Little talked about energy source;
Earth’s core is around 5,700°C, but we can’t reach it.
What we can reach is the geothermal gradient — the natural increase in temperature as you go deeper underground.
• Near the surface: ~10–30°C
• A few kilometers down: 150–300°C
• Deeper: 500°C+
This heat is constantly replenished by:
• Radioactive decay
• Primordial heat
• Core crystallization
So it’s effectively a renewable energy source
A. Hydrothermal Geothermal Plants (Traditional)
These use naturally occurring:
• Hot water
• Steam
• Geothermal reservoirs
How it works:
1. Drill into a hot aquifer
2. Hot water or steam rises
3. Steam spins a turbine
4. Turbine generates electricity
5. Cooled water is pumped back down
This is used in:
• Iceland
• California
• Italy
• New Zealand
B. Enhanced Geothermal Systems (EGS)
This is the future — and it’s where things get exciting.
EGS creates artificial geothermal reservoirs in hot dry rock.
How it works:
1. Drill 3–10 km down into hot rock
2. Inject water under pressure
3. Water circulates, heats up
4. Pump hot water back up
5. Use it to generate electricity
This method can work almost anywhere, not just volcanic regions.
C. Super‑Deep Geothermal (Next‑Gen Concepts)
Companies are developing:
• Plasma drilling
• Millimeter‑wave drilling
• Laser drilling
These could reach 20 km deep, where temperatures exceed 500°C.
At that depth, you can run:
• Supercritical steam turbines
• Which are far more efficient than normal geothermal
This could produce baseload power (24/7) with zero emissions.
🌍 4. How Much Energy Is Available?
Earth leaks about 47 terawatts of heat continuously.
Human civilization uses about 18 terawatts.
In theory, geothermal could power the entire planet many times over.
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