Geothermal energy is a term many energy enthusiasts have heard about, but only a few fully understand. By now, you might be familiar with organizations that raise awareness about the pros and cons of geothermal energy and why people should make the effort to learn about it.

Geothermal energy is not new to humans. In fact, it has been used for thousands of years in many countries for heating and cooking. The term geothermal energy stems from the Greek words Geo, which means earth, and Thermal, or heat.

Most of the processes involving geothermal energy cannot be seen. This is the reason why many people think it is not as lavish as a vast array of solar panels or towering wind turbines.

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Geothermal energy is responsible for taking the natural functions of the planet and turning them into energy. This can help immensely to shift from fossil fuels which can intensify global warming.

But how does it work? We’ve rounded up the pros and cons of geothermal energy and everything you need to know about this amazing renewable energy source.

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What Is Geothermal Energy?


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Before moving on to the pros and cons of geothermal energy, it is important to know what it is exactly. The temperature of the Earth gets warmer as you get deeper into its crust. This is because the planet’s crust is full of heat, and that heat is called geothermal energy.

The earth’s core is approximately 4,000 kilometers beneath the surface and around 7,200 degrees Fahrenheit.The heat inside the Earth is so intense that it creates a core comprised of molten magma.

Although the temperature of the earth gets cooler closer to the surface, it is still hot enough to bring energy to the world. Heat sometimes breaks through the Earth’s surface through geysers or volcanoes.

By harnessing the natural heat generated from the Earth’s crust, people can produce electricity without making use of other resources. And geothermal energy is a renewable energy source.

This means that it is basically infinite. Furthermore, it is great for the planet because it does not emit harmful greenhouse gases which can harm the environment and humans as well as plant and animal health.

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History of Geothermal Energy

The history of geothermal energy can be traced to Paleo-Indians who used geothermal resources over 10,000 years ago in North America. The settlements of Paleo-Indians had an abundance of hot springs.

Similar to the Paleo-Indians, the ancient Romans also used hot springs to heat their water and homes. This “magic water” was also used by people for cooking and medicine.

In America, the initial commercial use of geothermal energy occurred in 1830 in Arkansas as Asa Thompson charged people to use spring-fed baths. Furthermore, another hotel in Oregon used underground hot springs to heat rooms in 1864.

Geothermal Energy for Industrial Uses


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Geothermal energy then boomed as it was used industrially in the late 19th century in Pisa, Italy. The steam which originated from natural vents and drilled holes were used to extract boric acid from the hot pools. This is now known as the Larderello fields.

The twentieth century marked a significant milestone in geothermal energy. It was during this time when this energy source was finally used to harness electricity. In 1904, the owner of Larderello fields, Price Piero Conti, ended an ongoing conflict with an electric company and attached a generator to a steam-driven engine. This successful small generator experiment lit four light bulbs.

Conti then developed the technology to build the first-ever geothermal power plant which finally became operational in 1911. This power plant provided electricity for the Italian railway system. It was the only one of its kind in operation until 1922.

Then, John Grant launched the second geothermal power plant in 1922 which produced 250 kilowatts of electricity. It was used to power street lights and buildings around the local area. However, it closed after a short time due to tight competition in the electricity market.

In 1958, New Zealand’s Wairakei Power Station had a breakthrough. When it finally became operational, it was the first one to use flash steam technology. This power plant is considered the second major industrial producer of geothermal electricity.

The United States finally found success in geothermal energy in the 1960s when the first large-scale geothermal power plant began operations. This power plant produced 11 megawatts of electricity and paved the way for greater efficiency and scale in the field.

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Use of Geothermal Energy Today

The largest geothermal energy producer today is the United States. In 2013, the country amassed a total capacity of just under 3,500 megawatts. Philippines and Indonesia are also moving forward as major producers of geothermal electricity, with Italy and New Zealand ranking fourth and fifth globally, respectively.

What Awaits Geothermal Energy

Geothermal energy is bound to keep increasing its reach as larger power plants are built in the coming years. The use of this kind of renewable energy can positively impact the future by decreasing the dependence on non-renewable resources such as gas, oil, and coal.

How Geothermal Energy Is Used

There are many ways to tap into geothermal energy. The underground reservoirs of hot water and steam can be used to generate electricity or to cool and heat buildings. A geothermal heat pump system can also be used to heat homes in the winter.

Types of Geothermal Power Plants

There are four types of geothermal power plants which are commercially used all over the world.

Flash Steam Plants

This type of power plant uses high-pressure hot water to produce steam. The hot water is pumped to a generator and released due to the pressure of the reservoir. When the pressure drops, the water vaporizes which make the turbines spin to generate electricity.

Flash steam power plants and dry steam power plants give off small amounts of carbon dioxide, nitric oxide, and sulfur. Compared to power plants which use fossil fuels, this is still less damaging. The hot water which does not turn into vapor is returned to reservoirs through injection wells.

Dry Steam Plants

This power plant makes use of hot steam and minimal water from geothermal reservoirs. The steam passes through a turbine to a pipe that rotates the generator in order to produce electricity. This kind of geothermal power plant is also the oldest.

Binary Cycle Plants

The binary cycle plants use moderate-temperature water from a reservoir. The hot geothermal fluids are passed from one side of a heat exchanger in order to heat a working fluid in another pipe. The working fluid is then turned into vapor and passed through a turbine to generate electricity. The working fluid can be Pentafluoropropane or Isobutene.

Flash or Binary Combined Cycle

This plant combines binary and flash technologies. Here, geothermal water is vaporized into steam using pressure. Then, it is converted into electricity. The low-pressure steam escapes the turbine and is condensed using a binary system.

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Why Do We Need Geothermal Energy?

Before discussing the pros and cons of geothermal energy, you need to know why there is a need for it. Because geothermal is a clean and renewable source of energy, the need for it is increasing. Here are other reasons why we should promote the use of geothermal energy.

It Creates Jobs and Supports the Economy

Geothermal projects legitimately change the lives of people not just because it supplies energy, but also because it creates jobs and economic growth. For example, CalEnergy in California has boosted the local economy by investing around $1 billion in the area. During the four years that it takes to build the geothermal plant, this project will employ over 300 construction workers. When it is completed, it will hire over 50 full-time workers.

Furthermore, since geothermal power plants are constructed locally, it stimulates economic activity for local economies. Aside from employment opportunities, geothermal plants pay huge amounts in taxes which could be used to support local projects.

Geothermal Energy Is Good for the Environment

Geothermal plants do not harm mother nature. In fact, it emits a low amount of greenhouse gases because it does not involve combustion, unlike fossil fuel plants. Additionally, binary geothermal plants and flash/binary geothermal power plants produce essentially zero gas emissions.

Geothermal Power Is Dependable

Regardless of the climate or weather, geothermal plants function 24/7. This provides a fantastic source of energy that never runs out and is never interrupted. Geothermal power is also versatile enough to support other intermittent energy sources such as solar and wind. Furthermore, geothermal plants can be scaled depending on the needs of the community.

Pros and Cons of Geothermal Energy

Geothermal energy has its fair share of upsides and downsides. Here’s a closer look at some pros and cons of geothermal energy.

It Is Widely Available

Because the heat from the earth’s crust can be accessed almost everywhere, humans all over the world can use geothermal energy if they have the technology to do so. Now, homes and businesses which use geothermal pumps for heat are increasing and will continue to do so in the future.

Environmentally Friendly

Carbon emissions from power plants contribute to climate change. One of the most important advantages of geothermal energy is that it is a clean energy option compared to other fuel sources. With geothermal energy, there is minimal waste that is produced when extracting power.

Additionally, geothermal energy has a low environmental impact because it requires no transportation or extensive drills. Furthermore, a geothermal system is expected to reduce a home or building’s carbon footprint.

It Is Renewable

Geothermal energy will be available for humans as long as the planet is here. Think about it—fossil fuels will run out. However, renewable resources such as geothermal energy will not be expiring anytime soon.

There is also no shortage of geothermal energy. Unlike solar or wind power which can’t be used if the environment is not cooperating, geothermal energy is virtually limitless.

Saves Money

Homeowners and business owners who use geothermal heat pumps for heating and cooling purposes consume less energy. This results in huge savings. Although purchasing this technology can be quite expensive initially, it pays off in the long run. You are expected to save 30% to 60% on heating and 25% to 50% on cooling using geothermal energy.

Additionally, more and more people are investing in extraction sites, therefore making geothermal energy more affordable. Because of the competitive market, the price of geothermal pumps and even the energy itself has significantly lowered.


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Great Potential

The worldwide consumption of energy is approximately 15 terawatts. This is not even close to the enormous amount of energy that is stored in our crust. On the other hand, fossil fuels are finite and take millions of years to form. Because of this, we might soon run out of oil or gas from the planet’s reserves. Soon, it will be ineffective and even environmentally destructive to drill for petroleum.

Furthermore, the risk in geothermal production is less compared to other sources of renewable energy. Today, there are many emerging technological methods that allow engineers to lower the temperatures and drill deeper than before. This can potentially increase access to geothermal power.

Little Geothermal System Maintenance

Because most geothermal systems only have minimal moveable parts, the average lifespan of a heat pump is high. Heat pump pipes even feature an astonishing warranty of up to 50 years while the pump can function well for around 20 years.

High Investment

One of the most common disadvantages of geothermal energy is its initial cost for residential and business owners who want to use it. Many people cannot afford to install a geothermal system.

Extensive drilling and installation is a complicated process which makes the price go up. For an average-sized home, heat pumps can be priced at around $10,000-$20,000. However, the investment will pay off in an estimated 5 to 10 years.

Meanwhile commercial geothermal power plants are also immensely expensive. The drilling together with exploration can amount to approximately $2 million to $7 million for just a 1-megawatt capacity plant.

Seismic Activity

Because of the injection of high-pressure water into the ground, it causes minor seismic activity or earthquakes. However, this is more common with large-scale plants. An earthquake can be challenging especially in third world countries which are not equipped with sophisticated pipelines and infrastructure.

Despite this disadvantage, no recorded earthquake due to geothermal plants has exceeded a magnitude of 3. Earthquakes with this level of magnitude are not even noticed by the public.

Not Suitable Everywhere

You cannot just build a geothermal plant anywhere you want. The locations of these power plants are very specific. These prime locations are also out of the way of urban centers.

Nowadays, good geothermal reservoirs are hard to find. Notably, several countries such as the Philippines and Iceland meet the electricity demand through geothermal energy. However, if this type of energy is transported across long distances through hot water, a lot of energy is lost.


Geothermal power can only last for a long time if it is properly managed. Rainwater can also be a big issue when it seeps through the earth’s surface and enters geothermal reservoirs. However, this issue does not pose a threat to homeowners who use geothermal heating and cooling and only affects geothermal power plants.

Fickle at Times

Geothermal activity can sometimes be fickle. For example, if a hot spring suddenly shuts off without any prior indication, it can cause issues to whoever depends on geothermal energy as an energy source.

Cannot Be Moved

Unfortunately, modern technology still has not found a way to transport geothermal energy over long distances. Because of this, geothermal energy is impossible to move easily. It does not function the same as electricity and oil which can be transported over long distances without losing significant amounts. A power plant can only provide power to the surrounding area.

Dangerous Chemicals

Heat is not the only thing that comes up with energy extracted from the Earth’s core. Some of the hazardous chemicals that are released include hydrogen, mercury, ammonia, and sulfide.

Disposing of these chemicals safely can be challenging because it has the possibility to pollute the surrounding area. Thankfully, modern geothermal plants have found a way to inject these chemicals back to its geothermal source.

Assessing the Pros and Cons of Geothermal Energy Is It Worth It?

A look at the pros and cons of geothermal energy proves that not all that glitters is gold. As expected, getting energy from below the Earth’s surface is not as fantastic as many people say. Considering its advantages and disadvantages, one should research before deciding to build a geothermal plant.

However, considering the list of pros and cons of geothermal energy, it’s safe to say that the advantages far outweigh the drawbacks. This type of energy is one of the most sustainable, reliable, and environmentally friendly fuel sources. Soon, geothermal energy may become the leading source of energy throughout the world.