How Geothermal Power Plant Work System

What exactly is a Geothermal Power Plant?
Geothermal Power Plant is a power plant that uses geothermal energy as its energy source.
Geothermal energy is one of the natural resources in the form of hot water or steam which is formed through natural heating.
The word geothermal  comes from the Greek “geo” which means earth and “therme” which means heat. In other words, geothermal energy refers to the energy produced by heat stored in the earth’s core. As a source of energy that comes directly from nature and is renewable in nature, its use does not have a negative impact on the environment and humans.
Indonesia is very fortunate to be blessed with abundant geothermal resources because of the many volcanoes in Indonesia.

Things that need attention in choosing technology for using geothermal energy to be converted into electrical energy are:

  1. Temperature; geothermal fluids with a high temperature of> 225 oC have long been used for electricity generation. Medium temperature 150 – 225 oC
  2. Resource reserves of up to 25-30 years
  3. Steam Quality; It is expected that the pH is almost neutral, because if the pH is very low the corrosion rate of the material will be faster.
  4. Well Depth and Chemical Content Usually not very deep (no more than 3 km). The location is relatively easy to reach.
  5. The likelihood of a hydrothermal eruption is relatively low. The production of hot fluid from the bowels of the earth can increase the risk of hydrothermal eruptions.

Geological Characteristics of Geothermal Areas

  1. Heat Source: Magma which has a temperature of ~ 700 C
  2. Bed Rock: The bedrock layer which is the hard rock of the lower layer
  3. Aquifer (Permeable Zone Layer): is a layer that can be flowed by water. This layer serves as a reservoir
  4. Cap Rock: A layer of hard rock as a cover rock layer.
  5. Water Replishment: as water enhancer.
  6. Surface Manifestation, namely: Symptoms that appear on the earth’s surface (craters, hot springs, geysers, volcanoes, etc.).

Benefits of Geothermal Energy

The benefits of geothermal energy obtained from the center of the earth is one of the environmentally friendly alternative energies.
The way to take advantage of geothermal energy is to drill the part that is the location of geothermal energy to release steam at a certain depth.
In modern times, geothermal energy is not only used as electricity generation, it turns out that energy from geothermal can also be used as other means such as to help plant growth or other agricultural products that are in the greenhouse during winter. Even this energy can also be used as a space heater and guard the road or sidewalk so that it is not too slippery.
In the future geothermal energy will be of great help to us in many ways. However, we also have to know that not all regions have locations that have the potential to be used as a source of geothermal energy. With the increasing need for energy in modern times, there are many benefits that we get by taking advantage of geothermal energy.

How Geothermal Power Plants Work

How does Geothermal Power Plant work?
For more details on how the PLTP works, let’s look at the picture and description below.

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1. Steam is supplied from production wells through a steam transmission system which then enters the Steam Receiving Header as a steam collecting medium. The Steam Receiving Header is equipped with a Rupture Disc which functions as the last safety unit. If there is over pressure in the Steam Receiving, the steam will be discharged through the Vent Structure. The Vent Structure functions for warming-up in the pipe line when starting the unit and as a safety valve that will relieve pressure if a sudden trip occurs.

2. From the Steam Receiving Header, the steam is then flowed to a Separator (Cyclone Type) which functions to separate steam (pure steam) from foreign objects such as heavy particles (Sodium, Potassium, Calcium, Silica, Boron, Ammonia, Fluor etc.).

3. Then the steam enters the Demister which functions to separate the moisture contained in the steam, so it is hoped that clean steam will enter the turbine.

4. The steam enters the turbine so that the energy conversion occurs from the heat energy contained in the steam into kinetic energy which is received by the turbine blades. The turbine which is coupled with the generator will cause the generator to rotate when the turbine rotates so that there is a conversion from kinetic energy to mechanical energy.

5. The rotating generator produces Electricity

6. Exhaust Steam from the Turbine is condensed in the Condenser with a Jet Spray system (Direct Contact Condensor).

7. NCG (Non Condensable Gas) which enters the Condenser is sucked by the First Ejector then enters the Intercondensor as a cooling medium and NCG catcher. After from the Intercondensor, NCG is sucked again by the Second Ejector into the Aftercondensor as a cooling medium and then discharged into the atmosphere through the Cooling Tower.

8. From the condenser, the water from the condensation is flowed by the Main Cooling Water Pump into the Cooling Tower. Furthermore, the cooling water from the cooling tower, dry steam, is recirculated back into the condenser as a cooling medium.

9. The Primary Cooling System besides being a cooler the Secondary Cooling System also fills the cooling water to the Intercondensor and Aftercondensor.

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10. The overflow from the Cold Basin Cooling Tower will be accommodated for the benefit of the Reinjection Pump.

11. River Make-Up Pump operates only when filling the Basin Cooling Tower.

Advantages And Disadvantages of Geothermal Power Plants


There are actually many advantages to geothermal power. Here are the advantages of geothermal power:
1. First and foremost, geothermal energy is renewable energy, which means that as long as we don’t pump too much water the energy will continue to exist.
2. Geothermal energy does not produce pollution, and at the same time, does not contribute to the greenhouse effect.
3. The location of the power plant for geothermal energy does not require a large area and therefore tends to have little impact on the surrounding environment.
4. Since geothermal energy is energy that comes from within and from itself, no sources outside of fuel are required to keep the generator running.



Although it has many benefits, there are still some disadvantages of geothermal energy. These deficiencies can affect or all three stages of production – pre-production, production and post-production:
1. Perhaps the biggest drawback of geothermal power is that you don’t build a geothermal power plant anywhere you want. You will need an exact location containing hot rock. After that, not all of these rocks can be drilled because they are too hard. These rocks must also have a depth that allows them to be drilled.
2. There are also other risks to consider – sometimes a geothermal site may be drilled but has run out of steam. It could be that this happens when the dry season lasts for a long time.
3. The final loss concerns the potential hazards of geothermal energy. When it is carried out into the soil and which can be mined, this could also mean that there is a possibility that other substances that are not environmentally friendly could also be involved. Harmful gases and minerals can seep from underground and it is very difficult to find ways to safely dispose of these substances into the surrounding environment.
However, there are certainly advantages and disadvantages caused by exploration. However, with increasingly sophisticated technology, these losses can be anticipated and minimized.
Why is PLTP now prioritized in Indonesia? Because the profit aspect is greater and Indonesia has abundant geothermal wealth.