal resources are at a lower temperature of below 100° Fahrenheit. In this method, the heat exchanger is used. This geothermal plant requires two liquid water (low heated) and secondary liquid (with a low boiling point). That’s why this is called the Binary cycle power plant.
Pros and Cons of Geothermal Energy
There are many pro and cons of this source of energy, which are
Pros of Geothermal energy:-
• Smallest land space:– this power plant requires minimum land space as compared to the other power plants. Because of that, we don’t need to make a store of fuel, like in other power plants.
• Renewable:– It is renewable because once water or stem is used; it can be pumped back to the ground.
• Environment-friendly:- It does not pollute the environment. Because it doesn’t produce greenhouse gases that are harmful to the environment.
• No fuel needed:- Does not need any fuel for the production of electricity. It saves expenses on fuel. However, the thermal and nuclear power plant needs fuel for the production of electricity.
• Abundant supply:- We know that it is abundant in nature. Our earth is a storehouse of energy. Also, we can use this energy for up to thousands of years.
• Significant saving for house owner:- At some places, geothermal energy is readily available on the ground level, and there we can use this energy for heating water, air conditioning, electrical generation, greenhouse, etc.
• Innovation in technology:- It is the innovation in technology. If we want to generate more power from this source, then we have to need to do some work in this field.
You can also read about nuclear energy here.
Cons of Geothermal Energy
• High installation cost: – For extracting it, we have to install a power plant. Moreover, the cost of infrastructure and drilling is also very high.
• Suitable only for the particular region:- The geothermal energy favorable area is not available universally; these power plants are very less.
• Cost of powering the pump:- we know that we need to send water again inside the surface of the earth, for the production of it. So the cost of the pump also effect.
• Surface instability:- Due to drilling, an earthquake may occur. Here we can take the example of Iceland. They stopped the work of the geothermal power plant, due to this problem. They got an earthquake of 3.0 values due to drilling.
• Environment concern:- We know that the emission of gases in this process is very low. However, we get methane like gases, during this process, which is much more dangerous for the environment. We can say that there is a fear of the production of toxic gases.
• The high temperature needed: – we know that, if we get good heat then our efficiency will be increased. However, at most places, we did not get this high temperature friendly geothermal energy.
• Low efficiency: – The efficiency of it is very less near 12% to 15%. Like if we are getting the heat of 100 W, then we are using only 12% to 15% out of them.
Facts about Geothermal Energy
• It is used for heating homes and offices, generate power, grow plants in the greenhouse, under rods and sidewalk to prevent ice formation we can use it.
• The positioning of the geothermal power plant is significantly affected by geological activity. The area with active volcano and earthquake are more suitable to extract it.
• It can be found in the form of a volcano, hot spring, and geysers.
• In 1904, Italy was the first place to produce geothermal energy from beneath the surface of the earth.
• Geothermal energy is the most significant source of energy available on the earth, but due to geological reasons, we are not able to harness the energy everywhere.
• Today there are more than 40 geothermal power plants across the USA and by the 2050 geothermal energy can produce 10% of electricity.
• It has very low emission of greenhouse gases, and the other gases which are produced during the process of extraction are not much harmful to the environment.
Geothermal Power Output in the World
• Iceland gets 65% of total energy from this source, because, Iceland has a geothermal energy favorable field.
• Philippine getting 17% of the total power of their country from this source.
• The USA has the biggest geothermal power plant in the world. This geothermal plant is giving 900 MW continuously. This power plant is in The Geysers, USA. However, we know that this is producing a very less amount of power in comparison to total USA power consumption.
• Indonesia’s geothermal power plant is of 225 Mw. It is the Wayang Windu plant.
The Advantage of Geothermal Energy
• Geothermal energy is renewable energy. Because once water or steam is used, it is again pumped back to the ground.
• It is abundant in nature.
• Geothermal energy is clean energy. It produces decidedly fewer greenhouse gases.
• It also decreases the dependency of the country on imported fuel.
• Once this plant is installed then the only maintenance is required, so we can say that the running cost is very less.