Ethanol is often cited as a cleaner alternative to fossil fuels. In Brazil, it plays a central role in the energy matrix and in the debate on sustainability, climate, and energy security. But is ethanol really sustainable? The answer lies in understanding its origin, its impacts, and the challenges of its production.
What is ethanol?
Ethanol is a biofuel produced from the fermentation of plant-based raw materials rich in sugar or starch. Chemically, it is ethyl alcohol (CH₃CH₂OH), a clear, colorless liquid, widely known also for its use in alcoholic beverages, pharmaceuticals, and cosmetics.
In the energy sector, ethanol has gained prominence as an alternative to fossil fuels. It can be produced from different crops, depending on the climate and agricultural characteristics of each country. In the United States, corn is the main source. In Brazil, sugarcane dominates production.
After the sugars are fermented by yeast, the liquid undergoes distillation and dehydration processes until it reaches a high alcohol content. The main use of ethanol is in blends with gasoline; in Brazil, this proportion reaches more than 25%, with the aim of reducing emissions and improving the fuel's octane rating.
Is ethanol sustainable?
Ethanol is considered a sustainable fuel, and the main reason is its plant origin. The plants used in its production absorb carbon dioxide (CO₂) from the atmosphere during their growth through photosynthesis.
When ethanol is burned in an engine, this carbon is returned to the environment, creating a cycle considered close to carbon neutrality. Unlike fossil fuels, which release carbon stored for millions of years, ethanol is part of a shorter cycle.
However, the sustainability of ethanol depends directly on the agricultural practices adopted. When there is deforestation, excessive water use, or soil degradation, the environmental gains diminish, and may even be lost.
Which is better, ethanol from corn or from sugarcane?
Sugarcane ethanol has an energy balance up to seven times higher than that of corn ethanol. This means that the amount of energy generated by the fuel is much greater in relation to the energy spent to produce it.
In corn, only about 50% of the dry mass, the starch, can be converted into ethanol. Furthermore, the starch needs to be transformed into sugar before fermentation, which requires more steps, energy, and costs.
Sugarcane, on the other hand, has sugars that are readily available for fermentation, making the process simpler and more efficient. Another decisive factor is productivity: one hectare of sugarcane produces, on average, twice as much ethanol compared to corn.
According to information from the Brazilian Association of Corn and Sorghum Producers, the main differences between corn and sugarcane ethanol lie in their production methods. Sugarcane ethanol is easier to extract, since ethanol is a byproduct of sugar. In up to 11 hours of fermentation, sugar molasses ferments and transforms into ethanol.
However, sugarcane has less sugar than corn, and one ton of the Brazilian commodity produces only 89,5 liters of ethanol. A ton of corn, on the other hand, can produce up to 407 liters of ethanol. The difference is that corn starch needs to be chemically transformed into sugar, which is more laborious. Therefore, the fermentation process can take up to 70 hours.
The advantage of sugarcane is that its productivity is even higher. One hectare can yield up to 90 tons of sugarcane, enough to produce up to 8 liters of ethanol. Corn, on the other hand, yields a maximum of 20 tons per hectare, which can be transformed into 3.500 liters of ethanol.
Why is ethanol renewable?
Ethanol is classified as a renewable resource because it is produced from agricultural crops that can be replanted year after year. Sugarcane, corn, and other raw materials grow in relatively short cycles, using sun, water, and soil nutrients.
This rapid rate of renewal is a direct contrast to fossil fuels, which take millions of years to form. Furthermore, new crops are planted immediately after the harvest of previous ones, keeping the productive cycle active.
When produced responsibly, ethanol can reduce greenhouse gas emissions by up to 50% compared to gasoline, considering its entire life cycle.
What does it mean to be a renewable fuel?
The main difference between renewable fuels and fossil fuels lies in their origin. Fossil fuels, such as oil, coal, and natural gas, are finite resources formed over millions of years. When burned, they release carbon into the atmosphere that was stored underground, contributing to increased greenhouse gas emissions.
Renewable fuels, on the other hand, are produced from raw materials of biological origin, such as organic waste, used oils, and plant biomass. These sources have the capacity to reabsorb carbon dioxide. carbon (CO₂) from the atmosphere during its growth cycle, through photosynthesis, which reduces the environmental impact of energy use.
In practice, renewable fuels are liquid fuels obtained from organic waste and can be used in internal combustion engines. One of the main advantages is the possibility of using the same existing transport and supply infrastructure, such as fuel stations and pipelines.
The adoption of this type of fuel is especially strategic in sectors where decarbonization is more difficult, such as heavy road freight transport, aviation, and maritime transport. In these areas, renewable fuels emerge as a viable and immediate solution to reduce emissions.
The Paris Agreement sets 2050 as the year in which the world should achieve carbon neutrality, that is, net-zero emissions. Although this goal still seems distant, the increasingly visible effects of climate change demand swift action to accelerate the energy transition.
Brazil in ethanol production
Brazil has been a pioneer in the large-scale use of ethanol fuel since the late 1970s with the National Alcohol Program (Proálcool). Currently, the country is the world's second-largest producer of ethanol, behind only the United States, and one of the largest consumers.
According to the first survey of the 2025/26 harvest by the National Supply Company (Conab), Brazilian sugarcane production is estimated at 663,4 million tons, a volume slightly lower than the previous harvest, impacted by adverse weather conditions such as drought, high temperatures and fires in producing regions, especially in São Paulo.
Even so, total ethanol production is expected to reach 8,7 billion liters, an 11% increase compared to the previous harvest. Of this total, approximately 5,97 billion liters correspond to hydrated ethanol, while 2,73 billion liters are expected to be anhydrous ethanol.
The Conab survey also highlights the continued growth of ethanol produced from corn, mainly in states such as Mato Grosso, Goiás, and Mato Grosso do Sul, reinforcing the importance of biofuel for national energy security.
Advantages of ethanol
One of the main advantages of using ethanol as fuel is its renewability. Unlike non-renewable energy sources such as oil and gas, ethanol can be produced from crops that can be grown year after year. This makes ethanol a more sustainable fuel source in the long term. Learn about the main benefits:
1 – Renewable energy: Ethanol is produced from biomass, a renewable source that uses the sun's energy and regenerates in short cycles. During photosynthesis, plants absorb carbon dioxide (CO₂), which is released again during combustion, forming a cycle close to carbon neutrality.
2 – Lower greenhouse gas emissions: it has a lower carbon intensity than fossil fuels. While gasoline and diesel release carbon accumulated over millions of years, ethanol participates in a short cycle. Studies indicate that corn ethanol produced in the United States can emit between 44% and 52% less greenhouse gases over its life cycle compared to gasoline.
3 – Strengthening rural economies: the ethanol production chain generates jobs and income in rural areas, contributing to regional development, economic diversification, and the retention of labor in the countryside.
4 – Greater energy independence: domestic ethanol production reduces dependence on imported fossil fuels and strengthens energy security. Recent geopolitical crises highlight the importance of domestic and renewable energy sources.
5 – More stable prices: Fossil fuels are subject to strong price volatility. Biofuels, on the other hand, tend to be more stable, as they can be produced locally and with more predictable costs after the infrastructure is in place.
What is the disadvantage of ethanol?
Despite its benefits, ethanol is not without its critics. One of the main disadvantages is the intensive use of agricultural land. The expansion of crops can stimulate deforestation and loss of biodiversity, especially when it occurs in a disorganized manner.
Another sensitive point is water consumption. Both corn and sugarcane require large volumes of water, which can put pressure on regions already affected by droughts.
There is also the debate about food versus fuel. Using land to produce energy reduces the area available for food production, which can raise prices and increase food insecurity, especially in a scenario of global population growth.
From the consumer's point of view, ethanol also has a lower energy density than gasoline. This means that, per liter, it yields fewer kilometers, impacting fuel consumption depending on the type of engine.
So, is ethanol good for the environment?
Ethanol is not considered a perfect solution, but it plays a relevant role in the energy transition. It reduces emissions, diversifies the fuel mix, and decreases dependence on fossil fuels.
In the short and medium term, the conscious and planned use of ethanol can bring real environmental benefits. In the long term, however, experts point out that other technologies, such as electric vehicles and green hydrogen, should take on a more prominent role.
Meanwhile, ethanol remains a viable alternative, provided it is produced with environmental and social responsibility.
Alutal's role in the sugar and ethanol industry
The sustainability of ethanol is not built solely in the fields. It increasingly depends on the factory floor of the mills. In a sector pressured to produce more, spend less, and emit less, the efficiency of industrial processes has become a key factor for the competitiveness of the sugar and ethanol industry.
A Total It operates precisely on this front, offering solutions focused on controlling and measuring sensitive stages of production, such as fermentation, distillation, and steam generation. In practice, more precise systems help plants to better understand their own processes: they identify losses, adjust energy use, and increase the reliability of day-to-day operations.
When industry invests in efficiency, the gains go beyond productivity. It reduces waste, improves environmental performance, and strengthens ethanol's position as a relevant biofuel in the debate on energy transition and decarbonization of the transportation matrix.
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