The Energy Source That Never Sleeps: Geothermal

An exciting new study led by Mark Jacobson at Stanford University found that using geothermal energy—which is power from heat deep inside the Earth—could be a big help in moving the world toward clean, renewable energy.

Geothermal energy works kind of like this: deep underground the rock is super hot, and we can turn that heat into electricity that doesn’t produce pollution. The cool thing is, it can run 24/7—even when the sun isn’t shining and the wind isn’t blowing.

This study shows that if we add this underground heat energy to wind, solar, and batteries, we wouldn’t need as much land or as many big energy systems to make clean power. That means we could keep electricity costs low while still replacing dirty energy from coal and other fossil fuels.

The scientists also found that geothermal could act like a steady “back-up” power source that keeps the lights on all the time—just like nuclear or coal does now—but without the pollution and other environmental impacts. That’s especially useful for places that need power all the time, like data centers that run huge computers.

In short, this research suggests that tapping the Earth’s heat might be a smart piece of the clean energy puzzle as we try to cut pollution and fight climate change.

How Does Geothermal Electricity Really Work?

To make electricity from geothermal energy, we need very high heat from deep inside the Earth.

Right now, almost all geothermal electricity comes from conventional geothermal plants. These are built in special places where heat is already close to the surface—near volcanoes, geysers, hot springs, and tectonic plate boundaries. That’s why most geothermal plants today are in places like Iceland or parts of California.

But here’s the exciting part: you don’t need a volcano to make geothermal power.

Going Deeper: Enhanced Geothermal Systems (EGS)

As you go deeper underground, the Earth naturally gets hotter—about 25°C (45°F) hotter for every kilometer you go down. That means if you drill about 3 to 8 kilometers deep, there’s enough heat almost anywhere to make electricity.

This is where Enhanced Geothermal Systems (EGS) come in.

With EGS:

• Engineers drill two or more deep wells
• One well sends cool fluid down into hot rock (the injection well)
• Another well brings hot fluid back up (the production well)

To help the fluid move through the rock, engineers use techniques borrowed from the oil and gas industry to gently crack the rock underground. This lets the fluid flow through and heat up.

What Kind of Fluid Is Used?

The fluid isn’t always fresh drinking water. It can be:

• Treated wastewater
• Contaminated groundwater
• Industrial wastewater
• Stormwater runoff
• Brackish (slightly salty) water
• Or freshwater

About 1% chemicals are sometimes added to help the fluid expand and move through tiny cracks in the rock. As the fluid flows underground, it heats up naturally.

You might hear people compare geothermal drilling to oil and gas fracking—but the fluids used in Enhanced Geothermal Systems (EGS) are very different.

EGS uses far fewer chemicals—usually about 1% of the fluid—and adds them mainly to help water flow through hot rock. In contrast, oil and gas fracking fluids can contain hundreds of different chemicals. In fact, the U.S. Environmental Protection Agency identified more than 1,000 different chemicals used in fracking formulas between 2005 and 2013. Some common ones include methanol and ethylene glycol, which can be harmful to human health. Even more concerning, scientists still don’t fully understand the health effects of many fracking chemicals and many are considered “trade secrets” and are not disclosed.

In geothermal systems, the fluid stays in a closed loop, meaning it is reused over and over and does not escape into the environment. This makes geothermal energy much safer and cleaner than fossil fuel fracking.

Turning Heat Into Electricity

1. Its heat is transferred to a special liquid that boils at a low temperature
2. That liquid turns into vapor
3. The vapor spins a turbine
4. The turbine makes electricity ⚡
5. Everything is cooled, condensed, and reused in a closed loop

Nothing is burned. Nothing escapes into the air.

Why EGS Is a Big Deal

🌍 Enough energy for the entire world
Scientists estimate that deep geothermal heat could meet all global energy needs once we electrify transportation, buildings, and industry.

🗺️ Available almost everywhere
About 25% of land worldwide could be suitable for EGS.

🌱 Clean and renewable
The Earth naturally replenishes the heat, and the system produces no air pollution or greenhouse gas emissions.

⚡ Always on
EGS provides baseload electricity, meaning it runs 24/7—day, night, rain, or shine.

Don’t forget to keep an eye out on our solutions page for all kinds of exciting progress!