What is geothermal energy
Geothermal energy is the energy that can be obtained by harnessing the heat from inside the Earth. It is part of what is known as "clean" energies along with others such as solar or wind energy.
It is being studied and applied in various parts of the world to replace fossil fuels, such as coal, oil or gas.
This internal heat heats even the deepest layers of water: when ascending, hot water or steam produce manifestations, such as geysers or hot springs, used for heating since Roman times.
Currently, advances in drilling and pumping methods allow the exploitation of geothermal energy in many parts of the world.
Experts believe that just below Cornwall there is enough potential energy to be able to supply 10% of all the electrical energy required in all of England.
In areas of hot thermal waters at shallow depths, the heat released by the interior of the earth is used. Hot water or steam can flow naturally, by pumping or by impulses from water and steam flows (flashing). The method to choose depends on which in each case is economically profitable.
One example, in England, was the "Hot Stones Project HDR" (abbreviation in English: HDR, Hot Dry Rocks), abandoned after checking its economic infeasibility in 1989. HDR programs are being developed in Australia, France, Switzerland, Germany. The resources of magma (molten rocks) offer geothermal energy of very high temperature, but with the existing technology can not take advantage of these sources economically.
In most cases the exploitation must be done with two wells (or an even number of wells), so that one obtains the hot water and on the other re-injects it into the aquifer, after cooling the flow obtained. The advantages of this system are multiple:
- There is less chance of exhausting the thermal reservoir, since the re-injected water still contains a significant amount of thermal energy.
- Neither does the reservoir water run out, since the total amount is maintained.
- The possible salts or emissions of gases dissolved in the water do not manifest themselves when circulating in a closed circuit through the pipes, which avoids contamination.
Advantages and disadvantages of geothermal energy
Advantages of geothermal energy
The advantages of geothermal energy are multiple, of which we can highlight the following, which are not ordered in any way:
– It is a source that would avoid dependence on energy from abroad.
– It's ecological.
– The waste produced is minimal and causes less environmental impact than those caused by oil and coal.
– Employs a system of great savings, both economic and energy.
– Absence of exterior noise.
– The geothermal resources are greater than the resources of coal, oil, natural gas and uranium combined, since the land is completely replete with geothermal energy resources.
– It is not subject to international prices, but can always be maintained at national or local prices.
– The area of land required by geothermal plants per megawatt is lower than other types of plants. It does not require the construction of dams, clearing of forests, or the construction of fuel storage tanks.
– The emission of CO2, with an increase in greenhouse effect, is lower than that which would be emitted to obtain the same energy by combustion.
Disadvantages of geothermal energy
– In certain cases, hydrogen sulfide emission is detected by its smell of rotten eggs, but in large quantities it is not perceived and is lethal.
– Contamination of nearby waters with substances such as arsenic, ammonia, etc.
– Deterioration of the landscape.
– It can not be transported (as primary energy).
– It is available only in certain places.
Extended uses of geothermal energy
The most common uses of geothermal energy are:
- Generation of electricity
- Direct use of heat.
- Heating geothermal and ACS.
- Cooling by absorption.
The geothermal air conditioning serves both geothermal heating and cooling. This system uses the great thermal inertia of the subsoil to take advantage of both the cold and the heat and modifies the temperature of the homes.
It is a form of heating or air conditioning increasingly extended, because it does not need many resources as other energy sources. What it is that today, this system of air conditioning for homes is still very expensive.
How geothermal energy works
This energy source is responsible for the current topography of our world, from the configuration of high and lowlands (continents and ocean beds) to the formation of mountains.
The most instantaneous manifestations of this activity are volcanism and seismic phenomena. The core of our planet is a sphere of magma at very high temperature and pressure.
In fact, the heat increases as it descends towards the center of the Earth. In many oil wells it reaches 100 degrees Celsius to about 4 kilometers deep. But it is not necessary to install very long collectors to collect a usable part of that heat generated by the geological activity of the Earth.
It can be absorbed from natural collectors, such as geysers or simple hot springs.
Countries that use it on a large scale
In addition to being used in many households, energy production in this way is booming on a large scale. The world leaders in geothermal energy generation are China 8724 GWh / year, the United States 5640 GWh / year, Iceland 5603 GWh / year and Turkey 4377 GWh / year. Argentina is ranked 31 with 125 GWh / year, with some experimental plants.
It is reliable, sustainable, renewable, friendly to the environment and cheap in relation to its cost.
The United States, which together with China leads the list of countries with the highest production of geothermal energy, represents barely 0.3 percent of the national electricity production. In the Philippines we find the opposite case, it is the second country with the highest installed capacity, with 1904 megawatts, which represent 27 percent of its total electric power production. It is followed by Indonesia, Mexico and Italy with more than 800 megawatts installed.