According to the roadmap, from June 1, 2026, unleaded gasoline (under current national technical regulations) must be blended and formulated into E10 gasoline for use in gasoline engines nationwide. 

The blending and formulation of E5 RON92 gasoline will continue for use in gasoline engines until the end of December 31, 2030.

However, due to energy market fluctuations worldwide, the Ministry of Industry and Trade (MOIT) has been promoting the use of biofuel (E10), reviewing conditions to implement the transition roadmap to E10 gasoline in April instead of June, contributing to a 10 percent reduction in mineral gasoline consumption.

Deputy Minister Nguyen Sinh Nhat Tan emphasized that promoting E5 and E10 biofuels not only helps reduce emissions compared to traditional gasoline, but also contributes to environmental protection, supports the development of the biofuel industry, creates stable demand for agricultural production, and reduces dependence on imported fossil fuels.

As for concerns that E10 may affect vehicle engines, Dang Tat Thanh of the Authority of Innovation, Green Transition and Industrial Promotion said that during the drafting of Circular 50, the ministry consulted major automakers such as Toyota, Honda and Ford, as well as technical organizations like the Society of Automotive Engineers (SAE).

“These organizations affirm that E5 and E10 biofuels do not harm engines. On the contrary, E10 has a higher octane rating, helping engines operate more efficiently and reducing knocking,” he said.

Key notes for vehicle users 

Lo Hai Nam, Head of the Technical Committee of the Vietnam Association of Motorcycle Manufacturers (VAMM), warned that with biofuel, if a vehicle is left for too long without use, it will be harder to start compared to using mineral gasoline, due to the water-absorbing characteristic of biofuel.

In addition, biofuel has cleaning properties. With fuel systems using metal tanks, after a period of time, there will be patches of sediment buildup. When using biofuel, a process of cleaning those substances will occur and create small particles, which can cause clogging or slight difficulty during the pumping and suction process.

Manufacturers recommend that users regularly check and maintain the vehicle's fuel system. If this recommendation is followed, this situation can be completely avoided, he said.

“The car I am currently using can also run on E20 gasoline, and the manufacturer has committed to this,” Associate Prof Dam Hoang Phuc (Hanoi University of Science and Technology) said.

The greatest risk does not lie in the E10 gasoline itself, but in using the wrong fuel standard. Before refueling, consumers need to clearly understand whether their vehicle meets Euro 3, Euro 4, or Euro 5 standards to choose the correct type of gasoline. 

One can check right on the fuel tank cap; if the manufacturer writes “Euro 5 E20,” then the appropriate type of gasoline for the vehicle can be identified.

For vehicles that do not have the E symbol when the fuel cap is opened, which are usually car models that have been used for over 20 years, Phuc said they need more care, especially a check of the entire fuel system. 

This is mandatory because even when not using E10 gasoline, the fuel system also needs to be checked and replaced periodically to ensure safety as well as the stable operating capability of the vehicle.

Phuc went on to say that ethanol has cleaning properties, so it can make long-standing sediment in the fuel tank dissolve faster and follow the fuel system into the engine. However, in newer car models, the fuel tank and fuel system have been improved, so sedimentation almost does not occur.

Conversely, with motorbikes, especially older models, this risk may still exist, so users need to be cautious when switching to E10 gasoline.

“In fact, using E10 only makes the sediment dissolution process happen faster, rather than E10 gasoline generating sediment itself. Users need to correctly understand the nature of this issue,” Phuc emphasized.

Phuc stated that ethanol has water-absorbing characteristics, increasing the water content in the fuel, which can affect the combustion capability of the engine, especially for vehicles using carburetors. Therefore, besides complying with fuel quality standards and regulations, it is necessary to ensure the circulation cycle is fast enough to limit the risk of water absorption.

Tam An