The use of ethanol-blended fuels such as E85 (85% ethanol and 15% gasoline) can reduce the net emissions of greenhouse gases by as much as 37.1%, which is a significant amount.

Positive energy balance – Depending to the type of raw stock it can vary from 1.24 to 8. The output of energy during the production is more than the input. (controversial) 

You can use any plant for production of bioethanol, it only has to contain sugar and starch. The best choice is sugar cane, but you can also use potatoes, barley, wheat etc.

It is carbon neutral i.e. the carbon dioxide released in the bioethanol production process is the same amount as the one the crops previously absorbed during photosynthes 

Ethanol-blended fuel as E10 (10% ethanol and 90% gasoline) reduces greenhouse gases by up to 3.9%.

The net effect of ethanol use results in an overall decrease in ozone formation, an important environmental issue. (The emissions produced by burning ethanol are less reactive with sunlight than those produced by burning gasoline, which results in a lower potential for forming the damaging ozone).

Ethanol is considered a renewable energy resource because it is primarily the result of conversion of the sun's energy into usable energy. Creation of ethanol starts with photosynthesis, which causes feedstocks, such as sugar cane, to grow. These particular feedstocks are processed into ethanol. 

It benefits energy security as it shifts the need for some foreign-produced oil to domestically-produced energy sources. Countries that do not have access to crude oil resources can grow crops for energy use and gain some economic freedom.

It reduces greenhouse gases.

It reduces the amount of high-octane additives.

The fuel spills are more easily biodegraded or diluted to non toxic concentrations.

·         The energy content of petrol is much higher than the one of bioethanol. Burning 1 liter of ethanol gives 34% less energy than burning the same amount of petrol. In other words, Bioethanol is not as efficient as petroleum. 

·         There are also concerns over the fuel systems used. Too many older cars are currently unequipped to handle even 10% ethanol while there is concern that using 100% ethanol decreases fuel economy by around 15-30% compared with 100% petroleum.

·         The octane number of bioethanol is at around 105. It means that this substance can be burned in the engines with much higher compression ratio. The engines made for working on the new energy cannot be used for their petrol or diesel variants.

·         It can negatively affect electric fuel pumps by increasing internal wear and undesirable spark generation.

rogen used in the production have negative effect on the environment

·         Transportation – ethanol is hygroscopic, it means that it absorbs water from the air and thus has high corrosion aggressiveness. That’s why it is transported only by auto transport or railroad.

·         Pure ethanol is also difficult to vaporise which can make starting a car in cold weather difficult and that is why most fuels retain at least a small amount of petrol – such as E85 cars with 85% ethanol and 15% petroleum.