The study highlights that biofuels are not CO2-neutral due to low levels of CO2 uptake by plants.
Deforestation for the production of biofuels has led to a large increase in carbon dioxide emissions.
Although there are more sustainable alternatives, such as second-generation biofuels or synthetic fuels, their adoption remains limited.
Today, biofuels are used in some economic activities. The most commonly used are ethanol and biodiesel. It is understood that the carbon dioxide gas emitted by biofuels is completely balanced by the carbon dioxide absorbed by plants through photosynthesis. But that does not seem to be entirely the case. According to a study led by John decicco at the University of Michigan's Energy Institute, the amount of heat retained by CO2 emitted from the burning of biofuels is out of balance with the amount of CO2 absorbed by plants during photosynthesis during crop growth.
The study is based on research from the United States Department of Agriculture. During the period of intensified biofuel production, the CO2 emissions absorbed by crops were offset by only 37% of the total CO2 emissions by burning biofuels.
The Michigan findings clearly show that biofuel use continues to increase the amount of carbon dioxide released into the atmosphere and that it is not decreasing as much as thought. Although the source of CO2 emissions comes from biofuels such as ethanol or biodiesel, the net emissions entering the atmosphere are greater than those absorbed by crops, meaning they continue to exacerbate the effects of global warming.
What are biofuels?
Biofuels are fuels derived from biomass (i.e. organic matter). There are several generations of biofuels, but the best known and currently in use are ethanol and biodiesel, which are increasingly important in areas such as transportation.
Ethanol is produced through the fermentation of crops such as corn and sugar cane, while biodiesel is obtained from vegetable oils such as palm oil, soybean oil or recycled cooking oil. Its main feature is that, in theory, it has less impact on carbon dioxide emissions, because during the life cycle of biofuels, plants absorb carbon dioxide as they grow, creating a theoretically neutral balance in terms of emissions.
What are the concerns about its practical 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 emissions from their production and final use are taken into account. "This is the first study to carefully examine carbon emissions on land where biofuels are grown, rather than making assumptions about it." "When we looked at what was actually happening on the ground, we found that not enough carbon was being removed from the atmosphere to offset what was coming out of the tailpipe," decicco said.
Studies have shown that burning biofuels is not completely carbon neutral, but emits more greenhouse gases than plants absorb as they grow. In addition, other factors such as deforestation, fertilizer use and the energy used to process biofuels also play an important role in their overall environmental impact.
Biofuel production and production.
There are many types of biofuels, which can be divided into several categories. This first generation of biofuels is derived from edible crops, such as corn or sugar cane, while the second generation of biofuels they use non-edible raw materials, such as agro-industrial waste or non-food biomass.
First-generation biofuels, such as biools (ethanol and methanol) and biodiesel, have become major alternatives to fossil fuels. • However, its use has sparked controversy over its sustainability, partly due to rising agricultural prices and deforestation caused by the production of biodiesel from crops such as palm.
Globally, biodiesel and other biofuels are also having a negative impact on deforestation. A report on Transport and Environment has revealed that biofuels derived from palm oil and soybeans could be up to 80% more polluting than conventional diesel when emissions from deforestation are taken into account.
Deforestation and land use change.
A big problem with biofuels is that producing them requires a lot of agricultural land. This has led to what is known as "indirect land use change, which involves the expansion of agricultural land in areas that were previously forest or jungle." The environmental cost of this conversion is high, as large amounts of carbon dioxide stored in cleared vegetation and soil are released. In Brazil, for example, millions of hectares of the Amazon rainforest have been logged to grow soybean crops for biofuel production. These types of practices not only affect the carbon dioxide balance, but also endanger biodiversity and local ecosystems.
The mass production of biofuels from crops such as palm has led to large-scale deforestation in countries such as Indonesia. According to Ecologisticas en Accion, the growing demand for biofuels could lead to up to 70,000 hectares of forest being cleared, releasing 1.1 billion tons of carbon dioxide into the atmosphere.
Other alternatives to conventional biofuels
Despite the challenges, new innovations seek to optimize the use of sustainable biofuels in second and even third generations, using industrial waste or algae, thereby minimizing environmental impact.
Examples include hydrotreated vegetable oil (HVO), which can be obtained from waste cooking oil and animal fat and is a more environmentally friendly option. In fact, in several European countries, large energy companies are starting to produce HVO as a less polluting alternative to conventional biodiesel.
On the other hand, there is new research exploring the use of bacteria such as Streptomyces to create more efficient and less polluting biofuels by using molecules such as « jasamycin «. This innovation could revolutionize the way biofuels are produced in the future.
Finally, synthetic fuels, such as e-fuels, which combine green hydrogen with captured carbon dioxide to form a closed carbon cycle, will significantly reduce net greenhouse gas emissions from the transport sector. In short, biofuels have a long way to go before they become a true ecological solution. As new technologies advance and more sustainable alternatives are sought, it is vital to maintain key approaches and consider all the environmental impacts of their production and use.
