Renewable Energy Review

A set of flashcards covering key concepts, definitions, and facts related to renewable energy sources including geothermal, hydropower, and bioenergy.

What is geothermal energy?

Geothermal energy is thermal energy that arises from beneath the Earth’s surface.

What are the most productive areas for harnessing geothermal energy?

Areas that have a magma source close to the Earth’s surface.

How do we harness geothermal energy for heating?

Wells can be drilled toward heated groundwater to provide direct heating of buildings.

What do geothermal power plants utilize to generate electricity?

Heated underground water and steam.

What is a major advantage of Enhanced Geothermal Systems (EGS)?

EGS can repeatedly pump cold water into dry underground rock and draw it back up to generate power.

What is a potential drawback of Enhanced Geothermal Systems?

EGS can trigger minor earthquakes.

How do ground-source heat pumps (GSHPs) operate in winter?

They transfer heat from the ground to the building.

How do ground-source heat pumps function in summer?

They transfer heat from the building to the ground.

What is the key benefit of using ground-source heat pumps?

They are highly energy-efficient, moving heat instead of producing it.

What generates hydroelectric power?

The kinetic energy of flowing river water turning turbines connected to generators.

What are the three approaches to hydropower?

Storage technique, run-of-river technique, and pumped storage hydropower.

What does the storage technique in hydropower involve?

Storing and releasing water through a series of turbines in a dam.

What is the effect of damming rivers?

It destroys wildlife habitats, disrupts natural flooding cycles, and blocks fish passage.

Why might hydropower expansion be limited?

Most large rivers have already been dammed, and ecological impacts make people resist construction.

What is bioenergy?

Energy obtained from biomass, which includes organic material from living organisms.

What are the three distinct sources of biomass for bioenergy?

Municipal and industrial wastes, agricultural crop residue, and energy plantations.

How is bioenergy harnessed for energy?

By burning biomass for heating, generating electricity, and processing biomass for liquid fuels.

What is the advantage of biopower?

It increases efficiency and waste recycling, and reduces CO2 emissions.

What is a significant environmental concern with corn-based ethanol?

It drives up food prices and impacts ecosystems due to the use of pesticides and fertilizers.

What do flexible-fuel vehicles run on?

E-85, which is 85% ethanol and 15% gasoline.

What is biodiesel produced from?

Vegetable oil, cooking grease, animal fat, soybeans, oil palms, and rapeseed.

Why are novel biofuels being developed?

To explore alternative crops like wheat, sorghum, and algae for more sustainable fuel options.