CINE debate addresses the technologies needed to decarbonize transport in Brazil
Batteries, biofuels, green hydrogen, solar cells. All these technologies, and not just them, are needed to reduce carbon emissions in the transport sector in Brazil and thus contribute to the mitigation of climate change. More precisely, it is necessary to look at the local reality and find the most appropriate technologies for each application: passenger cars, long-distance buses, rural vehicles, ships, etc.
This was one of the main conclusions of the debate “Electric Mobility and Challenges of the Energy Transition”, organized by CINE at the end of April. Held at the administrative headquarters of CINE, at Unicamp, the event had the participation of three researchers, specialists in technologies for decarbonization: professors Ricardo Rüther (UFSC) and Hudson Zanin (Unicamp) as debaters, and professor Gustavo Doubek (Unicamp) as a moderator.
The focus of the debate was to discuss how Brazil, which is one of the largest vehicle producers in the world, can position itself in this emerging scenario in order to guarantee energy security for its population and generate employment and income.
Carbon footprint and efficiency
Panelists agreed on the need to consider the total carbon footprint of each technology when assessing its impact on reducing emissions. In this sense, Zanin recalled that vehicles that run on biofuel, such as ethanol, emit greenhouse gases, but offset these emissions with the absorption of carbon dioxide that sugarcane (the raw material for Brazilian ethanol) performs through photosynthesis while it grows.
On the other hand, said Zanin, it is necessary to be aware that the electric vehicle, even if it does not emit CO2 in the exhaust, can have a large carbon footprint embedded during the manufacturing process of its battery. In this sense, the local production of batteries would be beneficial not only from an economic point of view, but also from an environmental point of view. In the case of Brazil, in addition to avoiding emissions generated in the transport of products, the national production of batteries would use energy from our energy matrix, which is one of the cleanest in the world thanks to the large share of hydroelectric plants and the growing share of photovoltaics and wind. “A battery made in China, for example, where the matrix is based on burning fossil fuels, has a much larger carbon footprint than a Brazilian battery would”, said Zanin, who is a CINE researcher in the division of Advanced Energy Storage.
In addition to the carbon footprint, another important parameter must be considered when comparing technologies: energy conversion efficiency. “It’s about 300 times more efficient to convert sunlight into electricity and use it in electric motors than to use that same sun to grow sugarcane and then produce ethanol to run your car”, said Professor Rüther, who, in addition to professor and researcher at UFSC, he is vice-president of the International Solar Energy Society (ISES) and technical director of the Institute for the Development of Alternative Energies in Latin America (IDEAL).
However, one of the main limiters of the expansion of electric vehicles is their price. Today, the cheapest cost around R$ 150,000. “State policy needs to organize itself to promote the mass adoption of the electric car”, opined Rüther. “When that time comes, Brazil needs to be prepared to produce these vehicles and their batteries”, he added.
According to Rüther and Zanin, the reuse and recycling of batteries can be very important to popularize electric cars. Reuse, also called “second life”, refers to using a car battery in a less demanding stationary application after the end of its useful life in the vehicle. In this way, a battery that should no longer be used in an electric car could store photovoltaic solar energy in a residence, for example. Recycling, on the other hand, refers to the extraction of the elements that make up the batteries when they can no longer be used in any context. “We need to organize who will be responsible for taking the battery for reuse or recycling. Everything must be regulated”, said Zanin.
Different applications, different technologies
In the view of the debaters, cars that are charged at the socket and store energy in batteries would be perfect for traveling short distances, such as daily trips within the city. However, for large vehicles that travel long distances, such as trucks and buses, batteries have limitations. In these cases, biofuels and green hydrogen (the one produced with clean energy) would be good alternatives to the use of fossil fuels such as diesel and gasoline. Furthermore, the decentralized production of biofuels from agro-industrial residues should be considered in rural areas. “Each small producer could produce their biomethane for their own use”, said Zanin.
In all cases, for the country to be prepared for the moment when fossil fuels leave the scene, academia, industry and government must work together to create a range of options: batteries of various types (lithium, sodium, lead, flow), sustainable processes to produce biofuels, new solar cells, more efficient engines and fuel cells. “There won’t be ethanol or batteries for everyone; there won’t be lithium or lead for everyone; we have to diversify in terms of raw materials and technologies,” said Zanin.
This debate, which was held in Portuguese, was published on CINE’s YouTube channel: https://www.youtube.com/watch?v=LWj1fmChTnA&t=375s.