Geothermal Energy and Geothermal Power Plants | Lesson 7.1| Earth Science

Jr Grande

20 Nov 202009:16

Summary

TLDRThis video lesson covers geothermal energy and its significance in the Philippines, where it is a leading source of renewable energy. It explains the basics of geothermal energy, how it is generated from heat within the Earth's subsurface, and highlights the geothermal gradient, which shows how temperature increases with depth. The video also describes the three main types of geothermal power plants: binary cycle, dry steam, and flash steam, detailing their processes and how they generate electricity. Lastly, it discusses the re-injection of water to preserve geothermal reservoirs.

Takeaways

🌍 Geothermal energy is a major renewable energy source in the Philippines, making up almost 45% of the country's renewable energy production.
🔥 Geothermal energy is the heat derived from the decay of radioactive elements like potassium, uranium, and thorium, as well as residual heat from Earth's formation.
🌡️ Aquifers are rock reservoirs containing groundwater, but not all aquifers are capable of producing geothermal energy.
💧 For an aquifer to be classified as a geothermal reservoir, it must have a heat source, like a hot rock or magma chamber.
📉 The geothermal gradient refers to the increase in temperature as you go deeper into the Earth's surface, typically around 3°C per 100 meters.
🔁 There are three types of geothermal power plants: binary cycle, dry steam, and flash steam.
⚡ In a binary cycle power plant, heat is transferred from geothermal water to a secondary liquid with a low boiling point, which drives a turbine to generate power.
💨 A dry steam power plant directly uses steam from a geothermal reservoir to rotate a turbine and generate electricity.
💥 A flash steam power plant uses hot water from a geothermal reservoir, which flashes into steam in a cold tank, turning a turbine to generate power.
♻️ In all geothermal power plants, the water or steam used is re-injected back into the geothermal reservoir to maintain sustainability.

Q & A

What is geothermal energy?
-Geothermal energy is the heat that comes from the decay of radioactive elements like potassium, uranium, and thorium, as well as residual heat from Earth's formation. It involves techniques to recover heat from Earth's subsurface, particularly from aquifers containing groundwater.
How significant is geothermal energy in the Philippines?
-Geothermal energy is a major renewable energy source in the Philippines, accounting for almost 45% of the country’s renewable energy. The Philippines is the second-largest producer of geothermal energy in the world.
What is an aquifer, and how is it related to geothermal energy?
-An aquifer is a rock reservoir that contains groundwater. Not all aquifers can produce geothermal energy, but those connected with a heat source, such as heated rocks or magma chambers, are capable of generating geothermal energy.
What is a geothermal gradient?
-A geothermal gradient is the rate at which temperature increases as you go deeper into the Earth. The average geothermal gradient is around 3°C for every 100 meters of depth.
What are the three types of geothermal power plants?
-The three types of geothermal power plants are binary cycle, dry steam, and flash steam power plants.
How does a binary cycle geothermal power plant work?
-In a binary cycle power plant, water from the geothermal reservoir is pumped into a chamber where it transfers heat to another liquid with a lower boiling point. This second liquid vaporizes, turning a turbine to generate electricity. The water is then re-injected into the reservoir to maintain the supply.
How does a dry steam geothermal power plant operate?
-A dry steam power plant directly captures steam from a geothermal reservoir, which turns a turbine to generate electricity. The steam condenses into water, which is then re-injected into the geothermal reservoir.
How does a flash steam geothermal power plant function?
-In a flash steam power plant, hot water from the geothermal reservoir enters a tank where it rapidly vaporizes into steam. This steam turns a turbine to generate electricity. After cooling and condensing, the water is re-inserted into the reservoir.
What role do radioactive elements play in geothermal energy?
-Radioactive elements like potassium, uranium, and thorium decay over time, producing heat. This heat contributes to geothermal energy by heating rocks and aquifers deep within the Earth.
Why is it important to re-inject water into geothermal reservoirs?
-Re-injecting water into geothermal reservoirs is essential to prevent depletion of groundwater and to ensure the sustainability of the geothermal energy production process.

Outlines

00:00

🌍 Introduction to Geothermal Energy and Aquifers

The lesson introduces geothermal energy, explaining its significance as a renewable energy source, particularly in the Philippines, where it contributes nearly 45% of the renewable energy supply. Geothermal energy is derived from the Earth's heat, produced by the decay of radioactive elements like potassium, uranium, and thorium. The energy comes from both residual heat from the Earth's formation and heat stored in aquifers. These aquifers, which are rock reservoirs containing groundwater, are not always capable of producing geothermal energy. Only those connected to a heat source, such as a magma chamber or radioactive elements, can create geothermal reservoirs. The concept of geothermal gradient anomaly is introduced, stating that as we go deeper into the Earth, temperature increases by roughly 3°C per 100 meters.

05:02

🔋 Types of Geothermal Power Plants: Binary, Dry Steam, and Flash Steam

This section explores the three types of geothermal power plants: binary cycle, dry steam, and flash steam. In a binary cycle plant, heat is transferred from geothermal water to another liquid with a lower boiling point, which then drives a turbine. The used water is re-injected to prevent depletion of the geothermal reservoir. A dry steam plant, on the other hand, directly uses steam from the geothermal reservoir to power a turbine, after which the condensed water is reinserted into the reservoir. Flash steam plants operate by turning hot water into steam inside a flash tank, which powers the turbine, and then re-injecting the condensed water back into the geothermal reservoir. This efficient cycle helps maintain the sustainability of the energy source.

Mindmap

Keywords

💡Geothermal Energy

Geothermal energy refers to the heat derived from the Earth's internal processes, such as the decay of radioactive elements like potassium, uranium, and thorium, or from the Earth’s formation. In the context of the video, it is presented as a significant renewable energy source in the Philippines, which is the second largest producer globally. This energy is used to generate electricity through various power plants.

💡Aquifer

An aquifer is a rock reservoir that contains groundwater. In the context of geothermal energy, an aquifer may be connected to geothermal reservoirs capable of producing energy if it contains a heat source, such as a hot rock or magma chamber. The video emphasizes that not all aquifers are suitable for geothermal energy extraction.

💡Geothermal Reservoir

A geothermal reservoir is an underground location where heat from the Earth is stored and can be used for geothermal energy production. It contains hot water and steam, which can be extracted to generate power. The video highlights that for an aquifer to become a geothermal reservoir, it must have a heat source.

💡Binary Cycle Power Plant

A binary cycle power plant is a type of geothermal power plant where the heat from geothermal water is transferred to a secondary liquid with a lower boiling point, which then vaporizes to drive a turbine and generate electricity. This system allows geothermal energy production even from lower-temperature geothermal reservoirs.

💡Dry Steam Power Plant

A dry steam power plant extracts steam directly from a geothermal reservoir and uses it to turn turbines and generate electricity. The steam is later condensed and reinserted into the ground. The video describes this method as an efficient way to harness geothermal energy from steam-producing reservoirs.

💡Flash Steam Power Plant

In a flash steam power plant, hot water from the geothermal reservoir is depressurized in a tank, causing it to 'flash' into steam. This steam is then used to turn turbines and generate power. The video explains that once the steam condenses, the water is reinjected into the geothermal reservoir to maintain sustainability.

💡Geothermal Gradient

The geothermal gradient refers to the rate at which temperature increases as you go deeper into the Earth. In the video, it is explained that for every 100 meters you go deeper, the temperature increases by about 3°C, which is key for understanding how geothermal energy is accessed from different depths.

💡Renewable Energy

Renewable energy is energy derived from natural resources that are replenished on a human timescale, such as geothermal, solar, wind, and hydro energy. In the video, geothermal energy is discussed as the primary renewable energy source in the Philippines, contributing to nearly half of its renewable energy generation.

💡Magma Chamber

A magma chamber is a reservoir of molten rock beneath the Earth's surface. In the context of geothermal energy, it serves as a source of heat for geothermal reservoirs. The video explains how the heat from magma chambers can make nearby rocks and groundwater hot enough to be used for energy production.

💡Radioactive Elements

Radioactive elements such as potassium, uranium, and thorium naturally decay and release heat, which contributes to geothermal energy. The video highlights that the presence of these elements in the Earth’s crust is one of the sources of geothermal heat used in power generation.

Highlights

Introduction to geothermal energy and its significance in the Philippines.

Almost 30% of the generated power in the Philippines comes from renewable sources, with geothermal energy as the major contributor.

The Philippines is the second top producer of geothermal energy globally.

Geothermal energy comes from the decay of radioactive elements like potassium, uranium, and thorium, as well as from residual heat from the Earth's formation.

Geothermal energy refers to techniques used to recover heat from the Earth's subsurface, particularly in aquifers.

Aquifers are rock reservoirs containing groundwater, but not all aquifers are capable of producing geothermal energy.

If an aquifer has a heat source, such as a hot rock or magma chamber, it becomes a geothermal reservoir.

Geothermal gradient anomaly: the temperature increases by about 3°C per 100 meters of depth below the surface.

Three types of geothermal power plants are discussed: binary cycle, dry steam, and flash steam.

Binary cycle power plants use a secondary liquid with a lower boiling point to transfer heat and power the turbine.

Dry steam power plants extract steam directly from the geothermal reservoir to turn the turbine.

Flash steam power plants use a tank to vaporize hot water into steam, which powers the turbine.

All three types of power plants reinject water back into the geothermal reservoir to prevent depletion.

Geothermal energy relies on natural heat sources like hot rocks and magma chambers to create steam or heat for power generation.

The next video will focus on hydrothermal energy and hydrothermal power plants.