Why isn’t geothermal energy used more often?

In this article, we enumerate the various reasons why geothermal energy, a clean and renewable form of energy, is not being used as widely as other renewable energy sources, such as solar and wind energy.

Why isn’t geothermal energy used more often?

Geothermal energy isn’t more used today mostly because of three reasons: 

  • Surface instability (earthquakes may occur)
  • Expensive 
  • Location-specific
  • Environmental issues
  • Sustainability issues
  • Infrastructure
  • Renewable Does Not Mean Unlimited

What is geothermal energy?

Geothermal energy is heat derived from the earth’s subsurface. The geothermal energy is carried to the Earth’s surface via water and/or steam. 

Geothermal energy may be utilised for heating and cooling or for generating clean power, depending on its features. 

For power, however, high or medium temperature resources are required, which are typically found near tectonically active areas.

This important renewable energy source meets a considerable portion of power demand in nations such as Iceland, El Salvador, New Zealand, Kenya, and the Philippines, as well as more than 90% of Iceland’s heating requirement.

The key advantages are that it is not affected by weather and has extremely high capacity factors. 

As a result, geothermal power plants may provide baseload energy as well as auxiliary services for short- and long-term flexibility in some circumstances.

Different geothermal technologies are at different stages of development. Direct-use technologies, such as district heating, geothermal heat pumps, greenhouses, and other applications, are widely utilised and established. 

The technique for generating power from naturally high permeability hydrothermal reservoirs is likewise mature and dependable, having been in use since 1913. 

Many of today’s power plants are dry steam or flash plants (single, double, and triple) that use temperatures of more than 180°C to generate electricity.

However, because of the advent of binary cycle technology, which uses geothermal fluid to heat a process fluid in a closed loop via heat exchangers, medium temperature fields are increasingly being employed for electricity production or combined heat and power. New technologies, like Enhanced Geothermal Systems (EGS), are also being developed and are in the demonstration stage.

Advantages of geothermal energy

Geothermal energy, like other forms of renewable energy sources, is a clean form of energy. Other than this, there are many other advantages of geothermal energy, which are:

  • Environmentally friendly 
  • Renewable and sustainable 
  • Massive potential
  • Stable
  • Great for heating and cooling

We shall discuss these in more detail below.

Environmentally friendly

Geothermal energy has the advantage of being ecologically benign. The carbon impact of geothermal energy is quite low. 

The typical geothermal power plant emits 99 percent less carbon (IV) oxide for every megawatt per hour (MWh) of energy it generates, according to the EIA.

Harnessing geothermal energy involves certain polluting processes, although they are minor in comparison to pollution caused by traditional fossil fuels such as natural gas and coal. 

If properly utilised, our geothermal resources can aid in the fight against global warming.

Renewable and sustainable 

Another benefit of geothermal energy is that its reservoirs are made of natural resources, which means they are renewed naturally. 

As a result, geothermal energy may be classified as a renewable energy source. Geothermal energy, like other renewable energy sources, is long-term. 

This indicates that geothermal energy is a resource that can maintain its consumption rate, which is something that traditional energy sources like fossil fuels and coal do not have. 

Geothermal reservoirs, according to experts, have enough energy to endure billions of years.

Massive potential

Global energy consumption is estimated to be around 17 terawatts (TW) from all fossil and renewable sources. This may appear to be a lot, but there is a lot more energy stored in the universe than there is on the planet. 

The problem is that the majority of geothermal energy is either unprofitable or difficult to obtain (sometimes both). Geothermal power plant potential has been predicted to range from 0.035 to 2 TW.

In recent years, geothermal power plants have delivered around 12.7 gigawatts (GW) of electricity throughout the world. 

The capacity of installed geothermal heating is somewhat higher, at 28 GW. As a result, there is a lot of room for increased geothermal energy production.

Stable

Another advantage of geothermal energy is that it is a dependable source of energy. Any geothermal power plant’s electricity production can be accurately anticipated. 

This is not the case with wind and solar, where the weather has a significant impact on electricity generation. As a result, geothermal power plants are ideal for supplying baseload electricity.

In addition, geothermal power facilities have a large capacity factor. 

Their real power production is quite close to the overall capacity installed. In 2017, worldwide average power output exceeded 80% of total installed capacity (capacity factor), but only 96 percent was achieved.

Great for heating and cooling

Another benefit of geothermal energy is that it is non-polluting. High water temperatures are required when geothermal energy is used to generate power. 

The water must be at least 150 degrees Celsius (300 degrees Fahrenheit). It will not properly crank the power-generating turbines if the temperature is less than 150°C. 

Another simple way to make use of geothermal energy is to use it for cooling and heating. The very tiny temperature difference between the surface and a ground source is exploited in this method.

Seasonal temperature changes are frequently more resistive to the ground than they are to the air. 

As a consequence, the geothermal heat pump may use the earth a few feet below the surface as a heat sink or source, similar to how an electrical heat pump uses the heat in the air.

The number of houses that utilise geothermal cooling or heating has risen dramatically in recent years.

Why isn’t geothermal energy used more often?

Geothermal energy isn’t more used today mostly because of three reasons: 

  • Surface instability (earthquakes may occur)
  • Expensive 
  • Location-specific
  • Environmental issues
  • Sustainability issues
  • Infrastructure
  • Renewable Does Not Mean Unlimited

We shall discuss these in more detail below.

Surface instability (earthquakes may occur)

When geothermal power facilities are built, the terrain is prone to become unstable. Geothermal power facilities have caused the earth’s surface to sink in various places in Germany, New Zealand, and Switzerland. 

Hydraulic fracturing, which is a necessary step in the development of improved geothermal system power plants, can induce earthquakes.

In 2006, an earthquake was induced by a geothermal power plant built in Switzerland. On the Richter scale, the earthquake had a magnitude of 3.4.

Expensive 

A commercial geothermal power plant is extremely expensive to build. A geothermal power plant with a capacity of 1 megawatt (MW) will cost between $2.5 and $5 million to build. 

Drilling and exploration of new reservoirs have a significant part in pushing up costs, accounting for almost half of all expenses.

As previously stated, most geothermal resources are not cost-effective to exploit, given existing subsidies, technology, and energy pricing. 

Furthermore, the cost of geothermal cooling and heating systems for both commercial and residential buildings is prohibitively high.

However, these systems are expected to save money for years to come, and should thus be considered a long-term investment. 

The cost of ground source heat pumps is about $12,000 to $30,000 for installation and mostly has a ten to twenty years payback time.

Location-specific

Finding excellent geothermal reservoirs is not always straightforward. However, a few countries have been endowed with a wealth of natural resources. 

In the Philippines and Iceland, for example, geothermal energy meets one-third of the country’s electrical needs. 

When geothermal energy is transmitted over long distances using hot water instead of electricity, a significant proportion of energy is lost.

Even though geothermal energy exists over the whole surface of the planet, not all of it can be utilised. Only a tiny portion of the land is above steam and water pockets that can be used to heat homes or power power plants. 

This makes it difficult to build geothermal power plants in some areas. 

However, the majority of the best locations for generating large amounts of geothermal energy that may be converted to power are generally found in tectonically active areas. 

Corporations are hesitant to build large-scale energy producing facilities because of the ongoing threat of volcanic activity and earthquakes.

Environmental issues

The environmental difficulties linked with geothermal energy are one of the most apparent downsides. Many greenhouse gases can be found under the earth’s surface. 

Some gases may escape to the earth’s surface and atmosphere when geothermal energy is used. These emissions are often greater in the vicinity of geothermal power facilities.

Small quantities of silica and sulphur (IV) oxide are emitted by geothermal power plants. In addition, poisonous heavy metals such as arsenic, mercury, and boron may be present in reservoirs. 

Having said that, geothermal facilities do not harm the environment as much as other energy sources. Only a small portion of what you might expect from fossil fuels and coal electricity. 

According to the Union of Concerned Scientists, no water pollution instances have been documented from any geothermal installation in the United States.

Sustainability issues

Another issue linked with geothermal energy generation is sustainability. Rainwater seeps into the earth’s surface over time and into geothermal reservoirs. 

According to studies, these reservoirs can be exhausted if the fluid is taken quicker than it is supplied. 

Once the thermal energy has been consumed, the fluid can be reintroduced back into the geothermal reservoir (i.e., when the turbine has produced electricity).

If reservoirs are correctly maintained, geothermal power may be sustained. This is not an instance of domestic geothermal cooling and heating, which uses geothermal energy differently from geothermal power plants. 

Nonetheless, geothermal energy is a long-term, ecologically benign, and dependable source of energy. In certain cases, this makes it a no-brainer, but significant initial expenses might prevent you from realising the full potential. 

The future impact of geothermal energy on our power systems is heavily influenced by energy pricing, technical breakthroughs, and politics (i.e., subsidies). 

You can not truly predict what the scenario would be like in a decade or two.

Infrastructure

Geothermal power is not commonly employed in the United States due to a lack of infrastructure, in addition to a lack of suitable resources. 

Naturally, a geothermal energy source can only provide the grid’s baseline power, which might pose problems. Furthermore, the equipment required for constructing power plants and digging wells is exceedingly costly. 

People must also be trained to work at the geothermal power plant, which is an expensive and time-consuming procedure. There is also a limit to where geothermal energy may be used. 

The electricity obtained from the subterranean wells cannot be transferred to another facility whose grid needs it more urgently. Once the energy has been harvested, it must be put to use.

Conclusion

In this article, we covered why geothermal energy is not used as often as the other sources of renewable energy.

FAQs

Is geothermal energy unlimited?

The majority of people assume that the amount of water and steam taken from the ground is limitless. 

However, this is not the case since each well has a finite amount of water that may be utilised to create electricity without the need to re-inject spent water into the wells. 

Water and steam are never able to rise due to insufficient pressure. When the pressure gradient is not correctly restored, the energy source has a tendency to diminish. 

There is also the chance of more geological consequences, such as sinkhole formation.

References

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