The exponential growth in the global population has caused a boom in energy demand, resulting in a global energy supply crisis. This insufficiency will adversely impact the energy-dependent global economy. 

This has prompted a search for renewable and environmentally friendly alternative energy sources. 

Over the last few years, researchers have attempted to access various energy sources, including hydrogen, natural gas, vegetable oil, biofuel, and other biomass sources as alternatives to petroleum diesel. 

Among these alternative fuels, biofuel is expected to reduce the dependence on fossil fuels while also speeding up renewable energy transformations. 

What is biofuel?

The phrase “biofuels” has several definitions, but it mainly refers to fuels that are cultivated, such as maise ethanol that are alternatives to fossil fuels. 

While biofuels may be any fuel made from plant-based materials, they have traditionally been produced from food crops like maise and soy. However, new technology allows biofuel synthesis from non-edible gases, wood, and other plant waste.

As a result, they are an appealing alternative to fossil fuels such as coal, oil, and natural gas. Unfortunately, these compounds must be created over millennia and retrieved from deep beneath the earth using costly and ecologically destructive techniques. 

They are also being consumed much quicker than they are being generated, implying that the world’s fossil fuel reserves will be depleted sooner or later.

How are biofuels classified?

Biofuels such as bioethanol and biodiesel are combustible fuels derived from biomass. Biofuel can be produced from plants, agricultural, domestic and industrial waste. 

They can be classified as first, second, third and fourth-generation biofuels. The first generation of biofuels is bioethanol and biodiesel derived from food crops. These food crops are rich in starch, sugar, and oil are converted into biofuel using transesterification or yeast fermentation. 

The second-generation biofuels are fuels made from lignocellulosic, non-food cellulosic biomass and agricultural waste. The feedstock includes straw, bagasse, perennial grasses, jatropha, waste vegetable oil, municipal solid waste, etc. 

The third generation is biofuels generated from cyanobacteria, microalgae and other microbes, which is the most promising approach to meet the global energy demands. Finally, the fourth-generation biofuels include electrofuels and solar fuels. 

The products are butanol, biodiesel, hydrogen, and other alcohols and carbon-containing gases such as methane and butane.

How are biofuels converted?

Advanced biofuels, cellulosic ethanol and renewable hydrocarbon fuels, for example, are often made in a multistep process. 

First, the plant cell wall’s stiff complex structure – which contains the biological components cellulose, hemicellulose, and lignin linked securely together – must be deconstructed. There are two ways to do this: high-temperature deconstruction or low-temperature deconstruction

The next step is called upgrading. Intermediates such as crude bio-oils, syngas, sugars, and other chemical building blocks must be improved after deconstruction to generate a completed product. This stage might either be biological or chemical.

Sugar or gaseous intermediates can be fermented into fuel blendstocks and chemicals by microorganisms such as bacteria, yeast, and cyanobacteria. Sugars and other intermediary streams, such as bio-oil and syngas, can also be treated with a catalyst to eliminate undesirable or reactive chemicals, improving storage and handling qualities.

The end products of upgrading might be commercially viable bioproducts suitable for completion in a petroleum refinery or chemical manufacturing facility.

Why is biofuel important for our future?

Biofuel contributes to Sustainable Development Goal (SDG) number seven: affordable and clean energy. This goal aims to ensure access to affordable, reliable, sustainable and modern energy for all.  

Biofuels play a crucial role in pursuing this goal by being reliable and modern energy sources and having a significant impact on the global economy and environment. In addition, they can reduce greenhouse gas emissions and increase energy security by providing an alternative to fossil fuels. 

Currently, research is going towards the advancement of biofuel production technologies to accelerate the biofuel yield and other novel techniques and methods to improve the efficiency of biofuel utilisation in petrol and diesel engines. 

Besides that, since bioethanol is less expensive to produce than petrol, combining the two might be a wonderful way to save money in the transportation business. Biodiesel and diesel are in the same boat. Furthermore, when fossil fuel inventories deplete, their prices will surely rise. Biofuels’ price is more stable due to their long-term nature.

Additionally, bioethanol and biodiesel have lower quantities of chemicals such as chlorine and sulphur than fossil fuels. This implies that when combined with gasoline or diesel, they can dilute the pollutants in the fuel source, resulting in cleaner emissions.

Lastly, did you know if spilt or discharged into the environment, biodiesel in its pure, unblended form causes significantly less damage than petroleum fuel? It is less flammable than petroleum diesel, making it safer. Biodiesel has a flashpoint of more than 130°C, compared to 52°C for petroleum diesel. Handling, storing, and transporting biodiesel is safer compared to others.

Are there any disadvantages of using biofuel?

There are some drawbacks in biofuel properties such as high viscosity, low heating value, high oxides of nitrogen, and etc. Hence, additives can help in playing an essential role in minimising the drawbacks of biofuels and meeting the international fuel standards. 

In some research studies, novel additives were added into biofuel blends to improve the quality and properties of fuels, engine performance, combustion characteristics and reduce the exhaust emissions in diesel engines. 

Furthermore, some researchers carried out experiments to study the effect of adding an anti-corrosion additive to blended biofuel and lubricating oil to improve biofuel engines’ emission and wear characteristics. 

Another disadvantage of biofuels is that they require energy to grow; fertilizer, tractors, transportation, and energy are required to transform the plants to liquid fuels. Moreover, planting and cultivating these crops can alter the amount of carbon stored in the soil.  If this causes farms to be extended elsewhere to compensate for lost food production, exploiting current food crops or arable land for biofuel production, it may result in deforestation.

Final remarks

Future research in biofuel should be placed on researching novel biofuel production techniques, new biofuel feedstock species, optimisation and improvement of biofuel properties, engine performance, combustion and emission characteristics in combustion engines.

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