Liquid biological fuels are renewable fuels derived from organic matter or biomass. They are made from plant or animal materials such as vegetable oils, animal fats, corn, sugarcane, vegetable waste and algae. The two main types of liquid biological fuels that are commonly used are bioethanol and biodiesel. With rising concerns over climate change and energy security, liquid biological fuels offer a greener alternative to gasoline and diesel.

Bioethanol Production and Uses

Bioethanol is an alcohol made by fermenting and distilling simple sugars from starch crops such as corn, sugarcane or sweet sorghum. Currently, the US and Brazil are the largest producers of bioethanol, primarily from corn and sugarcane respectively. Bioethanol is most commonly used as a gasoline additive or substitute. It can be blended with gasoline at concentrations of up to 85% or E85. Some flex-fuel vehicles can run on any blend from pure gasoline to E85. Until bioethanol becomes cost-competitive as a standalone fuel, blending is an effective way to reduce dependence on crude oil.

Biodiesel Production and Benefits

Biodiesel is produced from vegetable oils, animal fats or recycled cooking oils through a chemical process called transesterification. This process converts the fat or vegetable oil into fatty acid methyl esters — the main component of biodiesel. Common feedstocks include soybean and canola oils in the US, rapeseed and palm oils in Europe. Compared to petrodiesel, biodiesel has lower carbon emissions over its full lifecycle and is less toxic. It can be used in ordinary diesel engines without modification and offers similar performance as petrodiesel. Biodiesel blends up to B20 (20% biodiesel, 80% petrodiesel) are widely used with existing infrastructure.

Microalgae are emerging as one of the most promising feedstocks for advanced Liquid Biofuels due to their high productivity and ability to be grown on non-arable land without disrupting food production. Algae store lipids that can be extracted and converted to biodiesel or green diesel through various refining processes. Research suggests algal fuels could one day compete with petroleum fuels on price and scale. Companies like ExxonMobil and Shell have invested heavily in algal biofuel development through collaborations with startups. Challenges around achieving commercial scale and reducing costs still remain but algal fuels hold great potential for future sustainable fuels.

Economic Viability and Government Support

For liquid biofuels to become cost-competitive with gasoline and diesel on a large scale, production costs need to reduce further. Factors like high feedstock prices, technology limitations and lack of infrastructure pose challenges. Fluctuating crude oil prices also impact their competitiveness. Most analysts estimate that the current production costs for bioethanol and biodiesel are still higher than their petroleum equivalents. Government policies play a crucial role in boosting biofuel industries through tax incentives, tariffs, mandates and subsidies. The US and EU have set ambitious targets for incorporating renewable fuels into their transportation sectors to reduce emissions as well achieve energy security goals.

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