Explore how we use geothermal energy every day - from powering cities to heating greenhouses. Balanced pros and cons, real examples, and classroom-ready explanations.
Geothermal energy isn’t just for making electricity. It shows up in more places than you might expect. From heating a single home in rural Idaho to powering an entire city in Iceland, geothermal energy is already hard at work.
But like every energy source, it comes with trade-offs.
This is the most well-known use. Geothermal power plants use heat from the Earth to spin turbines. The spinning turns generators, and those generators produce electricity.
Globally, geothermal plants produce about 15 gigawatts of electricity. That’s roughly the same as 15 large nuclear reactors. The United States leads the world, followed by Indonesia, the Philippines, and Turkey.
Sometimes you don’t need electricity. You just need heat. Direct-use systems pipe hot geothermal water straight into buildings, greenhouses, or industrial facilities. This is far more efficient than converting heat to electricity first.
The math is simple: if you need heat, using Earth’s heat directly saves about 70% of the energy compared to using electric heaters.
Farmers love geothermal energy. Greenhouses in cold climates - think Hungary, Iceland, and parts of the US - use geothermal water to keep plants warm through winter. This lets them grow tomatoes, peppers, and flowers year-round without burning fossil fuels.
Fish farms use it too. Warm geothermal water speeds up the growth of tilapia, catfish, shrimp, and even alligators. New Zealand has a prawn farm heated entirely by geothermal wastewater from a nearby power plant.
Factories use geothermal heat for drying lumber, pasteurizing milk, dehydrating fruits and vegetables, and even extracting gold from ore. These processes need steady, reliable heat - exactly what geothermal provides.
Heat pumps are the most common new use of geothermal energy. They use the constant 50-to-60-degree temperature just beneath the surface to heat and cool buildings. Schools, office buildings, and homes across the US and Europe are installing them. They cut heating and cooling costs by 30% to 60%.
Renewable and reliable. The Earth won’t stop producing heat anytime soon. And unlike solar and wind, geothermal runs 24/7. No cloudy days. No calm nights.
Very low emissions. Geothermal plants release about 95% less carbon dioxide than coal plants. They also produce almost no sulfur dioxide or nitrogen oxides.
Small land footprint. A geothermal plant produces as much electricity per acre as a solar farm, but uses far less land than wind or hydropower.
Long lifespan. Geothermal wells and plants can operate for 30 to 50 years with proper maintenance.
Energy independence. Countries with geothermal resources don’t need to import fuel. The energy is right there, underground.
Location matters. The best geothermal sites are along tectonic plate boundaries. Not every country has them. Enhanced Geothermal Systems are expanding the possibilities, but they’re still in development.
High upfront cost. Drilling deep wells is expensive. A single geothermal well can cost $2 to $7 million. The plant itself adds tens or hundreds of millions.
Some environmental concerns. Geothermal fluids often contain dissolved minerals and gases. If not handled properly, these can pollute groundwater. And while it’s rare, geothermal projects have been linked to small earthquakes.
Not completely carbon-free. Geothermal plants do release some carbon dioxide and hydrogen sulfide gas trapped underground. It’s far less than fossil fuels — about 5% of coal’s emissions — but it’s not zero.
Imagine you have a mug of hot chocolate. The heat from the mug warms your hands. Now imagine that feeling, but the mug is the whole Earth, and the heat never goes away. That’s geothermal energy.
We use this Earth-heat in three main ways:
To make electricity. Think of it like a steam-powered toy. Underground heat boils water. The steam shoots up and spins a big fan. The spinning fan makes electricity for lights, TVs, and schools.
To warm buildings. Some people pipe hot water from underground directly into their homes. It’s like having a radiator that never runs out of hot water.
To grow food. Farmers in cold places use warm underground water to heat greenhouses. This keeps plants cozy even when it’s snowing outside.
Geothermal energy is a helper. It keeps us warm, powers our stuff, and helps grow our food - all without making a mess.
Here’s the big question: if geothermal is so great, why doesn’t everyone use it?
The answer comes down to location and money.
Geothermal resources aren’t spread evenly. The best spots - where hot water or steam is close to the surface - are in places like Iceland, the western US, Indonesia, and East Africa. If you live in the middle of a continent far from tectonic activity, you’d need to drill much deeper. That’s expensive.
But geothermal heat pumps change the equation. They don’t need volcanic heat. They just need ground - any ground - a few feet down. That’s why heat pumps are becoming common in places like Sweden, Germany, and the northeastern US.
The cost varies too. A large geothermal power plant might cost $2 to $5 per watt of capacity. That’s comparable to coal or nuclear. But the fuel is free. So over 30 years, a geothermal plant can be cheaper than almost any fossil fuel option. You can’t beat free fuel.
Countries are starting to notice. Kenya gets about 45% of its electricity from geothermal. El Salvador gets about 25%. The Philippines gets about 17%. These aren’t wealthy countries - they’re places that chose the cheapest, most reliable option.
Iceland is the world’s best example of geothermal energy. The country sits on a volcanic hotspot, giving it enormous geothermal resources. Five major geothermal power plants provide about 30% of Iceland’s total electricity. The rest comes from hydropower. And 90% of Icelandic homes use geothermal water for heating.
Reykjavik’s district heating system pipes hot water from geothermal fields into the city through insulated pipes. The water arrives at about 80 degrees Celsius and circulates through radiators in homes and businesses. The cooled water then flows back to be reheated.
District heating isn’t unique to Iceland. Paris has used geothermal heating since the 1960s. The city’s system heats about 200,000 homes. In the US, Boise, Idaho has a geothermal district heating system that dates back to 1893. It still heats more than 100 buildings downtown.
In Hungary, about 80% of the country’s geothermal energy goes to agriculture - mostly heating greenhouses. Hungary is one of Europe’s largest producers of greenhouse vegetables, thanks in large part to geothermal heat.
“Geothermal energy is too expensive to be practical.”
Upfront costs are high, but operating costs are low. Over the life of a plant, geothermal is often cheaper than coal or natural gas — especially when you consider fuel costs and carbon pricing.
“Geothermal heat pumps are only for new buildings.”
Not at all. Existing buildings can retrofit geothermal heat pump systems. The process involves drilling boreholes in the yard and connecting them to the existing heating system.
“Geothermal energy causes pollution.”
It causes far less than any fossil fuel. The main concern is hydrogen sulfide gas (that “rotten egg” smell near some hot springs), but modern plants capture and treat it.
“We’ve already found all the good geothermal sites.”
We’re still discovering new resources. Enhanced Geothermal Systems (EGS) could unlock geothermal energy almost anywhere. The US Department of Energy estimates EGS could provide 100 gigawatts of electricity by 2050.
Last updated: June 15, 2026
What percentage of Iceland's homes are heated with geothermal energy?
Which of these is NOT a direct use of geothermal energy?
Compared to coal, how much less carbon dioxide does geothermal energy produce?
What is a major disadvantage of geothermal energy?
What is district heating?
Answers: C: About 90%, C: Generating electricity in a nuclear plant, C: About 95% less, B: It only works in specific locations, B: Hot water from one source is piped to many buildings
What are the main uses of geothermal energy?
The three main uses are generating electricity, heating and cooling buildings through geothermal heat pumps, and direct uses like heating greenhouses, fish farms, and hot springs for bathing.
Is geothermal energy better for the environment than fossil fuels?
Yes. Geothermal power plants release about 95% less carbon dioxide than coal plants. They also take up less land per unit of electricity than solar or wind farms.
What's the biggest disadvantage of geothermal energy?
It's location-dependent. The best geothermal resources are near tectonic plate boundaries. Drilling deep wells is expensive, and upfront costs can be high.
Can geothermal energy power an entire country?
Iceland proves it can. About 30% of Iceland's electricity and 90% of its home heating come from geothermal sources. Other countries like Kenya and El Salvador also get significant portions of their power from geothermal.
How long do geothermal power plants last?
Geothermal plants are built to last 30 to 50 years. The turbines and other equipment are durable, and the fuel source (Earth's heat) never runs out.
Does geothermal energy cause earthquakes?
In very rare cases, Enhanced Geothermal Systems (EGS) can trigger small earthquakes - usually too small to feel. Conventional geothermal plants rarely cause noticeable seismic activity.
What is district heating?
District heating is a system where hot water from a geothermal source is piped through a network of insulated pipes to heat many buildings at once. Reykjavik, Iceland has one of the largest systems in the world.
