The automotive industry is undergoing a fundamental transformation in today's world, driven by the need to reduce its carbon footprint and move away from fossil fuels. Drivers and fleet owners are increasingly faced with the abbreviations E10, E85, B7 and B100 at gas pumps, but not everyone understands what exactly is hidden behind these designations and how they relate to the concept of “green” energy.
Biofuel is a group of liquid or gaseous fuels obtained from biological raw materials, which are capable of rapid recovery in nature. Unlike oil, coal and gas, whose reserves took millions of years to form, biofuels come from agricultural crops, wood waste, algae and even organic household waste.
It is critical for motorists to understand which types of fuel fall under this definition, since using the wrong fuel can lead to serious technical problems. Some engines are designed with harsh bio-additive chemistry in mind, while others can fail after the first fill. In this article we will analyze in detail which of the listed fuels belongs to the concept of biofuel, and how this affects the operation of your vehicle.
Bioethanol: alcohol as an alternative to gasoline
The most common liquid biofuel in the world today is bioethanol. This is ethyl alcohol, which is produced by fermentation of sugars contained in plant materials. The main crops for its production are corn (mainly in the USA), sugar cane (Brazil) and wheat or beets (Europe). The technological process includes grinding raw materials, fermenting starch or sugar with yeast and subsequent distillation.
Pure ethanol is rarely used in modern cars without modifications, as it is highly hygroscopic (absorbs water) and can cause corrosion of some metals and rubber seals. However, its octane rating is significantly higher than that of regular gasoline, which allows it to increase the compression ratio in the engine and increase power.
When purchasing a used car from the USA or Brazil, be sure to check the compatibility of the fuel system with ethanol-containing mixtures, since fuel standards in these countries differ from Russian ones.
Most often, bioethanol is mixed with traditional gasoline in various proportions. The most famous mixture is E10, containing 10% alcohol, which is approved for use in most modern gasoline vehicles without modification. There is also a mixture E85, where the ethanol content reaches 85%, but it requires special engines Flex-Fuel, equipped with mixture correction sensors and alcohol-resistant materials.
The use of ethanol has its own characteristics in terms of energy efficiency. Since the heating value of alcohol is approximately 30% lower than that of gasoline, fuel consumption will inevitably increase when switching to high concentrations of ethanol. This is an important economic factor that should be taken into account when deciding whether to switch to alternative fuels.
Biodiesel: a renewable alternative to diesel fuel
The second key player in the renewable fuel market is biodiesel. Unlike ethanol, which is an alcohol, biodiesel is a mixture of fatty acid methyl esters (FAME). The raw materials for its production are vegetable oils (rapeseed, soybean, palm) and animal fats, including processed frying oil from restaurants.
Biodiesel is produced through a chemical transesterification reaction in which triglycerides from oils are reacted with methanol or ethanol in the presence of a catalyst. The resulting product is very close in its physical and chemical properties to conventional diesel fuel, but has an important advantage - it contains bound oxygen, which promotes more complete combustion of the mixture.
⚠️ Attention: Biodiesel has powerful solvent properties. When high concentrations of biodiesel are used for the first time in older vehicles, deposits in the tank may be sloughed off, leading to clogged fuel filters. It is recommended to replace the filter after the first 500 km.
Biodiesel is classified by percentage in the mixture. Pure biodiesel is designated as B100, however, it is rarely used in its pure form due to problems with fluidity at low temperatures. The most common mixtures B5 (5% biodiesel) and B7, which are compatible with most modern diesel engines. Higher concentrations such as B20 or B100, require special training of equipment and the use of winter additives.
An important aspect is the lubricity of biodiesel, which is even higher than that of conventional diesel fuel. This has a positive effect on the service life of fuel equipment, especially plunger pairs of high-pressure pumps. However, biodiesel is less stable during storage and can oxidize, forming sediment, so it is not recommended to store it in a car tank for a long time without use.
Biogas and compressed biomethane
The third important direction in the development of alternative energy is the use of gases obtained from biological waste. Biogas is formed as a result of anaerobic digestion of organic matter: manure, wastewater, food waste and silage. The main components of biogas are methane (up to 70%) and carbon dioxide.
After purification from impurities and carbon dioxide, biogas turns into biomethane, which is identical in properties to natural gas. This allows it to be pumped into general gas pipelines or used as motor fuel for cars equipped with gas equipment (CNG/LNG). Biomethane is considered one of the most environmentally friendly fuels because it prevents the release of methane (a greenhouse gas) into the atmosphere from decomposing waste.
Vehicles running on compressed natural gas can consume biomethane without any modifications if it is supplied through a gas filling station. This makes the transition to this type of fuel the easiest for owners of gasified transport. The energy density of methane is lower than that of liquid fuel, which requires the installation of larger cylinders, but the cost per kilometer is significantly reduced.
The development of biomethane infrastructure is actively underway in Europe, where there are strict CO2 emissions quotas for transport companies. In Russia, this sector is also beginning to develop, especially in the field of public transport and freight transport, where large vehicle fleets can be based on their own refueling complexes.
Comparative table of biofuel characteristics
In order to better navigate the variety of options, it is necessary to consider their key technical and operational parameters in comparison with traditional analogues. Below is a table showing the main differences.
| Parameter | Bioethanol (E100) | Biodiesel (B100) | Gasoline AI-95 | Diesel fuel |
|---|---|---|---|---|
| Octane number | 105-110 | — | 95 | — |
| Cetane number | — | 50-60 | — | 45-51 |
| Heat of combustion (MJ/kg) | 26.8 | 37.5 | 44.0 | 42.5 |
| Flash point (°C) | 13 | 150 | -40 | 55 |
| Impact on CO2 | Neutral* | Neutral* | High | High |
The table shows that bioethanol has a high octane number, but low energy content. Biodiesel, on the other hand, has a high cetane number, which improves the combustion characteristics of diesel. The CO2 neutral designation means that when the biofuel burns, it releases as much carbon dioxide as the plant absorbed during growth, closing the carbon cycle.
However, it is worth considering that actual environmental friendliness depends on the production technology. If forests were cut down to grow crops or large amounts of diesel machinery were used, the carbon footprint of such biofuels could be comparable to fossil fuels. Therefore, when choosing a green fuel, it is important to look for sustainability certifications such as ISCC or RSB.
Technical risks and engine compatibility
Switching to biofuel is not just a change of gas station, it is a change in the operating conditions of the engine. The aggressiveness of alcohols to rubber and plastic components of the fuel system is a known fact. Old hoses, gaskets, and O-rings in injectors can swell, lose elasticity, and deteriorate when exposed to ethanol.
In addition, bioethanol conducts electricity, unlike pure gasoline. This can lead to electrochemical corrosion of metal parts of the tank and fuel lines if they do not have a special protective coating. Owners of vehicles not certified to operate on Flex-Fuel, you should be extremely careful with high concentrations of alcohol.
The myth of engine washout
There is an opinion that biofuel “cleans” the engine better than chemicals. This is partially true, but dirt that gets into the filter can completely cut off the fuel supply. Be prepared to change filters frequently.
In the case of biodiesel, the main problem remains the pour point. When the temperature drops below -5°C...-10°C (depending on the raw material), paraffin crystals begin to form in the fuel, which clog the fuel filter. Winter operation on pure biodiesel without heating the tank and special additives is impossible in temperate latitudes.
Biodiesel also promotes the growth of microbes and bacteria in the tank, especially if there is water (condensation) there. This leads to the formation of mucus, which also clogs the system. Regular treatment with biocides and draining the sludge from the tank are becoming mandatory procedures for those who use biodiesel.
Economic efficiency and prospects
The question of the feasibility of switching to biofuel often comes down to economics. In countries where the production of ethanol or biodiesel is subsidized by the state, the cost of a liter of such fuel can be significantly lower than gasoline. However, due to lower mileage per liter (consumption is 15-30% higher), the final cost per kilometer may be comparable or even higher.
However, for commercial vehicles and fleets, the use of biofuels opens up access to tax incentives and green corridors in cities with environmental class restrictions. In the long term, as oil fields deplete and environmental regulations become stricter, the share of biological additives in fuel will only increase.
☑️ Check before refueling with biofuel
Technologies for the production of second and third generation biofuels are being developed. If the first generation is food crops, then the second is waste from the forest industry (cellulosic ethanol), and the third is algae, which does not require arable land. These technologies promise to reduce the cost of production and eliminate fuel versus food competition.
Frequently asked questions (FAQ)
Is it possible to mix regular gasoline with bioethanol yourself?
It is strictly not recommended to do this yourself in a garage. Violation of the proportions can lead to engine detonation or, conversely, to interruptions in operation. In addition, regular 92 octane or 95 octane gasoline may already contain up to 5-10% ethanol, and adding pure alcohol will change the octane number in unpredictable ways.
Will biodiesel damage my modern diesel car?
Modern cars (Euro 5 and above) are usually compatible with the mixture B7 (7% biodiesel), which is standard in many countries. Usage B20 or B100 This is only possible if the car manufacturer explicitly allows this in the instructions. Otherwise, there may be problems with the seals and the high-pressure fuel pump.
Why does biofuel freeze faster than usual?
This is due to the chemical composition. Vegetable oils and alcohols have a higher crystallization and pour point than light fractions of petroleum. That is why winter grades of biofuel require special depressant additives or mixing with conventional fuel in certain proportions.
Is there a difference in engine power when running on biofuel?
Yes, there is a difference. Due to the lower energy content of bioethanol, power may drop slightly, but the high octane rating allows the engine electronics to adjust the ignition timing, which sometimes even increases power at high speeds. Biodiesel, due to its high cetane number, often makes the diesel engine run smoother and quieter.
Where can you refuel with clean biofuel in Russia?
At the moment, the network of filling stations with pure biofuel (E85, B100) in Russia is poorly developed and is of an experimental nature. Most often, biofuel is sold as a mixture with regular gasoline or diesel (for example, Ecto 100 or diesel with bioadditivation), but the labeling may not be obvious. The main infrastructure is concentrated in large cities and on federal highways as part of pilot projects.
Biofuels are not the future, but the present. Knowing its properties will help you avoid breakdowns and choose the right fuel for your car, no matter where you are.