In Germany, ethanol is primarily used as an additive to gasoline. Typically, standard gasoline contains up to 5% (E5) or 10% (E10) ethanol. These blends help reduce greenhouse gas emissions and dependence on fossil fuels. However, the introduction of E10 has sparked discussions about its compatibility with older vehicles, and further adjustments to vehicles would be necessary to increase the ethanol content. Gasoline and bioethanol blends containing 85% ethanol (E85) are currently not available at gas stations in Germany. In other countries, such as the USA, Sweden, and Brazil, E85 and other high-ethanol blends are offered as alternative fuels for specially adapted vehicles. These vehicles are often called Flexible Fuel Vehicles (FFV), which can run on both gasoline and higher ethanol blends. Pure bioethanol can also be burned in existing engines, but these engines are not typically designed for ethanol combustion, which leads to several disadvantages:

Corrosion and damage to fuel systems::

Ethanol is hydrophilic and attracts water, which can cause corrosion in fuel lines and tanks that are not designed for high ethanol concentrations.

Decreased engine performance:

Conventional engines are not optimized for the higher octane number and combustion properties of E85, leading to incomplete combustion, power loss, and inefficient fuel consumption.

Issues with fuel system components:

E85 can degrade seals, hoses, and other non-metallic components in the fuel system, potentially causing leaks and other mechanical issues.

Adjustment issues:

Engine controls are calibrated for gasoline or lower ethanol blends like E10, which can cause problems with adjusting the air-fuel mixture and may result in engine damage.

Starting problems and cold engine operation:

Ethanol has a lower energy density than gasoline, which can lead to starting difficulties and prolonged warm-up times, particularly in cold temperatures.