Growing Fuel: The Environmental Trade-offs of Ethanol

 The debate around ethanol fuel, or rather E20, in India often appears to be a simple choice between cleaner energy and conventional petrol. Supporters describe ethanol as a greener, home-grown fuel that can reduce India's dependence on imported crude oil. However, critics argue that producing large quantities of ethanol may unintentionally deepen India's already serious water crisis. Like many environmental debates, the truth lies somewhere between these two positions.

India's interest in ethanol did not emerge overnight; we import roughly 85% of our crude oil requirement, making us heavily dependent on international markets (Petroleum Planning & Analysis Cell). Whenever global oil prices rise because of wars, political instability, production cuts or some world leaders playing dice and risking the peace of the whole planet, we are forced to spend billions of dollars more on fuel imports. Reducing this dependence has therefore become a major national priority.

In 2003, India introduced the Ethanol Blended Petrol (EBP) Programme, which initially aimed to mix around 5% ethanol with petrol (Niti Ayog). Progress was slow during the early years because ethanol production was limited and supply chains were underdeveloped.

The policy gained momentum after the National Biofuel Policy of 2018, which encouraged ethanol production from a wider range of crops and agricultural products. The government also announced an ambitious roadmap to achieve 20% ethanol blending in petrol much earlier than originally planned. By 2025–26, E20 fuel had become available across the country, while preparations also began for flex-fuel vehicles capable of using fuels containing much higher proportions of ethanol, including pure (100%) ethanol.

📦 Explanation Box: What do E20, E85 and E100 mean?

The letter "E" simply stands for ethanol.

• E20 contains 20% ethanol and 80% petrol.

• E85 contains 85% ethanol and 15% petrol.

• E100 is almost pure ethanol.

Higher ethanol blends require specially designed engines because ethanol behaves differently from petrol during combustion.

The government's enthusiasm for ethanol is understandable. Every litre of ethanol blended into petrol reduces the amount of imported crude oil required. This improves India's energy security and helps reduce foreign exchange expenditure. Ethanol production also creates an additional market for farmers, particularly those cultivating sugarcane and maize, thereby providing another source of income. Since ethanol originates from plants that absorb carbon dioxide during growth, it can also reduce greenhouse gas emissions compared with conventional fossil fuels, although the extent of this benefit depends on how the ethanol is produced.

If these advantages are so significant, why has ethanol become controversial?

The answer lies not in ethanol itself but in the crops used to produce it. Among all the crops currently used for ethanol production in India, sugarcane occupies a central position. Sugarcane is an exceptionally productive crop for producing sugar and ethanol, but it is also one of the thirstiest crops grown in Indian agriculture.

Producing one litre of ethanol from sugarcane may require approximately 2,500–3,600 litres of water when the entire cultivation process is considered (Gerbens-Leenes et al., 2009). This includes rainfall, irrigation water and water used during processing. The exact number varies depending on climate, irrigation practices and crop yield.

Maize generally requires around 4,500–4,700 litres of water per litre of ethanol, while rice can require over 10,000 litres for every litre of ethanol produced (Gerbens-Leenes et al., 2009). These numbers often surprise people because they are much larger than the few litres of water actually used inside ethanol factories.

📦 Explanation Box: Why are these water numbers so high?

Most of the water is not consumed inside the ethanol factory; the majority is used while growing the crop itself. Water is needed to irrigate fields, support plant growth and produce the biomass that eventually becomes ethanol. The factory may only require around 3–5 litres of water to process one litre of ethanol, but the crop may have already consumed thousands of litres before reaching the factory.

At this point, an obvious question arises. If agriculture already consumes large amounts of water, why would ethanol make the situation worse? Imagine a region where farmers traditionally cultivate wheat, pulses and vegetables. Now suppose ethanol factories begin offering attractive prices for sugarcane or maize. Many farmers may decide to switch to these crops because they provide higher profits.

As more farmers adopt water-intensive crops, irrigation demand rises sharply. Rivers, reservoirs and groundwater aquifers are then required to supply increasing quantities of water. In areas that already experience seasonal droughts or declining groundwater levels, this additional demand can become unsustainable.

This concern is particularly relevant in India because the country already extracts more groundwater than any other nation in the world. Several major sugarcane-growing states, including Maharashtra, Karnataka and parts of Uttar Pradesh, have experienced recurring droughts and groundwater depletion. Expanding water-intensive crops in such regions could place additional pressure on already stressed water resources. Another important concern involves the relationship between food production and fuel production.

📦 Explanation Box: The Food versus Fuel Debate

Agricultural land is limited; if our farmers use more land to grow crops for fuel, less land may remain available for food crops. When this happens on a large scale, food production can decline, food prices may increase and national food security may become more vulnerable. This conflict is known as the "Food versus Fuel" debate. See Searchinger et al. (2008) for a deeper understanding.

The debate extends beyond water and food. Large-scale expansion of sugarcane or maize cultivation can also affect biodiversity. Natural grasslands, wetlands and mixed agricultural landscapes may gradually be converted into extensive monocultures.

📦 Explanation Box: What is a Monoculture?

A monoculture is a farming system where a single crop is grown over a very large area. While efficient for farming, monocultures generally support fewer species of birds, insects, mammals and plants than diverse natural ecosystems.

Does this mean ethanol is environmentally harmful? Not necessarily. Many scientists argue that the real issue is not ethanol itself but the source from which it is produced. This is where second-generation, or 2G, ethanol becomes particularly important.

📦 Explanation Box: What is Second-Generation (2G) Ethanol?

Instead of using food crops, 2G ethanol is produced from agricultural residues and plant waste, such as rice straw, wheat straw, sugarcane bagasse and corn stalks. Because these materials are by-products of crops already grown for food, they require little or no additional irrigation. Consequently, their environmental impact is generally much lower than ethanol produced from dedicated food crops.

For this reason, many researchers believe India's long-term ethanol strategy should gradually shift away from relying heavily on water-intensive crops and towards agricultural residues, waste biomass and other sustainable feedstocks (Niti Ayog). Such an approach could reduce pressure on groundwater while still providing the benefits of domestic biofuel production.

Ultimately, the debate surrounding ethanol is not a simple battle between supporters and opponents. Both sides raise legitimate concerns: supporters correctly point out that ethanol can reduce oil imports, improve energy security, provide additional income to farmers and lower greenhouse gas emissions under suitable conditions; critics are equally justified in warning that expanding ethanol production through water-intensive crops could accelerate groundwater depletion, increase competition between food and fuel production and place additional stress on ecosystems already under pressure.

Perhaps the most important lesson from this debate is that no fuel is inherently sustainable or unsustainable in isolation. The environmental impact depends on how that fuel is produced, where it is produced and what natural resources are consumed in the process. Ethanol produced from agricultural waste in a water-secure region may represent an environmentally responsible solution. The same ethanol produced by expanding irrigated sugarcane cultivation into drought-prone landscapes may carry significant ecological costs, which I, coming from a drought-prone sugarcane dominated region, personally feel will be a dire situation.