Universidade de Lisboa PhD candidate develops an energy systems model to decarbonise transportation in Brazil

Climate Exp0
5 min readJun 3, 2021


Tatiana Bruce da Silva, Bizibrains Okpeh

Artwork: Dr Cécile Girardin

While greenhouse gas emissions may be nationalised, the devastating effect of climate change is universal. It ensures unequal suffering around the world, with developing countries bearing a greater burden of the damaging impacts of increasing global warming. To rid the global atmosphere of greenhouse gases, we need mitigation solutions, effective, efficient, and sustainable technologies.

Meet Tatiana Bruce da Silva

One of the many renowned researchers who are creatively innovating new ways to combat climate change is Tatiana Bruce da Silva. Born in Pernambuco, a state in one of the poorest regions in the Northeastern Brazil, Tatiana grew up watching the state suffer the pernicious effects of desertification and droughts. Having studied at the Federal University of Pernambuco, Brazil, and the University of Pennsylvania, Philadelphia, USA, she worked as a public administrator in Brazil. But it was her work with a think tank in energy policy that got her to know the urgency of the climate change problem.

Currently a PhD candidate in Sustainable Energy Systems at Instituto Superior Tecnico, Universidade de Lisboa, she spoke at Climate Exp0 on the topic, “Climate Change Mitigation Policies in the Transportation Sector in Rio de Janeiro, Brazil” where she unveiled an energy systems model which aims at analysing sustainable ways to decrease transportation’s inefficiencies, both from the supply side (using more efficient engines) and the demand side (using transportation more sustainably: “matching capacity to use”), and proposing policies to attain this goal.

The climate crisis in Brazil

In Brazil, the transportation sector emits the most greenhouse gases from energy consumption. Data from Brazil’s National Traffic Department show that more than 90 million vehicles operate in Brazil. In the past years, there has been an increase in the use of private cars, increasing the welfare of those who use them, but worsening the overall quality of life in cities and contributes to climate change.

This sector is difficult decarbonise because the technologies used are highly locked-in fossil fuel consumption. It is also a sector with high inefficiencies– around 80% of the energy in the fuels that power these cars is wasted because the internal combustion engine is highly inefficient. Also, the cars that drive around Brazilian roads are rarely at full capacity. On average, a car can fit 5 people, but most vehicles drive around with just one person/passenger. All these inefficiencies contribute to more energy being consumed and more carbon dioxide being emitted.

Even though we have, at most, this decade to reach peak emissions to get to net-zero greenhouse gas emissions by 2050 and mitigate the worse impacts of climate change, stakeholders in Brazil, especially the federal administration, do not seem to understand the urgency of the climate change problem. For instance, recently, a new law to expand natural gas production and consumption in Brazil was enacted. New oil and natural gas tenders are scheduled to happen in the next few months, including in the Amazon region. Deforestation in Brazilian forests has been on the rise, and last April witnessed the worse month for preservation in the Amazon. Worse still, many environmental laws to protect Brazilian biomes are being scaled back, which will not contribute to preservation. The country is already seeing the impacts of climate change. This year, Brazil is experiencing one of the worst droughts in decades, which is affecting hydropower generation.

The energy systems model

Tatiana Silva’s energy systems model aims to analyse how to decarbonise passenger transportation in Brazil, particularly in the state of Rio de Janeiro, in a sustainable way. In this model, there are no governments, no stakeholders, no choices or trade-offs to be made­– it is a “neutral” environment. The model is anchored on at least two simple, yet important results:

  • Electrification is profitable for the decarbonisation of transportation. When electricity generation capacity is not provided by renewables, decarbonisation in the transportation sector gets hindered.
  • Shared mobility can play a very important role in decarbonising transportation. If we use transportation more effectively, increasing passenger capacity within vehicles, we will need fewer vehicles, less energy will be consumed, resulting in fewer carbon emissions.

These results are straightforward, but they are important to show that some answers to global warming are simpler than we might think. The model also incorporates an economic choice analysis to better understand the choices, trade-offs, and behavioural aspects of energy use.

Policy recommendations

Though “neutral” in terms of behavioural aspects and economic choice, the model does provide some direction on where policy can act:

  • Investment in quality and increasing public transportation supply. If the offer of buses, rail, metro, etc. increases and is inclusive enough to serve the whole population in a city, the need for private cars would decrease, which will then decrease energy use and emissions. Likewise, if there is a system that provides options, with quality, comfort, and security, users will choose public transit.
  • Shared mobility is also important to improve the efficiency of transportation. But shared mobility needs to be well regulated so that it can complement public transit instead of substituting it.
  • The use of renewable fuels both in transportation and electricity supply. Investing in renewable fuels, e.g. solar and wind power, while using the remaining hydropower capacity as a backup generation, is necessary to keep Brazil’s electricity mix one of the cleanest in the world (renewables supplied more than 80% of electricity in 2019) and to completely decarbonise its power supply.

Decarbonising the transportation sector in Brazil is a task in the realm of possibilities. It is important to study technological solutions in transportation (electrification and shared mobility) and the behavioural aspects of energy use. With Tatiana Silva’s energy systems model, we can see that a big difference can be made if we begin by focusing on these two simple measures.

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Climate Exp0

Climate Exp0 was the first virtual conference from the COP26 Universities Network and the Italian University Network for Sustainable Development (RUS).