Final answer:
The geothermal gradient, which is true, refers to the rate at which the Earth's interior temperature increases with depth, generally around 25-30 °C per kilometer. This concept is fundamental for geothermal energy extraction, which necessitates drilling into the Earth's crust to harness the sustainable but challenging to access heat flow.
Step-by-step explanation:
The statement that the geothermal gradient is a curve showing the increase of temperature with depth within Earth's interior is true. The geothermal gradient represents the rate of temperature change with respect to increasing depth in the Earth's crust. Typically, this gradient is about 25-30 °C for every kilometer you go below the surface, away from the edges of lithospheric plates. Geothermal energy is a result of the thermal energy inside the Earth, which primarily comes from two sources: the original formation of the planet and the radioactive decay of elements such as uranium, thorium, and potassium.
Understanding the geothermal gradient is essential for geothermal energy extraction. If we wanted to match the efficiency of fossil fuels with geothermal power plants, we must drill deep enough to access higher temperatures provided by the Earth's geothermal gradient. This requires significant drilling, sometimes over a kilometer deep, which brings its own set of challenges and limitations.
Geothermal heat extraction can be done sustainably by drilling boreholes to tap into the steady flow of heat from the Earth's interior, which is replenished by radioactive decay. However, accessing this geothermal energy for large-scale usage can be a complex endeavor due to the depth required and the potential depletion of heat in isolated rock areas if not managed properly.