Why is Geothermal Energy not Always a Renewable Energy Source?

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Geothermal energy is not always a renewable energy resource because the steam pressure that powers the turbines may run out. There will always be new places to build geothermal power stations, but a single location may not always produce power forever. It depends on rock strata dynamics and usage intensity.

While this is more renewable than oil or gas, it is also not always a fully renewable resource. A company may eventually have to abandon a location and find a new place to generate power. Geothermal energy is renewable, but maybe less so than wind power is.

How common is geothermal energy in the world?

Geothermal energy is little used and is not so common compared to other renewable energy sources, such as solar or wind energy. This is because extracting energy from the subsoil is not an easy task, as complications can arise that affect both the environment and the cost of energy.

While geothermal energy has enormous potential to help meet the world’s growing demand for clean energy, there are also some drawbacks to consider. On disadvantage of geothermal energy is that it is dependent on location. Even so, engineers think that it could provided up to 8% of the globe’s energy needs.

Video – Geothermal energy is not always renewable

 

Where is geothermal energy found?

What is geothermal energy?

Geothermal energy is the energy that the Earth transmits in the form of heat from its internal layers to the surface. This energy is stored in rocks, soils, and groundwater at various depths and temperatures, and can be used to produce heat and electricity.

Types of geothermal energy

This form of energy is classified based on its temperature:

* High temperature – This is found in areas where the layer of the earth’s crust is still active, with temperatures ranging between 150 and 400 . Drilling to extract it is similar to oil wells.

* Low temperature – This can be found in extensive sedimentary basins, with temperatures ranging between 50 and 70 . It is used in small power plants and in homes.

But also on its use in plants:

* Dry steam – This uses dry steam that comes out of cracks in the earth’s surface.

* Flash steam – This uses water at a temperature greater than 182 C that comes out at high pressure from the wells.

* Binary steam – This method uses steam to heat another fluid that, when evaporated, drives electric turbines.

Best locations for geothermal energy

Most geothermal sources are found around the Earth’s tectonic plates, near the Pacific Ring of Fire. The hydrothermal resources in these areas are located underground and are released to the outside through fumaroles, hot springs, and geysers.

Disadvantages of geothermal energy

  1. Physical deterioration of the area where the energy is extracted
  2. Contamination of nearby water deposits
  3. Greater difficulty of transport and storage
  4. High initial installation costs
  5. Complex ground studies
  6. Very specialized and expensive machinery

How is geothermal energy generated?

Steps to generate electricity in a geothermal power plant

Although there are various methods for converting this energy into electricity, basically they all work in a similar way.

Geothermal power plants take advantage of heat reserves under the ground, which may or may not contain water — in the latter case, they inject water underground. That heat is extracted in the form of steam to rotate a turbine that ultimately activates a generator, producing electricity.

Where does geothermal energy come from?

Geothermal energy comes from the heat of molten rock or magma deep within the Earth that rises through cracks in the Earth’s crust.

Who uses geothermal energy and for what purposes?

Steam is used to move a turbine and generate electricity, whether for industrial or domestic use, but the heat obtained from the subsoil can also be used directly to meet the different heating needs of the population and the industry.

How does geothermal energy work?

Tap into heat close to the earth’s surface to heat water or provide heat for buildings

The medium to low temperature geothermal sources that are used directly for heating do so by accumulating heat from the subsoil and redistributing it through a network of pipes that connect houses, buildings, and industries.

How is geothermal energy harnessed?

In addition to being used directly for heating, this thermal energy can also be used to heat water that is injected into the subsoil, so that it later returns to the surface as steam capable of rotating a turbine that generates electricity.

Is geothermal energy renewable or nonrenewable?

Is geothermal energy sustainable?

The core of the Earth is an almost unlimited resource of thermal energy and this is considered a renewable energy. However, some low temperature areas can cool down over time, depending on the amount of energy stored.

Geothermal energy advantages and disadvantages

Table – Geotherm advantages and disadvantages

Geothermal Advantages (Pros/benefits)

Geothermal Disdavantages (drawbacks/cons)

Low running costs once established

High installation & surveying costs (investment)

Low carbon footprint (38 gms CO2/kWh)

Machines needed to extract and convert heat

Low ecological impact

Above machines made by fossil fuel energy

Renewable and sustainable

Can cause minor earthquakes

Generate electricity cleanly

Location dependent to some extent

Heat buildings directly

Deep drilling needed for high temperature plant (higher temp. = higher efficiency)

Flexible agricultural use 

Possible release of greenhouse and toxic gases

Why is geothermal energy not used as frequently as other renewable energy sources?

Although there are several reasons, the main reason is the high cost installation cost, especially for a single-family building. Therefore, most people choose to install natural gas.

Surface instability of geothermal energy

When companies drill underground for thermal energy, there is a danger of instability on the earth’s surface and earthquakes due to colliding forces underground, something that has already happened several times.

Health hazards of geothermal energy

In addition to the risk already mentioned, there is also the risk of releasing greenhouse gases trapped underground, including gases that are very dangerous for human health, such as carbon dioxide, silica, methane, sulfur dioxide, among others.

Is geothermal energy reliable?

It is reliable as long as the source lasts. That’s to say, it doesn’t fluctuate like wind or solar.

Does geothermal energy cause pollution

Geothermal energy can generate toxic emissions in the event of an accident or leak. In these cases, there is a risk of releasing toxic substances such as arsenic or ammonia, which can cause water pollution in nearby rivers or lakes, in addition to greenhouse gases.

Is geothermal energy expensive?

Although the costs of a geothermal installation in the form of heat pump for home use can vary from country to country, taking as a reference the costs in the United States, the total expenses can be around $18,000 and $45,000. By comparison, a natural gas installation can run around $2,000.

What are examples of geothermal energy?

Examples of geothermal energy in the Philippines

The Philippines is the world’s second largest producer of geothermal energy, currently having three of the largest producing plants:

  1. Makban Geothermal Complex in Batangas Provinces (458 MW output capacity)
  2. Tiwi Geothermal Complex in Albay (289 MW output capacity)
  3. Maltibog Geothermal Power Station in Leyte (232.5 MW capacity)

5 uses of geothermal energy

  • Electricity generation – From a temperature of 150 ºC and above, the heat emitted generates high-pressure steam for electricity production by means of generators.
  • Heating of buildings and homes – With temperatures between 30 and 90 ºC — considered low — very useful thermal energy is generated for heating buildings and homes.
  • In sanitary hot water – With a temperature below 30 ºC, it can be used to obtain domestic hot water. This process requires the use of special pumps to transfer heat emanating from the center of the earth to residential water.
  • For drying wood – Thermal energy can be used to remove moisture from wood, optimizing it for its different uses.
  • For drying food – This energy source can be used to dry food products and for milk pasteurization. This promotes food safety, since it extends the shelf life of foods such as fish and vegetables, so that they are available throughout the year.

Infographic – What are 5 uses of geothermal energy?

What are the 5 main uses of geothermal energy?

These are the five direct uses of geothermal energy

History of geothermal energy

The ability to harness the heat from the interior of the Earth and transform it into energy began in the early 19th century. In 1818, Francesco Giacomo Larderel began to use, with great success, steam from geothermal waters near Montecerboli (Italy) to heat the boilers in a factory producing boric acid.

About 100 years later, in 1904, the first geothermal power plants for the production of electricity were founded, based on Larderel’s invention. This first plant was followed by many others, especially after the Second World War, when more and more plants of this type began to be installed throughout the world until today.

Conclusion – Is geothermal energy a good idea?

Geothermal energy is renewable energy that, although expensive, can be much more profitable in the long term than other similar energies. This is because the resource is basically always available.

However, the high initial costs of installation are a great obstacle to its widespread use, in addition to the fact that in the event of an accident, there is a risk of environmental contamination, although very slight. These are factors that must be carefully evaluated before deciding on this energy source.

References:

Geothermal explained – U.S. Energy Information Administration

Geothermal Electricity Production Basics

Geothermal Energy Advantages and Disadvantages – Earth & Human

Geothermal energy pros and cons – Energy sage

How Much Will a Geothermal Heating and Cooling System Cost for My Home in 2021? – Climate Master

Geothermal Country Overview: Philippines – GeoEnergy

History of Geothermal Energy – Earth & Human

Other resources relating to geothermal energy:

Geothermal FAQs | Department of Energy

Why is geothermal energy not always a renewable energy 

Why is geothermal energy a renewable resource?

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