What is geothermal energy?
Heat derived within the sub-surface of the Earth, carried to the surface by water or steam.
What are the two main uses of geothermal energy depending on its characteristics?
Heating/cooling or generating electricity.
Why is geothermal energy reliable compared to solar or wind?
It is not dependent on weather conditions and has high capacity factors.
What type of electricity supply can geothermal plants provide?
Baseload power and ancillary services for flexibility.
What is shallow geothermal energy also called?
Ground source heat, often used with heat pumps for heating or cooling.
What is deep geothermal energy used for?
Direct heating or, if hot enough, power generation through steam turbines.
What temperature range is typically used in geothermal energy applications?
150–370 °C (300–700 °F).
What percentage of global electricity in 2023 came from geothermal energy?
About 2.1%.
Where was the first geothermal power generator tested and first power plant built?
Larderello, Italy — generator in 1904, plant in 1911.
About how many countries use geothermal energy today?
Nearly 90 countries.
What is the basic principle of geothermal energy use?
Heat from the Earth is extracted, transferred to fluids, and used directly or to generate electricity.
What are the three geothermal temperature ranges?
High (>180 °C)
Intermediate (100–180 °C)
Low (ambient to 100 °C)
What does EGS stand for in geothermal energy?
Enhanced (or engineered) geothermal systems.
What does GHP stand for in geothermal energy?
Geothermal heat pump.
What are hydrothermal convective systems used for?
Power generation and direct use.
What is a shallow conductive geothermal system used for?
Direct heating via geothermal heat pumps.
What is the future potential of hot rock (EGS) systems?
Power generation and direct use.
What form of energy can geothermal resources provide if hot enough?
Electricity generation.
How many countries produce geothermal electricity?
24 countries.
What type of geothermal plant uses very hot dry steam directly?
Dry steam system (>235 °C).
What type of geothermal plant uses flash tanks to separate steam from water?
Single or double flash systems.
How does a binary-cycle geothermal plant work?
Heat exchanger transfers heat to a secondary circuit, producing steam to drive turbines.
What are advantages of binary-cycle plants?
Use of lower-quality heat sources and cleaner turbines due to closed secondary circuit.
What does a single flash geothermal configuration include?
A flash tank separating steam and water for turbine use.
