Non-renewable energy sources are those that are limited in nature time wise, because their consumption implies their disappearance without the possibility of renewal. Among their other characteristics is the production of emissions and waste that damages the environment and they are only found in specific areas of the planet.
Non-renewable energy sources correspond to the so-called fossil fuels (oil, natural gas and coal) and uranium (nuclear energy).
Oil
It is an organic compound mainly originating from waste of aquatic organisms, vegetables and animals that lived in the seas, lagoons or mouths of rivers near the sea that accumulated sedimentary layers of the Earth’s crust. Hydrogen and carbon are the basic elements that make up oil.
The formation of an oil field takes hundreds of millions of years and once it has been detected through geological prospecting, deep wells are made using drilling towers to extract the oil.
After the extraction, oil is separated from the gas and water, and then, through oil pipelines, it is taken to be used as fuel or for further treatment (for example, to transform it into different sub products).
This last bit implies a process that is conducted in refineries and is known as fractioned distillation, which allows the division of the crude into different fractions.
Fractioning consists of heating up the crude using special equipment for it to then pass on to a distillation column, in which, making use of the different volatility of the components, a separation is achieved into different fractions that include liquid gas, gasoline, paraffin, kerosene, diesel, lubricating oils, among others.
Nuclear energy
It is the one contained in the atoms’ nuclei and is released as a result of a nuclear reaction.
Nuclear power plants produce electricity by using the energy let off by uranium atoms, because this mineral is capable of producing energy through nuclear fission upon making contact with neutrons. Uranium is found in mineral form in nature.
It must be refined in order to increase its concentration to 3%, level in which it is ready for the nuclear reaction.
Nuclear reactions can be of two types: through fission or fusion.
– Fission: it is the most used way and consists on a reaction in which the nucleus of the uranium atom, upon being bombarded with neutrons, decomposes into two smaller nuclei, producing a great unleashing of energy, besides the emission of two or more neutrons that attack other uranium atoms, which causes the same effect and sets off a chain reaction.
At a nuclear power plant, the uranium used in nuclear fission is stored in tubes made of a highly resistant zirconium alloy. Fission is carried out in the nucleus within the nuclear reactor (closed receptacle that is isolated by thick concrete walls that absorb the radiation).
Within the reactor these is a steel vessel where fission is produced. This process generates heat that raises the temperature of the cooling water to up to 325°C, until it becomes steam. The control bars (boron carbide) found in the reactor core absorb neutrons, decreasing the number of fissions in the reactor to keep it from exploding.
The steam passes through an interchanger, where it transmits heat to the water reserve. There, the water passes through pipes in order to trigger the turbine. It moves an alternator, which produces electricity.
Nuclear energy is also applied in medicine, industry, agriculture and food.
– Fusion: it occurs in stars (Like the sun), generating great amounts of energy. It is produced when two atomic nuclei (like hydrogen for example) join to create a larger one (helium). This type of energy is better than fission because it uses a highly abundant source, as is hydrogen, and also ecological because, at the beginning, it wouldn’t pollute.
However, nuclear fusion needs millions of degrees to take place, but presently, there is no receptacle capable of withstanding such temperatures.
Coal
It is a mineral of organic origin basically made up of carbon. Its formation is the result of the gradual condensation of partially decomposed plant matter over a period of millions of years.
According to the pressures and temperatures that formed it, four types of coal are distinguished: peat, lignite, bituminous coal and anthracite.
This way, upon decomposing, plants form a layer called peat, which is poor in carbon. Lignite comes next in the richness scale, but is still a bad fuel because it contains little carbon (30% concentration) and more water. Bituminous coal is originated by the compression of lignite and is much richer in carbon (between 75 and 80%) and has high calorific power, reason for which it is used in energy production plants. Anthracite comes from the transformation of bituminous coal and is the best coal (95%), pollutes very little and has a high calorific power.
The energetic use (at a large scale) of coal is performed in thermal plants or thermoelectric plants with the objective of producing electricity. In this place, coal is reduced to a fine dust and is then bombarded into a boiler by means of a hot air jet. The heat generated is used to boil water that passes through the boiler’s pipes. The steam (which reaches 600°C) is sent to the turbine in order to make it spin at high speed. The turbine’s shaft is connected to a generator that produces electricity. Its voltage is raised through transformers to then send it to the high-tension grid.
Natural gas
Fuel of fossil origin that forms from the degradation of million-year-old organic matter.
Natural gas is a mix of light hydrocarbons mainly made up of methane (in a higher percentage), nitrogen, carbon dioxide and ethane.
It is found in the depths of the earth, and on many occasions shares the same fields with oil and coal.
Generally, these deposits are located in the subsoil or under the sea, between 1.5 and 4 km deep.
Once natural gas has been extracted in a way that is similar to oil, meaning, through drillings that reach the deposits (through drilling towers), the excess water and impurities are removed. Then, it is stored until it is transported to the consumption areas through pipes called pipelines that come directly out of the storage tanks. However, sometimes, the distances are long and the gas has to be transported in large tankers. But in order to do so, the gas must be liquefied, as this brings its volume down 600 fold compared to the original. This is done in liquefaction plants, where the gas is turned into liquid by cooling it at temperatures that reach –161°C.
Once it reaches its destination, it must be transformed into gas again in regasification plants and stored until its later consumption. Natural gas has several energetic uses, among them:
– Generating electricity: through the operation of gas and steam or combined- cycle turbines (gas and steam).
– Fuel for vehicles: compressed natural gas is used as a cleaner, less expensive and less polluting alternative (20% less than cars that use gasoline or diesel).
– Domestic use: the applications of natural gas in the home are numerous. One can cook with it, heat or obtain hot water for the bathing.
– Industrial use: it is used in textile, plastic and steel industries and also as raw material in the manufacturing of nitrogenated fertilizers.
Diesel and gasoline are two petroleum sub products. Pipelines oil passes through to be used as fuel or to be transformed into sub products.
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