What Should We Do When Oil Runs Out Environmental Sciences

Oil. The lifeblood of the modern world 1. It could be said that the world would be unmaintanable without it. Oil is a fossil fuel meaning that the majority of oil used today has been produced from organisms that were roaming the earth some million years ago. The extractable oil comes from the remains of these organisms at the bottom of oceans. 1 Their chemical composition was changed throughout the years as pressure on the sediments above them increased, and henceforth increasing the temperature.

If oil was to be investigated further than its visual appearance, it would be found that the substance contains fatty acids and steroids, the two are more renowned as lipids. Generally, lipids have high hydrogen and carbon levels, however they tend to lack in oxygen levels. They also tend to be non polar molecules however Phospholipids and Steroids may consist of polar and non polar states. Oil with natural gas makes up petroleum. Petroleum is merely a mixture of organic compounds found within the earth that mainly contain hydrogen, carbon and oxygen. When petroleum is extracted from the ground it is more renowned as Crude oil.

Crude oil consists mostly of Alkanes with up to 40 carbon atoms along with water, sulphur and sand. The oil can be refined into various fractions using a method known as fractional distillation. Fractional distillation can separate the compounds according to their boiling point; at each level a mixture of compounds in a similar boiling range is capped off. When fractions obtained are rough and inaccurate, they can be distilled further to obtain narrower boiling ranges. Usually the lower boiling point fractions are the more valuable ones.

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Figure 1 - The fractional distillation column illustrating how the boiling points are used in order to separate each substance.

Figure 1 illustrates how each product is used in our modern world today. In 2010, the US were consuming 19,180,000 barrels of crude oil per day2- It is clear that the world has a great demand for crude oil, as it has many modern applications today (displayed in Figure 1).

2.1 Severe lack of supply of Crude Oil

Unfortunately however, this demand is rising by approx 2% each year and as already more than 50% of the available crude oil has been extracted3, the supply is falling by a much greater figure. (see figure 2) Using the past decades figures of supply and demand for crude oil, the supply will meet the demand between the year 2015 and 2020. At this point, unless the appropriate parties have developed a renewable energy source with approximately the same efficiency as crude oil, the world will be impacted by severe regulations in order to control supply of all energy.

At the point where more than half of the supply of crude oil and petroleum products has been consumed, production is expected to enter an irreversible decline due to geological limitations being reached. The term that describes this point is known as 'peak oil'. 3 The majority of crude oil is used for transportation purposes. J Nilles states that 'transportation systems and vehicles account for roughly 75% of US consumption of oil'. 4 It could be said the world's main concern regarding oil is due to the lack of transportation systems and vehicles ability to run on renewable energy sources. An example of this is the Toyota Prius Hybrid, a car engineered to be fuelled by more environmentally friendly sources of energy (splits between electric fuel cells and fuel), however in 2011, there where still only 1034 being used in the UK.5

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Figure 2 - The graph estimates the increase in demand for the years to come

3.1 New renewable sources of energy

There are a variety of new renewable sources of energy that have been introduced for example tidal power, wind power and hydroelectricity, however none of these options have proved to be as energy efficient or economically efficient as crude oil. Renewable sources of energy are being used today, for example 19% of electricity production in Denmark, 11% in Spain and 7% in Germany in 2008 were via wind turbines.6 However, evidently they do not hold a dominant role in terms of energy production; the majority of the time they are very unreliable as production relies on the weather, which cannot be controlled. Furthermore they are also land consuming and very expensive to operate and manage.

Albeit, it is important to note that renewable sources of energy such that are stated above, do hold a greater amount of social and environmental benefits than crude oil, as they are more sustainable in the long term. Therefore, in the long run we should look for alternative energy options that realistically meet the economic demands of energy consuming countries, as well as aiming to have the least negative environment and social impacts as possible.

3.2 Renewable sources of energy for transport

The greatest invention to date to replace the current energy source for transportation could be Hydrogen powered cars. However, although the cars were ready to be made years ago, apart from demonstration cars, none have yet to be sold to the public. The manufacturers believe that this is due to countries not having enough hydrogen refuelling points (1 in the UK, 19 in the US) .7

There are also the difficulties and dangers of using hydrogen storage cells. The majority of the hydrogen found on earth is bound together with other atoms to form various substances i.e. CH4 (Methane) H2O (Water). The hydrogen needs to be extracted from compounds such as these before it is enclosed in a highly compressed liquid state. Hydrogen requires just a 10th of energy required to combust than gasoline. In fact, just a static spark of electricity from nylon clothing could ignite the substance. When hydrogen ignites, it is merely a translucent flame making them difficult to control. Furthermore, if hydrogen was to leak into an enclosed environment i.e. a garage, any human(s) inside could die of asphyxiation, as they would not be respiring with a sufficient amount of oxygen.

4.1 Substituting the fractional distillation of crude oil

A substitute to the fractional distillation of crude oil could be synthesising petroleum from natural minerals research has been in ongoing since 1919 when the first coal liquefaction plant was developed. Although it is now classed as a process used in the past, coal liquefaction is a process that was mainly used in the past centuries, initially starting in the 19th century where it was used to provide gas for lighting. There are two main stages that occur in the process; coal gasification and gas to liquid.

The coal gasification stage consists of raw coal being introduced to air and water vapour, the combination are then heated to between 320 and 360°C. Consequently the carbon (from the coal) reacts with the oxygen and water therefore produces substances such as carbon dioxide (CO2), carbon monoxide (CO), hydrogen (H) and methane (CH4). Although the CO2 is waste, the rest of the gases can be processed further. Once these gases have been processed they can go onto the second stage of coal liquefaction; the Fischer-Tropsch process. This process uses the hydrogen and carbon monoxide to make various types of hydrocarbons with a range of H2: CO ratios. The ratio can be adjusted by adding carbon dioxide or hydrogen respectively. The process can be described by the following equation:

(2n+1)H2+ nCO → CnH(2n+2)+ nH2O

The gas is passed over a catalyst which then allows the two substances to be formed into water along with long hydrocarbon chains. The water can be recycled back into the coal gasification process whilst the hydrocarbon chains can be used as replacements for the products that are obtained from the fractional distillation of crude oil.

Whilst coal liquefaction can manufacture products that would be a suitable substitute for products obtained from crude oil in terms of availability and simplicity, it is relatively more expensive in comparison.

4.2 Air fuel synthesis

A more promising and recent discovery regarding realistic renewable energy sources could be the Air Fuel Synthesis programme. A company has recently managed to manufacture a chemical process that can synthesise gasoline from just air and water. The process has been suggested by numerous respected individuals over the years however it had never managed to make it to a commercial level. As oppose to mining for coal for coal liquefaction, the company gain their carbon from the carbon dioxide in the atmosphere.

The company's process is surprisingly simple considering the concept of their work. Air is passed through a tunnel containing sodium hydroxide (NAOH) which subsequently converts the carbon dioxide to sodium carbonate (NA2CO3). By way of electrolysis, carbon dioxide is removed from the sodium carbonate. Carbon dioxide then undergoes the reverse water gas shift reaction producing carbon monoxide. Hydrogen gas is created using electrolysis prior to it being used along side with the carbon monoxide in the Fischer-Tropsch process to produce the final product, petroleum.

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Figure 3 - The process of synthesising fuel from atmospheric carbon dioxide

Despite the fact that hydrogen fuel sources are highly efficient in terms of a environmental aspect, the risks and costs required to run the manufacturing and maintenance would outweigh the benefits, this is subsequently the main reasons as to why the modern world does not utilise the energy source. It is said that almost all stationary energy users would be in better economical positions if they use energy sources other than hydrogen fuel cells.

Ironically, the most suitable process for the creation of renewable energy sources is one that had stopped commercial manufacturing many eras ago, synthesis of petroleum from natural minerals. The method outlined by Air fuel synthesis has proven to be extremely beneficial in terms of environmental, social and economical factors

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