(Santa Barbara, Calif.) — Reducing travel speeds and using an intelligent queuing system at busy ports can reduce greenhouse gas (GHG) emissions from oceangoing container vessels by 16-24%, according to researchers at UC Santa Barbara. Not only would those relatively simple interventions reduce emissions from a major (?), direct source of greenhouse gases, the technology to implement these measures already exists.
"Arguably the most impactful thing we can do to slow climate change is to cut CO2 emissions," said Rachel Rhodes, a project scientist at the Benioff Ocean Science Laboratory at UC Santa Barbara, and lead author of a paper that appears in the journal Marine Pollution Bulletin. "This has scientists looking at all sectors for places to trim."
One promising candidate for CO2 reduction is the maritime shipping industry, which contributes about 3% of the world's total greenhouse gases, an amount that is forecasted to grow as globalization increases. Typically, these vessels race across the ocean and then queue and idle at ports as they wait to be unloaded.
"Many ports worldwide still use the century-old 'first come, first-served' system for ship berthing, systems that are reminiscent of the 'take a number' systems you might know from visits to the DMV," tktktk said. In normal times at the Ports of Los Angeles and Long Beach, this results in a typical backlog of 0-4 vessels waiting to be unloaded. However, during disruptions, such as the delays brought by the COVID pandemic, the inefficiency can increase to around 100 container vessels just idling in the waters.
Here's the potential low hanging fruit: During the pandemic, marine industry stakeholders came together to quickly design and implement a queueing system primarily to prevent such congestion.
"Instead of using the old approach, container ships get a spot in line based on when they left their previous port," said tktkt. "Think of it like making a restaurant reservation before you leave home, rather than racing across town, hoping to beat others to the door." With their place in line secure, vessels delivering cargo to Los Angeles/Long Beach, didn't have to rush to or crowd at their destination.
While the vessel queueing system was developed for the purpose of eliminating the bottleneck at the twin ports, Rhodes, McCauley and other collaborators from UCSB, NOAA, the California Marine Sanctuary Foundation, the marine exchanges of Alaska and Southern California, and Global Fishing Watch were curious: Could this measure also reduce greenhouse gas emissions?
To find out, the researchers analyzed more than 47 million miles of traffic crossing the Pacific, spread over 10,000 voyages by 1157 container ships from 2017-2023. Using a bottom-up approach, they calculated the emissions generated by cargo vessels before and after the queueing system's 2021 implementation.
They found that this simple change appeared to make a big difference, with apparent reductions of 16-24% less carbon pollution produced per trip, after the new system was implemented.
"Without needing to rush to secure their spot in line, ships are saving fuel by traveling at slower, more efficient speeds," tktkt said. "Just like how your car gets better gas mileage when you drive 65 mph instead of 85 mph."
The queueing system, conducted by Pacific Management Systems — a partnership between the Marine Exchange of California and the Marine Exchange of Alaska — can serve as a model for other ports around the world that are or could be facing congestion as demand rises for goods in an increasingly globalized economy, according to the researchers. Its built-in resilience mechanism can help these ports maintain operations during times of disruption, with the added benefit of lowering CO2 emissions at a source. What's more, implementation of this system is quick.
"Unlike technological solutions that require significant investment and time, this operational innovation was designed and implemented at the world's ninth busiest port within just one month of the working group convening, showing how rapid changes are possible," tktktk noted.
Reducing cargo vessel speeds would also greatly benefit the creatures we share our shipping lanes with: whales. Research conducted by the same UCSB lab has found that slower ships have fewer lethal collisions with endangered whales, making this intervention a potential win for them too.
Looking ahead, the researchers continue to investigate more ways to reduce CO2 emissions at shipping ports. In comparing the emissions between the twin LA/LB ports and others on the West Coast that had not adopted the new system, they found that the other ports also had indications of more moderate emissions reductions, signs that other key factors may exist that could further drive down emissions in addition to slower speeds and intelligent queuing.
Additional fine tuning of the queueing system may also yield even bigger climate wins, say the researchers.
"For example, tweaking the system slightly so ship travelled at an average speed of 17 instead of 18 knots across the Pacific appears to have the capacity to shave off another approximately 308,000 tons of CO2 emissions — that's an additional 9% reduction," said tktktk. "While travelling at marginally slower speeds is not always feasible for all types of shipping today, these early insights can help us contemplate ways to reduce both climate impact and improve operational efficiency in the future if the industry trends toward more digitization in the ports, fleets of self-driving ships and more AI connected supply chains that accurately anticipate market trends and shipping needs."
