Today, biofuels are used for certain economic activities. The most commonly used are ethanol and biodiesel . It is understood that the carbon dioxide gas emitted by biofuels is fully balanced by the CO2 absorbed through plant photosynthesis.
But it seems that this isn't entirely the case. According to a study by the University of Michigan Energy Institute led by John DeCicco , the amount of heat retained by the CO2 emitted from burning biofuels is not in balance with the amount of CO2 absorbed by plants during photosynthesis as they grow into crops.
The study was based on data from the United States Department of Agriculture . It analyzed periods when biofuel production intensified, and found that the absorption of carbon dioxide emissions by crops only offset 37% of the total CO2 emissions from burning biofuels.
The findings of studies conducted in Michigan clearly indicate that biofuel use continues to increase the amount of CO2 emitted into the atmosphere , rather than decreasing it as previously thought. Even when the source of CO2 emissions is a biofuel such as ethanol or biodiesel, the net emissions into the atmosphere are greater than the amount absorbed by plants during harvesting, meaning they continue to contribute to global warming.
What are biofuels?
Biofuels are fuels obtained from biomass, i.e. organic matter. There are several generations of biofuels, but the best known and most widely used are ethanol and biodiesel, which have been gaining importance in sectors such as transport.
Ethanol is produced from the fermentation of crops such as corn and sugar cane, while biodiesel is obtained from vegetable oils, such as palm, soybean or recycled cooking oil. Its main characteristic is that, in theory, it should have a lower impact on CO2 emissions, since, in the life cycle of the biofuel, plants absorb CO2 during their growth, producing a theoretically neutral balance in terms of emissions.
What are the concerns about its actual impact?
However, several recent studies have challenged this assumption. According to the work of John DeCicco , the environmental benefits of biofuels are significantly diminished when the emissions resulting from their production and end use are taken into account.
"This is the first study to look carefully at the carbon emitted on land where biofuels are grown, rather than making assumptions about it. When we look at what's actually happening on the ground, we see that there's not enough carbon being removed from the atmosphere to offset what's coming out of the tailpipe," DeCicco said.
Rather than being completely carbon neutral, it has been shown that more greenhouse gases are emitted during the burning of biofuels than the plants can capture during their growth. In addition, other factors such as deforestation, the use of fertilizers and the energy to process biofuels play a significant role in their overall environmental impact.
Production and generation of biofuels
There are multiple types of biofuels, which are grouped into several categories. First-generation biofuels are those obtained from edible crops, such as corn or sugarcane, while second-generation biofuels use non-edible raw materials, such as agro-industrial waste or non-food biomass.
- First-generation biofuels, such as bioalcohols (ethanol and methanol) and biodiesel, have been the main substitutes for fossil fuels.
- However, its use has generated controversy over its sustainability, partly due to the increase in the price of agricultural products and deforestation caused by crops such as palm to produce biodiesel.
On a global scale, biodiesel and other biofuels also have negative impacts on deforestation. A report by Transport & Environment has revealed that biofuels derived from palm oil and soy can be up to 80% more polluting than traditional diesel when emissions caused by deforestation are taken into account.
The problem of deforestation and land use change
One of the major problems with biofuels is that their production requires a large amount of agricultural land. This has led to a phenomenon known as indirect land-use change , which involves the expansion of agricultural land into areas that were previously forests or jungles. This conversion has a high environmental cost, as it releases large quantities of CO2 stored in the cleared vegetation and soil.
In Brazil, for example, the clearing of millions of hectares of Amazon rainforest to make way for soybean crops for biofuel production has been documented. Such practices not only affect the CO2 balance, but also endanger biodiversity and local ecosystems.
Intensive production of biofuels from crops such as palm has led to massive deforestation in countries such as Indonesia. According to Ecologists in Action, the growing demand for biofuels could lead to the deforestation of up to 7 million hectares of forest, releasing 11 billion tons of CO500 into the atmosphere.
Other alternatives to traditional biofuels
Despite the challenges, new innovations seek to optimize the use of second-generation or even third-generation sustainable biofuels , which use industrial waste or algae, thus minimizing the environmental impact.
Examples include hydrotreated vegetable oil (HVO) , which can be obtained from waste cooking oils and animal fats, a more environmentally friendly option. In fact, in several European countries, large energy companies are beginning to produce HVO, offering a less polluting alternative to traditional biodiesel.
On the other hand, new research is exploring the use of bacteria like Streptomyces to create more efficient and less polluting biofuels using molecules such as Jawsamycin . This innovation could revolutionize how biofuels are produced in the future.
Finally, synthetic fuels such as e-fuels are also being explored , which combine green hydrogen with captured carbon dioxide, creating a closed carbon cycle that would significantly reduce net greenhouse gas emissions in the transport sector.
Ultimately, biofuels still have a long way to go to be a truly green solution. As new technologies advance and more sustainable alternatives are sought, it is crucial to maintain a critical approach and consider all the environmental implications of their production and use.