There are two types of geothermal energy types:
Small facilities. Houses and small buildings use this technology to obtain domestic hot water and supply heat to the heating system.
Large geothermal plants of electricity generation. These plants convert geothermal resources into electricity.
The use of geothermal energy implies the following pros and cons:
Advantages of geothermal energy
In general, the advantages of geothermal energy outweigh the disadvantages. The main benefits are listed below:
1. High efficiency
It is the most efficient energy of all renewable sources. The amount of thermal energy lost by transporting heat from the bottom of the well to the surface is minimal.
2. Constant production
Geothermal energy remains stable throughout the different seasons of the year. Since the heat source is several meters underground, the thermal inertia is very high. The earth above it performs an insulating function that prevents thermal transmissions. The effect is similar to that of a cave where the temperature is practically constant throughout the year.
3. It exists everywhere
It is a source that is found anywhere on Earth, unlike those that depend on deposits.
For particulars uses, the need for energy is not so high as that power plants need; so, this system can be used everywhere.
However, there are more favorable sites than others. For example, in volcanic areas, the temperature in the subsoil tends to be much higher.
4. It does not depend on the meteorology
It does not depend on meteorological variations. It is an essential difference compared to solar energy. It does not matter if it is cloudy, raining or if the swamps related to hydropower are full or empty.
5. Useful in summer and winter
Geothermal heat pump systems take advantage of stable ground temperature. Heating and cooling systems provide heating in winter, cooling in summer, and hot water year-round.
6. It is viable for private individuals
It can be used in a particular way. For example, in isolated houses where electricity does not arrive. It is an alternative to solar thermal energy.
Moreover, the maintenance of these systems is simple.
7. It is a source of renewable energy
Geothermal is a renewable and environmentally friendly source of energy.
This is the reason why it is considered renewable energy.
It doesn’t generate greenhouse gases be. Thus, this energy resource is environmentally friendly.
8. It generates very little waste
The waste it produces is minimal and causes less environmental impact than combustion, nuclear, or fossil fuel energy. A typical single-family home stops emitting two tons of carbon dioxide per year if it uses geothermal energy compared to a natural gas boiler house.
9. Economic savings
Geothermal energy has high performance and low consumption that implies economic savings in the bills.
For example, in a house of about 150 to 180 square meters, the economic savings it represents is 70%.
A geothermal energy facility pays for itself over four to six years. It means that at this time, all the money saved in energy is equal to the price that it has been necessary to install the technology.
10. Visual impact is minimal
Geothermal energy for homes has a minimal impact as it is an underground installation. In the case of air conditioning, it is usually done with underfloor heating. The heating and cooling system in a home doesn’t need fans or interior devices in the rooms or outdoors, just a pump.
Disadvantages of geothermal energy
The main drawbacks of geothermal energy are:
1. High initial cost
The installation costs tend to be high.
Geothermal reservoirs are under the earth’s crust. These systems need to get the heat from the subsoil. For this reason, the first stages of the process are lengthy and expensive.
To carry out a project for a new installation it is necessary to carry out previous studies. These studies require specific machinery and significant investments in the initial phase of the project.
2. Location restricted
Impossibility of exploiting this energy source everywhere, we must first identify the suitable place and terrain’s geological characteristics. Geothermal energy is not viable on rocky and unstable terrain due to the difficulty of constructing wells.
A significant disadvantage is that it is location-specific. Concerning the geothermal plants, they need to get access the heat resources. Some areas are not able to exploit this resource in power plants.
3. Unviable in large cities
It is more difficult to install, particularly in large cities. The drawback of cities is that the subsoil belongs to the city council. It is usually occupied by other services such as sewerage, natural gas and electricity pipes, etc.
4. Possible toxic emissions
In the event of an accident or leak, hydrogen sulfide can be released. Its smell generally detects it, but it is not perceived in large quantities, and it is lethal.
In those cases there would also be a specific risk that toxic substances, such as arsenic, ammonia, etc., will be released and contaminate nearby waters.
5. Environmental impact
To exploit this energy type, it is necessary to drill the geothermal deposit’s earth surface with the landscape’s consequent deterioration. This disadvantage is especially significant in large geothermal installations; in single-family houses, geothermal energy’s environmental impact is practically imperceptible.
6. Only local exploitation
It cannot be transported as a primary source of heat; it must be consumed in the same place from where it comes. On the other hand, in geothermal power plants, this drawback disappears since electricity can be transported.
The injection of wastewater to produce geothermal energy is linked to earthquakes.
Also, drilling holes in the ground to obtain heat from inside can cause small earthquakes capable of causing extensive damage to the surface. This problem is more significant with geothermal power plants and is similar to fracking techniques.