What is biofuel?
It is acknowledged that we live in a world with limited natural resources, and the scientific community has been hard at work trying to find a sustainable, renewable and energy-dense replacement for the fossil fuels upon which we have become dependent. The answer may just lie in a fascinating process of biofuel.
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Biofuel is any combustible fuel that has come from the processing of biomass, i.e., waste, plant matter, or a combination of the two. Biofuel is considered to be a source of renewable energy, unlike fossil fuels such as petroleum, coal, and natural gas. Biofuels can be gaseous, liquid or solids, but for the sake of today's question and its relation to motor vehicles, we will look at the liquid type.
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How is it made?
If one takes any biological matter and allows it to decompose either by a man-made process or by bacterial one, the biomass will release either combustible gas, liquid or a leftover solid, which can then be captured and stored for later use. Processing sugars or starches will create Ethanol. Waste products will decompose naturally and create Methane gas, while the leftover solids can be burned like charcoal to produce steam for turbines for electricity production.
How does it work?
Biofuels can be used on their own to produce energy by ignition or as an additive to increase the effective combustion of standard fossil fuels in order to reduce emmissions. In general, biofuels emit fewer greenhouse gas emissions when burned in an engine and are generally considered carbon-neutral fuels as the carbon emitted has been captured from the atmosphere by the biomass used.
Types of biofuel
There are two main types of biofuel used in motor vehicles.
Bioethanol is an alcohol made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as maize, sugarcane, or sweet sorghum. Cellulosic biomass, derived from non-food sources, such as trees and grasses, is also being developed as a feedstock for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form (E100), but it is usually used as a gasoline additive to increase octane ratings and improve vehicle emissions.
Biodiesel is produced from oils or fats using transesterification. It can be used as a fuel for vehicles in its pure form (B100), but it is usually used as a diesel additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel-powered vehicles.
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Pros
- Cleaner burning
- less pollutants released into atmosphere
- used cooking oil recycling (biodiesel)
Cons
- Marginal power loss
- incorrectly mixed or manufactured fuels can harm engines
- costs associated with arable land (food vs fuel argument)
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In Closing
Currently, in South Africa, we do not have any commercial operations or biofuel distribution on masse. There may be a few startups that are manufacturing their own fuels for self-supply, but unlike the UK and USA that have dedicated E10 and biodiesel fuel pumps, we do not have that facility yet. The good news is that every single car manufactured since 2011 should be capable of running E10 or biodiesel for the coal burners.
