In 2025, we were presented with news related to the implementation of ethanol as a mixture in the fuel for motor vehicles that we use every day. Ethanol itself is essentially a by-product of the fermentation of plant-based fuels such as sugarcane, corn, cassava, or straw, which are rich in sugar or starch.

In the manufacturing process, these plant-based materials are converted into ethanol by microorganisms. Ethanol can also be produced through petrochemical processes, which essentially refine the fuel to make it safe and efficient for engines through the breakdown of hydrocarbon molecules. 

Responding to ethanol's capabilities as an environmentally friendly alternative with the potential to improve fuel quality, one of the lecturers in the Mechanical Engineering Study Program at Dian Nusantara University (UNDIRA), Mr. Anggananda Berlian R.M.S., ST., MT., said that ethanol does indeed have several benefits.

Ethanol has instant additive properties that are useful for quickly increasing octane. For your information, octane is a value that indicates the ability of gasoline to withstand pressure and heat so that the engine does not spontaneously combust (knocking). The higher the octane number (92 to 95), the better the quality of the fuel. 

Ethanol (and also bioethanol) itself has properties that tend to be environmentally friendly and does not produce large amounts of carbon monoxide (CO) emissions. However, even though ethanol is a fuel quality enhancer and is good for the environment, it is not very compatible with engines.

Technically, the use of ethanol has a negative impact on the durability of vehicle engines. Anggananda Berlian R.M.S., S.T., M.T., emphasized that the majority of current engine specifications are not designed to accommodate high ethanol concentrations. This is exacerbated by the hygroscopic nature of ethanol, which absorbs water vapor, causing corrosion and accelerating the degradation of engine components such as rubber and seals in the long term.

Mr. Anggananda explained the classification of ethanol blends ranging from low concentrations (E5-E10) to high concentrations (E20-E85). The ‘E’ nomenclature represents the percentage of ethanol by volume in the fuel; for example, E5 contains 5% ethanol and 95% pure gasoline. 

Currently, the majority of standard vehicles are only compatible with E5 to E10 blends. Meanwhile, the use of high concentrations (E20 and above) requires special technological specifications known as Flexible-Fuel Vehicles (FFVs) so that engines can adapt to high ethanol content.

In closing, Anggananda emphasized the urgency for prospective UNDIRA Mechanical Engineering engineers to prioritize professional responsibility in the future. Engine design should not only be oriented towards optimizing short-term performance, but must also take into account long-term durability aspects. Therefore, mastery of the disciplines of Metallurgy, Mechatronics, and Materials Engineering is an absolute competency so that graduates are able to design engines that are not only efficient, but also adaptive to the challenges of energy transition and fuel variability.