Nature: Emissions from international shipping can be reduced by up to 86%

Coppe/UFRJ researchers are among the authors of an international study on maritime shipping decarbonization. The article International shipping in a world below 2 °C was published on May 22 on the Nature Climate Change website. Professors Roberto Schaeffer, Alexandre Szklo, Joana Portugal-Pereira, and Pedro Rochedo and PPE (Energy Planning Program) researchers at the Cenergia laboratory, Eduardo Müller-Casseres (lead author of the paper), Luiz Bernardo Baptista, and Rebecca Draeger, are among its authors.

The article will be published in the print edition of Nature Climate Change this June and indicated that international maritime transport has a high level of technological inertia, revealing the need for investments in low-carbon fuels, new engines, and new infrastructure (for storage and supply) to prepare the sector for the transition to renewable energy.

The study is the result of an international collaboration involving several integrated assessment models (IAMs) and demonstrated the potential to decarbonize maritime transport, with a reduction of up to 86% in annual emissions by 2050 after implementing low-carbon fuels. The authors highlight how important it is to implement a renewable energy portfolio, with fuels ranging from drop-in biofuels, renewable alcohol fuels, and green ammonia to conventional marine fuels, and reiterate the concept of green corridors for sustainable shipping practices.

According to researcher Luiz Bernardo Baptista, the study was motivated by a recurring international discussion among researchers about the need to “zoom in” on hard-to-abate sectors. “Is international maritime transport difficult to decarbonize or are we not paying enough attention?” This question motivated the lead author’s doctoral thesis and studies on integrated assessment models, such as Coffee (an IAM model developed by Coppe), and how they would behave with changes in the variables for maritime transport.

“We and five other research groups from different countries have the support of the Navigate project, funded by the EU2020 European fund, and we are working together to analyze the decarbonization goals that the International Maritime Organization (IMO) has set for 2050”, he added.

According to Bernardo, some of the reasons that classify maritime shipping as a hard-to-abate sector are the long service life of an operating fleet and its high replacement cost. “It takes about 25 to 40 years to decommission ships, similar to large power plants. By implementing drop-in fuels – straight or hydrotreated vegetable oil, biodiesel (FAME), among others – there is no need to replace the existing fleet”, he explained. He also pointed out that there are challenges in fuel storage and distribution logistics, as they are different depending on the country.

“Brazilian gas stations have no difficulty having ethanol fuel because it is common in our country. Our supply chain is prepared for it because there was a political decision to do so. Studies and goals need to be revisited, otherwise decisions cannot be made and the window of opportunity to reduce emissions in a timely manner will become narrower. We need to regard feasibility under a critical lens”, he added.