Question

Which type of energy uses magma or hot dry rocks to generate electricity? A. geothermal B. hydroelectric C. nuclear D. solar

Short answer

A. geothermal

Step-by-step solution

Understand the Sources of Energy

We need to identify the source of energy listed in the question. Magma and hot dry rocks are underground and are associated with heat from within the Earth. This is a clue to identify the type of energy.

Identify Key Characteristics of Energy Types

Let's review some types of energy: - A. Geothermal energy comes from heat within the Earth, such as magma or hot dry rocks. - B. Hydroelectric energy is generated by the movement of water. - C. Nuclear energy comes from nuclear reactions. - D. Solar energy comes from sunlight.

Match the Characteristics with Options

Given that geothermal energy is associated with heat from the Earth, including heat sources like magma and hot dry rocks, it matches the characteristics described in the exercise.

Confirm the Correct Answer

Based on the information above, option A, geothermal energy, is the type of energy that uses magma or hot dry rocks to generate electricity.

Key concepts

Energy Sources

Energy sources are diverse and can originate from different natural processes. These sources can be categorized into renewable and non-renewable. Geothermal energy is one of these sources and falls under the renewable category. It harnesses the heat from the Earth, primarily from volcanic areas where magma and hot dry rocks are accessible. This heat can be tapped to generate power and is a stable and sustainable energy form.
Other renewable energy sources include:

• Solar energy, which utilizes sunlight.
• Wind energy, derived from air movement.
• Hydroelectric energy, from water flow.

On the other hand, fossil fuels, such as coal, oil, and natural gas, are examples of non-renewable sources. They rely on ancient organic material and can lead to resource depletion. Understanding the source of an energy type is essential for harnessing it efficiently.

Electricity Generation

Electricity generation involves converting various forms of energy into electrical power that can be transported through power grids. Geothermal energy is particularly efficient in this process due to its ability to provide continuous power as long as the geothermal source is maintained.
Here's how geothermal energy contributes to electricity generation:

• High temperature geothermal resources produce steam that drives turbines connected to electricity generators.
• Binary cycle power plants use moderate temperature resources by transferring heat from geothermal fluid to another liquid, which then vaporizes and powers the turbine.
• Both methods are sustainable and have a low environmental footprint compared to fossil fuels.

This method of electricity generation is reliable and can provide baseload power, meaning it can continuously supply power to the grid without interruption. Challenges such as location dependency and initial drilling costs exist, but the benefits often outweigh these concerns.

Heat from the Earth

Heat from the Earth is the foundation of geothermal energy. This heat originates from two primary sources:

• The original heat from the planet's formation, which is retained in the Earth's core.
• The continuous heat produced by radioactive decay of minerals in the Earth.

The core and mantle layers of the Earth are extremely hot, and this geothermal heat can reach the surface via conduction or through volcanic activity. When hot rocks or magma near the surface, they heat the adjacent groundwater, creating geothermal reservoirs.
These reservoirs can be accessed by drilling wells to bring the hot water or steam to the surface. This process allows us to harness and convert the geothermal energy into usable forms, such as electricity and direct heating, providing a clean and reliable energy source.