Chemistry

The Death of the Petrol Car?

The Death of the Petrol Car?

I love Top Gear – the old Top Gear. I love reclining on a Sunday night, watching a few middle-aged men and a quiet driver, dressed in white, irresponsibly screech exotic cars round a track for an hour. Undeniably, my obsession with the fuel guzzling Ferraris runs in conjunction with the populations’ worrying and insatiable desire to consume the limited resource of crude oil. At present, as a global population, we use 96 million barrels of it every day and at this rate of consumption, it would last us only another fifty years according to BP estimates. Regardless of our opinions of it, it seems that we are unable to live without it.

Unfortunately, these figures cause great concern for the car industry, in 2015 the UK alone used 40.5 million tonnes[1] of oil for road transport. Despite this, it is clear that many car companies are making concerted efforts to move away from their dependency on petrol, and are mass producing alternatives, such as the hybrid Toyota Prius (much to Jeremy Clarkson’s disappointment), or the all electric Mitsubishi Phev. However, there are some lesser-known fuel sources that could be just as successful and beneficial as the two previously stated.

Biodiesel[2]

Fundamentally, biodiesel can be made from vegetable oils, animal fats or recycled restaurant grease. For example, recycled oil could be sourced from a local chip shop or even a McDonald’s branch. All biodiesels are produced by using the process of transesterification[3] due to its high conversion yield (98%) and economic viability. Mechanistically speaking, this process works by reacting the lipids with alcohol in a the presence of a catalyst, such as sodium hydroxide, to form mainly biodiesel and glycerol. After this, the immiscible products are separated and the biodiesel is purified by flash evaporation to remove excess alcohol[4]; methyl-ester wash also helps to remove any residual catalyst. The prices of the above processes are not insignificant; and while we are left with an alternative fuel source, this is unfortunately one and a half times more expensive than diesel. Nonetheless, biodiesel can be used to power some cars without the need for modifications, such as the Ford F-250 Super Duty pickup, which renders it as a more realistic candidate as an alternative to petrol or diesel. Usage of this renewable fuel can lengthen the lifespan of a catalytic converter (due to the absence of sulphur), as well as extending the lifetime of an engine due to its lubricating properties.

Hydrogen Fuel Cell

In comparison to biodiesel, hydrogen fuel cells have the potential for household production, but is unsustainable as of current. In the past couple of years, however, companies such as Panasonic have been striving to make this technology mainstream. Systematically, hydrogen (from the abundant sea or air) is fed into a fuel cell at an anode where electrons are removed from the hydrogen atoms[5], hence forming hydrogen ions. The hydrogen ions and electrons help to create and carry an electric current, which allows the generation of power. One advantage of using a fuel cell is that the minimal number of steps in the process permits fuel cells to be more efficient than conventional diesel or petrol engines[6]. In addition, the waste product from this electrolytic process is water, which means that it is a ‘green’ alternative. Recently, Mercedes produced the F-Cell, a hydrogen fuel cell car that could travel approximately 52 miles per kilogram of hydrogen, the equivalent to a gallon (approximately 4.55 litres) of petrol, irrefutably making it a very worthy substitute.

Liquefied Petroleum Gas

Notwithstanding, Liquefied Petroleum Gas (usually abbreviated as LPG) is a form of natural liquefied or compressed gas which produces a similar mileage to that of petrol but is less polluting (33% less carbon dioxide emissions)[7]. LPG is extracted during the fractional distillation of crude oil where it is split into its three primary parts according to boiling point: propane, butane and isobutane. Surpassing this, catalytic cracking and crude distillation help to purify the gases. Although LPG is produced from crude oil, if efforts are made to make its use more widespread (such as Honda producing LPG Honda Civics since 1998), it can help to conserve our limited resources of petrol and diesel. One disadvantage, on the other hand, is that it can cost up to £2000[8] to convert a regular engine to run on LPG, with a payback time of two years on average. Globally, more and more vehicles are being converted to LPG with over sixteen million already on the roads[9]; and whilst locations to fill up such cars are limited, it is unquestionable that LPG could be the petrol of the future.

Conclusion

To conclude, it is evident that the need to find an alternative to petrol or diesel is of utmost importance. Last year alone, vehicles travelled 323.7 billion miles[10] on UK roads, exhibiting how important cars (and by extension, their fuels) are for individuals as well as the national economy. Through the price mechanism, the increased scarcity and profitability of fossil fuels should encourage more companies to join the sector which as a result might be able to boost the development of petrol and diesel alternatives through research and innovation. Hopefully, the drying oil wells can be used to our advantage to stimulate research in the fuel source field (rather than the relatively gloomy alternative that can be left unsaid).

References:

  1. https://www.gov.uk/government/statistical-data-sets/env01-fuel-consumption#table-env0102
  2. http://fortune.com/2013/11/01/10-alternatives-to-the-gasoline-powered-engine/
  3. http://www.esru.strath.ac.uk/EandE/Web_sites/02-03/biofuels/what_biodiesel.htm
  4. https://en.m.wikipedia.org/wiki/Biodiesel_production
  5. http://americanhistory.si.edu/fuelcells/basics.htm
  6. http://www.fuelcelltoday.com/about-fuel-cells/benefits
  7. http://www.lpg.in/lpg-and-pollution.html
  8. https://www.theguardian.com/money/2012/jul/13/petrol-lpg-fuel-cost-savings
  9. http://www.parkers.co.uk/car-buying/2013/is-lpg-the-fuel-of-the-future/
  10. https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/611304/annual-road-traffic-estimates-2016.pdf

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