Biofuel: Everything you need to know
For the most part, conventional engines in cars, trucks and other vehicles burn petrol or diesel. This causes carbon dioxide and nitrogen oxide emissions – poisonous greenhouse gases (GHG) that contribute to global warming. The world needs cleaner sources of fuel for transport, and biofuel produces fewer GHGs than fossil fuels when burnt. But, is it really clean?
Biofuel is made from biomass materials, meaning that it is made from renewable, organic sources like animals or plants. Biomass can be burned for heat or turned into fuel for transport. Some examples of biomass sources include:
- Wood and wood processing wastes (e.g. firewood and wood pellets)
- Agricultural crops and waste materials (e.g. corn, soybeans and sugar cane)
- Biogenic materials in municipal solid waste (e.g. paper, cotton and wool products)
- Human sewage and animal manure
Biomass is primarily turned into ethanol and biomass-based diesel when used as a fuel for transportation.
Ethanol is made from sugar, which can come from a variety of sources, like rice, sugar cane and even some grains. It is often combined with petrol to reduce the amount of crude oil required to produce fuel. Most petrol sold in the US contains some ethanol. It is important for countries, like the US, that want to reduce their reliance on crude oil to make fuel like petrol.
Also known as biodiesel, this fuel is made by combining alcohol with fats, like recycled cooking grease, vegetable oil or animal fat. It is a biodegradable and non-toxic alternative to diesel for diesel engines.
There are three main types of biofuel:
- First-generation biofuels come from food
- Second-generation biofuels come from non-food biomass, like wood
- Third-generation biofuels come from renewable sources of energy, like algae
Fossil fuels vs biofuels
In short, biofuels are generally considered a renewable energy source whereas fossil fuels are not. Fossil fuels are not renewable because they take millions of years to form underground. Once they are used, they cannot be replaced.
On the other hand, biomass, which is used to make biofuel, is considered renewable, given that biomass sources like trees can be replaced in a relatively short amount of time. That said, some experts have raised concerns about whether biofuel can be considered renewable if it is processed using non-renewable sources of energy.
Biofuels and GHG emissions
Just like fossil fuels, biofuels emit carbon dioxide when burned. But, there is a key difference. Biofuels absorb carbon dioxide as biomass grows, balancing out the carbon dioxide emitted when biofuels are burned. For this reason, biofuels are theoretically carbon neutral.
But, not all scientists are convinced that biofuels are carbon neutral. When calculating the real environmental and climate impact of biofuel, some caution that a “life cycle analysis” should be completed. This involves taking into account all emissions from the entire production process when calculating the carbon footprint of biofuel. This includes the emissions from growing the biomass sources, fuel production, transportation and other processes in the life cycle that emit GHGs.
Biofuel production and carbon dioxide
In one study, researchers found that the amount of carbon dioxide emitted during the burning of biofuels over a period of time in the US actually exceeded the amount absorbed during biomass’ lifecycle. This research was funded by the American Petroleum Institute, although the author stated that this did not influence the outcome.
It is worth noting that advanced biofuel technologies under development could remove the need for whole food sources, reducing the carbon footprint of some biofuels.
Efficiency of biofuel energy
Biofuels are extremely efficient compared to fossil fuels. For example, ethanol has the highest octane rating of all fuels, and it has little impact on the fuel economy of vehicles or vehicle performance. Ethanol also has a positive energy balance, meaning it produces more energy than is used to make it.
Biodiesel is also efficient. It provides better lubrication for a vehicle’s engine, leaves less fuel residue behind and is safer than traditional diesel. This is because it has a higher ignition point. Biodiesel also has a higher fuel economy than similar diesel vehicles, meaning a vehicle using biodiesel can travel further using the same amount of fuel as a traditional diesel vehicle.
Biofuel use in South Africa
As of 2021, biofuels are not used on a commercial scale for transport in South Africa. However, the government has taken steps to develop the industry. For example, in December 2019, the South African Cabinet approved a biofuels regulatory framework outlining the rules and regulations regarding the development of this technology.
But, the lack of this kind of framework previously did not stop local entrepreneurs from experimenting with biofuel technologies. Furthermore, it did not halt O.R.Tambo International Airport’s plans to include biodiesel in its ground-handling operations.