Electric cars: Lack of consensus in evaluations generates controversy over greenhouse gas emissions

The lack of consensus in electric car emissions assessments has generated a lot of controversy. The best technology to decarbonize the automotive sector is a subject that still creates controversy. What is the most efficient way to reduce greenhouse gas (GHG) emissions is a question with very different answers. It depends on the criteria adopted in research carried out in various parts of the world.

“Every time a new study is released showing that decarbonization mobility depends on this or that technology”, says Luiz Augusto Horta Nogueira, specialist in energy studies at the Interdisciplinary Center for Energy Planning (nipe), from the State University of Campinas (Unicamp). “The conclusion depends on the parameters of the analyses, which often serve economic and geopolitical interests more than technical and scientific ones.”

To reinforce Nogueira’s thesis, two recent surveys on decarbonization in Brazil – one international and the other carried out in the country – place the results on opposite sides. The first points out that the 100% electric vehicle is the ideal alternative for the national fleet. The second concludes that hybrids are the best option. “Both are theoretically correct, according to the chosen premises. But what, in fact, is more viable?”, he asks.

The analysis raises doubts mainly regarding the car’s life cycle time. One of them considered 160 thousand kilometers driven, or approximately 10 years — time compatible with the warranty of the batteries. The study by the international institute took into account an average of 288 thousand kilometers, without changing the battery.

In this way, GHG emissions are diluted over a much longer life cycle and mileage. Each study also used different criteria and levels of carbon dioxide (CO2) emissions for the production of ethanol and the manufacture of electric car batteries.

Emissions in rural areas

Faced with the controversy surrounding the definition of more assertive rules, the International Energy Agency (IEA) prepared a formal document, with the aim of guiding discussions on the topic. Released in October, the report “Carbon accounting for sustainable biofuels”  does not establish technical criteria for evaluating CO2 emissions associated with the production and use of biofuels.

On the other hand, it offers indications regarding the importance of biofuels in decarbonization. In particular, it addresses a controversial aspect of ILUC (acronym in English for Indirect Land Use Chamge or indirect land use exchange). 

The concept determines that a rural area destined for the production of biofuels must undergo analysis of greenhouse gas emissions due to deforestation, which probably occurred to promote the migration of the original crop to other soil that is still intact.

“It is impossible to know the fate of the original crop. She may have moved to a pasture area or degraded land that has been recovered. There are many possibilities and uncertainties”, explains Nogueira. Therefore, the IEA determined the exclusion of ILUC in the calculation of biofuel emissions, due to the difficulty of calculating their effects.

Economic focus

For the engineer and sustainable mobility consultant, Ricardo Simões de Abreu, many developed countries have chosen to leave the social and environmental factors of sustainability in the background. “The focus is clearly economic and on the search for energy security”, he states.

Despite the discussion about the study criteria, Abreu believes it is possible to identify the best option for automotive decarbonization. “There are studies by researchers or autonomous entities around the world that give hybrids an advantage. They are the most sustainable alternative in the medium and long term”, he argues.

Also read: Check out 4 actions that strengthen the electric car charging systems

According to bioenergy specialist, Marcelo Gauto, all available technologies are important in the energy transition. “But it is important to know the added benefits of each of them. Each country must seek the most appropriate solutions for its reality”, he ponders. Amid so much divergence, Gauto highlights that in the battery manufacturing process, electric cars are less effective in decarbonization.

“Some studies show that the metals used to produce the battery of a large 100% electric vehicle are enough to make six batteries for plug-in hybrid cars or 90 for non-plug-in hybrids”, he states. “Therefore, hybrids present a better balance between the rational use of biofuels and mineral reserves.”

Also read: See how to take care of electric car batteries

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Author: Dante Grecco