A team of researchers from Northwestern University, Illinois have developed a novel means of decarbonising the shipping industry, using CO2-capturing solid oxide fuel cells to make vessels carbon neutral – or even carbon negative. These fuel cells ‘burn’ traditional carbon-based fuels and generate their own CO2 onboard the ship, which is later sequestered or recycled into renewable hydrocarbon fuel.
Currently, cargo and tanker vessels are responsible for 3% of all global carbon emissions, though transport decarbonisation efforts typically focus on road-bound vehicles rather than on ships and other long-range vehicles.
“It might be harder for people to see onboard CO2 capture as climate friendly because it uses conventional, carbon-based fuels,” said Scott A. Barnett, senior author of the study. “People tend to assume hydrogen fuel cells and electric vehicles are more climate friendly. In reality, they often are not. Electricity might come from burning coal, and hydrogen is often produced by natural gas, which generates a lot of CO2 in the process.”
The size of the battery needed to effectively power long-range ships would be economically and physically unfeasible. Similarly the team says a hydrogen fuel tank would be too large to make it a viable option for cargo ships, rendering these typical decarbonising technologies toothless in the marine sector. As such, harnessing carbon capture is seen as the only way to effectively curb emissions in the industry.
The Northwestern team have also created a dual-chamber tank to store both the fuel and the captured CO2. The divider between the two chambers can move and so make space accordingly for CO2 as it is created.
“This technology really doesn’t have any major hurdles to making it work,” Barnett said. “You just have to replace the fuel tank with the double-chamber tank and add CO2compressors. And, of course, the infrastructure eventually has to be developed to off-load the CO2 and either sequester or use it.”
Using this technology, the team says it’s possible to make long-range vessels carbon negative. Findings from the team were published yesterday (18 August) in the journal ACS Energy Letters. In the paper, the authors compared onboard carbon capture technology efficacy to battery and hydrogen fuel cells alternatives.