• Ethanol blending is a process of adding ethanol to petrol.
  • Because of the growing environmental concerns, the use of ethanol as a motor fuel or as an additive is gaining rapid popularity.
  • Properties of Ethanol closely resembles petrol.
  • Moreover, you can obtain ethanol from various plants making it a renewable fuel.
  • Chemically, ethanol i.e. ethyl alcohol (C2H5OH) is a clear, colorless and flammable liquid.
  • It has an octane number of 108 which is higher in comparison to standard gasoline.
  • Ethanol can either be manufactured from petroleum products or from biomass.
  • In the former case, ethylene is the raw material whereas, in latter, various plant-based materials serve the purpose.
  • Ethanol obtained from the material of plant origin is called bio-ethanol.
  • Sugarcane, Maize, Potato, Sweet-potato, agricultural waste are some of the major raw materials for the production of bio-ethanol.
  • Fermentation of plant material of this ilk yields ethanol.
  • Worldwide, the automotive industry has adopted a standard nomenclature to denote ethanol fuels which is EX.
  • Here, E stands for Ethanol. X is a number denoting the percentage of ethanol in fuel by volume.
  • According to the above nomenclature, E10 means fuel that contains 10% by volume of ethanol.
  • Similarly, E50, E85 refers to fuels having 50% and 85% by volume of ethanol.

Advantages of ethanol blending:

  • Ethanol has a higher octane rating compared to petrol.
  • Thus, petrol containing ethanol reduces knocking tendency of the engine.
  • Compared to petrol, ethanol is cheaper. Therefore, ethanol blending offers a cheap substitute for gasoline.
  • Because of its possible bio-origin, it is a renewable source of energy.
  • It helps to reduce vehicular pollution as combustion of ethanol produces less CO and SOX.

Disadvantages of ethanol blending:

  • The energy content of ethanol is low (almost 35%) than that of petrol.
  • Thus, vehicles running on ethanol have poor mileage.
  • Ethanol is corrosive in nature. Hence, the use of a higher percentage of ethanol may corrode engine parts.
  • Natural rubber dissolves in ethanol.
  • Thus natural rubber components, if any, need replacement with some special grade of rubber.
  • Ethanol has a high affinity for water which leads to ‘phase separation’.
  • This means that if ethanol blended petrol comes in contact with water, the entire portion of ethanol separates from petrol. It causes two separate layers of water and petrol.
  • This may lead to engine stalling.

Global scenario of ethanol blending:

  • Countries like the United States, Brazil and some parts of Europe employ higher blends of ethanol like E50, E85, and even E100.
  • The Indian government has recently introduced the E10 mandate and is planning to extend it to E20.

Why ethanol blending in petrol might not work for India

  • Increasing the production of biofuels can strain India’s water resources and affect food availability.
  • Among biofuels, ethanol appears to be the most viable alternative, and the government intends to raise ethanol blending in petrol to 20% by 2030 from the current 2-3%.
  • Other biofuels, such as jatropha, have often proven to be commercially unviable.
  • While India has become one of the top producers of ethanol in recent years, it lags top producers, the US and Brazil, by a huge margin and remains inefficient in terms of water usage.
  • Water footprint, that is water required to produce a litre of ethanol, includes rainwater at the root zone used by ethanol-producing plants such as sugarcane, and surface, ground water, and fresh water required to wash away pollutants.
  • Estimates of water footprints are available from the Water Footprint Network.
  • India’s water footprint is not only high in overall terms, but India also uses more surface and groundwater than the US and Brazil.
  • Most of our daily uses of water come from this source.
  • India has the least internal surface and groundwater compared with both countries.
  • While the US and Brazil have 2,818 billion cubic metres (BCM) and 5,661 BCM/year of water respectively, India has only 1,446 BCM per year.
  • While India’s internal surface and ground water availability is just one-fourth of Brazil’s, its usage of such water for ethanol fuel production is slowly catching up with that of Brazil — and even exceeded Brazil in 2016—despite there being a huge gap in the ‘blend rates’.
  • In India, the blend rate—the amount of ethanol mixed with petrol—is only 2-3%.
  • For Brazil, which uses both an ethanol-petrol blend and just ethanol as fuel, the overall blend rate is 45-50%.
  • India’s surface and ground water requirement will hugely exceed that of Brazil if India were to achieve its targeted 20% blend rate.
  • In other words, while Brazil used 0.025% of its internal surface and ground water for ethanol production to achieve a 45% overall blend rate in 2017, India would use 0.701% even for 20%.
  • Water is not the only limited resource we have.
  • Sugarcane currently accounts for around 3% of India’s net sown area.
  • A simple calculation of extra area required for the 2010 to 2017 period shows that to raise the petrol-ethanol blend rate to even 10%, India will have to devote another 4% of its net sown area to sugarcane.
  • In order to achieve 20% blend rate, almost one-tenth of the existing net sown area will have to be diverted for sugarcane production.
  • Any such land requirement is likely to put a stress on other crops and has the potential to increase food prices.
  • India’s biofuel policy stipulates that fuel requirements must not compete with food requirements and that only surplus food crops should be used for fuel production, if at all.
  • Producing ethanol from crop residue will then be a good alternative, except that the annual capacity of required bio-refineries is stipulated to be 300-400 million litres, which is still not enough to meet the 5% petrol-ethanol blending requirement.
  • Increasing petrol-ethanol blending, therefore, does not seem viable in the current scenario, unless concerted efforts are made to either increase sugarcane yield and decrease water usage through better irrigation practices, or increase the ethanol production capacity of bio-refineries.
  • Trying to increase blending without these efforts can encroach upon land and water available for food production.