Technical experts and regulators agree that biofuels offer clear environmental benefits thanks to their ability to reduce emissions compared with conventional mineral gasoline.

Assoc. Prof. Dr. Dam Hoang Phuc, director of the Automotive Engineering Training Program at Hanoi University of Science and Technology (HUST), said E10 is a biofuel blended from base gasoline and bioethanol, which acts as an “oxidizing agent” during combustion.

As a result, the combustion process inside the engine becomes more complete, reducing harmful emissions such as carbon monoxide (CO), hydrocarbons (HC), and part of the carbon dioxide (CO2) generated during vehicle operation. This is also why many countries consider biofuels an important solution in their carbon-emission reduction strategies.

According to Phuc, the biggest advantage of biofuels has been widely discussed, particularly their environmental friendliness and ability to reduce harmful emissions compared with conventional gasoline. Using E10 can help reduce CO2 emissions compared with pure mineral gasoline, especially when considering the lifecycle of biofuel production from plant-based sources.

However, consumers are often most concerned about fuel consumption, operating costs, and compatibility with their vehicles.

In 2023, when E10 gasoline was introduced in Vietnam and had not yet been widely adopted, a research team led by Phuc at HUST conducted practical studies using Toyota Corolla Cross models, including both hybrid and conventional internal-combustion versions.

The tests were carried out in laboratories as well as in real-world conditions, including Hanoi's urban streets and Thang Long Boulevard, under various operating environments.

“The results showed that fuel consumption depends heavily on driving conditions. For example, in traffic congestion, E10 can reduce fuel consumption by around 2.3 percent for conventional gasoline vehicles and up to 7.8 percent for hybrid electric vehicles (HEVs) compared with RON 95 gasoline. However, when driving at speeds of around 60-70 km/h, E10 consumption can be higher,” Phuc explained.

He noted that E10 tends to consume slightly more fuel overall, but under certain operating conditions it can deliver better efficiency. In general, the difference fluctuates within plus or minus 5 percent. Some users may find it more economical, while others may experience higher fuel consumption.

Regarding concerns about compatibility with older vehicles, Phuc emphasized that E10 contains ethanol, which has stronger solvent properties than conventional gasoline.

In vehicles that have been used for many years, fuel systems often contain accumulated deposits. When E10 is used, these deposits may dissolve more quickly, potentially causing blockages or other issues.

“It should be understood that the risk already exists within the vehicle. E10 simply accelerates the process. You could think of E10 as a kind of ‘test’ for a vehicle's fuel system. E10 is not the direct cause of faults but rather helps reveal hidden problems sooner,” he said.

What does the ministry say?

The Ministry of Industry and Trade (MOIT) has released a set of 85 questions and answers addressing consumer concerns, most of which focus on engine compatibility, fuel consumption, and fuel-system durability.

One of the most common concerns is whether E10 affects vehicle performance, making cars feel less powerful or even damaging engines.

According to the ministry, if such issues occur, they are generally not caused by the fuel itself but may be linked to inadequate vehicle maintenance, allowing deposits in the fuel system to interfere with stable fuel delivery.

However, the “chemical differences” between ethanol and conventional gasoline remain a source of concern for many consumers.

Ethanol absorbs moisture more readily than traditional gasoline, meaning storage tanks and fuel systems must be better sealed to limit water absorption from the environment. This is one technical factor that makes long-term storage of E10 more sensitive than conventional gasoline.

Regarding potential material damage, the ministry said there is no evidence that E10 harms spark plugs or engine oil. However, ethanol can dissolve old deposits within fuel systems, causing loosened residue during the initial phase of use. While this effectively cleans the system, some users may mistake the process for clogging or reduced engine performance.

Another notable issue is compatibility with older vehicles. The ministry stated that E10 is suitable for most modern vehicles, including fuel-injected motorcycles and large-displacement motorcycles. However, owners of older carbureted vehicles should consult manufacturer guidelines to ensure safe operation.

Hoang Hiep