With insufficient supply of alternative fuels for the needs of the global shipping fleet and new ship designs years away from commercial and economic viability, industry experts say optimizing operational efficiencies may be the only route to meeting mandated short- and mid-term decarbonization targets.
The International Maritime Organization’s (IMO's) 2018 initial strategy on greenhouse gas (GHG) emissions requires a 40 percent reduction in GHG emissions from 2008 levels by 2030 and interim measures by 2023. While some industry experts say operational efficiencies, such as reducing ship speeds, may effectively start the shipping sector on a path to meet IMO GHG reduction goals, others believe the measure may compromise the global supply chain and have a net-zero effect on decarbonization in the long-run.
Container ships vs. bulk on slow-steaming
Jasper Faber, an aviation and maritime transport expert at CE Delft, told JOC.com that “until these fuels are more widely available, and we have a feel of what the best fuel will be, in order to address GHG emissions, the only thing that can be done is to improve operational efficiencies as much as possible.”
A proponent of alternative, low-carbon fuels as a long-term solution for reducing shipping emissions, Faber supports the idea of mandatory operational efficiency measures for ocean vessels as a short-term operational solution to decarbonization. “In many cases, these operational measures will affect the speed at which ships sail,” Faber said. Also referred to as “slow-steaming,” reducing the speed of a vessel reduces the amount of fuel burned in transit, thereby limiting GHG emissions on a per-voyage basis. However, industry experts are split on the impact slow-steaming may have as a measure to reduce GHG emissions, with some saying it may ultimately do more harm than good.
To meet the goals of the IMO strategy, measures that reduce ship speeds must be mandated, a measure that many ports are already starting to implement, although voluntary initiatives may also help, said Faber. “Many ports, such as the Port of Rotterdam, for example, are investing in technologies to communicate with ships well in advance on the availability of vessels so that ships can optimize their speeds.”
“Worldwide implementation of such systems would be very beneficial,” he argued. “The most cost effective, and also the most effective measures, are global measures — measures that are agreed to by the IMO.”
The American Bureau of Shipping (ABS) proposed a similar concept in its June report, Setting the Course to Low Carbon Shipping: 2030 Outlook 2050 Vision. Increased use of just-in-time (JIT) shipping, an inventory control strategy in which materials are delivered to manufacturers precisely when they are needed, would slow ship speeds without imposing mandatory speed limits, according to the report. Data-driven technology that provides information such as estimated time of arrival, arrival port, draught, and navigational speeds plays a critical role in JIT shipping practices, which further increases total landed costs. As a result, JIT strategies have generally been limited to shippers of higher-value, higher-margin freight. In other words, while it might help reduce emissions when used, the price of a JIT strategy will likely keep it from becoming standard practice for a large percentage of shippers.
An analysis by Maritime Strategies International (MSI) that modeled operational improvements credited to JIT shipping, assuming a 5 percent reduction in speed, found an annual carbon dioxide (CO2) emissions savings of 10 to 11 percent, excluding the impact on cargo carrying capacity and any adjustments to fleet size.
Last April, France asked the IMO to impose mandatory speed limits on ships during the May 13-17 meeting of the organization’s GHG working group. The proposal was supported by more than 110 primarily bulk shipping companies but was met with fervent opposition from the container sector.
Container carriers see mandatory slow-steaming as counterproductive to global decarbonization goals. Emphasizing the need for additional ships to maintain weekly schedules, lines say reduced ship speeds will have net-zero effects on reducing GHG emissions and may cause delays in new low-carbon ship designs due to the surge in demand for additional vessels to ensure schedule reliability.
While some industry analysts say slow-steaming is an effective short-term means to decarbonization, others argue that mandated speed limits are essentially a half-measure, enabling shipbuilders to continue using the same engine designs and operators to continue burning CO2 emitting fossil fuels, just at a slower rate.
Stephen Cadden, executive director at the Coalition for Responsible Transportation (CRT), said the proposal also fails to consider the downstream effects of slow-steaming on other portions of the global supply chain.
According to Cadden, mandating slow-steaming may negatively impact the land-based distribution side of the global supply chain. “If carriers and cargo owners want to negotiate supply chain terms [that include reduced ship speeds], that’s fine. But to mandate it as the bulk shipping industry was advocating for, in our view, could be quite counterproductive to the goals of greenhouse gas reduction.”
CDP, formerly the Carbon Disclosure Project, also referred to slow-steaming as “an important short-term solution capable of reducing carbon emissions by up to 30 percent” in their June report, A Sea Change. The London-based climate researcher provider ranked 18 of the shipping sector’s largest publicly listed companies based on their “readiness for a low-carbon transition,” noting that 13 out of 18 companies were found to have a formal slow-steaming policy.
Despite 72 percent of the companies in the study engaging in some form of slow-steaming, CDP warned that “although slow-steaming is positive in the short term, it could result in more voyages to meet growing demand, eroding the emission reductions made by slowing down ships.”
Katharine Palmer, global head of sustainability for maritime consultant Lloyd’s Register, also questioned slow-steaming’s ability to significantly impact GHG reductions. “Energy efficiency only delivers marginal gains and delivering the IMO level of ambition cannot be met by this,” she said in an interview.
Reducing transit times, total fleet
Another measure to optimize shipping operations is to enhance vessel utilization, reducing the number of sub-optimal cargo loads in transit. According to ABS, advanced information-driven technology can be used to determine cargo movements and transit patterns which, in turn, could help develop strategies to lower the industry’s total fleet requirement.
MSI modeled this strategy by observing the three primary shipping sectors — bulkers, tankers, and container ships. The analytics and forecasting company found that CO2 emissions were reduced 3.3 percent, 3.6 percent, and 3.7 percent for bulkers, tankers, and container ships, respectively.
Roger Strevens, vice president of global sustainability at Wallenius Wilhelmsen, noted that sophisticated route optimization systems can also reduce a vessel’s fuel comsumption by taking factors like prevailing weather conditions, ocean currents, and tides into account in determining the ideal course to decrease the amount of time a ship spends in transit. Less time on the seas means less fuel burned, and less GHG emissions produced.
Hull fouling management is another potential energy-efficient measure to reduce greenhouse gases in ocean shipping, according to Strevens. As a ship crosses the seas, it picks up algae, barnacles, and other plant and animal species that attach themselves to the bottom of the ship’s hull. The drag created by these aquatic stowaways increases dramatically as they spread across the hull, and can consume significant amounts of energy and fuel, analogous to swimming with clothes on, Strevens said. Use of sophisticated technology that quantifies the impact of hull performance on overall vessel energy efficiency can help ships operate more efficiently from a fuel consumption standpoint, thereby reducing CO2 emissions.
Peter Keller, chairman of SEA\LNG, a multi-sector industry coalition created to accelerate the widespread adoption of liquefied natural gas (LNG) as a marine fuel, said in his previous role as president of ocean carrier Sea Star — now Tote Maritime Puerto Rico — he saw a 10 percent reduction in fuel utilization thanks to hull fouling optimization.
Although some operational strategies are less effective than others in terms of overall GHG reduction, as Palmer noted, “the earlier we start the transition [to a carbon neutral shipping environment] the less disruptive it will be, and it can provide business opportunity for shipping.”
Contact Danielle Sukharenko at firstname.lastname@example.org.